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WISCONSIN GEOLOGICAL AND NATURAL HISTORY SURVEY
W. O. HOTCHKISS. Director
BULLETIN NO. 57 SCIENTIFIC SERIES NO. 12
Phytoplankton of the Inland
Lakes of Wisconsin
Part I
Myxophyceae, Phaeophyceae, Heterokonteae, and
Chlorophyceae exclusive of the Desmidiaceae.
BY
GILBERT MORGAN SMITH
MADISON, WIS.
Published by the State
1920
Wisconsin Geological and Natural History Survey
BOARD OF COMMISSIONERS.
EMANUEL L. PHILIPP,
Governor of the State.
EDWARD A. BIRGE, President.
President of the University of Wisconsin.
President of the Wisconsin Academy of Sciences, Arts, and Letters.
CHARLES P. CARY, Vice-President.
State Superintendent of Public Instruction.
STAFF OF THE SURVEY, 1919.
/^ADMINISTRATION:
William 0. Hotchkiss, State Geologist, Director and Superintendent.
In immediate charge of Geology Division.
Ernest P. Bean, Assistant State Geologist.
Lillian M. Veerhusen, Chief Clerk.
Frances Walker, Clerk and Stenographer.
Angeline Doll, Clerk.
GEOLOGY DIVISION:
William 0. Hotchkiss, In charge.
Ernest P. Bean, Geologist, Mineral Land Classification.
T. C. Chamberlin, Consulting Geologist, Pleistocene Geology.
E. O. Ulrich, Consulting Geologist, Stratigraphy, by cooperation of the
U. S. G. S.
H. R. Aldrich, Geologist.
Clare Gillis, Geologist.
R. H. Whitbeck, Geographer.
T. J. Dunnewald, Field Assistant and Analyst.
P. T. Thwaites, Geologist, Well Records, Educational Rock Collection.
NATURAL HISTORY DIVISION:
Edward A. Birge, In charge.
Chancey Juday, Lake Survey.
DIVISION OF SOILS:
A. R. Whitson, In charge.
W. .1. Geib, Inspector and Editor.
M. .1. Dunnewald, Field Assistant and Analyst.
H. W. Stewart, Pheld Assistant and Physicist.
557
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TABLE OF CONTENTS
Preface
Introduction
List of lakes investigated . . ,
Analytical key to the genera
Myxophyceae
Phaeophyceae
Heterokonteae
Chlorophyceae
Page
1
5
J.3
21
26
65
79
88
1 300 I 6
PREFACE
The general name plankton is given to the organisms which live iree-
floating in the deeper parts of lakes and ponds; the plant individuals
being designated the phytoplankton and the animal the zooplankton.
Investigations have shown that there is a very special algal flora liv-
ing exclusively in the plankton, in addition to the chance wanderers
from the littoral, or marginal, region which do not multiply when in
the plankton. These will be designated as the euplanktonts and tycho-
planktonts respectively in this work. There is still another group of
organisms found in lakes, namely those which thrive equally under
littoral or pelagic conditions. This group will be referred to as the
facultative planktonts. Attempts have been made to differentiate be-
tween organisms of these three groups by the Wests, Telling, and
others, although a different terminology has been used. Since the
question of a proper habitual classification for any particular species
will always be a matter of individual opinion, I have indicated at the
end of the description my conception of the natural habitat of the
organisms found in the lakes of this state.
It is only within the past twenty -five years that the phytoplankton has
been studied, and our knowledge of the various members constituting
this specialized flora has come almost exclusively from European phyco-
logists. William West, G. S. West and Pritsch in England; Chodat
and Bachmann in Switzerland ; Lemmermann, Schmidle, Schroder and
Volk in Germany; von Keissler, Pascher and Woloszynska in Austria-
Hungary; and Wesenberg-Lund in Denmark have been the chief stu-
dents of European phytoplankton. The central African lakes have
been investigated by G. S. West, Schmidle, and Woloszynska. G. S.
West and Playfair have studied the phytoplankton of Australia. With
the exception of Miss Snow’s work on Lake Erie nothing was known
concerning the taxonomy of North American phytoplankton at the
time the present work was undertaken, the pioneer work on the micros-
copy of the Massachussetts and Brooklyn water supplies being of little
value to the systematist since determinations were not carried beyond
the genus.
These studies of Wisconsin lakes, carried out under the auspices of
the Wisconsin Geological and Natural History Survey, were commenced
in the fall of 1913. Field work was continued during the summers of
2
PREFACE
1914-15-16-17 and all lake areas of the state have been visited during
the progress of the investigation. Collections have been made from
the lakes around Madison and Oconomowoc during the entire season
that they are open. The June, August and early September flora of
the northeastern lakes is represented, while the northwestern lakes were
visited for two successive seasons during August. Only single collec-
tions were made from the northern lakes so that the data for any par-
ticular one of them are undoubtedly very fragmentary.
The limits of the survey are determined by the political boundaries
of the state and not by ecological or regional unity. There is a con-
tinuation of the southeastern lake group in northeastern Illinois; of
the northeastern lake group in the northern peninsula of Michigan ; and
of the northwestern lake area in Minnesota. However, variation in
depth and surface area together with variation in chemical content of
Wisconsin lakes gives a sufficient range of habitat to cover conditions
found in almost all other parts of the world if temperature and altitude
are excluded. The cosmopolitan nature of phytoplankton, therefore,
makes this work of value to the student of these microorganisms in
other sections of the United States or even other continents, and he will
probably find a majority of the species in any region represented in
the Wisconsin flora. There is a temptation to include species that have
not been observed in order to round out the work for the student in
other parts of the world. This practice has been followed in certain
algal floras and while it may be helpful to the general student, it causes
endless confusion to the phytogeographer. Only those species are in-
cluded in this flora which have been collected from the state.
Descriptions of plankton algae are scattered through a large number
of periodical publications and transactions of learned societies, many
with only a limited circulation, so that considerable effort has been
spent in giving full and correct citations for the original descriptions.
When subsequent descriptions have been better or have given more
characteristic figures references are also made to theiti. A great deal
of time has also been spent making camera lucida drawings since an
accurate figure is frequently more valuable than a description. Draw-
ings of the various species of a genus are generally on the same scale,
but there has been no attempt to draw the different genera on the same
scale. The finer details of cytological structure, such as the nature of
the chloroplast or structure of the pyrenoid, are frequently lost in pre-
served material ; so all of the Chlorophyceae, with the exception of the
Desmidiaceae, the Phaeophyceae, Heterokonteae and the Myxophyceae,
have been drawn from living material.
The original plan for the study of Wisconsin lake algae included those
attached to rocky shores or lying among the macroscopic vegetation in
the quieter portions of lakes in order to get the relation between the
PREFACE
3
benthos and the plankton, but it soon became apparent that limitations
of both time and space precluded an adequate presentation of the lit-
toral flora; attention, therefore, has been confined to phytoplankton
since the second season ^s work. The great amount of material on the
phytoplankton has necessitated dividing the work into two portions;
the material included in the present volume, and the Desmidiaceae and
Bacillareae which are reserved for a later one. A considerable amount
of work has been done already on these two groups and it is hoped that
the complete report can be published shortly.
Phycologists are generally agreed on the broader principles of algal
classification but naturally differ on minor details. The classification
here adopted for the Myxophyceae is used almost universally. The
group of flagellates with brown chromatophores is frequently consid-
ered more animal than plant. One section, the Chrysomonadineae,
where there are golden brown chromatophores, seems to be sufficiently
related to the Phaeophyceae to warrant placing them in a description
of plankton algae and in the arrangement of the group I have followed
Pascher’s classification. Since Luther’s establishment of the Hetero-
konteae, the question of whether to recognize this group as a separate
class or a division of the Chlorophyceae has arisen. The evidence
seems fairly clear, however, that the origin of the group is from a
primitive flagellate of the Chloramoeha type and since this phylogenetic
starting point is so markedly different from the phylogenetic starting
point of the Chlorophyceae (the Polyblepharidaceae) I feel that the
two should be considered distinct classes. The classification used is
that of G. S. West, although it should be noted that he considers the
Heterokonteae a division of the Chlorophyceae. I have also, with a
few exceptions, followed West’s arrangement of the Chlorophyceae.
It is hoped that the keys found in this work will prove usable. They
are based solely upon characters of the species described herein; so
will be of no value for those not mentioned.
During the seasons of 1916 and 1917 the field work was assisted by a
grant of money from the United States Bureau of Fisheries; and the
extension of these studies to the lakes of northwestern Wisconsin has
thus been made possible.
The University of Wisconsin,
Department of Botany,
February, 1919.
INTEODUCTION
Geography and geology of Wisconsin. The state of Wisconsin lies
between Lake Superior, Lake Michigan and the Mississippi river and
has an area of 56,066 square miles, cr an area somewhat larger than
England. Its greatest breadth is about 295 miles and greatest length
320 miles. Within its borders are numerous lakes, the total number
probably reaching well into the thousands, with an estimated surface
area of about 1500 square miles. They vary in size from small lakelets
and ponds that cover but a few acres, to Lake Winnebago with an
area of 215 square miles. The great majority of the lakes, however,
have less than a square mile of surface area. There is likewise great
variation in depth, but for the most part they are shallow since the
deepest (Green Lake) has a maximum depth of 237 feet and only a
few have a depth of over a hundred feet. Certain phycologists have
tried to differentiate between the plankton floras of ponds (heleoplank-
ton) and lakes (limnoplankton). The lakes of this state grade so im-
perceptibly from the ‘‘pond’’ to the “lake” type that it has been im-
possible to distinguish between the two. To set arbitrarily a surface
area of a square mile and depth of 25 feet as the maximal limits for a
pond would involve many difficulties ; since the state presents such ex-
amples as Beasley Lake with a surface area of 0.019 square miles and
a depth of 51 feet or Lake Winnebago with a surface area of 215 square
miles and a maximum depth of 21 feet. I have, therefore, listed all
bodies of water as lakes but have given, in Table 2, all available data
on area and depth for those desiring to recapitulate into heleoplank-
ton and limnoplankton.
There are, roughly speaking, three lake areas in the state ; the south-
eastern, northwestern and northeastern, all of which owe their origin
to glaciation. These lake areas are not uniformly distributed over the
state since the glacier invading this region was divided into lobes and
lakes are found in greatest abundance along the terminal and kettle
moraines of these various lobes. The southwestern portion of the state
possesses no lakes since it lies in a non-glaciated region. The south-
eastern lake area includes several scattered moderately sized lakes and
groups of smaller lakes some of which are among the deepest in the
state. The majority of them lie in a region of kames and pitted plains,
where the pits and lake basins owe their origin to the burial and sub-
6
INTRODUCTION
sequent melting of large irregular blocks of ice. The Oconomowoc,
Lauderdale and Waupaca lake groups are of this type. A few of
the larger and deeper lakes, as Green and Mendota, are situated in
valleys eroded by preglacial streams that were possibly modified by
glacial action and then closed by the building of a morainal dam which
impounded the waters of the present lake.
The northeastern lake group lies chiefly in Vilas, Oneida and Iron
counties. There are hundreds of lakes in this area and their closeness
of position may readily be inferred from the fact that while the largest
of them, Trout Lake, covers only 6.5 square miles the 346 lakes and
ponds in Vilas county occupy 140 square miles or over 15 percent of
the area of a county nearly as large as Rhode Island. In few parts of
the world are there more lakes to the square mile. Parts of the State
of Minnesota, the Province of Ontario, and Finland furnish the
only parallel. These lakes are small, irregularly shaped, and connected
by streams with most irregular courses. They are all glacial in origin
and formed either by shallow depressions of the ground moraine, hol-
lows in outwash plains, or damming of recessional moraines. > The en-
tire region is so deeply buried by the glacial drift that no lake is due
to a damming of a preglacial valley. This entire region also contains
numerous swamps (muskegs) characteristics of a poorly drained area.
The northwestern lake area lies in Barron, Polk, Burnett, Washburn,
and Sawyer counties. In general it is similar to the northeastern lake
area in structure and origin but the lakes do not occupy so great a
portion of the land’s surface. It has been suggested that some of the
lakes in this region were formed before the last glacial invasion or Late
V/isconsin glacial epoch. Here we find a few lakes formed by a dam-
ming of preglacial valleys; Bone, Beaverdam, and Wapagossett lakes
for example.
The mean average temperature of Wisconsin varies from 6.6° C. in
the southern portion to 3.3° C. in the northern. The state has a mean
summer temperature similar to that of Prance, Germany, or south-
eastern England (14.5° to 18°) ; the average winter temperature is com-
parable to that of northern Sweden or central Russia (-5.4° to -8.8°).
All lakes in the state are frozen over during the winter, ice forming
during November and December and lasting until March or April in
the southern ones, while on some of the northern lakes ice appears in
October and remains until the latter part of May. The midsummer
surface temperature of the northern lakes is 18°-24° C. and 20°-26^
in the southern lakes.
The altitude of the lakes in the northeastern part of the state varies
from 1550-1700 feet above sea level; in the northwestern area 1050-
1350 feet, and from 750 to 900 feet in the southeastern. These differ-
ences in elevation ai*e too slight to be of any biological significance.
INTRODUCTION
7
Likewise differences in the amount of mean annual precipitation, which
j’ange from 28-44 inches in various parts of the state, need no discus-
sion since rainfall in all regions is sufficient to maintain lakes at their
normal level.
The underlying geological formations are, however, of prime import-
ance and have a marked influence on the distribution of plankton or-
ganisms, especially the plankton desmids. Within the state are found
areas of igneous, metamorphic, and sedimentary rocks each of which
have a different direct influence on the chemical environment of the
plankton organisms. The underlying rock formations of the south-
eastern lake area are the Niagara limestone of the Silurian; the Cin-
cinnati shale. Galena limestone. Lower Magnesian limestone and St.
Peter sandstone of the Ordovician. In the northwestern lake region
is found the Cambrian Potsdam sandstone, the Ordovician Lower Mag-
nesian limestone, together with areas of Keeweenawan trap rock and
Precambrian granites. The northeastern area is entirely Precambrian
granites.
Overlying all of these regions is a mantle of glacial drift some of
which is local in origin while other constituents have been transported
from distant regions. This ground moraine in southeastern Wisconsin
varies in thickness from a few feet on hill tops to over 400 feet in the
bottom of preglacial valleys. Mechanical analyses show that 13% con-
sists of crystalline rocks transported from Canada while the remaining
87% is local sand- and limestone. In the northeastern lake area the
glacial mantle varies from 75-100 feet in thickness with a maximum
depth of 350 feet at the southern boundary of the area. This glacial
accumulation is not the result of one ice invasion but of several; the
last, and the one which left the most material, came from the north-
east and transported the conspicuous sand deposits of Vilas and north-
ern Oneida counties from the sandstone region of northern Michigan.
Previous ice invasions came from the northwest and their deposits, in
some instances, have not been disturbed by succeeding invasions. None
of the drift in this region is calcareous so that all soils are acid in
character. The mantle of drift in the northwestern area varies from
500 to a few feet in thickness and is composed of material from granitic
and sandstone regions. There is, however, a certain amount of lime
in the drift at the southern limit of the lake area.
Chemical composition of the lake waters. Birge and Juday* have
made investigations on the chemical composition of the waters of Wis-
consin lakes in connection with their biochemical studies. They divide
the waters into three general classes; soft, medium, and hard. These
* Birge, E. A. and Juday, C. The inland lakes of Wisconsin. The dissolved
gases of the water and their biological significance. Bull. 22 Wis. Geol. and
Nat. Hist. Survey. (Sci. Ser. 7.) pp. 1-259. 1911.
8
INTRODUCTION
varying degrees of hardness are due to the combination of the carbon
dioxide with calcium and magnesium to form carbonates, the fixed
(CaCOg and MgCOg) and the half-bound (CaCOg.HgCOg and
MgCOg.HaCOg). In neutral and acid lakes the two types of carbon
dioxide are present in equal amounts but in alkaline lakes there is an
excess of fixed carbon dioxide. This is due to the ability of the chloro-
phyll bearing organisms to draw upon the half-bound carbon dioxide
as a source of supply after the disappearance of the free carbon diox-
ide. The amounts of magnesium and calcium vary from lake to lake
and there is an almost continuous series from those having the softest
waters to those having the hardest. They consider those lakes whose
average fixed carbon dioxide does not exceed 5 cc. per liter as soft
water lakes, while medium waters have 6-22 cc. of carbon dioxide per
liter and the hard waters from 23-50 cc. per liter. The carbon dioxide
content varies with the depth at which the sample is taken and also
with the season of the year; some of the medium class lakes, for ex-
ample, have a sufficiently low content at times to qualify as soft water
lakes. All of the soft and medium waters, with the exception of Devils
lake in Sauk county, are located in the northeastern and northwestern
lake areas and many of them have sufficient free carbon dioxide to
give an acid reaction with phenolphthalein. The hardwater lakes are
all in the southeastern area and the upper stratum in them is alkaline
to phenolphthalein for the greater part of the year.
Aside from the question of the hardness of the water complete min-
eral analyses of a few lakes are also available. These results are em-
bodied in Table 1 and represent average conditions. They are taken
from the data given by Birge and Juday and their data show that
there is a seasonal variation and a vertical variation in the amounts of
certain elements present. These variations in vertical distribution are
well shown in their Fig. 7, p. 106 (1. c.) The lakes of southeastern
Wisconsin contain a rich flora of Chlorophyceae, Myxophyceae and
Phaeophyceae, both in quantity and quality. In the northern lake
areas the total volume of the plankton is, generally speaking, consider-
ably smaller and quite different in character. These lakes have a con-
siderable desmid flora in many instances, while with the exception of
one or two species desmids are not found in the hard waters of the
southeastern region. The volume of phytoplankton that can be pro-
duced in a lake is primarily dependent upon the available supply of
carbon dioxide for photosynthesis. In the northern lakes this supply
is chiefly the carbon dioxide dissolved in the water but in the southern
lakes there is in addition considerable quantities of half -bound carbon
dioxide which may be drawn upon after the free carbon dioxide is ex-
hausted. It is not surprising, therefore, that the southern lakes with
greater supplies of potential food materials have a greater production
INTRODUCTION
9
of algae. There are certain factors modifying the growth of algae in
hard water lakes ; in those deep ones which become thermally stratified
in the summer most of the algae are restricted to the epilimnion. The
thickness of the epilimnion is in part dependent upon the size and shape
of the lake, since the wind is more effective in keeping water in circula-
tion on large surfaces. Algae are continually sinking to the bottom and
giving rise to carbon dioxide and nitrogenous products. In the deep
Table 1. — Results of mineral analyses stated in parts per million. These shoic
aderage content of m/nous depths and at different dates.
lakes these products of decay are chiefiy in the hypolimnion and are
not immediately available for reutiiization by other algae. In shal-
low lakes without thermal stratification these products are immediately
available for the vegetative activities of algae. Shallow lakes, there-
fore, support proportionally larger algal floras. The restriction of
the desmids to the soft water lakes was first pointed out by the Wests
and their observations have been confirmed in Wisconsin (Birge and
Juday, 1. c. p. 138). An examination of the chemical analyses of such
soft water lakes as Devils, Trout and Kawaguesaga (Table 1) shows
that in these lakes which contain numerous desmids the calcium and
magnesium content is relatively small. The influence of calcium and
magnesium on the distribution of desmids may be that of a direct in-
hibition of growth or the absence of these elements may permit an
acid condition which is favorable for the growth of desmids. Data on
organic matter and distribution of nitrogen in lakes of the state are
lacking. The scarcity or abundance of available nitrogen is doubtless
an important factor in the volume of algae produced in a lake, and it
is a well known fact that as regions become more thickly settled and
drainage entering the lake becomes richer in nitrogenous material the
growth of plankton algae becomes more luxuriant.
10
INTRODUCTION
Methods of collection and study. All plankton collections have been
made with nets. In general both the bolting silk net and the cotton
disc net were used. The bolting silk net of No. 20 bolting cloth (new
No. 25) is that described by Juday*. The cotton disc net is made by
attaching a filter designed for purifying drinking water (Jones Mod-
ern Filter made by the Jones Mfg. Co., Boston, Mass.) to the bottom
of an eighteen inch cone of canvas whose mouth is held open by a light
metal ring ten inches in diameter. In using this filter a special cot-
ton disc supplied by the manufacturer is placed in the filter and the
whole apparatus drawn through the water. The algae collect on the
disc and when there is a sufficient accumulation the disc is taken from
the filter and shaken in a bottle with a small amount of water which
removes the algae. This net catches many of the smaller organisms
that pass through the bolting silk (the nannoplankton) and it is also
very useful in obtaining samples by dipping when no boat is available.
Whenever possible samples have been gathered by towing the nets at
the surface and all collections have been made in the deep parts of all
lakes to avoid, as far as possible, the littoral flora. No attempt has
been made to study the vertical distribution of the algae in any lake.
In studying the flora of any region a field laboratory was established
and with that as a center excursions were made to the surrounding
lakes. By traveling from lake to lake in an automobile collections
could be made in the morning and the material studied the same after-
noon and the following day. In the northeastern lake area where
there are no roads in many cases, but where lakes are close together,
they can be visited by portaging a canoe from lake to lake. Collections
have been made from row boats, where they were obtainable, but in a
few instances collections had to be made by repeatedly dipping the
net after wading to where the water was 3-4 feet deep or from rafts.
Upon returning to the temporary laboratory equipped with compound
microscope, camera lueida, and drawing materials, the living specimens
were studied and numerous pencil camera lueida drawings made of all
doubtful, interesting, or rare organisms, together with notes on occur-
rence and ocular micrometer measurements of known forms. No ob-
servations were made on desmids or diatoms at this time. The study
of the Chlorophyceae, Myxophyceae and Phaeophyceae in the living
condition is particularly important since many of them do not preserve
well and certain features such as cilia, chloroplasts, and contractile
vacuoles are lost when material is preserved. All drawings of one
species are mounted on the same sheet and corresponding notes on an-
other. The.se ai-e then filed in species and genus covers in the usual
* Juday, C. Limnological apparatus. Trans. Wis. Acad. Sci. Arts & Lett.
18 ^: 566 - 592 . 1916 .
INTRODUCTION
11
manner for herbarium specimens so that all data on any particular spe-
cies are immediately accessible. The figures for the plates of this work
have been redrawn from camera lucida sketches made in field labora-
tories. The confined space of a vial is not favorable for algae and the
more delicate forms, as Uglenopsis, frequently go to pieces after stand-
ing a few hours. It is impossible to have the vials uncorked while
transporting them from station to station but they should be opened
immediately on return to field headquarters. I have also found it
helpful to keep them as cool as possible and have stored them in hotel
refrigerators until ready to make observations. Formalin has proven
a satisfactory means of preserving the desmids and diatoms until their
study can be taken up during the winter months.
The following list of simple reagents is helpful in studying the vari-
ous structures of living algae. Cilia of motile forms are more easily
seen when the cells have been rendered immobile by mounting in a 1%
cocaine solution. Mounting in a dilute aqueous acid fuchsin also helps.
Pyrenoids can be recognized by the grouping of the starch grains when
the latter have been stained with iodine. It is difficult to strain pyre-
Roids of living cells. Gelatinous envelopes are best demonstrated by
Errera's method of mounting in dilute India ink which gives the col-
orless envelope the appearance of a halo around the cells in contrast
to the dark background of water containing the ink. Nuclei can be
demonstrated by Strasburger ’s solution of methyl green in 1% acetic
acid. Simple microchemical tests are Sudan III for fats, iodine for
starch, zinc chloriodide for cellulose, and Euthineum Red for pectin.
Lakes studied. The following table gives a list of lakes in the state
from which plankton samples have been taken. All known hydro-
graphic maps, morphometric data, general descriptions of many lakes
and general maps of the various lake areas have been given by Birge
and Juday^' so that any one wishing further data concerning a particu-
lar lake is referred to their work. They have not, however, mapped or
discussed many of the smaller lakes of the northern regions. Since
most of the lakes in the state were named by the settlers of the region
considerable poverty of vocabulary is noticed and Round, Mud, Devils,
Long, and Sand are repeated many times. In other instances Indian
(Chippewa) names have been retained as the white man settled the
region. In these also there is a certain amount of duplication and
Sishebogema (lake with many bays) or Pokegama (side or branch lake)
may be cited as examples. It is too bad that these names have not been
retained to a greater extent, but certain of the English names like
Razorback, Crawling Stone, Lost Canoe, Tenderfoot or Fishtrap are not
* Birge, E. A. and Juday, C. The inland lakes of Wisconsin. Bull. 27: Wis.
Geol. & Nat. Hist. Survey. (Sci. Ser. 9). pp. 1-137. 1914.
12
INTRODUCTION ^
without interest. This is not the place, however, for the legends on
the origin of these peculiar names nor for a discussion of the occurrence
of several French names in the list. In order to avoid misunder-
standing the town and range in which the lake occurs is given. When
more than one lake with the same name has been visited, a serial num-
ber has been added and both the lake name and serial number are used
in giving stations for the various algae.
INTRODUCTION
13
Table 2. — 'Table giving available data on location and size of lakes visited during the
course of this investigation. 'The first column refers to the page on which a mop
of the lake may be found in Birge and Juday, The inland lakes of Wisconsin, the
hydrography and morphometry. Bull. 27. Wis. Geol. and Nat. Hist. Survey.
Papre
map-
ped
Lake
County
Town
Ranffe
Lenffth
(Miles)
Maxi-
mum
breadth
(miles)
Maxi-
mum
depth
(Feet)
Area
(Acres)
Adelaide
Vilas
43N
5E
1 .47
.32
68.9
45 . 0
Rusk
34 N
1
8W i
1.06
.30
1?0
Polk
34N
1
17W
3.00
l.OO
18.0
1,785.6
Bass 0)
Vilas
40N
HE
.50
.24
Bass (2)
Vilas
42N
GE
.93
irr.
40N
14W
Bear (1)
34N
14W
.45
.40
Bear (2)
Polk
33N
17W
.88
.59
120
Bear (3) ■.
36N
12W
4.50
1.00
Washburn.
Bear Trap
Polk
.33N
17W
1.05
.48
104
Beasley
Waupaca ....
21N
HE
.25
.10
51.2
13.5
Beavei* (1)
Vilas
44N
5E
,44
• 25
40
Beaver (2)
Waukesha ...
8N
18E
MO
.44
49.0
305.4
120
Beaverdam
Barron
33N
14W
3.80
.75
91.9
1,267.2
36N
13W
Bettine
Vilas
43N
7E
.75
.56
120
Biff
Polk
32N
18W
.80
.65
33N
120
Biff Butternut
Polk
36N
17W
1.20
.60
21.3
384.0
120
Biff McKenzie
• Burnett
40N
14W
2.25
1.05
116
Biff St, Germain
Vilas
40N
8E
2.62
1.25
118
Birch (1)
Vilas
43N
5E
1.50
.74
120
Birch (2)
Washburn .. .
37N
low
.90
.70
57.4
243.2
120
Birch Island
Burnett
40N
14W
2.10
irr.
Blake
Polk
35N
16W
1.90
irr.
Bloom
Burnett
37N
18W
Blue Gill
Vilas
43N
7E
.12
.09
120
Bone
Polk
35N
16W
4.80
1.00
49.2
2,054.4
36N
118
Boulder
Vilas
42N
7E
2.25
1.20
19.7
614.4
74
Browns
Racine
2N
19E
1.25
.75
23.0
390.4
3N
Bullhead
Vilas
4CN
6E
.31
.26
IZ
Camp
Kenosha
IN
20E
1.50
1.00
19.7
256.0
Canteen
Vilas
43N
7E
.31
.17
116
Carroll
Vilas
SON
7E
1.30
.47
23.0
288.0
40N
Carson (see Flora)
14
INTRODUCTION
Table 2. — (Continued)
Pa^e
map-
p<'.d
Lake
County
Town
Range
Length
V Miles)
Maxi-
mum
breadth
(miles)
Maxi-
mum
depth
(Feet)
Area
(Acres)
116
Vilas
SON
lOE
2.87
irr.
19.7
902.4
40N
HE
116
Vilas
38N
6E
2.25
Avv.
27.9
008. 0
75
IN
20E
.72
.3")
Polk
35N
13W
37N
120
38N
9W
6.40
1.10
120
33N
low
3.25
irr.
120
38N
low
3.84
1.92
39N
Polk
35N
IGW
. ^5
.3G
116
Oneida
SON
7E
2.10
irr.
82.0
921.6
116
Vilas
42N
7E
1.40
1.12
32.8
672.0
43N
8E
.69
.36
116
Crab
Vilas
43N
6E
2.12
1.35
44.3
1,318.4
116
Cranberry
Vilas
40N
HE
1.25
.70
11.5
332.8
116
Crawl in» Stone
Vilas
40N
5E
2.40
1.65
93.0
1,600.0
Rnrnet.t
38N
16W
1.44
.44
II
P.n rlis
Oneida
SON
6E
.76
.25
120
DpAr
Polk
S4N
17W
2.80
.70
39.4
806.4
18W
70
Delavan
Walworth
2N
16E
3.75
1.10
56.7
1,813.2
J')p< Mninp.s
Itnrnett
41N
14 W
1.00
.30
30, 32
Devils (1)
Pauk
IIN
6E
1.25
.61
43.2
360.8
120
J vj 1
Ua iTon
36N
HW
1.60
.40
J i ] s
Vilas
4SN
8E
.44
.26
nininrmd
Polk
37N
17W
.60
.60
120
' I'inpk .
Ba.rvnn
SON
13W
.50
.30
Rn.rT'on
86N
13W
.60
.25
J>nTihflnn
Bn I'tiplt
38N
17W
ma nn
Rn iTief t
38N
17W
74
Eaffle
Kacine
SN
20E
1.31
1.00
13.1
486.4
120
‘Fla.'it.
Polk
33N
18W
.74
.52
75
Elizabeth
Kenosha
IN
19E
2.62
.87
26.2
800.0
116
Eenp.e
Vilas
40N
5E
3.25
2.10
93.0
3,492.0
120
Fish
Burnett
40N
14W
1.30
.55
116
Fishtrap
Vilas
42N
7E
1.50
.62
29.5
326.4
116
Flora
Vilas
43N
7E
1.31
irr.
Listed as Clear Lake by Birtre and Juday.
INTRODVCTIOIi
15
Table 2 (Continued)
Page
map-
ped
Lake
County
Town
Range
Length
(Miles)
Maxi-
mum
breadth
(Miles)
Maxi-
mum
depth
(Feet)
Area
(Acres)
116
Found
Vilas
inxT
8E
1.06
.69
52
Fowler
Waukesha ...
8N
17E
.94
.44
50.0
W 83.5
66
Geneva
Walworth
IN
16E
7.50
2.00
142.0
5,451.3
2N
17E
George
Vilas
44N
5E
.56
.33
120
Granite
Barron
36N
13W
1.60
.30
Grassy
Vilas
42N
7E
1.31
.64
92
Green (1)
Green Lake. .
15N
12E
7.40
2.00
237.0
7,342.4
16N
1.SE
76
Green (2)
Walworth
4N
16E
1.09
.66
56.8
277.9
120
Grindstone
Sawyer
40N
8W
3.40
2.10
47.6
3,462.4
120
Half Moon
Polk
35N
9W
17W
1.77
.50
116
Harris
Vilas
44N
5E
1.51
irr.
Helen (1)
Vilas
40N
HE
.58
.14
Helen (2)
Vilas
44N
5E
.47
.20
116
High
Vilas
42N
7E
2.00
1.00
31.2
761.6
43N
8E
Hill
Oneida
39N
6E
.18
.14
Hillman
Barron
34N
14W
.60
.25
75
Hooker
Kcnosiha.
IN
20E
.75
.37
23.0
64.0
120
Horse
Polk
33N
18W
1.22
.40
120
Horseshoe® (1 )
Polk
34N
15W
2. .50
1.00
59.0
800.0
120
Horseshoe (2)
Polk
33N
17W
.80
.62
Howey
Polk
34N
17W
.25
.20
120
Island
Busk
33N
8W
1.75
.65
47.6
435.2
118
Jag
Vilas
42N
6E
1.00
irr.
Jennie
Vilas
43N
6E
.44
.34
Jones
Vilas
43N
8E
.58
.21
116
Kawaguesaga
Oneida
39N
6E
4.25
irr.
55.8
2067 . 2
26
Kegonsa
T)a,ne
6N
7E
lOE
3.00
2.25
31.4
3,145.2
HE
Kimball
Washburn . . .
42N
13W
1.68
.80
Kitten
Vilas
43N
7E
.34
.19
120
Lac Court Oreilles.. .
Sawyer
39N
8W
5.65
1.90
67.2
5 248.0
40N
9W
116
Lac du Flambeau
Vilas
40N
4E
2.00
irr.
49.2
1,280,0
5E
52
Lac la Belle
Waukesha ...
8N
17E
2.70
1.12
46.4
1,137.5
116
Laura
Vilas
41N
8E
1.50
.90
39.4
640.0
Lake of the Woods. .
Burnett
38N
17W
’ Listed as Big: Horseshoe by Birge and Juday.
16
INTRODUCTION
Table 2 — (Continued)
Page
map-
ped
Lake
County
Townj
Range
Length
(Miles)
Maxi-
mum
breadth
(Miles)
Maxi-
mum
depth
(Feet)
Area
(Acres)
Lily
41N
14W
Lindy
Burnett
40N
14W
Little Bass (1)
Vilas
42N
6E
.28
.19
Polk
34N
17 W'
Little Bear
Vilas
43N
6E
.69
.44
Polk
36N
17W
.60
.35
Little Crooked
Vilas
42N
6E
1.06
irr.
38N
17W
,45
.30
T.ittle Rice (1)
33N
8W
.70
.40
118
Little Rice (2i
Vilas
42N
7E
.76
.38
120
38N
18W
.82
.48
T.rmg n 1
Burnett
41N
14W
1.85
.35
120
Long (2).,
Polk
34N
17W
1.70
.55
24.6
384.0
liOng CSl
Vilas
40N
1 5E
1.40
.60
55.8
448.0
104
Long (4)
Waupaca . . . .
21N
HE
.94
.36
77.7
108.4
TiOmi
Barron
34N
1 14W
1.00
.45
116
T .osjt',
Vilas
40N
8E
1.69
.86
118
T.nst Canoe
Vilas
42N
7E
1.25
.38
41.0
204.8
120
T,r>veless
Polk
34N
17W
1.09
.32
21.3
153.6
T.ynv
Vilas
43N
i 7E
.75
.66
1
1
! Vilas
44N
I r>E
.37
.19
104
Marion j
Marl !
Waupaca
21N
HE
.51
.19
60.6
21.3
75
Mary
Kenosha
IN
19E
1.20
.70
26.2
275.2
12
Mendota 1
1 Dane.
7N
9E
5.90
4.60
84.0
9,729.8
8N
Mercer
Oneida
39N
5E
1.30
.69
Mernnt . .
j Rnrnet.t
40N
14W
i M etfl
Vilas
40N
HE
.64
.26
76
Middle
Walworth. . . .
4N
16E
1.60
.45
50.0
284.0
120
Middle McKenzie ® . .
Rn rnet.t.
40N
14W
1.10
.90
78
Mill
Walworth —
• 4N
16E
.75
.49
50.0
296.4
20
Monona
Dane
7N
9E
4.16
2.40
74.0
3,482.7
lOE
Mild (11 . . .
Polk
34N
17W
.66
.28
Mnd (21
Vilas
40N
5E
.81
.56
114
Mud (8)
Vilas
.89N
7E
.87
.36
* Listed as McKenzie lakes.
INTRODUCTION
17
Table 2 — (Continued)
1
1
1 Lake
County
1
! Town
1
Rang’e
Length
(Miles)
Maxi-
mum
breadth
(Miles)
Maxi-
mum
depth
(Feet)
Area
(Acres)
104
Mud (4)
Waupaca
21N
HE
.13
.06
32.0
i
i 9.7
38N
17 W
1.68
1.10
i
116
Vilas
41N
7E
i 1.93
irr .
1
1
^20
42N
13W
1 2.00
1.25
54
Naerawicka
Waukesha .. .
7N
18E
I 2.75
1.12
94.4
917.6
54
Nashotah (Upper).. .
Waukesha .. .
7N
17E
.81
.40
57.2
1.36.7
54
Nashotah (Lower) . .
Waukesha .. .
7N
17E
.79
.25
46.2
100.3
Nell
Vilas
44N
5E
1 .46
.15
54
Nemahbin (Upper)..
Waukesha .. .
7N
17E
1.05
.56
62.0
271.1
54
Nemahbin (Lower). .
Waukesha .. .
7N
17E
.93
.60
35.2
265.5
41N
14W
116
Vilas
44N
5E
1.00
.69
North Twin
Polk
33N
16W
.92
.30
Number One
Sawyer
37N
9W'
.25
.18
Oak
Burnett
40N
14W
.70
• 45
46
Oconomowoc
Waukesha. . .
7N
17E
1.75
.83
62.6
631.3
46
Okauchee
Waukesha. . .
8N
17E
2.37
1.80
94.0
1,0.57.0
18E
Old Taylors
Waupaca ....
22N
HE
104
Otter
Waupaca
22N
HE
.40
.08
40.0
14.5
120
Owen
Bavfield ....
44N
7W
6.25
irr.
88.6
2.032.0
43N
75
Paddock
Keno.sha,
IN
20E
.62
.37
31.0
9.5
116
Palmer
Vilas
43N
8E
1.75
1.25
14.8
614.4
116
Pardee
Vilas
44N
4E
.94 1
.87
63
Pewaukee
Waukesha .. .
7N
18E
4.50
1.20
45.0
2,298.0
19E
Pike
Polk
33N
16W
1.18
.30
40
Pine (1)
Waukesha... .
8N
18E
2.30
1.05
90.0
755.7
Pine (2)
Polk
33N
17W^
.66
.28
Pine Tree
Polk
32N
16W
.92
irr.
116
Plum
Vilas
41N
7E
4.20
1.25
50.8
1,088.0
8E
120
Pokegrama (1)
Washburn
42N
12W
2.40
.60
23.0
505.6
116
Pokegrama (2)
Vilas
40N
5E
3.25
1.90
42.6
1,216.0
41N
120
Poke^ama (3)
Barron
33N
low
3.50
.70
Poor Farm
Polk
33N
ICW'
104
Pope
Wa.npac.Ji ....
21N
HE
.22
.11
40.6
16.2
120
Poplar
Polk
33N
18W
.72
.38
9
18
INTRODUCTION
Tablb 2. — (Continued)
Page
map-
ped
Lake
County
Town
Range
Length
(Miles)
Maxi-
mum
breadth
(Miles)
Maxi-
mum
depth
(Feet)
Area
(Acres)
8
Poygan
Waushara ...
19N
13E
7.70
3.50
10.8
10,992.2
120
Prairie
33N
IIW
6.50
.70
34N
104
Rainbow (1)
22N
HE
.62
.55
95.1
137.5
116
Rainbow (2)
Vilas
44N
5E
.63
.44
116
Razorback
Vilas
41N
8E
1.10
.90
31.1
352.0
Red Bass
Vilas
43N
7E
.40
.13
Reserve
39N
8W
1.00
.55
Rice (1)
35N
IIW
2.75
.60
Rice (2)
Vilas
42N
6E
.45
.30
Rock
Vilas
44N
5E
1.12
.37
Roonev
40N
14 W
Rose
Vilas
40N
7E
1.14
.25
Round O)
Vilas
43N
6E
.62
.40
Round (2)
Polk
33N
18W
.58
.41
Round (3)
Polk
32N
17W
.26
.20
104
Round (4)
Waupaca
22N
HE
.55
.35
66.6
106.2
Rozen
Vilas
40N
7E
.68
.50
116
Rudolnh
Vilas
43N
7E
.52
.22
120
St. Croix
Douglas
45N
IIW
4.00
.55
19.7
1,030.4
12W
Sand (1)
Burnett,
38N
16W
120
Sand (2)
Burnett
40N
15W
1.70
1.45
120
Sand (3)
Polk
33N
18W
1.22
.45
116
Sand< (4)
Vilas
42N
7E
1.65
.87
67.2
793.6
Sanford
Vilas
43N
6E
.77
.40
120
Shell
Washburn. . .
37N
12W
3.25
2.50
49.2
3,200.0
38N
13W
120
Silver HI
Ba.rron
36N
13W
75
Silver (2)
Kenosha
IN
20E
1.25
.87
42.6
582.0
58
Silver (3)
Waukesha... .
7N
17E
.97
.56
44.0
231.9
Sishebocema
Vilas
39N
5E
2.50
irr.
40N
58
Soft
Waukesha... .
7N
17E
.32
.20
Speese
Oneida
39N
5E
.32
.31
116
SQuirrel
Oneida.
39N
5E
3.75
1.00
33.8
1,568.0
Sonl.h Crab
Vilas
43N
6E
.68
.20
120
Spirit
Burnett
37N
18W
1.70
1.00
24.6
640.0
116
Star
Vilas
41N
8E
2.12
1.60
26.2
1,152.0
* Listed as White Sand Lake by Birg-e and Juday.
INTRODUCTION
19
Table 2 --(Continued)
Page
map-
ped
Lake
County
Town
Range
Length
(Miles)
Maxi-
mum
breadth
(Miles)
Maxi-
mum
depth
(Feet)
Area
(Acres)
Vilas
42N
6E
.44
.28
39N
5E
. 75
.37
Vilas
4SN
5E
.56
.40
Tank
ON
6E
.24
.08
104
22N
HE
.45
.31
55.7
51.2
116
43N
8E
1.60
1.50
27.9
646.4
Tied Canoe ®
Travis
Polk
33N
17W
116
Trout
Vilas
41N
6E
4.50
2.40
115.0
4,160.0
42N
7E
116
Turtle (North)
Vilas
43N
5E
1.25
.80
47.6
640.0
116
Turtle (South)
Vilas
43N
5E
2.25
.63
43.0
793.6
120
Turtle (Lower)
Barron
34N
14W
1.50
.45
120
Turtle (Upper)
Barron
34N
14W
2.30
.40
23.0
480.0
120
Vermilion
Barron
3f)N
13W
1.70
1.20
120
WapagossetU
Polk
33N
ICW
3.50
1.20
27.9
1,452.8
17W
24
Waubesa
Dane
6N
lOE
4.20
1.40
36.6
2,034.4
7N
White Ash
Polk
34N
low
1.77
.40
120
Whitefish
Sa.wypr
39N
9W
2.60
. 65
73.8
896.0
116
White Sand
Vilas
41N
5E
2.75
1.00
Whitney
Vila.s
42N
6E
.56
.45
116
Wildcat
Vilas
43N
7E
.87
.60
120
Wild Goose
Polk
34N
17W
.95
.64
14.8
256.0
92
Winnebago
15N
17E
28.00
10.40
21.0
137,708.0
20N
116
Wolf
Vilas
42N
7E
1.21
.84
104
Youngs
Waupaca
21N
HE
.09
.07
11.6
3.0
®See Lost Canoe.
•Listed as Sucker Lake by Birge and Juday.
KEY TO THE GENEEA BASED UPON THE
VEGETATIVE CHAKACTERS.
1. (35) Celoring matter not restricted to definite plastids
Class Myxophyceae
2. (22) Cells solitary or in colonies, never in filaments
Order Coccogoneales
3. (12) Cells solitary or in colonies that never contain more than
a few cells
4. ( 7) Cells spherical or hemispherical
5. ( 6) Cells without a definite arrangement Chroococcus p.
6. ( 5) Cells in a flat plate Merismopedia p.
7. ( 4) Cells longer than they are broad
8. (11) Individual cells not enclosed by a special gelatinous vesicle
9. (10) Ends of cells rounded Rhabdoderma p.
10. ( 9) Ends of cells pointed Dactylococcopsis p.
11. ( 8) Individual cells or groups of cells enclosed by a gelatinous
vesicle Gloeothece p.
12. ( 3) Cells in colonies that contain many cells when mature
13. ( 18) Cellular arrangement within colony definite
14. ( 15) Cells forming a flat plate Merismopedia p.
15. ( 14) Cells forming a hollow sphere one cell in thickness
16. ( 17) Center of colony with radiating gelatinous strands
Gomphosphaeria p.
17. ( 16) Center of colony without radiating gelatinous strands
Coelosphaerium p.
18. ( 21) Cells spherical
1’9. ( 20) Cells densely aggregated Microcystis p.
20. ( 19) Cells some distance from one another Aphanocapsa p.
21. ( 18) Cells longer than they are broad Aphanothece p.
22. ( 2) Cells in simple or branched filaments. .Order Hormogoneales
23. ( 30) Trichomes without heterocysts Family Oscillatoriaceae
24. ( 29) Trichomes solitary or in flocculent readily dissociating
masses
25. ( 26) Trichomes containing but one spirally twisted cell
Spirulina p.
26. ( 25) Trichomes containing more than one cell
27. ( 28) Sheaths of filament firm, generally projecting beyond the
trichome Lyngbya p.
28. ( 27) Sheath delicate or lacking, not projecting beyond the tri-
chome Osclllatorla p.
29. ( 24) Trichomes laterally united to form free-floating bundles
which do not dissociate readily Trichodesmium p.
30. ( 23) Trichomes with heterocysts
2
3
4
5
27
31
8
9
46
47
15
13
14
31
16
36
33
19
38
41
43
23
24
25
,49
27
. 52
.50
,54
31
22
WISCONSIN PHYTOPLANKTON
31. ( 34) Trichomes not attenuated Family Nostocaceae 32
32. ( 33) Filaments solitary or interwoven to form flocculent masses
of small size Anabaena
33. ( 32) Filaments laterally joined to form small plate-like colonies
of macroscopic size Aphanizomenon
Trichomes attenuated to a hair-like point Gloeotrichia
Coloring matter in definite chromatophores
Chromoplasts golden brown in color
Wall heavily impregnated with silica and definitely marked
with grooves or rows of dots Bacillarieae (see part 2).
Wall not heavily impregnated with silica
Class Phaeophyceae
Cells generally motile, rarely forming palmella or rhizopo-
dial stages Division Euchrysomonadinae
Cells with one flagellum Order Chromulinales
Cells naked Chrysamoeba
Cells with a differentiated periplast
Family Mallomonadaceae
Cells solitary Mallomonas
Cells in colonies Chrysosphaerella
Cells with two flagella
Flagella of equal length Synura
Flagella of unequal length Order Ochromonadales
Cells in a definite receptacle Family Dinobryaceae
Receptacles homogeneous, without growth rings. .Dinobryon
Receptacles with successive growth rings Hyalobryon
Cells never in a definite receptacle Uroglenopsis
( 39) Cells usually immobile, rarely motile
( 54) Cells spherical to ovoid, embedded in a gelatinous mass
Phaeococcus
54. ( 53) Cells with pseudopodial processes
Division Rhlzochrysidinae
Cells solitary or in irregular colonies Rhizochrysis
Cells in a linear series Chrysidastrum
Chromoplast grass-green or yellowish-green in color
Chromoplast yellowish-green, with oil not starch the assimi-
lation product Class Heterokonteae
Vegetative cells motile Chlorochromonas
Vegetative cells immobile
Cells solitary or in colonies, never in filaments
Order Heterococcales
Cells epiphytic Peroniella
Cells free-floating
Length of cells several times the diameter Ophiocytium
Length of cells less than twice the diameter
Cells irregularly distributed throughout an ovoid, gelatinous
envelope Chlorobotrys
67. ( C6) Cells arranged about a common center and enclosed by an
irregular, gelatinous envelope Botryococcus
68. ( 61) Cells united to form simple filaments Tribonema
69. ( 58) Chloroplast grass-green, generally with pyrenoids and starch
Class Chlorophyceae 70
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
46.
47.
48.
49.
50.
51.
52.
53.
55.
56.
57.
58.
59.
60.
61.
62.
63.
64.
65.
66 .
( 31)
( 1 )
( 57)
( 38)
( 37)
( 52)
( 45)
( 42)
( 41)
( 44)
( 43)
( 40)
( 47)
( 46)
( 51)
( 50)
( 49)
( 48)
9)
( 56)
( 55)
( 36)
( 69)
( 60)
( 59)
{ 68 )
( 63)
( 62)
( 65)
( 64)
( 67)
p. 55
p. 61
p. 63
36
37
39
40
41
p. 67
43
p. 67
p. 69
46
p. 70
48
49
p. 72
p. 75
p. 71
53
p. 76
55
p. 77
p. 78
58
59
p. 80
61
62
p. 81
64
p. 85
66
p. 82
p. 33
p. 87
70.
( 71)
71.
( 70)
72.
( 85)
73.
( 84)
74.
( 75)
75.
( 74)
76.
( 77)
77.
( 76)
78.
( 79)
79.
( 78)
80.
( 83)
81.
( 82)
82.
( 81)
83.
( 80)
84.
( 73)
85.
( 72)
86.
(183)
87.
(122)
88.
(121)
89.
( 92)
90.
( 91)
81.
( 90)
92.
( 89)
93.
(116)
94.
(109:)
95.
(102)
96.
( 99)
■97.
( 98)
98.
( 97)
99.
( 96)
100.
(101)
101.
(100)
102.
( 95)
103.
(108)
104.
(107)
105.
(106)
106.
(105)
107.
(104)
108.
(103)
109.
( 94)
110.
(111)
111.
(110)
112.
(113)
113.
(112)
WISCONSIN PHYTOPLANKTON
23
Cells solitary or in families, divided into two symmetrical
halves with a chloroplast in each half. Median region
generally constricted . . Family Desmidiaceae (See Part 2 )
Cells not divided into two symmetrical halves and without
median constrictions
Cilia normally present in vegetative cells. .Order Volvocales
Anterior end of cells with two cilia
Cells solitary Chlamydomonas
Cells in colonies Family Volvocaceae
Colony a flat plate Gonium
Colony a hollow sphere
Cells mutually compressed Pandorina
Cells some distance from one another
Colony with not more than 256 cells
Asexual reproduction by division of all cells to form daugh-
ter colonies Eudorina
Asexual reproduction by division of certain cells to form
daughter colonies Pleodorina
Colony generally containing many cells Volvox
Anterior end of cells with four cilia Carteria
Cilia not present in vegetative cells
Cells solitary or in colonies, never in simple or branched
filaments Order Protococcales
Cells solitary
Cells free-floating
Cell shape angular
Angles simple or with spines, never with long setae
Tetraedron
Angles with tufts of long setae Polyedriopsis
Cells spherical, ovoid, or elongate
Length of cells not more than three times the diameter. . . .
Cells spherical
Cell w^all smooth
Cells embedded in a gelatinous sheath
Gelatinous sheath lamellated Gloeocystis
Gelatinous sheath not lamellated Planktosphaeria
Cells not embedded in a gelatinous sheath
Wall lamellated Gloeotaenium
Wall not lamellated Chlorella
Wall sculptured, denticulate, or with long spines or setae..
Setae or long spines covering the wall
Wall with setae
Setae the same thickness throughout, or gradually' taper-
ing Golenkinia
Setae visibly thickened in the lower third. . Acanthosphaeria
Walls with long spines Echinosphaerella
Denticulations or ridges covering the walls Trochiscia
Cells ovoid to reniform
Cells reniform Nephrocytium
Cells ovoid
Walls without setae or spines Oocystis
Walls with spines or setae
72
73
74
p. 90
76
p. 94
78
p. 95
80
81
p. 95
p. 96
p. 97
p. 92
86
87
88
89
90
p. 115
p. 124
93
94
95
96
97
p. 100
p. 103
100
p. 115
p. 108
103
104
105
p. 127
p. 128
p. 128
108
110
p. 114
112
p. 110
114
24 WISCONSIN PHYTOPLANKTON
114. (116) Setae somewhat tapering Lagerheimia p.
115. (114) Setae not tapering Franceia p.
116. ( 93) LfCngth of cells several times the diameter
117. (118) Ends of cells produced into setae Schroederia p.
118. (117) Ends of cells not produced into setae
119. (120) Chloroplast with an axial row of pyrenoids Closteriopsis p.
120. (119) Chloroplast without or with one pyrenoid. . Ankistrodesmus p.
121. ( 88) Cells epiphytic or epizootic Characium p.
122. ( 87) Cells in colonies
123. (142) Colonies enclosed by a conspicuous gelatinous sheath
124. (125) Cells connected by branching remains of old cell walls
Dictyosphaerium p.
125. (124) Cells not connected by branching remains of old cell walls. .
126. (137) Cells spherical to ovoid or reniform
127. (136) Chloroplast cup to disc-shaped and parietal
128. (129) Cells with pseudocilia Tetraspora p.
129. (128) Cells without pseudocilia -
130. (131) Colonies never containing more than eight cells. .Gloeocystis p.
131. (130) Colonies always with at least eight cells
132. (133) Cells ovoid to reniform Gloeocystopsis p.
j 33. (132) Cells spherical
134. (136) Chloroplasts of old cells cup-shaped.. Sphaerocystis p.
io5. (134) Chloroplasts of old cells disciform Planktosphaeria p.
136. (127) Chloroplasts star-shaped and central Asterococcus p.
1S7. (126) Cells elongate
138. (141) Cells straight
139. (140) Colonies with cells in groups of two Elaktothrix p.
140. (139) Colonies with cells in groups of 2-4-8 Quadrigula p.
141. (138) Cells curved Kirchneriella p.
112. (123) Cells not enclosed by a gelatinous sheath
148. (156) Colonies always forming a flat plate
144. (155) Number of cells, except in rare cases, greater than two
145. (152) Cells quadrately arranged
146. (147) Quadrate arrangement apparent in end view of colony
Tetradesmus p.
147. (146) Quadrate arrangement apparent in front view of colony
148. (149) Cells without setae or spines Crucigenia p.
149. (148) Cells with spines or setae
150. (151) Long setae or spines on outer face of cells. . . .Micractinium p.
151. (150) Short spines on outer face of cells Tetrastrum p.
152. (145) Cells not quadrately arranged
153. (154) Colony a fiat circular or oval disc Pediastrum p.
154. (153) Colony a single or double row of cells Scenedesmus p.
155. (144) Number of cells in colony always two Euastropsis p.
156. (143) Colony not forming a flat plate
157. (166) Colony enclosed by old cell wall
158. (165) Wall enclosing colony greatly expanded and homogeneous..
159. (162) Wall with spines or setae
160. (161) Setae somewhat tapering Lagerheimia p.
161. (160) Setae not tapering Franceia p.
162. (159) Wall without spines or setae
163. (164) Cells ovoid Obcystis p.
129
,131
117
136
119
,136
,134
175
123
124
, 104
126
127
128
102
130
100
132
102
134
101
103
103
138
139
139
137
140
143
144
145
146
150
148
144
150
125
149
153
166
150
174
157
168
159
160
129
131
163
110
WISCONSIN PHYTOPLANKTON
25
184. (163) Cells ovoid to reniform Nephrocytium p. 114
165. (158) Wall lamellated but not expanded Gloeotaenium p. 115
166. (157) Colony not enclosed by old cell wall 167
167. (176) Length of cell not more than twice the breadth 168
168. (171) Remains of old cell walls at center of and holding colony
together 169
169. (170) Cells spherical Westella p. 106
170. (169) Cells ovoid to reniform Dimorphococcus p. 106
171. (168) Colonies without remains of old cell wall at center 172
172. (173) Outer face of cells with long setae Micractinium p. 125
173. (172) Outer face of cells with short spines or without ornamenta-
tion 174
174. (175) Cells without spines on outer face Coelastrum p. 160
175. (174) Cells with short spines on outer face Sorastrum p. 162
176. (167) Length of cells several times the breadth 177
177. (178) Colony forming a closed hollow sac Hydrodictyon p. 165
178. (177) Colony not forming a closed hollow sac 179
179. (180) Cells radiating from a common center Actinastrum p. 164
380. (179) Cells not radiating from a common center 181
381. (182) Cells straight or arcuate Ankistrodesmus p. 134
182. (181) Cells markedly curved Selenastrum p. 132
183. ( 86) Cells in simple or branched filaments 184
184. (195) Cells with one to eight chloroplasts, chloroplasts never re-
ticulate 185
185. (192) Chloroplasts parietal 186
186. (191) Chloroplasts laminate to disciform 187
187. (188) Cells in simple filaments Ulothrix p. 179
188. (187) Cells in branching filaments 189
18'9. (190) Setae confined to terminal cells or lacking. .. Stigeoclonium p. 180
190. (189) Setae occurring on any cell of filament Aphanochaete p. 181
191. (186) Chloroplast a spiral band Spirogyra p. 185
192. (185) Chloroplast central 193
193. (194) Chloroplast an axial plate Mougeotia p. 184
194. (193) Chloroplasts stellate Zygnema p. 184
395. (184) Chloroplasts numerous or united to form a single reticulate
mass Cladophora p. 182
26
WISCONSIN PHYTOPLANKTON
Class MYXOPHYCEAE.
Cells solitary, in colonies of definite or indefinite shape, or in fila-
ments but always surrounded by a gelatinous to tough envelope which
is generally hyaline but may be colored. Plants living a free-fioating,
sessile, epiphytic or endophytic existence. Cell shape various; spheri-
cal, hemispherical, ovoid, bacilliform, disciform or angular. Cells with
the coloring matter localized at the periphery but not in definite, visible
ehromatophores. Color of cells typically blue-green but at times grey,
yellowish, reddish, brownish or nearly grass-green. The color variation
being due to different amounts of the three component pigments, caro-
tin, chlorophyll, and phycocyan; the latter being found only in this
class of plants. Cells containing a single nucleus of a primitive type
(the central body) that contains linin and chromatin but is without a
membrane or nucleole.
Reproduction always asexual, either by vegetative division of cells;
fragmentation of the filaments into smaller portions (hormogones)
which may move a short distance by spontaneous movement and then
come to rest; or by special non-motile reproductive bodies (gonidia and
resting spores) .
KEY TO THE ORDERS.
Cells solitary or in colonies, never in filaments Coccogoneau»
Cells in simple or branched filaments Hobmoqoneaubs
Order COCCOGONEALES.
Cells rarely solitary, generally in colonies of regular or irregular
shape, and with the cells definitely or indefinitely arranged within a
copious gelatinous envelope. Colonies living a free-fioating, sessile,
epiphytic or endophytic existence. Cells differentiated into a basal
and distal portion or without such differentiation. Cell shape various;
spherical, ovoid, cylindrical, acicular, or angular.
Asexual reproduction by vegetative division of the cells or, in rare
cases, by a division of the cell contents into non-motile gonidia. Rest-
ing cells and sexual reproduction unknown.
There are two families in the order only one of which, the Chroococ-
caceae, is found in the plankton.
WISCONSIN PHYTOPLANKTON
27
Family CHROOCOCCACEAE.
Cells not differentiated into an apical and basal portion ; rarely soli-
tary, generally in colonies of definite or indefinite shape and always
enclosed by a gelatinous sheath. Cell shape various, and cellular ar-
rangement within the colonial envelope definite or indefinite.
Asexual reproduction by vegetative cell division and the fragmenta-
tion of the colonies. Gonidia formation occasionally taking place in
certain genera.
KEY TO THE GENERA.
Cells solitary or in colonies that never contain more than a few cells.
Cells spherical or hemispherical ' Chboocxk'CUS
Cells longer than they are broad.
Individual cells or groups of cells enclosed by a gelatinous
vesicle Gloeothece
Individual cells or groups of cells without vesicles.
Ends of cells rounded Rhabdodebma
Binds of cells pointed Dactylococcopsis
Cells always. in colonies that contain many cells when mature.
Cellular arrangement within colony definite.
Cells forming a flat plate Merismopedia
Cells forming a hollow sphere one cell in thickness.
Center of colony with radiating gelatinous strands . Gomphosphaeria
Center of colony without radiating strands Coelosphaeriem:
Cellular arrangement within colony indefinite.
Cells spherical.
Cells densely aggregated Microcystis
Cells some distance from one another Aphanocapsa
Cells longer than they are broad Aphanothbck
CHROOCOCCUS Nageli 1849.
Cells spherical, usually hemispherical for some time after division;
solitary or 2-4r-8-16 or more united in colonies enclosed by a hyaline
or colored, homogeneous or lamellated sheath; free-floating, sessile, or
epiphytic. Individual cells of colony at times surrounded by a homo-
geneous or lamellated sheath. Cell contents grey, grey-green, blue-
green, olive-green, yellowish, orange, reddish or violet in color; homo-
geneous or granular.
Reproduction by vegetative division of cells in three directions.
KEY TO THE SPECIES.
Sheaths enclosing cells homogeneous.
Cells solitary, in twos, and in fours C. Minutes
Cells in colonies of 4-8-16 or more.
Individual cells or groups of cells some distance from one
another C. Disperses
Individual cells or groups of cells fairly close together . . C. Limneticus
28
WISCONSIN PHYTOPLANKTON
Sheaths enclosing cells distinctly lamellated.
Diameter of cell and sheath not exceeding 40 /x C. Turgidus
Diameter of cell and sheath over 60 /x C. Giganteus
Chroococcus Minutus (Kiitzing) Nageli. PL 1, Fig. 1.
Gatt. einz. Algen 46. 1849.
Protococcus minutus Kiitzing, Tabulae Phycol. 1: pi. 5.
Cells spherical or hemispherical, solitary or in colonies of 2-4 en-
closed by a wide, spherical, homogeneous, gelatinous sheath. Cell con-
tents pale blue-green to grey, homogeneous or granulose. (Tychoplank-
tont) .
Diam. cells (without sheath) 5-7 ix, (with sheath) 6-12 /x; length
(without sheath) 5-10 /x, (with sheath) 5-13 /x.
Wolf (rrr).^
Chroococcus dispersus (v. Keissler) Lemmermann. PI. 1, Fig. 2 .
Arkiv. f. Botanik 2, No. 2: 102. 1904.
Chroococcus minor var. dispersus v. Keissler, Verh. d. zool.-bot. Ges. Wien
52: 311, fig. 6. 1902.
Cells spherical, 4-16 or more united to form spherical, ovoid, or ir-
regular colonies. Individual cells some distance from one another,
or in compact groups that lie some distance from one another within
the colony. Individual cell sheaths frequently confluent with the col-
onial sheath. Cell contents homogeneous, pale to bright blue-green.
(Euplanktont).
Diam. cells (without sheath) 3-4 /x; (with sheath) 6 /x. Distance be-
tween cells or groups of cells 15-20 /x.
Browns (rr), Pokegama (1) (rr).
A species that is closely related to C. limneticus but one where the
number of cells in the colony is usually greater, and where the indi-
vidual cells or groups of cells are some distance from one another.
var. minor var. nov. PI. 1, Fig. 3.
Cells smaller than the typical form and with pale grey contents.
(Euplanktont).
Diam. cells 1. 75-2. 5 /x.
Long (3) (rrr), Middle McKenzie (rr). Palmer (rr).
♦ The relative abundance of the individual species is shown by the following
symbols; (aaa) very abundant, (aa) abundant, (a) fairly abundant, (ccc) very
common, (cc) common, (c) fairly common, (s) fairly scarce, (ss) scarce,
(sss) very scarce, (r) fairly rare, (rr) rare, (rrr) very rare.
WISCONSIN PHYTOPLANKTON
29
Chroococcus Limneticus Lemmermann. PI. 1, Fig. 4.
Bot. Cent. 76: 153. 1898; Forschungsbr. a. d. Biol. Stat. zu Pl5n 7: 132, pi. 1,
figs. 22-23. 1899.
Mature cells spherical to subspherical, 4-32 in a free-floating spheri-
cal to ovoid colony. Cells fairly close together and equidistant from
one another within the colony, sometimes in groups of 2-4 but with
the groups lying close together. Cell division in all three planes but
a majority of the cells dividing in the same plane and giving the colony
a somewhat tabular appearance. Many hemispherical cells present be-
cause of the slow maturation after division. Individual cell sheaths
homogeneous and frequently confluent with colonial envelope. Cell
contents homogeneous; grey, pale to bright blue-green, or olive-green.
(Euplanktont).
Diam. cells (without sheath) 6-12 fx, (with sheath) 8-14 /t.
Balsam (r), Bear (1) (rr), Bear (2) (rrr), Bear Trap (sss), Beasley (rr),
Beaver (1) (r), Beaver (2) (ss), Big Butternut (r), Birch (1) (rr), Birch (2)
(ss), Birch Island (s), Blake (sss). Bloom (s), Boulder (rrr), Browns (s),
Camp (rr). Catfish (rr), Chetac (r), Chetek (rrr). Cranberry (sss), Dunham
(rr), Dutchmans (r). Eagle (rr). East (rr). Fish (rr). Found (rr), Fowler
(rr), Grassy (rr). Grindstone (rr). Half Moon (rr), Horseshoe (1) (r).
Island (rr), Kawaguesaga (rr), Kimball (rr), Lac Court Oreilles (rr). Lac la
Belle (r). Little Bass (2) (ss). Little Butternut (rr). Little Rice (2) (rr).
Little Wood (sss), Loveless (r), Mary (rr). Middle McKenzie (r). Mill (rr),
Mud (1) (rr). Mud (2) (rr), Mudhen (r), Nicaboyne (r). North Twin (rr),
Oconomowoc (rr). Old Taylors (rr), Pewaukee (rr). Pike (rr). Pine Tree (rr),
Pokegama (1) (r), Pokegama (2) (rrr), Pokegama (3) (rr). Poor Farm (rr).
Poplar (ss). Reserve (sss). Rice (1) (r), Round (3) (rr). Sand (1) (s).
Sand (3) (sss). Sand (4) (rr). Shell (sss), Silver (2) (r). Spirit (r). Squir-
rel (r). Tenderfoot (rrr), Travis (rrr). Upper Nashotah (rr). Upper Nemah-
bln (rr). White Ash (ss), Whitefish (s). Wildcat (rr), Winnebago (r). Wolf
(rr).
This is preeminently a plankton species. It is widely distributed
throughout the state and may be the dominant member of the Myxo-
phyceae in lakes with very soft water, but it never occurs in sufficient
abundance to cause the familiar phenomenon of blooming. The cells
are quite variable in both color and size.
var. SUBSAI..SUS Lemmermann. PI. 1, Fig. 5.
Forschungsbr. a. d. Biol. Stat. zu P16n 8: 84. 1901; Arkiv f. Botanik 2: No. 2:
101, pi. 1, fg. 9. 1904.
Cells spherical to subspherical, 8-16-32 in a somewhat spherical or
broadly ellipsoidal colony with a wide gelatinous envelope. Cell con-
tents homogeneous; pale to bright blue-green. (Euplanktont).
30
WISCONSIN PHYTOPLANKTON
Diam. cells (without sheath) 3. 5-4.5 /x; (with sheath) 4.5-5.5 fi.
Big Bass (sss), Blake (rr), Lac Court Oreilles (ss), Owen (ss), Paddock (r).
The chief distinction of this and the following varieties is in the size
of the cells.
var. CARNEUS (Chodat) Lemmermann. PI. 1, Fig. 6.
Arkiv for Botanik 2, No. 2: 101. 1904.
Cells spherical to hemispherical, 4-8-16 irregularly distributed
throughout a spherical to ovoid gelatinous matrix. Individual sheaths
of ceUs confluent with the colonial envelope. Cell contents homogene-
ous; color variable, ochraceous, grey, blue-green or olive green. (Eu-
planktont) .
Diam. cells (without sheath) 7-9 fi.
Big Bass (ss), Harris (r), Mendota (rr), Nancy (r), Oconomowoc (rr).
var. DiSTANS G. M. Smith. PI. 1, Pig. 7.
Bull. Torr. Bot. Cl. 43: 481, pi. 26, fig. 26. 1916.
Cells spherical to hemispherical, 8-32 in a colony and lying some
distance from one another within a spherical to ovoid, hyaline, homo-
geneous, gelatinous, colonial envelope. Individual cell sheaths con-
fluent with the colonial envelope. Cell contents homogeneous, grey to
pale blue-green in color. (Euplanktont).
Diam. cells (without sheath) 6.5-7 /x.
Bear Trap (s), Birch Island (rr), Browns (sss), Cochrane (r). Cranberry
(sss), Lindy (rr), Muskallonge (rr).
var. ELEGANS G. M. Smith. PI. 1, Pig. 8.
Trans. Wis. Acad. Sci., Arts, & Lett. 19^: 619. 1918.
Cells circular to semicircular in front view, somewhat flattened in
side view. Colonies enclosed by a spherical, homogeneous, hyaline, gel-
atinous envelope. Individual sheaths of cells conspicuous. Cell con-
tents homogeneous; generally bright blue-green in color. (Euplank-
tont).
Diam. cells (without sheath) 18-22 fx; (with sheath) 20-26 /x.
Delavan (rr).
Chroococcus giganteus W. West. PI. 2, Pig. 1.
Jour. Roy. Micr. Soc. 1892: 741, pi. 10, figs. 59-60. 1892.
Cells ordinarily hemispherical, rarely becoming spherical or ovoid
after division. Solitary or in colonies of two (rarely 3-4) enclosed by
WISCONSIN PHYTOPLANKTON
31
a thick, hyaline, markedly lamellate, gelatinous envelope. Envelope of
individual cells conspicuous, lamellated. Cell contents distinctly gran-
ulose, bright blue-green. (Tychoplanktont).
Diam. cells (without sheath) 54—58 ix\ (with sheath) 67-70 /x.
Mary (rrr).
Chroococcus turgidus (Kiitzing) Nageli. PI. 1, Fig. 9.
Gatt. einz. Algen 46. 1849; G. S. West, Brit. Fresh w. Algae 352, fig. 166g. 1904.
Cells hemispherical, spherical, ovoid, or somewhat flattened by mutual
compression. Cells solitary or in colonies of 2-4 (rarely 8) enclosed
by a thick, hyaline, generally lamellated, gelatinous sheath. Individual
cells also with hyaline, lamellated sheaths. Cell contents homogeneous
or finely granulose; pale to bright blue-green or rarely brownish in
color. ( Tychoplanktont ) .
Diam. cells (without sheath) 8-32 /x; (with sheath) 13-40 /x.
Beasley (rrr), Beaver (2X (rr). Browns (rr), Hillman (rr), Horse (rrr),
Oconomowoc (rr), Otter (rr), Rudolph (rr). Sand (2) (rr), Upper Turtle (rr),
Waubesa (rrr).
MERISMOPEDIA Meyen 1839.
Colonies always forming flat, curved, or irregularly twisted plates
one cell in thickness with the constituent cells in rectilinear series and
usually in groups of four.' Cells spherical to subspherical with rounded
ends, hemispherical for some time after division. Individual sheaths
of cells rarely distinct, generally confluent with the copious, hyaline,
homogeneous, colonial envelope. Number of cells in colony 4 — 4(K)0,
cell number a multiple of two in young colonies, not a multiple of two
in old colonies. Cell contents generally homogeneous, rarely with
pseudovacuoles. Color varying from grey through light to bright blue-
green, rarely rose pink to violet.
KEY TO THE SPECIES.
Cells bright blue-green M. Elegans
Cells pale blue-green.
Cells some distance from one another M. Punctata
Cells close together (not mutually compressed).
Diameter of cells 1. 5-2 /x M. Tenuissima
Diameter of cells 3-6 /x M. Glauca
32
WISCONSIN PHYTOPLANKTON
Merismopedia elegans a. Braun. PL 2, Fig. 6.
in Kiitzing, Species algarum 472. 1849; G. S. West, Brit. Fresh w. Algae 348:
fig. 162^. 1904.
Colonies small or large, of 16-4000 cells regularly arranged in recti-
linear series and groups of four; with the cell number a multiple of
two in young colonies but becoming irregular in arrangement and num-
ber in old colonies. Colonies flat except when containing many cells.
Cells spherical to broadly ovoid, with homogeneous, bright blue-green
contents. (Facultative Planktont).
Cells 5-7 /A broad, 5-9 fi long.
Carson (rr), Center (rr), Green (1) (rr), Kegonsa (rr), Little Bear (rrr),
Mendota (r), Monona (r), Mud (1) (rr), Nancy (r), Upper Nashotah (rrr),
Waubesa (rr).
This alga is a good example of a typical benthitic organism that is
able to thrive under limnetic conditions. It never becomes a conspicu-
ous member of the plankton but the colonies attain a much larger size
and I have observed specimens 60-70 cells broad and 60-90 cells long.
There is a certain amount of irregularity in such colonies so exact de-
terminations of cell numbers are impossible.
var. major var. nov. PL 2, Fig. 6.
Colonies usually containing many cells. Cell shape the same as in
the typical form'. Cell contents homogeneous, bright blue-green. (Bu-
planktont).
Cells 10-11 fi broad, 12-14 /jl long.
Beaverdam (r), Lindy (rr).
Merismopedia glauca (Ehrenberg) Nageli. PL 2, Fig. 4.
Gatt. einz. Algen 56, pi. 1, fig. IP. 1849.
Colonies generally containing less than 64 cells, compactly and regu-
larly arranged. Cells spherical to broadly ellipsoid, hemispherical for
some time after division. Cell contents homogeneous, generally pale
blue-green. (Facultative Planktont).
Diam. cells 3-5 jm.
George (rr), Jones (rrr). Lac Court Oreilles (rrr). Loon (rrr), Meta (rr),
Mill (rr), Waubesa (rr).
This species resembles M. punctata in the size of the cells but differs
in the distance between the cells.
WISCONSIN PHYTOPLANKTON
33
Merismopedia punctata Meyen. PI. 2, Fig. 3.
Arch. f. Naturgesch. 5*: 67. 1839; Kiitzing, Tabulae Phycol. 5: 18, pi. 38, /Ip. 3.
1855.
Colonies small, with the cells some distance from one another but
regularly arranged in rectilinear series. Cells spherical to broadly
ovoid or hemispherical. Cell contents homogeneous, grey to pale blue-
green. (Tychoplanktont).
Diam. cells 2.5-3.5 /x.
Big Bass (rrr).
Merismopedia tenuissima Lemmermann. PI. 2, Fig. 2.
Bot. Cent. 76: 154. 1898; Forschungsbr. a. d. Biol. Stat. zu P15n 7: 132, pi. 1,
Hg. 21. 1899.
Colonies rectangular, free-floating, generally with 16-100 cells lying
close together. Rectilinear arrangement of cells soon breaking down
and not evident when there are more than 32 cells in a colony. Col-
onies distorted when of any size. Cells spherical to ovoid, hemispheri-
cal for some time after division. Individual sheath of cells distinct
or confluent with colonial envelope. Cell contents homogeneous; grey
to pale blue-green. (Facultative Planktont).
Diam. cells (without sheath) 1.5-2 /x.
Camp (rr), Little Doctor (rr), Long (3) (r), Mary (rr).
The irregular cellular arrangement is very common in older colonies
and is not due to the size of the colony, since the species is one of the
smallest of the genus, but to irregularities in cell division.
COELOSPHAERIUM Nageli 1849.
Colonies microscopic, free-floating; spherical, ellipsoid, reniform, or
irregular ; enclosed by a delicate, hyaline, homogeneous or radially fibril-
lar, gelatinous envelope. Cells spherical, ovoid, ellipsoid, sub-pyriform
and arranged in a single layer to form a hollow sac just beneath the
periphery of the colonial envelope. Cell contents homogeneous and
grey to bright blue-green ; or reddish and containing numerous pseudo-
vacuoles.*
Reproduction by vegetative cell division in three directions.
♦These structures, which are also called gas vacuoles, are found in certain
plankton species of the Myxophyceae. They are minute bodies, which are
reddish through their refractive power, that occur in large numbers in all
cells of the colony. Various functions have been ascribed to them, the most
probable being a means of protection against too intense light, or a giving of
greater buoyancy to the colony.
3
34
WISCONSIN PHYTOPLANKTON
KEY TO THE SPECIES.
Cells spherical.
Diameter of cells not exceeding 4 C. Kuetzingiaum
Diameter of cells over 5 C. Dtjbium
Cells ovoid to ellipsoid C. Naegblianum
CoELOSPHAERiUM KuETZiNGiANUM Nageli. PI. 3, Figs. 4-5.
Gatt. einz. Algen 54, pi. 1, fig. C. 1849.
Colonies spherical to subsplierical, enclosed by a very hyaline, homo-
geneous, gelatinous envelope. Cells spherical to subspherical, forming
a single layer, with the individual cells or pairs of cells some distance
from one another or close together. Cell contents homogeneous, with-
out pseudovacuoles ; usually grey to pale blue-green, rarely bright blue-
green. (Facultative planktont).
Diam. cells 2.25-4 /x ; diam. colonies 20-90 /x.
Balsam (rr), Bass (2) (rr). Bear (3) (r), Bear Trap (rrr), Beaverdam (ss),
Big (ss). Big Butternut (sss), Birch Island (rrr), Blake (ss), Bone (rr).
Browns (rr), Carson (r). Catfish (r). Clam (ss), Cochrane (sss), Crab (rr).
Cranberry (ss). Crawling Stone (sss), Deer (rr). Diamond (rrr), Elizabeth
(s). Eagle (ss). Fence (sss). Fish (rr), Grindstone (rr). Green (2) (rr). Half
Moon (r). High (sss), Hillman (ss). Horseshoe (1) (rrr), Kegonsa (s). Kit-
ten (rr). Island (ss). Lac la Belle (rr), Lindy (rr). Little Bear (rrr). Little
Butternut (r). Little Crooked (rr). Little Rice (1) (ss). Little Wood (s),
Long (2) (rr). Long (3) (rr). Loveless (sss), Mary (s), Mendota (s), Mer-
cer (rrr). Mill (rrr). Mud (1) (cc). Mud (2) (r), Mudhen (s), Nancy (rrr),
Nicaboyne (rr), North Turtle (ss), Oconomowoc (r), Owen (rrr). Paddock
(ss). Palmer (ss), Pardee (cc), Pewaukee (rr). Pine (2) (rr). Fine Tree (rr),
Pokegama (1) (sss), Pokegama (2) (r), Pokegama (3) (rrr). Poplar (ss),
Reserve (ss). Rice (1) (rr). Rock (sss). Round (3) (sss). Sand (1) (rr),
Sand (3) (rr). Sand (4) (r). Silver (1) (ccc). Silver (2) (ss), South Turtle
(ss), Spirit (ss), iSunday (r). Tamarack (rr). Tenderfoot (sss). Tied Canoe
(rrr). Upper Nemahbin (rrr). Upper Turtle (sss). White Ash (sss). White-
fish (s), W’hite Sand (sss). Wildcat (rr). Wild Goose (rr), Winnebago (rr).
Wolf (r).
The gelatinous sheath is generally so delicate that it is necessary to
use Errera’s method of mounting colonies in dilute India ink to demon-
strate its presence. The specific limits of this species as established
by different authors frequently includes C. Naegelianum as a synonym.
C. Kuetzingianum and C. Naegelianum are two well defined species that
differ in colony shape^ cell shape, occurrence of pseudovacuoles, struc-
ture of colonial envelope, and relative abundance. C. Kuetzingianum
is a species that is widely distributed throughout the state but one which
rarely becomes a dominant member of the plankton and never occurs
in sufficient abundance to cause blooming.
V/I8C0NSIN PHYTOPLANKTON
35
CoELOSPHAERiuM DUBiUM Grunow. PI. 3, Fig. 7.
in Rabenhorst, Flora Eur. Algarum 2: 55. 1865; Scbmula, Beibl. z. Hedwigla
S7: (47), figs. 1-2. 1898.
Colonies spherical to irregular, with three or four smaller colonies
frequently enclosed by a common gelatinous envelope. Colonial en-
velope firm, hyaline, and homogeneous. Cells in a single layer and
very close together at the periphery of the colonial envelope. Cell con-
tents homogeneous or with p seudo vacuoles ; blue-green in color. (Fac-
ultative Planktont).
Cells 5-7 fx in diameter. Single colonies up to 150 /x in diam ; com-
pound colonies up to 300 fx.
Mud (3) (rr).
CoELOSPHAERiUM Naegelianum Unger. PI. 3, Fig. 6; PI. 4, Fig. 1.
Denkschr. d. kais. Ak. d. Wiss. Wien 7: 196. 1854; Leitgeb, Mitt. d. naturw.
Ver. Steiermark 2, Heft 1: 72, pi. 2, figs. 1-6. 1869; Borge, Bot. Not. 1900:
10, pi. 1, figs. 5a-5b. 1900.
Gomphosphaeria Naegeliana (Unger) Lemmermann. Kryptogamenfl. d.
Mark Brandenburg 3, Algen 1: 80, 44, fig. 19. 1907; Bachmann, Arch. f. Hy-
drobiol. u. Planktonkde. 3: 60, figs. IIP-IIP. 1908.
Colonies spherical, ovoid, renif orm or irregular ; with a wide, hyaline,
gelatinous envelope that is at times radially fibrillar in structure. Cells
ovoid to ellipsoid, radially arranged in a single layer some distance be-
neath the periphery of the colonial envelope, usually close together but
not mutually compressed. Cell contents rarely homogeneous and pale
to bright blue-green or grass-green ; usually with numerous pseudovacu-
oles and reddish to brownish in color. (Euplanktont).
Cells 2-3 IX broad ; 3.5-6 /a long.
Adelaide (ss), Amicoy (ss). Balsam (ss). Bear (1) (s). Bear (2) (rr),
Bear (3) (s), Bear Trap (sss), Beaverdam (cc). Big (ccc). Big Butternut
(r). Big McKenzie (ss). Big St. Germaine (rr), Birch (1) (ccc), Birch (2)
(aa), Birch Island (rrr), Blake (rr). Bloom (ss), Bone (ss), Boulder (rr).
Browns (rr), Camp (c). Catfish (aa), Center (aa), Chetac (aa). Clam (c),
Clare (rr). Crab (sss). Cranberry (aa). Devils (1) (rr). Devils (2) (ss).
Deer (rr). Duck (c). Dummy (rrr), Elizabeth (cc), Fish (sss). Found (ss),
Fowler (ss), Granite (ss). Grindstone (rr). Half Moon (s), Hillman (s).
Hooker (rr). Horseshoe (1) (ss). Horseshoe (2) (rrr). Island (cc), Jennie
(rr), Kawaguesaga (sss). Kitten (rrr), Kegonsa (aa). Lac du Flambeau (rr),
Lac la Belle (r), Laura (aa), Lindy (rr). Little Bass (2) (rr). Little Butter-
nut (rr). Little Rice (1) (cc). Long (1) (rr). Long (2) (a). Loon (rr). Lost
(aa), Lower Nemahbin (r). Marl (rr), Mendota (cc), Mercer (ss), Middle
McKenzie (cc), Mill (rr), Minocqua (rr), Monona (aa). Mud (1) (cc). Mud
(3) (aa), Mudhen (rr), Nancy (c), Nicaboyne (r). No Mans (aa). North
Twin (cc). North Turtle (aa). Number One (ss), Oconomowoc (rr), Okauchee
WISCONSIN PHYTOPLANKTON
rfb
(r), Otter (rr). Paddock (c), Palmer (ss), Pardee (rr), Pewaukee (ss),
Plum (ss), Pokegama (1) (c), Pokegama (2) (sss), Pokegama (3) (a), Pop-
lar (r), Prairie (s), Reserve (ss), Rainbow (r), Rice (1) (cc), Rock (a),
Rooney (aa). Round (1) (rrr). Round (2) (ss), Round (3) (ss), St. Croix
(cc), Sanford (r), Sand (1) (ss). Sand (2) (rr), Sand (3) (rr), Sand (4)
(rr). Silver (2) (c), tSishebogema (aa). South Turtle (sss). Upper Nashotah
(rr). Upper Nemahbin (rr). Upper Turtle (s), Wapagossett (cc), Waubesa
(cc). White Ash (rr), Whitefish (cc). White Sand (rrr). Wildcat (rrr), Win-
nebago (cc),WoK (rrr).
The radial fibrillar structure at the periphery of the gelatinous en-
velope is also found at times in the center of the colony. These radia-
tions have been compared by some to the gelatinous strands found in
GomphospJiaeria and the species transferred to that genus. I have
preferred to keep the alga in the genus where it was first described.
This alga is one of the important members of the Myxophyceae in the
formation of blooms but it is rarely found as the sole constituent of
any bloom. Bachmann’s figures of the alga are quite characteristic.
GOMPHOSPHAERIA Kiitzing 1836.
Colonies microscopic, spherical to ellipsoid, embedded in a copious,
hyaline, solid, homogeneous, gelatinous envelope. Cells spherical
to pyriform, solitary or in pairs, generally lying some distance from
one another and forming a layer one cell in thickness towards the pe-
riphery of the colonial envelope. Central portion of colonial envelope
containing a denser core from which projections radiate to the base of
the cells. Individual sheaths of cells distinct or confluent with the
colonial envelope. Cell contents homogeneous, rarely granulose; grey
to light or bright blue-green.
Reproduction by alternate vegetative division of cells in three planes.
KEY TO THE SPECIES.
Cells spherical G. Lacustris
Cells pyriform to cardioid G. Afonina
Gomphosphaeria lacustris Chodat. PI. 4, Fig. 5.
Bull. Herb. Boiss. 6: 180, figs. 1898; W. & G. S. West, Trans. Roy. Irish
Acad. 33, Sec. B: 112, pi. 11, figs. 24-27. 1906.
Colonies small, generally spherical or subspherical, rarely reniform;
with a hyaline, homogeneous, gelatinous envelope. Cells spherical to
broadly ellipsoid, irregularly spaced to form a single layer one cell in
thickness beneath the periphery of the colonial envelope. Individual
cell sheaths confluent with colonial envelope. Central portion of col-
ony containing a core of denser radiating gelatinous strands that run
WISCONSIN PHYTOPLANKTON
37
to the base of the cells. Cell contents homogeneous; grey to pale or
bright blue-green, rose colored in rare instances. (Euplanktont).
Cells 1. 5-2.5 IX broad, 1.5-4 /x long. Colonies rarely over 40 fx in diam.
Bear (1) (rr), Beaverdam (c), Big McKenzie (ss), Blake (sss)^ Cochrane
(r), Deer (rr), Diamond (r), Dunham (c), Fish (c), Half Moon (rr). Island
(rr), Kawaguesaga (r). Lac Court Oreilles (ss), Llndy (sss). Little Bass (2)
(rr), Long (1) (rr). Loon (rr), Mendota (s), Mercer (ss). Middle McKenzie
(ss), Mudhen (ss), Nicaboyne (r). North Twin (r), Pardee (rr). Plum (rr),
Pokegama (3) (rr). Sand (1) (r). Sand (2) (rr). Sand (4) (rr), Spirit (r),
Squirrel (sss). Star (sss), Wolf (r).
The colonies of this species resemble those of Coelosphaerium Kuetz-
ingianum in cell shape and arrangement but differ in the radiating
strands of gelatinous material running from the center of the colony
to the base of the cells. The gelatinous envelope is very delicate and
cells frequently break away leaving the central mass of gelatinous radi-
ations floating by itself.
Gomphosphaeria aponina Kiitzing. PI. 4, Figs. 2-3.
Decades 16: No. 151. 1836; G. S. West, Brit. Freshw. Algae 349, fig. 163g.
1904.
Colonies small, spherical to subspherical, with a fairly thick, hya-
line, homogeneous, gelatinous envelope. Cells pyriform to cuneate,
cardioid just before division; sparsely scattered and in a single layer
some distance beneath the periphery of the colonial envelope. Indi-
vidual sheaths of cells generally distinct, attached at the base to the
dense gelatinous strands radiating from the center of the colony. Cell
contents homogeneous or finely granulose; without pseudovacuoles;
generally a bright blue-green. (Tychoplanktont).
Cells 4-5 fx wide at the greatest breadth, 8-15 /x long. Diam. colonies
50-90 fx.
Beaverdam (sss). Big McKenzie (rrr). Browns (rr). Center (rr), Eagle
(rr), Elizabeth (rr), Hillman (rr), Kegonsa (rrr). Lower Nemahbin (rr),
Mendota (rr), Mary (rr), Monona (rrr), Mudhen (rr). North Turtle (rrr).
Otter (rrr), Pewaukee (rr). Pine (1) (rrr). Plum (rrr). Silver (2) (rr), Sil-
ver (3) (rr). South Turtle (rr), Waubesa (r).
var. coRDiFORMis Wolle. PI. 4 , Fig. 4 .
Bull. Torr. Bot. Cl. 9: 25, pi. 13, fig. 11. 1882.
Cells considerably larger than in the typical form and markedly
heart shaped instead of pyriform. Individual sheaths of cells conspicu-
ous. Cell contents bright blue-green. (Tychoplanktont).
Greatest breadth of cells 6-13 fx ; length 9-20 /x.
Bloom (rrr).
38
WISCONSIN PHYTOPLANKTON
The cells of the Wisconsin individuals are somewhat longer than
Wolle found them, his measurements for the length of the cell varying
from 9-16 fi.
MICROCYSTIS Kiitzing 1833.
Colonies free-floating; spherical, elongate, irregular, or perforate to
form reticulate or clathrate masses of microscopic or macroscopic size.
Frequently occurring in sufficient quantities to give the water a verdi-
gris-green color. Envelope of colonies generally copious, delicate to
firm. Cells small, spherical, distributed in a solid mass throughout the
colony and densely aggregated. Individual cell sheath confluent with
colonial envelope. Cell contents homogeneous or with numerous pseudo-
vacuoles ; light to dark blue-green, olive-green, or rose colored.
Reproduction by vegetative division of cells in three directions.
Certain species of the genus occur in prodigious quantities and cause
the familiar blooming of lakes. These species contain pseudovacuoles,
while species without pseudovacuoles rarely occur in quantity.
KEY TO THE SPECIES.
Cells with numerous pseudovacuoles.
Several colonies enclosed by the same envelope M. Ichthyoblabe
Colonies not differentiated into several within the same envelope.
Colony entire, not perforate M. Flos-Aquae
Colony saccate and perforate M. Aeruginosa
Cells without pseudovacuoles.
Diameter of cells less than 1.5 /x M. Inceeta
Diameter of cells 2-3 jx M. Pulvera
Microcystis ichthyoblabe Kiitzing.
Phycol. generalis 170. 1843.
Polycystis ichthyoblabe Kiitzing, Tabulae Phycol. 1: 7, pi. 8. 1845.
Colonies spherical or irregular, fragmented into several distinct sub-
colonies, each with its own gelatinous envelope, and with the sub-col-
onies enclosed by a common gelatinous envelope. Cells spherical, close
together. Individual cell sheaths confluent with colonial envelope. Cell
contents pale to bright blue-green. Generally containing numerous
pseudovacuolcs. (Facultative Planktont).
Diam. cells 2^ /x.
Catfish (rr), Clear (rr), Kawaguesaga (ss), Minocqua (r).
WISCONSIN PHYTOPLANKTON
39
Microcystis FLOS-AQUAE (Wittrock) Kirckner. PL 5, Fig. 1.
in Engler & Prantl, D. nat. Pflanzenfam. 1 (Abt. 1&) : 56, fig. 49j^. 1900.
Colonies spherical to ovoid, rarely elongate ; frequently reaching a
macroscopic size. Cells compactly and evenly distributed within a very
delicate, hyaline, homogeneous, gelatinous envelope. Margins of colony
not sharply defined. Cell contents rarely homogeneous and grey to
pale blue-green; usually with pseudovacuoles and reddish in color.
Plant mass yellowish to verdigris-green. (Euplanktont).
Diam. cells 3. 5-6.5 ju,.
Bear (2) (rr), Big St. Germain (rr), Birch (1) (c), Birch Island (sss),
Browns (cc), Catfish (ss), Center (ss), Cochrane (sss), Duck (ss), Dunham
(rr), Pishtrap (rr). Found (sss), Fowler (rr), High (rr). Horseshoe (1) (rr),
Kegonsa (cc). Loveless (r). Lower Nashotah (rr). Lower Nemahbin (r),
Mendota (aa), Mercer (rrr), Monona (aa). Mud (3) (cc), Nagawicka (rr).
No Mans (r). North Turtle (ss), Oconomowoc (ss). Paddock (ss). Palmer (ss),
Pardee (ss). Plum (ss), Pokegama (1) (ss), Rainbow (r). Rock (s). Rose
(ss). Sand (3) (r). Shell (rr), Sishebogema (ss). South Turtle (ss). Squirrel
(rr), Star (ss). Tamarack (ss). Tenderfoot (rr). Upper Nashotah (rrr), Wapa-
gossett (ss), Waubesa (ss), Whitefish (ss), Winnebago (cc).
Microcystis aeruginosa Kiitzing. PI. 5, Figs. 2-3.
Tabulae Phycol. 1: 6, pi. 8. 1845.
Clathrocystis aeruginosa (Kiitzing) Henfrey, Trans. Micr. Soc. London N. S.
4: 53, pi, 4, figs. 28-36. 1856 (in Quart. Jour. Micr. Sci. 4: 1856): Bachmann,
Arch. f. Hydrobiol. u. Planktonkde. 3: 61, figs. IW-IV®. 1908.
Colonies spherical to subspherical when young, later becoming saccate
and ultimately reticulate and clathrate. Gelatinous envelope of colony
homogeneous, hyaline, and indistinct. Colonies frequently occurring
in sufficient quantity to color water a bright green. Cells spherical to
subspherical, evenly distributed throughout the colony and close to-
gether. Cell contents rarely homogeneous and grey to pale or bright
blue-green; usually with numerous pseudovacuoles and reddish. (Eu-
planktont).
Diam. cells 3-4 p.
Balsam (ss). Bear (3) (rr). Big Butternut (ss). Bloom (ccc). Bone (ss).
Browns (cc). Center (rr). Clam (r). Crooked (rrr), Delavan (sss), Desmoines
(ss). Devils (2) (rr). Duck (rr), Dutchmans (rrr). Eagle (ccc), Elizabeth
(cc). Pish (ss), Fowler (rr). Grassy (ss). Grindstone (rr). Half Moon (ss).
Hooker (ss). Horseshoe (1) (rr), Kawaguesaga (rr), Kegonsa (a), Kimball
(ss). Lac du Flambeau (rr), Lac la Belle (rr). Lake of the Woods (r). Little
Bass (2) (sss). Little Butternut (cc), Little Crooked (ss). Little Wood (ss),
Loveless (ss), Mendota (a), Meronk (ss). Mill (sss), Monona (cc). Mud (2)
(r), Mudhen (ss), Nancy (ss), Nicaboyne (ss). North Turtle (ss), North
Twin (cc), Oconomowoc (rrr). Old Taylors (r), Otter (rr), Owen (rrr), Par-
dee (ss), Pewaukee (ss), Pokegama (2) (rr), Pokegama (3) (ss), Prairie
40
WISCONSIN PHYTOPLANKTON
(S8S), Rice (1) (rr), Rooney (r). Sand (1) (ss), Sand (4) (rr), Shell (rr),
Silver (2) (ss), Travis (rr), Upper Turtle (ss), Waubesa (cc). White Ash
(sf). Wildcat (ss). Wolf (rr).
var. MAJOR (Wittrock) G. M. Smith. PL 4 , Fig. 6 .
Trans. Wis. Acad. Sci., Arts, & Lett. 18 *: 535. 1916.
Mature colonies elongate; irregular, saccate, or clathrate. Colonial
envelope much firmer than in typical form and with larger cells. (Eu-
planktont) .
Diam. cells 5.5-G.5 fi.
Center (rr), Mendota (ss), Nancy (sss), St. Croix (rr). Vermilion (cc).
Microcystis incerta Lemmermann. PI. 5, Fig. 4 .
Abh. Naturw. Ver. Bremen 17: 342. 1903; Kryptogamenfl. d. Mark Branden-
burg 3; Algen 1 : 76, 44, fig. 12. 1907.
Colonies spherical or somewhat elongate, enclosed by a hyaline, homo-
geneous, and very delicate gelatinous envelope. Cells small, very close
together but equidistant from one another. Cell contents homogeneous,
without pseudovacuoles; grey to pale blue-green in color. (Faculta-
tive Planktont) .
Diam. cells 1-2 fi.
Camp (rr), Chetek (r). Hooker (s). Prairie (r), Whitefish (rr), Winne-
bago (c).
The cells of this species are very similar in appearance to those found
in Aphanocapsa elachista and A. delicatissima but their compact ar-
rangement shows that the alga is a 3Iicrocystis and not an Aphanocapsa.
Microcystis pulvera (Wood) Migula.
in Thomd, Flora v. Deutschl., Deutsch.-Osterr. u. d. Schw. 6, Kryptogamen 2,
Algen 1:36. 1907.
Anacystis pulverus Wood. Wolle, Preshw. Algae of U. S. 329, pi. 210, fig. 25.
1887.
Colonies spherical or elongate, with a very delicate, hyaline, gela-
tinous envelope. Cells spherical, very closely crowded together and
forming a solid mass. Cell contents homogeneous, without pseudovacu-
oles ; grey, pale olive-green, or blue-green in color. (Facultative Plank-
tont) .
Diam. cells 2-3 p.
Browns (rr), Mill (rrr), Pardee (ss), Sunday (r), Winnebago (sss).
Since the specific difference between this and the foregoing species
is mainly one of cell size it might be better to consider M. incerta a
variety of M. pvlvera.
WISCONSIN PHYTOPLANKTON
41
APHANOCAPSA Nageli 1849.
Cells united to form spherical, ovoid, or amorphous colonies of micro-
scopic or macroscopic size. Colonies, hyaline, yellow, brown, or blue-
green in color. Cells spherical, equally distributed throughout the
colony but always some distance from one another; generally solitary,
rarely in clusters. Individual sheaths of cells confluent with the homo-
geneous, hyaline or colored, colonial envelope. Cell contents homogene-
ous ; usually pale to bright blue-green or grey in color.
Reproduction by vegetative division of cells in three directions.
KEY TO THE SPECIES.
Cells growing within gelatinous envelope of other algae A. Endophytica
Cells forming free-floating or sessile colonies.
Cell contents grey to pale blue-green.
Diameter of cells 3. 5-4. 5 fi A. Pulchra
Diameter of cells less than 3 At.
Cell diameter not exceeding 1 fx A. Delicatissima
Cell diameter 1.5-2.5 fx A. Elachista
Cell contents brightly colored, generally blue-green.
Diameter of cells 3.5-5 fx A. Grevillei
Diameter of cells 5-6 a* A. Rivularis
Aphanocapsa delicatissima W. & Gr. S. West. PI. 2, Fig. 7.
Jour. Linn. Soc. Bot. 40 : 431, yl. 19, -figs. 2-3. 1912.
Colonies small, spherical, ovoid or irregular, free-floating. Colonial
envelope gelatinous, homogeneous, hyaline or ochraceous. Cells spheri-
cal, very small, more or less remote from one another. Cell contents
homogeneous, grey to pale blue-green. (Euplanktont).
Cells .5-.75 fx in diam. ; colonies 15-30 fx broad, 15-50 lonar.
Big Butternut (r). Chain (r), Little Butternut (ss). Loveless (ss), Mendota
(s), Poor Farm (r).
The cells of this species are smaller than many bacteria and during
the first two year ^s study of the plankton flora these small colonies were
considered bacteria and not recorded so that the record for distribution
is far from complete. When the colonies are of any considerable size
the mass of cells has a decided blue-green color so that the organism
must be called a blue-green bacterium or a blue-green alga of bacterial
size. The latter view seems to be the more logical. It is very probable
that the bacteria have been derived from the blue-green algae and the
Wests’ discovery of blue-green algae of bacterial size is very suggestive.
42
WISCONSIN PHYTOPLANKTON
Aphanocapsa elachista var. conferta W. & G. S. West. PL 2, Fig. 8.
Jour. Linn. Soc. Bot. 40: 432, pi. 19, fig. 1. 1912,
Colonies small, spherical, ovoid, or irregular ; with the cells enclosed
by a gelatinous, homogeneous, hyaline or ochraceous envelope. Indi-
vidual sheaths of cells confluent with colonial envelope. Cells spheri-
cal, fairly close together. Cell contents homogeneous, grey to pale
blue-green. (Euplanktont) .
Diam. cells 1. 6-2.0 [x. Colonies up to 75 /a broad and 100 fi long.
Birch Island (rr), Crawling Stone (rrr), Deer (ss), Lindy (r), Nancy (r),
Pine Tree (ss), Silver (2) (rr).
var. planctonica var. nov. PI. 3, Pig. 3.
Cells spherical, some distance from one another. Sheath enclosing
colony always hyaline. Contents of cells pale grey. (Euplanktont).
Diam. cells 2-3 fx.
Bear (1) (s). Bear Trap (rr), Poplar (ss). Round (3) (rr). Sand (1) (r).
Differing from the typical form in the larger cell size and grey color
of the cell contents.
Aphanocapsa endophytica sp. nov. PI. 2, Pig. 10.
Colonies endophytic within the gelatinous sheath of Microcystis col-
onies and with their envelopes confluent with the envelope of the host
colony. Cells spherical, equidistant from one another or in small
clumps. Cell contents homogeneous, grey to bright blue-green. (Eu-
planktont).
Diam. cells 2 jx.
Poor Farm (ss).
The occurrence of bacteria in the gelatinous envelope of colonial
Myxophyceae is a familiar phenomenon to the limnologist. The blue-
green color of the cells endophytic within the envelopes of Microcystis
colonies in Poor Farm Lake precludes their recognition as bacteria.
(See G. S. West’s remarks concerning a similar endophytic Aphano-
thece in Jour. Linn. Soc. Bot. 40: 432. 1912).
Aphanocapsa pulchra (Kiitzing) Rabenhorst. PI. 2, Pig. 9.
Flora Eur. Algarum 2: 49. 1865.
Colonics macroscopic or microscopic, free-floating or sessile, generally
spherical to ovoid when found in the plankton. Sheath of colony gela-
tinous, firm, hyaline, homogeneous; with the cells some distance from
WISCONSIN PHYTOPLANKTON
43
one another. Individual cell sheaths confluent with the colonial en-
velope. Cell contents homogeneous, grey to pale blue-green. (Tycho-
planktont) .
Diam. cells 3. 5-4.5 jx.
Beaver (r), Beaverdam (sss), Harris (rrr), Lac Court Oreilles (ss), Win-
nebago (rr).
Aphanocapsa grevillei (Hassall) Kabenhorst. PI. 3, Fig. 1.
Flora Eur. Algarum 2: 50. 1865; G. S. West, Brit. Freshw. Algae, 351, -fig-
165^. 1904.
Colonies free-floating or sessile ; spherical to ellipsoid when free-float-
ing, dirty green in color. Cells spherical, solitary or in pairs and some-
what crowded. Cell contents homogeneous or finely granulose, bright
blue-green in color. (Facultative Planktont).
Diam. cells 3.5-5 ix,
Beaverdam (rr), Birch (ss), Camp (ss), Chetac (sss), Muskallonge (rr).
Rice (1) (rr). Silver (1) (rrr), Whitefish (ss).
Aphanocapsa rivularis ( Carm. ) Rabenhorst. PI. 3, Fig. 2.
Flora Eur. Algarum 2: 49. 1865; Cooke, Brit. Freshw. Algae 210, pi. 86, fig. 2.
1884.
Colonies free-floating or sessile; spherical, tubular, or irregular in
shape. Cells spherical, solitary or in pairs and some distance from one
another within the colony. Individual sheaths of cells confluent with
the hyaline, homogeneous, colonial envelope. Cell contents homogene-
ous or finely granulose; bright blue-green in color. (Tychoplanktont).
Diam. cells 5-6 ju.
star (rrr).
APHANOTHECE Nageli 1849.
Colonies free-floating, sessile, or endophytic; spherical or expanded
into amorphous masses and enclosed by a firm, copious, homogeneous,
hyaline or colored envelope. Cells oblong to cylindrical, with rounded
ends. Cells forming a solid mass distributed throughout the colonial
envelope but lying some distance from one another. Individual cell
sheaths indistinct, confluent with the colonial envelope. Cell contents
homogeneous or finely granulose, never with pseudovacuoles ; grey, light
to bright blue-green, or olive-green in color.
Reproduction by vegetative division of cells in three planes, but with
cell divisions always taking place at right angles to the long axes of
cells.
44
WISCONSIN PHYTOPLANKTON
KEY TO THE SPECIES.
Colonies endophytic in gelatinous envelope of other algae. .
A. Nidulans V. Endophytica
Colonies not endophytic.
Cell contents grey to pale blue-green, never bright blue-green.
Colonies ovoid to spherical, never perforate A. Nidulans
Colonies reticulate to clathrate A. Clathrata
Cell contents bright blue-green.
Cells less than 5 fx broad A. Staqnina
Cells more than 5 /u broad A. Pbasina
Aphanothece clathrata W. & G. S. West. PI. 6, Fig. 3.
Trans. Roy. Irish Acad. 32, Sec. B: 111, pi. 10, /iffs. 9-11. 1906.
Colonies microscopic; free-floating; elongate and irregular in shape,
usually perforate and reticulate. Gelatinous colonial envelope hyaline
and homogeneous. Cells very small, bacilliform, straight or curved,
embedded in a solid mass in the colonial envelope. Cell contents homo-
geneous, grey to light blue-green. (Euplanktont).
Cells 0.6-1.0 fx broad, S.5-4.5 fx long.
Lindy (r). Little Crooked (sss), Nancy (ss), Pokegama (1) (r), Poor
Farm (rr). Sand (1) (ss), Wolf (ss).
Aphanothece nidulans P. Richter. PI. 6, Fig. 1.
Bot. Not. 1884: 128. 1884.
Colonies spherical, ovoid, or ‘‘nest-shaped^^; enclosed by a homogene-
ous, hyaline, gelatinous envelope. Cells broadly cylindrical, straight
or curved, of small size and fairly close together. Individual sheaths
of cells confluent with the colonial envelope. Cell contents homogene-
ous, grey to light blue-green. (Facultative Planktont).
Cells 1. 0-1.5 fx broad, up to 3.5 [x long.
Beaver (2) (ss). Deer (ss). Lower McKenzie (sss), Pokegama (sss). Ten-
derfoot (r).
Certain species of this genus resemble bacterial colonies in much the
same manner as the minute-celled species of Aphanooapsa. Here again
the color of the cell contents is good evidence of the algal nature of the
organism.
var. endophytica W. & G. S. West. PI. 5, Fig. 6.
Jour. Linn. Soc. Bot. 40: 432, pi. 19, fig. 14. 1912.
Cells embedded in gelatinous envelope of other colonial Myxophy-
ceae. Gelatinous envelope of colony confluent with envelope of host
WISCONSIN PHYTOPLANKTON
45
colony. Cells narrow, at least twice as long as they are broad. Cell
contents homogeneous; generally light blue-green, rarely grey. (Eu-
planktont).
Cells 0.8-1.5 fi broad, 2.5-4.5 fi long.
Endophytic in sheaths of Coelosphaerium Kuetzingianum and Micro-
Cystis aeruginosa,
Birch Island (r), Chetac (ss), Hound (3) (rr).
Aphanothece prasina a. Braun. PI. 5, Fig. 5.
In Rabenhorst, Flora Eur. Algarum 2: 65. 1865; Cooke, Brit. Fresh w. Algae,
218, vl. 88, Ms. 3a-3b. 1884.
Colonies spherical to cylindrical, reaching a diameter of 3-4 cm. un-
der favorable conditions; bright green in color. Cells evenly dis-
tributed throughout the colony, broadly cylindrical and with rounded
ends. Individual cell sheaths confluent with the colonial envelope.
Cell contents homogeneous, bright blue-green. (Tychoplanktont).
Cells 5-6.5 broad, 7.7-11 /a long.
Beaverdam (r), Nancy (rr), Pokegama (1) (rrr).
The determination of this and the following species is open to ques-
tion since specific differences in these species are based in part upon
the macroscopic appearance of the colony when growing attached to
the substratum. The determination of plankton species is from imma-
ture colonies and must rest upon cell shape, size, and color.
Aphanothece stagnina (Sprengel) A. Braun. PI. 6, Fig. 2.
in Rabenhorst, Algen No. 1572; Cooke, Brit. Fresh w. Algae 219, pZ. 88,
fig. 4. 1884.
Colony spherical, ellipsoidal, or cylindrical; generally macroscopic,
0.5-20 mm in diameter, pale verdigris-green. Cells broadly cylindrical,
their length never more than II /2 times their breadth. Individual
sheaths of cells confluent with the hyaline, homogeneous, gelatinous,
colonial envelope. Cell contents homogeneous; pale to bright blue-
green. ( Tychoplanktont) .
Cells 3-5 p, broad ; 5-8 fx long.
Lake of the Woods (rr), Whitefish (rr).
GLOEOTHECE Nageli 1849.
Colonies free-floating or sessile, of comparatively few cells enclosed
by a hyaline or variously colored, homogeneous, gelatinous envelope.
Individual sheaths of cells prominent, homogeneous or slightly lamel-
46
WISCONSIN PHYTOPLANKTON
lated, sometimes 2-8 cells enclosed by a single sheath. Cells elongate
to broadly cylindrical, with rounded ends and irregularly distributed
throughout the colonial envelope or with their longer axes pointing in
the same general direction. Cell contents homogeneous or finely granu-
lose ; grey, pale to bright blue-green, or olive green in color.
Keproduction by vegetative division of cells at right angles to their
long axes.
Gloeothece linearis Nageli. PI. 6, Fig. 5.
Gatt. einz. Algen 58, pi. 1, fig. G*. 1849.
Colonies small; dull yellow to flesh color or dirty olive-green; en-
closed by a broad, hyaline, homogeneous, gelatinous envelope. Cells
elongate-cylindrical, straight or arcuate, with rounded ends. Sheaths
containing one cell only, broad, hyaline, having the same general out-
line as the cell. Cell contents homogeneous ; pale to bright blue-green.
(Tychoplanktont) .
Cells (without sheath) 1.3-2. 5 /a broad, 10.5-18 (x long; (with sheath)
4r-6 fi broad, 13-22 jx long.
Harris (r), Muskallonge (rr).
var. composita var. nov. PI. 6, Fig. 6.
Cells shorter and 2-8 enclosed by a single, broad, firm, homogeneous
sheath. Individual sheaths of single cells or groups of cells not con-
fluent with the colonial envelope. (Tychoplanktont).
Cells (without sheath) 3.0-3.5 fx broad, 4-8 fx long; sheaths 10-12
fx broad, 20-35 fx long.
Deer (rrr).
RHABDODERMA Schmidle and Lauterborn. 1900.
Colonies free-floating, small, of comparatively few cells enclosed by a
hyaline, homogeneous, gelatinous envelope. Cells cylindrical, with
rounded apices, straight or arcuate; with their long axes pointing in
the same general direction. Individual sheaths of cells confluent with
colonial envelope. Cell contents homogeneous; grey to bright blue-
green in color.
Reproduction by vegetative division of cells, the divisions taking
place at right angles to the long axes of the cells.
WISCONSIN PHYTOPLANKTON
47
Ehabdoderma lineare Schmidle and Lauterborn. PI. 6, Fig. 4.
Ber. d. D. Bot. Ges. 18: 148, pi. 6, figs. 8-11. 1900.
Specific characters as those of the genns. (Euplanktont).
Cells 2-3 IX broad, 6-12 [x long.
Sand (2) (rrr), Whitefish (rr).
This genus is closely related to Gloeothece, the chief difference being
a lack of individual sheaths around the cells.
DACTYLOCOCCOPSIS Hansgirg 1888.
Colonies microscopic, free-floating or lying among other algae; em-
bedded in a copious, hyaline, homogeneous, acicular to fusiform, gela-
tinous envelope. Cells elongate, acicular and with pointed ends;
straight arcuate, sigmoid, or spirally twisted around one another. In-
dividual cell sheaths confluent with colonial envelope. Cell contents
homogeneous or with the color bearing area localized in a definite part
of the cell ; grey to bright blue-green in color.
Reproduction by vegetative division of cells at right angles to their
long axes.
KEY TO THE SPECIES.
Length of cells never more than sixteen times the breadth,
cells frequently bent D. Raphidioides
Length of cells at least twenty times the breadth, cells al-
ways straight D. Acicularis
Dactylococcopsis rhaphidioides Hansgirg. PI. 6, Pig. 7.
Prodr. d. Algenfl. v. Bohmen 139, fig. 49a. 1892; Lemmermann, Kryptogamenfl.
d. Mark Brandenburg 3, Algen 1: 50. 1907.
Colonies containing 2-8 or more cells. Cells fusiform ; straight, arcu-
ate or sigmoid ; frequently in pairs with one end rounded and the other
pointed. Colonies enclosed by a copious, hyaline, homogeneous en-
velope. Cell contents homogeneous, pale blue-green. (Facultative
Planktont) .
Cells 1-3 IX broad, 5-25 ix long.
Deer (sss). Long (2) (rrr), Mercer (rr), Reserve (rr). Rice (1) (rr).
Hansgirg gives eight as the maximal number of cells found in the
colony but I have observed colonies in which there are as many as a
48
WISCONSIN PHYTOPLANKTON
hundred cells. These cells are also proportionally longer than he statei
and may be, in extreme cases, sixteen times as long as they are broad.
In this respect they follow the cell dimensions delimited ,by Lemmer-
mann.
Dactylococcopsis acicularis Lemmermann. PI. 6 , Figs. 8 - 10 .
Ber. d. D. Bot. Ges. 18: 309. 1900; Kryptogamenfl. d. Mark Brandenburg 3,
Algen 1: 51, 44, iig. 5. 1907.
Cells solitary or in colonies enclosed by a wide, hyaline, homogeneous,
gelatinous sheath. Cells elongate, acicular, with poles attenuated to
fine points; straight or slightly arcuate. Cell contents homogeneous
and pale blue-green ; or with color bearing region restricted to one side
of cell. (Euplanktont).
Cells 2-2.5 fi broad, 55-80 /x long.
Browns (cc).
The localization of the color bearing portion at one side of the cell is
quite abnormal for a member of the Myxophyceae, but, as I have stated
elsewhere (Trans. Wis. Acad. Sci., Arts, & Lett. 19^: 620. 1918) not-
withstanding this fact the alga belongs to the Myxophyceae.
Order HORMOGONEALES.
Cells always in filaments that generally contain a number of cells.
Filaments simple or branched ; solitary or united to form definitely or
indefinitely shaped aggregates. Free-floating, sessile, epiphytic, or en-
dophytic. Cells serially arranged to form trichomes, which when en-
closed by a sheath are known as filaments. Trichomes either the same
thickness throughout, attenuated towards both extremities, or attenu-
ated from base to apex ; straight, arcuate, spirally or irregularly twisted.
Sheaths of filaments tough and leathery; or gelatinous, homogeneous
to lamellated, hyaline to variously colored, and distinct or confluent
with the colonial envelope. Cell shape various. Cell contents homo-
geneous, or with numerous pseudovacuoles; grey, light to dark blue-
green, olive-green, reddish-green, ochraceo.us, orange, violet, or black
in color.
Reproduction, aside from vegetative cell division, by hormogones and
resting spores.
WISCONSIN PHYTOPLANKTON
49
KEY TO THE FAMILIES.
Trichomes without heterocysts* Osciuatobiaceae
Trichomes with heterocysts.
Trichomes not attenuated Nostocaceae
Trichomes attenuated to a hair-like point Kivulariaceae
Family OSCILLATORIACEAE.
Trichomes free-floating, sessile, epiphytic, or endophytic; of one or
mere cells forming simple or branched filaments with one or more tri-
chomes within a single sheath. Sheaths of various forms; copious,
gelatinous, hyaline or colored, homogeneous to lamellated; firm, nar-
row and homogeneous or lamellated; or entirely lacking. Filaments
straight or spirally twisted. Cells disciform, cylindrical, or barrel-
shaped. Apical cell of trichomes frequently conical and capitate.
Heterocysts never present in the trichomes. Cell contents homogene-
ous, granulose, or with pseudovacuoles ; variously colored.
Reproduction by vegetative division of cells and the formation of
liormogones.
KEY TO THE GENERA.
Trichomes solitary or in flocculent, readily dissociating masses.
Trichomes containing but one cell Spiruuna
Trichomes containing more than one cell.
Sheaths of filaments firm, generally projecting beyond
the trichome Lyngbya
Sheaths delicate or lacking, not projecting beyond
trichome Oscillatoria
Trichomes laterally united to form free-floating bundles which
do not dissociate readily Trichodesmiiim
SPIRULINA Turpin 1827.
Trichome consisting of a single, elongate, cylindrical cell that is not
attenuated but with rounded ends. Filaments without sheaths and
twisted to form loose or compact regular spirals. Cell contents homo-
geneous or granulose ; light to dark blue-green in color.
Reproduction by vegetative division of cells at right angles to the
long axis. No hormogone formation possible.
*Cells commonly larger than the vegetative cells and with heavy walls that
have a conspicuous nodule at each pole. Cell contents a homogeneous, pellucid,
non-cytoplasmic substance.
4
50
WI8C02^SIN PHYTOPLANKTON
KEY TO THE SPECIES.
Turns of spirals not over 5 fji in diameter S. Majob
Turns of spirals over 10 fx in diameter S. Pbinceps
Spirulina major Kiitzing. PI. 7, Fig. 1.
Phycol. generalis 183. 1843; Gomont, Ann. Sci. Nat. 7 Ser., Bot. 16: 251, pi. 7,
fig. 29. 1892.
Filaments free-floating and solitary, or forming a greenish scum.
Trichomes in a more or less loose spiral that is straight or bent. Cell
contents homogeneous ; bright blue-green. Sheath of filament lacking.
( Tychoplanktont) .
Trichomes 1.2-1. 7 fx in diameter. Spirals 2.5-4 p. broad, 2.7-5
fx betv/een turns.
White Ash (rrr).
Spirulina princeps (W. & G. S. West) G. S. West emend. PI. 7, Pig. 2.
Jour. Linn. Soc. Bot. 38: 179, pi. 9, fig. 5. 1907; W. & G. S. West, Trans. Linn.
Soc. Bot. 2 iSer., Bot. 6: 205. 1902.
Trichomes solitary, in loose spirals that may be straight or curved.
Ends of trichomes blunt or rounded. Cell contents homogeneous or
with a few scattered granules; bright blue-green. (Tychoplanktont).
Trichomes 3-5 fx broad. Spirals 8.8-16 [x broad, 9.5-12 fx between
turns.
Poor Farm (rrr).
OSCILLATORIA Vaucher 1803.
Trichomes possessing a peculiar power of spontaneous movement of
an oscillating, rolling, or gliding type; free-floating; solitary or in
flocculcnt masses ; sometimes forming strata in moist places. Trichomes
unbranched, cylindrical, entirely without or Avith barely perceptible
sheaths. Ends of trichomes straight, slightly attenuated, but never at-
tenuated to a point. Terminal cells rounded or ealyptrate. Cell shape
cylindrical to disciform. Cell contents usually homogeneous or granu-
lose, rarely with pseudovacuoles. Color of cells variable.
Reproduction by hormogones.
WISCONSIN PHYTOPLANKTON
51
KEY TO THE SPECIES.
Apex of trichome gradually tapering
Apex of trichome not tapering
OsciLLATORiA PROLiFiCA (Greviile) Gomont. PI. 7, Figs. 3-5.
Ann. Sci. Nat. 7 Ser. Bot. 16: 205, pi. 6, fig. 8. 1892; Olive, Trans. Wis. Acad.
Sei., Arts, & Lett. 15": 124-134. 1905; Hyams and Richards, Technology Quart.
14: 302-310, figs. 1-8. 1901.
Filaments rarely solitary, generally irregularly matted to form free-
tioating flocculent masses. Plant masses blood-red to dirty purple, be-
coming lilac when dried. Trichomes straight, elongate, not constricted
at cross walls of cells, and slightly tapered at apex with the terminal
cell of mature trichomes obtuse-capitate. Cells cylindrical, slightly
longer than they are broad. Cell contents with numerous reddish
pseudovacuoles, sometimes with rows of granules at the cross walls.
(Euplanktont).
Cells 2.2-5 fx broad, 4-6 [x long.
Geneva (aa). Pine (1) (aa).
This species is closely related to 0. ruhescens D. C., but if GomonCs
monograph of the Oscillatoriaceae must be taken as the starting point
for nomenclature of the group the two are distinct. Both species are
peculiar in that they produce blooms in lakes at a time when the water
is very cold or covered with ice. The masses of filaments do not have
the usual yellowish-green color but are blood red to dirty purple and
the phenomenon is spoken of in Europe as ‘‘bloody’^ or ‘‘Burgundy”
bloom.
Olive has described the occurrence of such a bloom in Pine lake of
this state and discussed the literature of the subject. The alga also
appeared in profusion in Lake Geneva this (1918) spring at the time
w'hen the ice was beginning to disappear. It was not frozen in the ice
but grew luxuriantly in the water below the ice and gave a deep red-
dish color that was especially noticeable in the cracks between the ice.
The alga had not been noted in the lake before this time and its sporadic
appearance is quite like the sporadic appearance of 0. ruhescens in the
Swiss lakes. The excessive growth of 0. prolifica is not wholly corre-
lated with cold water since it has remained present throughout the
summer, but not in such quantities as early in the spring. This abund-
ant growth of the alga in the summer has also been noted in a Massa-
chusetts lake by Hyams and Richards and furnishes a physiological as
well as a morphological distinction between 0. prolifica and 0. ruhes-
cens.
O. Prolifica
. . .0. Tenuis
52
WISCONSIN PHYTOPLANKTON
OsciLLATORiA TENUIS C. A. Agardh. PI. 7, Fig. 6.
Algarum decades 2: 25. 1813; Gomont, Ann. Sci. Nat. 7 S§r. Bot. 16: 220,
j)J. 7, iigs. 2-3. 1832.
Filaments solitary or in floceose masses that are pale blue-green in
color. Trichomes straight, slightly constricted at the cross walls. Termi-
nal cells the same diameter as those in the median portion of the trich-
ome, straight or curved; apical cells rounded but not capitate. Cell
shape disciform. Cell contents homogeneous except for a row of gran-
ules along the cross walls. (Tychoplanktont) .
Cells 4—10 broad, 2.6-5 long.
Monona (rr).
var. TERGESTiNA (Kutzing) Rabenhorst. PI. 7, Figs. 7-8.
Flora Eur. Algarum 2: 102. 1865.
Trichomes narrower than the foregoing. (Tychoplanktont).
Cells 4-6 fx broad.
Geneva (ss).
LYNGBYA C. A. Agardh. 1824.
Filaments solitary or interwoven to form floceose masses; free-float-
ing or in an expanded stratum. Sheaths of filaments narrow, firm,
hyaline or colored, homogeneous or lamellated, generally projecting
for some distance beyond the trichome. Filaments unbranched, cylin-
drical ; straight, flexed, or twisted into regular spirals. Triciiomes gen-
erally the same thickness throughout, rarely slightly attenuated at the
apices ; sometimes constricted at the cross walls. Apical cell with distal
end rounded or slightly capitate. Cell contents homogeneous, granu-
lose, or with numerous pseudovacuoles ; grey, pale to bright blue-green
or variously colored.
Reproduction by the formation of hormogones.
KEY TO THE SPECIES.
Filaments not over 4 /a in thickness, with pale hlue-green to grey cell contents.
Filaments straight L. Limnetica
Filaments in regularly coiled spirals L. Contorta
Filaments over 10 ti in diameter, contents deeply colored L. Bibgei
Lyngbya limnetica Lemmermann. PI. 7, Figs. 9-11.
Bot. Cent. 76: 154. 1898; Kryptogamenfl. d. Mark Brandenburg 3, Algen 1 :
135, 102, fig. 8. 1907.
Filaments free-floating, generally solitary ; straight or slightly flexed.
Trichomes not constricted at the cross walls. Apical cells the same
WISCONSIN PHYTOPLANKTON
53
thickness as the other cells, with distal end rounded but not capitate.
Sheaths firm, hyaline, very narrow, extending for some distance beyond
the end of the trichome. Cells cylindrical, at least twice as long as
broad. Cell contents homogeneous; generally grey, rarely blue-green
in color. (Euplanktont).
Cells 1-1.5 fi broad, 3-8 /a long.
Bear (1) (c), Geneva (ss), Soft (rr), Upper Nashotah (rrr).
The length of the individual cells of Wisconsin specimens exceeds
that given by Lemmermann but it is very probable that I am dealing
with the same species that he names L. limnetica. Several plankton
“species’^ have been described which are closely related and it is very
probable that future investigations will show that all of these straight,
very narrow, colorless ‘‘species” should be included under one collect-
ive specific name.
Lyngbya contorta Lemmermann. PI. 7, Figs. 12-13.
Forschungsbr. a. d. Biol. Stat. zu Plon 6: 202, pi. 5, -figs. 10-13. 1898; G. S.
West Jour, of Bot. 47: 246, pi. 498, iigs. 5^-5g. 1909.
Filaments free-floating, solitary ; occasionally straight, generally
twisted to form regular, loose or compact spirals or helices. Sheaths
firm, very thin, extending for some distance beyond the trichomes. Trich-
omes the same thickness throughout, not constricted at the cross walls,
apical cells rounded but not capitate at the distal ends. Cell contents
homogeneous, grey to pale blue-green. (Euplanktont).
Cells 1.5-2 fi broad, 3-6 /a long. Spirals 15-20 /a broad, 6-14 fi be-
tween the turns.
Mendota (rr). Pine Tree (ss). Poor Farm (s). White Ash (cc).
The specific distinction of this species is based in large part upon the
spiral twisting of the filament. Since certain normally straight fila-
ments of other algae become spirally twisted under limnetic conditions
(vide W. & G. S. West, Proc. Roy. Soc. London Ser. B, 81: 169, fig. 1.
1909) the validity of spiral twisting as a specific character arises.
L. contorta was found in considerable quantity at different stations and
the vast majority of filaments were spirally twisted. On the other
hand numerous filaments with cells of the same size that showed no
signs of twisting were collected from other stations. I think that Lem-
mermann is correct in considering these distinct species and that the
spiral twisting of filaments in plankton species of the Myxophyceae is
a sufficiently constant character to warrant the establishment of species
in both this genus and Anahaena.
54
WISCONSIN PHYTOPLANKTON
Lyngbya birgei G. M. Smith. PI. 7, Figs. 14-15.
Bull. Torr. Bot. Cl. 43: 482, pi. 26, -fig. 28. 1916.
Filaments free-floating, solitary, never forming floccose masses;
straight or slightly flexed. Sheaths firm, at times of considerable thick-
ness, hyaline, generally homogeneous, rarely lamellated, extending for
some distance beyond the trichome. Trichomes not attenuated at apices
and without constrictions at the cross walls. Terminal cells rounded
but not capitate at distal ends. Cell shape disciform. Cell contents
rarely homogeneous and with grey to olive green contents ; usually with
numerous pseudovacuoles. (Euplanktont).
Cells 18-23 fx. broad, 2-5.5 long. Sheaths .5-4 p. thick.
Balsam (rr). Bear Trap (cc). Big (cc). Deer (rrr), Elizabetti (ss), Fowler
(rrr). Half Moon (c), Kegonsa (aa). Lac la Belle (rr). Little Crooked (r),
Little Wood (rr), Loveless (rr). Lower Nashotah (rr), Mary (ss), Mendota
(cc), Mercer (rr), Monona (cc), Mudhen (rr), Nagawicka (rr), Oconomowoc
(rr). Pope (rrr). Round (3) (sss). Sand (1) (r). Spirit (sss), Squirrel (sss),
Upper Nashotah (cc). Upper Turtle (rr), V/apagossett (cc), Waubesa (cc),
Wolf (r).
This is undoubtedly the alga that Trelease (Trans. Wis. Acad. Sci.,
Arts, & Lett. 7: 124, pi. 10, fig. 6. 1888) reported from Lake Mendota
as Lyngbya Wollei Farlow. L. Viollei has been shown to be a Fleet o-
nema (P. Wollei Farlow) and Trelease ’s determination is undoubtedly
a mistake.
TRICHODESMIUM Ehrenberg 1830.
Trichomes laterally joined to form spindle- to scale-shaped, free-
floating colonies that are not enclosed by a gelatinous sheath. Trichomes
cylindrical, straight or spirally twisted, of the same thickness through-
out or with apices slightly attenuated. Apical cell undifferentiated,
or rounded and slightly capitate. Sheaths of trichomes very delicate.
Cells disciform to barrel-shaped. Cell contents homogeneous, granu-
lose, or with numerous pseudovacuoles. Heterocysts and resting spores
lacking.
Reproduction by the formation of hormogones.
i RicHODESMiUM LACUSTRE Klebahn. PI. 8, Pig. 1.
Forschungsbr. a. d. Biol. Stat. zu Plon 3: 13. 1895; Flora 80 : 271, pi. 4, iigs.
31-33. 1895.
Trichomes laterally joined to form plate-like, free-floating masses
that are not enclosed by a gelatinous envelope. Filaments with a very
delicate, homogeneous sheath. Trichomes straight, not attenuated at
the apices, and with terminal cells rounded but not capitate. Cells
WISCONSIN PHYTOPLANKTON
55
disciform, with straight or markedly convex sides. Cell contents occa-
sionally homogeneons and pale to bright bine-green in color ; generally
with numerous pseudovacuoles. Trichomes without heterocysts or
spores. (Euplanktont).
Cells 5-7 II broad, 5-7 ix. long. Colonies up to 1 mm. in length.
Amicoy (rrr), Beaverdam (r), Island (rr), Lake of the Woods (rrr), Little
Bass (1) (rr),Mud (1) (s), Nicaboyne (rr),Bice (1) (rr),Wild Goose (rrr).
The general appearance of the colony at once suggests an ApJianizo-
menon species with cells shorter and more rounded than the familiar
A. flos-aquae. I have examined a sufficient number of colonies to feel
confident in confirming Klebahn’s statement that there are no spores
or heterocysts in the alga under consideration. This being the case it
is impossible to refer the species to AphanizomenoUj but it should be
considered a freshwater species of the common Tricliodesmium of tropi-
cal seas.
Family NOSTOCACEAE.
Filaments free-floating, sessile, epiphytic, or endophytic; solitary or
in colonies of microscopic to macroscopic size that are definitely or in-
definitely shaped. Trichomes always unbranched ; straight, flexed, spi-
rally twisted, or irregularly interwoven. Sheath rarely firm and nar-
row; generally copious, gelatinous, hyaline or colored, and distinct or
confluent with the colonial envelope. Trichomes generally the same
thickness throughout and with spherical to cylindrical cells. Hetero-
cysts either terminal or intercalary, solitary or catenate. Resting
spores variously shaped, adjacent to or remote from the heterocysts;
formed in all genera. Cell contents homogeneous, granulose, or with
pseudovacuoles ; grey or variously colored.
Reproduction by fragmentation of colony, hormogones, and resting
spores.
KEY TO THE GENERA.
Trichomes solitary or interwoven to form flocculent masses of
small size Anabaena
Trichomes laterally joined to form small plate-like colonies Aphanizomenon
ANABAENA Bory 1822.
Filaments free-floating or forming a delicate mucous layer; solitary
or in floccose colonies. Trichomes the same thickness throughout or
slightly attenuated at the apices; straight, spiral, circinate, or aggre-
gated without deflnite order. Sheaths delicate or copious, gelatinous,
hyaline, homogeneous, rarely confluent with the colonial envelope ; some-
56
WISCONSIN PHYTOPLANKTON
times entirely lacking. Cells spherical to barrel-shaped, rarely cylindri-
cal, never disciform. Heterocysts approximately spherical, always in-
tercalary, generally solitary and with several in a filament. Spores
variously shaped, contiguous to or remote from heterocysts, solitary or
in short catenate series. Cell contents homogeneous, granulose, or with
numerous pseudovacuoles; grey, blue-green, or variously colored.
Reproduction by hormogones and spores.
KEY TO THE SPECIES.
Filaments straight or slightly curved.
Spores spherical A. Planctoxica
Spores longer than they are broad.
Length of spores not over twice their breadth.
Breadth of spores less than twice that of vegetative cells.
Spores oval to elliptic in optical cross section.
Vegetative cells less than 8 ^ broad A. Arrmis
Vegetative cells over 10 ii broad A. Limwetica
Spores hexagonal in optical cross section A. Macrospora
Breadth of spores more than twice the vegetative cells A. Levanderi
Length of spores at least three times their breadth A. Bori^etiana
Filaments spirally, circinately, or irregularly twisted.
Trichomes solitary, not forming floccose masses.
Curving of trichome a definite spiral A. Spiro ides
Curving of trichome not a definite spiral.
Length of spore at least four times breadth . . A. Augstumalis I. C. Marchia
Length of spore about twice the breadth A. Circinalis
Trichomes forming a fioccose mass.
Spores in a mass at center of colony A. Lemmermanni
Spores not in a mass at the center of the colony.
Trichomes loosely associated, individual filaments some-
times in spiral turns A. Circinalis
Trichomes greatly and irregularly twisted to form com-
pact masses A. Flos-Aquab
Anabaena planctonica Brunnthaler. PI. 8, Fig. 2.
Sitzenbr. d. kais. Ak. d. Wiss. Wien 112, Abt. 1; 292. 1903.
Filaments free-floating, solitary, straight, or slightly bent. Trichomes
enclosed by a copious, hyaline, very gelatinous sheath. Vegetative cells
spherical, hemispherical, or broadly elliptic. Heterocysts spherical.
Spores solitary, remote from or adjacent to heterocysts, spherical or
slightly elongate, somewhat broader than the vegetative cells. Cell con-
tents rarely homogeneous, usually with numerous pseudovacuoles. (Eu-
planktont).
Vegetative cells 9-15 fi broad; heterocysts 12-14 /a broad; spores
12.5-20 /X broad, 12.5-30 fx long.
Birch (1) (cc), Center (oc), Cranberry (cc). Devils (2) (ss), Rock (cc).
WISCONSIN PHYTOPLANKTON
57
Many juvenile spores of other species are spherical but the spores of
this species never become appreciably elongated.
Anabaena affinis Lemmermann. PL 8, Fig. 7.
Abh. Nat. Ver. Bremen 14: 261, pi. 1, figs. 12-13, 16-17. 1897.
Filaments solitary, free-floating, straight or slightly flexed; with a
wide, homogeneous, hyaline, faintly discernible gelatinous envelope.
Mature vegetative cells generally spherical; rarely with homogeneous
contents, usually with pseudovacuoles. Heterocysts spherical. Spores
generally remote from heterocysts, short or elongate cylindrical, with
rounded ends and covered with a thick, smooth wall. (Facultative
planktont) .
Cells 5-6 /t broad ; heterocysts 7.5-10 (x broad ; spores 9.5-12 ix broad,
17-26 fx long.
Llndy (rr). Lost (rr). North Turtle (c), Pardee (sss), Poplar (ss). Sand
(1) (s).
Anabaena limnetica G. M. Smith. PI. 8, Fig. 8.
Bull. Torr. Bot. Cl. 43: 481, pi. 26, fig. 27. 1916.
Filaments free-floating, solitary, straight or slightly flexed; with a
copious, homogeneous, hyaline sheath. Vegetative cells spherical or
with poles flattened. Hdterocysts spherical. Spores smooth-walled,
solitary, broadly ovoid, remote from or adjacent to the heterocysts. Cell
contents rarely homogeneous, generally with numerous pseudovacuoles.
(Euplanktont).
Cells 12-15 fx broad ; heterocysts 10-14 fx broad; spores 17-20 fx broad,
20-30 fx long.
Bear Trap (ss), Birch (1) (cc). Soft (ss). Tamarack (cc). White Ash (ss).
Anabaena macrospora var. robust'a Lemmermann. PI. 8, Fig. 6.
Bot. Cent. 76: 154. 1898.
Filaments solitary, free-floating, straight or slightly bent, frequently
attaining a considerable length; with a copious, hyaline, homogeneous,
gelatinous envelope. Mature vegetative cells spherical or subspherical
with flattened ends. Heterocysts spherical. Spores solitary or in pairs,
adjacent to or remote from heterocysts, cylindrical with conical ends
and hexagonal in optical cross section. Spore wall smooth and thick.
Cells containing numerous pseudovacuoles. (Euplanktont).
Cells 12-16 fx broad, 9-12 ix long; heterocysts 12-16 fx broad; spores
17-19 /A broad, 30-34 fx long.
Camp (cc). Squirrel (ss).
58
WISCONSIN PHYTOPLANKTON
Anabaena Levanderi Lenimermann. PI. 8, Figs. 4-5.
Ber. d. D. Bot. Ges. 24: 536. 1906.
Filaments solitary, free-floating, straight or slightly flexed, not en-
closed by a gelatinous sheath. Trichomes cylindrical, slightly con-
stricted at the cross walls of the cells. Vegetative cells twice as long as
they are broad, cylindrical, with rounded ends. Heterocysts hyaline,
spherical or ellipsoid. Spores solitary, adjacent to or remote from the
lieterocysts, twice as broad as the vegetative cells, ellipsoid in shape.
Cell contents rarely homogeneous and pale blue-green to grey ; usually
with numerous pseudovacuoles. (Euplanktont).
Cells 4-6 IX, broad, 11-33 [x, long ; heteroeysts 6.5-8 broad, 6. 5-9. 5 /a
long ; spores 8-15 /x broad, 19-45 fi long.
Chain (sss).
The dimensions of all specimens found in Chain lake have been near
the minimal limits set by Lemmermann.
Anabaena Bornetiana Collins. PI. 8, Fig, 3.
Erythrea4: 120. 1896.
Filaments free-floating, straight or slightly curved. Vegetative cells
spherical or slightly shorter than they are broad, with homogeneous
pale blue-green contents. Sheaths of trichomes very delicate. Hetero-
cysts spherical to elongate. Spores elongate cylindrical, with rounded
ends, adjacent to and on both sides of, or remote from the heterocysts.
( Tychoplanktont) .
Vegetative cells 12 /x broad; heterocysts 13-14 /x broad, 13-20 (x. long;
spores 15-20 /x broad, 50-90 fx, long.
George (rr).
Only a few filaments of this species were found in George lake and
these contained but few spores which were not always adjacent to the
heterocysts. The species may, therefore, not be A. Bornetiana for Col-
lins states that the spores are always adjacent to the heterocysts.
Anabaena augstumalis var. marchica Lemmermann. PI. 8, Figs. 9-10.
Forschungsbr. a. d. Biol. Stat zu Plon 12: 147. 1905.
Filaments solitary, free-floating, more or less bent but not circinate,
without a gelatinous envelope. Vegetative cells spherical, broadly ellip-
soid or cylindrical ; with numerous pseudovacuoles. Heterocysts spheri-
cal or slightly elongate. Spores remote from heteroeysts, elongate cylin-
WISCONSIN PHYTOPLANKTON
59
drical, with, rounded ends. Spore wail delicate, smooth, and hyaline.
(Facultative planktont).
Cells 5-7 fx broad, 5-9.5 fx long; heterocysts 8-9.5 /x broad, 8-14 tx
long; spores 9.5-12 jx broad, 40-70 /x long.
Bone (ss). Center (cc).
Anabaena spiroides var. crassa Lemmermann. PL 9, Figs. 1-3.
Bot. Cent. 76: 155. 1898; Kryptogamenfl. d. Mark. Brandenburg 3, Algen 1 :
]88, 159, figs. 15-16. 1907.
Filaments solitary, free-floating; forming a regular, evenly spaced
spiral enclosed by a very transparent, homogeneous, gelatinous envelope.
Cells spherical or with flattened ends. Heterocysts spherical, hyaline
or pale yellow. Spores solitary, remote from the heterocysts, generally
broadly ovoid. Cell contents rarely homogeneous, usually with numer-
ous pseudovacuoles. (Euplanktont).
Cells 11-15 [X broad ; heterocysts 10-17 fx broad ; spores 20-25 [x broad,
27-42 (generally 27-31) /x long. Spirals 50-60 /x broad and 45-55 /x
between turns.
Big Butternut (cc), Big St. Germain (cc), Granite (cc). Hooker (c), Ke-
gonsa (a). Long (2) (sss), Little Butternut (cc), Mendota (cc), Monona (aa).
North Twin (sss). Round (3) (ss), South Turtle (c). Vermilion (ccc).
Anabaena circinalis (Kutzing)Eabenhorst. PI. 9, Figs. 4-5.
Algen No. 209. 1852; Phillips, Grevillea 9: 5, pi. 134, figs. e-g. 1880; Bornet
et Flahault, Ann. Sci. Nat. 7 Ser. Bot. 7: 230. 1888.
Anahaena Hassallii (Kiitzing) Wittrock. Bot. Not. 1882: 58. 1882.
Filaments free-floating, rarely solitary, curved or sigmoid; usually
greatly and irregularly twisted to form floccose masses. Filaments
v/ith or without a copious, hyaline, gelatinous envelope. Cells spheri-
cal or appreciably flattened at the poles, generally with numerous
pseudovacuoles. Heteroeysts spherical to subspherical. Spores usu-
ally remote from the heterocysts, cylindrical, with rounded ends when
mature, frequently curved and with smooth walls. (Euplanktont).
Cells 8-14 /X broad ; heterocysts 8-10 /x broad ; spores 16-18 /x broad,
26-30 /X long when mature.
Center (ss), Chain (sss). Lac la Belle (rr), Mercer (rr), Nagawicka (it).
Pike (r). Upper Nashotah (rr), Wapagossett (sss), Winnebago (ss).
This species differs from A. flos-aquae in the loose looping of the
trichomes, the larger vegetative cells and the broader spores.
60
WISCONSIN PHYTOPLANKTON
var. MACROSPORA (Wittrock) de Toni. PI. 9, Fig. 6; PI. 10, Fig. 1.
Sylloge algarum 5: 445. 1907.
Anabaena Hassallii var. macrospora Wittrock, Bot. Not. 1882 : 59, figs. 7-9.
1882.
Vegetative cells somewhat smaller but with much narrower and pro-
portionally longer spores.
Cells 7-8 /X broad ; heterocysts 7.5-10 fx broad ; spores 9-10.5 p. broad,
28-42 (i long.
Camp (sss).
Anabaena flos-aquae (Lyngbye) de Brebisson. PI. 10, Figs. 2-4.
Mem. de la soc. Acad, de Falaise 1835: 36. 1836; Kiitzing, Tabulae Phycol. 1:
51, pi. 94, fig. 4. 1848; Bornet et Flahault, Ann. Sci. Nat. 7 Ser. Bot. 7; 228.
1888.
Filaments free-floating, densely coiled, irregularly twisted and inter-
woven to form a floccose colony. Cells spherical or cylindrical with
convex sides ; generally containing numerous pseudovacuoles. Hetero-
cysts broader and longer than the vegetative cells. Spores cylindrical,
with rounded ends, usually curved, solitary or in short catenulate
series ; generally adjacent to, rarely remote from the heterocysts. (Eu-
planktont) .
Vegetative cells 4-8 (generally 5.5) /x broad; heterocysts 6-9 /x broad;
spores 7-13 /x broad, 20-50 /x long.
Bear (1) (cc), Birch Island (r). Browns (cc). Camp (ss). Catfish (ss),
Catherine (rr), Cochrane (sss). Crab (r), Crawling Stone (rrr). Crooked (sss),
Des Moines (rr). Devils (1) (r). Eagle (sss), Fish (rr). Grassy (r). Green
(2) (sss). Half Moon (rr). Hooker (r). Horse (rrr), Jag (rr), Jennie (ss),
Kegonsa (rr). Lac Court Oreilles (ss). Lac la Belle (r). Little Crooked (rr),
Little Wood (r). Long (1) (rr). Long (3) (rr). Lower Nashotah (rr). Lynx
(sss), Mary (rr), Mendota (c), Mercer (rr). Mill (rr) Mud (2) (c), Nancy (s),
Oconomowoc (r), Okauchee (rr). Palmer (rr). Pine Tree (rr). Poplar (rr).
Round (1) (rr). Round (3) (r), Rudolph (rrr), Sanford (c). Shell (rrr),
Sishebogema (rr). South Crab (rr), Squirrel (rr). Upper Nashotah (r). Upper
Nemahbin (rr), Waubesa (c). Wildcat (sss). Wolf (r).
var. Treleasii Bornet et Flahault. PI. 10, Figs. 5-7.
Ann. Sci. Nat. 7 Ser. Bot. 7: 230. 1888.
Anahaena mendotae Trelease, Trans. Wis. Acad. Sci., Arts, & Lett. 7: 123,
pi. 10, fig. 5. 1889.
Cells smaller and with spores somewhat narrower and proportionally
longer. ( Euplanktont ) .
Vegetative cells 3-5 /x broad, 4.5-12 /x long; heterocysts 4.5-6 /x broad,
6-8 /X long ; spores 6-8 /x broad, 20-40 fx long.
Mendota (aa), Waubesa (s).
WISCONSIN PHYTOPLANKTON
61
Anabaena Lemmermanni P. Richter. PI. 10, Fig. 8 ; PI. 11, Fig. 1.
Forschungsbr. a. d. Biol. Stat. zu Plon 10; 153. 1903.
Anabaena flos-aquae Klebahn non (Lyngbye) de Breb., Flora 80: 267, pi. 4 ,
figs. 21-22. 1895.
Filaments free-floating ; irregularly or circinately interwoven to form
a spherical or broadly ellipsoid mass, with filaments frequently radiat-
ing in loops from a common center. Vegetative cells spherical or
slightly elongate, usually containing numerous pseudovacuoles. Heter-
ocysts spherical, approximately the same size as the vegetative cells.
Spores cylindrical, with rounded ends, with inner side straight and the
outer convex; rarely remote from heterocysts, generally forming short
catenate series on both sides of heterocysts and lying in a dense mass
at the center of the colony. The spore masses and heterocysts fre-
quently persisting long after the disappearance of the vegetative cells.
(Euplanktont).
Vegetative cells 5.5-7 /a broad, 5-8 long; heterocysts 6-7.5 /x broad;
spores 8-11 /x broad, 19-33 fx long.
Crawling Stone (rr), Diamond (r), Kawaguesaga (rr), Long (rr), Marl
(r), Oconomowoc (r), Paddock (cc), Palmer (r), Pardee (ss), Rainbow (2)
(rr), Reserve (r). Rice (1) (s),iSand (2) (rr), Taylor (ss), Trout (s).
The species differs from A. fios-aquae in the regular looping of the
trichomes from a common center and the development of a large mass
of spores at the center of the colony. The persistence of the spores
after the disappearance of the vegetative cells is very common and
certain of the records for the species are based upon observation of the
spore masses only.
APHANIZOMENON Morren 1838.
Trichomes straight slightly flexed, or curved ; in lateral contact with
one another to form small, macroscopic, free-floating, feathery, plate
or scale-like opaque colonies. Trichomes destitute of a gelatinous
sheath, sometimes constricted at cross walls of cells, and slightly attenu-
ated at the apices. Cells cylindrical, with flattened ends. Heterocysts
intercalary, cylindrical. Spores elongate, cylindrical and with flattened
ends; solitary, adjacent to or remote from the heterocysts.
Reproduction by the formation of hormogones and resting spores.
Aphanizomenon flos-aquae (L)Ralfs. PI. 11, Pigs. 2-4.
Ann. & Mag. of Nat. Hist. 2 Ser. 5: 340, pi. 9, fig. 6. 1850; Klebahn, Flora 80;
271, pi. 4, figs. 27-30. 1895.
Trichomes straight or slightly curved, laterally joined to form a flat
flake- or scale-like plate. Cells cylindrical, with flattened ends, about
62
WISCONSIN PHYTOPLANKTON
three times as long as they are broad, generally with numerous pseudo-
vaeuoles. Heterocysts cylindrical, with straight or slightly convex sides,
without a distinct polar nodule. Spores elongate, cylindrical, with
rounded or somewhat flattened ends, generally some distance from the
heterocysts. ( Euplanktont ) .
Cells 4-6 IX broad, 5-15 fx long; heterocysts 5-7 ^x broad, 7-20 jx long;
spores 6-8 fx broad, 35-80 fx long.
Amicoy (aa), Balsam (ss), Bear (3) <rr), Beaverdam (rr), Big (r), Big
Butternut (rr), Birch (1) (c), Bone (rr), Camp (r), Catfish (sss), Center
(rrr), Chetac (aaa), Cranberry (ss). Crawling Stone (rrr), Deer (rrr), Dun-
ham (rr). Found (rr), Fowler (rr). Granite (a), Green (2) (ss). Half Moon
(sss), Hillman (sss). Hooker (cc). Horse (rrr). Horseshoe (1) (rr). Island
(c), Kawaguesaga (ccc), Kegonsa (cc). Lac la Belle (rr). Little Bass (2) (rr),
Little Butternut (s). Little Rice (1) (s). Little V/ood (rr). Long (3) (rr).
Lost (ss). Loveless (ss). Lower Nashotah (rr), Mendota (s), Mud (3) (rr),
Nagawicka (rr). North Twin (rrr), Oconomowoc (rr), Okauchee (rr), Pardee
(cc), Pewaukee (rr). Pike (rr). Plum (r), Pokegama (2) (rrr), Pokegama
(3) (aaa). Poplar (rrr). Prairie (aaa). Reserve (rr). Rice (1) (ss), Round
(1) (sss). Round (2) (ss), St. Croix (ccc). Sand (1) (r). Sand (3) (r). Sand
(4) (r), Sanford (sss), Shell (rrr). South Turtle (sss). Squirrel (a), Streitor
(rr), Tied Canoe (sss). Upper Nashotah (rr). Upper Nemahbin (r). Upper
Turtle (rr), Vermilion (r), Waubesa (s), White Ash (rr), Whitefish (rr).
White Sand (ss), Winnebago (r).
When the alga occurs in any quantity the lake appears to be fllled
with small pieces of macerated grass and it is one of the few plankton
genera that can be determined without the aid of a microscope. The
colony is so opague that the heterocysts cannot be seen while the colony
is intact but after a mount has been standing a few minutes the colonies
begin to dissociate into the component filaments and observation of the
heterocysts and spores is then an easy matter. The colonies are fre-
quently sterile and it is generally only during the colder months of the
year that there is a formation of spores.
Family ElVULARIACEAE.
Filaments rarely solitary, generally forming sessile or free-floating
spherical, hemispherical, or amorphous colonies. Trichomes gradually
attenuated from a broad basal cell to a hair-like apical cell. Sheaths
copious, homogeneous or lamellated, hyaline or colored, firm or gelat-
inous; enclosing one or more trichomes. Cells hemispherical, spheri-
cal, or disciform with convex sides at the basal portion of the triehome,
elongate cylindrical in the apical region. Cell contents variously col-
ored ; homogeneous, granulose, or with numerous pseudovacuoles. Trich-
omes simple or with “false branching’’. Heterocysts solitary; usually
WISCONSIN PHYTOPLANKTON
63
at base of triehomes, rarely intercalary. Spores, when present, soli-
tary and adjacent to heterocysts.
E-eprodnction by formation of triehomes and spores.
GLOEOTRICHIA J. G. Agardh 1842.
Filaments always in colonies; free-floating or sessile; spherical to
hemispherical, tough and leathery to gelatinous, hyaline or colored.
Triehomes attenuated to fine hair-like processes at the distal end, en-
closed by gelatinous sheaths that are distinct at the base and confluent
at the apex. Filaments containing one triehome, but at times showing
false branching. Heterocysts spherical to hemispherical, solitary; at
the base of the triehomes. Spores cylindrical, solitary, always adjacent
to the heterocysts. Vegetative cells convexly disciform to short cylin-
drical at base of triehomes, elongate cylindrical with straight sides at
apex of triehomes.
Reproduction by hormogones and resting spores.
Gloeotrichia echinulata ( J. E. Smith) P. Richter. PI. 11, Pigs. 5-6.
Forschungsbr. a. d. Biol. Stat. zu Plon 2: 31, figs. 1-8. 1894.
Conferva echinulata J. E. Smith, Eng. Bot., pi. 1378. 1804.
Rivularia echinulata J. E. Smith, Eng. Bot. index; P. Richter, Forschungsbr.
a. d. Biol. Stat. zu Plbn 2: 45. 1894; Lemmermann, Kryptogamenfi. d. Mark
Brandenburg 3, Algen 1: 255, 245, figs. 1, 6. 1907.
Gloeotrichia pisum Bornet et Flahault (p.p.) non Thuret, Bull. Soc. Bot.
France 31: 80. 1884; Ann. Sci. Nat. 7 Ser. Bot. 4: 366. 1886; Trelease, Trans.
Wis. Acad. Sci., Arts, & Lett. 7 : 124-125 (with fig.) 1889.
Colonies always free-floating, spherical; up to 2 mm. in diameter.
Filaments radially arranged about a common center but becoming ir-
regular in arrangement on slight pressure. Sheaths hyaline, homogene-
ous, distinct at base, apex frequently confluent with colonial envelope.
Triehomes broad at base, attenuated to long, colorless, hair-like pro-
cesses. Lowest vegetative cell of triehome hemispherical ; those a short
distance from base disciform with markedly convex sides; those in
middle of triehome cylindrical ; while the cells in the apical region are
elongate cylindrical. Basal cells completely filled with cytoplasm,
apical cells with cytoplasm restricted to the median portion. Cell con-
tents rarely homogeneous, usually with numerous pseudovacuoles.
Heterocysts at base of triehome, spherical. Spores, when present, ad-
jacent to heterocysts, elongate cylindrical with rounded ends.
Cells at base of triehome 8-10 /x broad; at apex 1-2 fx broad; hetero-
cysts 7-10 fx broad ; spores 8-10 fx broad, 40-54 fx long.
Bass (3) (rr). Bear (3) (rr). Bear Trap (rr), Beaverdam (rr), Birch (2)
(ss), Birch Island (r), Bone (rr), Carroll (rr), Catherine (sss), Chetac (ss),
64
WISCONSIN PHYTOPLANKTON
Clare (ss), Crawling Stone (rrr), Des Moines (cc), Diamond (ss), Duck (rr).
Dummy (rr), Dutchmans (ss), Fish (ss), Fowler (sss). Grindstone (rr).
Half Moon (ss). Horseshoe (1) (ss). Horseshoe (2) (rr), Howey (rr), Island
(ss), Jennie (rr), Kegonsa (aa), Kimball (rr), Lac Court Oreilles (ss). Lake
of the Woods (r), Lindy (rr), Long (1) (sss). Loon (r), Mendota (s), Monona
(cc), Nancy (ss). North Twin (r), Mercer (rrr). Middle McKenzie (ss), Mud
(3) (aa), Oconomowoc (rr), Owen (rrr), Razorback (aa). Reserve (rr), St.
Croix (rr). Sand (1) (rr). Sand (3) (rr). Shell (rr). Soft (rr). Trout (cc),
Waubesa (cc), Whitefish (sss). Wild Goose (rr), Winnebago (r).
A bloom of this alga can be recognized at once by the minute seed-like
colonies surrounded by an aureole of whitish threads. It was first
noted by Davis in England in 1804 and the plant figured and described
by Smith in his English Botany. The various references to the alga
before the recognition of a definite plankton flora have been compiled
by Bornet and Flahault as well as P. Richter. Since the study of the
plankton flora by phycologists the alga has been found in the lakes of
iQOst European countries. Although there seems to be but a single
species of the Rivulariaceae found free-floating in lakes and ponds the
nomenclatorial treatment of this species is quite varied. Bornet and
Flahault affirm that it is the common Gloeotrichia pisum, which ordi-
narily grows attached to submerged plants along the shore, that has
broken away and become free-floating. They hold that Rivularia
echinulata J. E. Smith (whose dimensions are the same as those of
G. pisum) is nothing but a free-floating G. pisum. In my observations
on the algae of our lakes there is no correlation between the appearance
of G. pisum and G. echinulata in the same lake in Wisconsin. In the
region of Madison, G. pisum does not appear until the middle of July
and yet at one time there was a heavy bloom of G. echinulata on the
28th of June, a time when there was no G. pisum along the shore. I
am convinced that the sessile Gloeotrichia is not the one found in the
plankton and that Richter is quite right in reviving the old specific
name echinulata. Some investigators hold that Gloeotrichia is but a
sub-genus of Rivuluria, but I have followed Bornet and Flahault in
considering the two distinct. This distinction is based upon the occur-
rence of spores in Gloeotrichia and a lack of spores in Rivularia.
WISCONSIN PHYTOPLANKTON
65
Class PHAEOPHYCEAE.
Plants usually of macroscopic size and definitely shaped. Cells vari-
ously shaped and containing brown chromatophores in which a brown
pigment, phaeophycin, masks the chlorophyll. Cell wall not conspicu-
ously impregnated with silica and cells generally immobile in the vege-
tative phases.
Asexual reproduction by vegetative cell division, aplanospores, and
zoospores.
Sexual reproduction by isogamous zoogametes ; or heterogamous with
a fusion of zoogametes of unequal size, or a union of a large immobile
oosphere and a small motile antherozooid.
All of the complex non-motile members of this class are marine and
only unicellular or simple colonial forms are found in fresh waters.
These freshwater forms have the motile phase dominant, as a rule, and
form the subclass Chrysomonadineae of the Phaeophyceae. Many
place all of the colorless or brown chromatophored motile unicellular
organisms in a class by themselves, the Flagellatae, but, as I have stated
elsewhere, the group of the Chrysomonadineae seems sufficiently related
to the Phaeophyceae to warrant uniting the two.
Sub-class CHRYSOMONADINEAE.
Cells with one or more definite, disciform, laminate, or reticulate,
golden-brown chromatophores. Cells free-swimming or sessile, solitary
or in colonies of definite to indefinite shape. Life cycle generally with
the motile phase dominant but sometimes developing into amorphous or
rhizopodial palmella stages. Cells either naked or with a gelatinous
to definitely constituted periplast. Individual cells with 1-2 anterior
or lateral cilia of equal or unequal length; 1-10 contractile vacuoles,
generally at the anterior end; with or without an eyespot; and with
one or more chromatophores. Symmetry of cells bilateral, not inter-
rupted by a lateral or longitudinal grooving. Nutrition holophytic or
saprophytic ; assimilation product leucosin or fat, never starch.
Asexual reproduction by longitudinal or transverse division of cells.
Resting stages with heavy walls known in many genera.
Sexual reproduction as yet unknown in the sub-class.
66
WISCONSIN PHYTOPLANKTON
KEY TO THE DIVISIONS.
Motile phase dominant, rhizopodial or palmella phase rare.EucHUYsoMONADiNAE
Immobile phase dominant, motile phase known or unknown.
Cells spherical to ovoid, embedded in a gelatinous envelope . . . Hydrurinae
Cells with pseudopodial processes Rhizochrysidinae
Division EUCHRYSOMONADINAE.
Cell structure and organization as noted in the description of the
sub-class. Ciliate phase dominating the life history. Palmella or
rhizopodial phases known but not the general rule.
KEY TO THE ORDERS.
Motile phase with one flagellum Chromulinales
Motile phase with two flagella.
Flagella of the same length Isochrysidaues
Flagella of unequal length Ochromonadales
Order CHROMULINALES.
Cells generally solitary, rarely colonial ; free-floating or sessile. ‘ Mo-
tile phase with a single apical flagellum. Chromatophores reticulate,
laminate, or disciform ; generally two in each cell. Apical contractile
vacuoles present or lacking. Cells either naked or with a deflnite, homo-
geneous or sculptured periplast.
Reproduction by vegetative division of cells. Thick-walled resting
stages known in certain genera.
KEY TO THE FAMILIES.
Cells naked Euohromtjlinaceae
Cells with a differentiated periplast Mallomonadaceae
Family EUCHROMULINACEAE.
Cells naked, without a differentiation of the periplast. Cells with
sharply defined disciform to laminate chromatophores, and without
contractile vacuoles. Flagellum single.
There are several genera with many species in the family but only
one of them, Chrysamoeha, has been noted in the plankton of the state.
WISCONSIN PHYTOPLANKTON
67
CHRYSAMOEBA Klebs 1893.
Cells solitary, free-floating, with a mono-flagellate motile phase and
an amoeboid non-motile phase. Motile phase broadly ovoid, naked,
with two elongate, laminate, golden-brown chromatophores ; a large
non-contractile vacuole, 2-3 small contraetile vacuoles; and a single
flagellum slightly longer than the cell. Eye-spot lacking.
Non-motile phase solitary or in small clumps, with several simple or
branching pseudopodial processes extending in all directions. Chro-
matophores and vacuoles as in the motile phase.
Chrysamoeba radians Klebs. PI. 12 , Fig. 1 .
Zeits. f. wiss. Zool. 55: 406, pi. 18, iigs. la-lb, 1893.
Speciflc characters as described above. (Euplanktont).
Motile phase 8-10 /x, broad, 12-15 long; amoeboid phase (without
processes) 12-17 fx broad, (with processes) 35-40 p. broad.
Round (4) (rr), Taylor (rr).
Family MALLOMONADACEAE.
Cells always free-swimming, solitary or colonial, never metamorphos-
ing into a palmella or rhizopodial phase. Periplast of cells or colonial
envelope with numerous small plates of silica that have long, siliceous,
needle-like processes. Cells ovoid to ellipsoid, with one flagellum, a
number of contractile vacuoles and two long laminate chromatophores.
KEY TO THE GENERA.
Cells solitary Maixomonas
Cells in spherical colonies Chbysosphaebklla
MALLOMONAS Perty 1852.
Cells always solitary, free-swimming, with a single flagellum at the
anterior end. Periplast of cells with small circular or angular siliceous
discs covering the entire surface of the cell or restricted to one or both
ends. Scales frequently arranged in regular transverse or diagonal
rows, produced into a single, long, simple or toothed, needle-like setae.
Cells containing one or more contractile vacuoles that may be apical,
median, or basal in position. Chromatophores two, parietal, laminate,
and golden-brown in color. Assimilation product leucosin.
Reproduction by vegetative cell division parallel to the long axis.
Akinetes known in many species.
68
WISCONSIN PHYTOPLANKTON
KEY TO THE SPECIES.
Setae restricted to one end of the cell.
Apical end with setae.
Cells cylindrical M. Alpina
Cells ovoid M. Tonsurata
Basal end with setae M. Producta
Setae covering whole cell M. Caudata
Mallomonas alpina Pascher & Kuttner. PI. 12, Fig. 4 .
in Pascher, D. Siisswasserfl. Deutschl., osterr., u. d. Schw. 2, Flagellatae 2: 36,
fig. 58a. 1913.
Cells ellipsoid to elongate cylindrical, with poles rounded or pointed.
Scales rhomboidal, in diagonal rows; with a single, long, straight or
curved seta. Setae confined to anterior end of cells. (Euplanktont).
Cells 8-12 broad, 25-45 long.
Camp (r). ‘
Mallomonas producta (Zacharias) Iwanofi. PI. 12, Fig. 2.
Bull, de TAcad. Imp. d. Sc. de St. Petersbourg 5 Ser., 11: 250, pi. A, figs. 4-6.
1899.
Cells cylindrical, with straight or slightly convex sides, ends rounded
and tapering. Scales in regular transverse to diagonal rows, diamond-
shaped or laterally elongate. Setae straight or bent, confined to basal
portion of cell. Chromatophores two, golden-brown, laminate, and
parietal. (Euplanktont).
Cells 9-13 fi broad, 40-70 /x long.
Catfish (sss). Cranberry (ss), Crawling Stone (sss), Lac la Belle (ss).
Long (1) (ss), Otter (r). South Turtle (rrr), Upper Nashotah (rr).
var. MARCHiCA Lemmermann. PI. 12, Pig. 3.
Zeits. f. Fischeri 1903: 106. 1903.
Cells shorter and relatively broader. Setae sometimes at both ends
of cells. (Euplanktont).
Cells 11-12 fx broad, 21-26 jx long.
Nancy (r), Oconomowoc (ss), Tamarack (ss).
Mallomonas tonsurata Teiling. PI. 12, Fig. 5.
Sv. Bot. Tids. 6: 277, fig. 3. 1912.
Cells ellipsoid, with posterior end rounded and anterior end pointed.
Setae confined to anterior third of cell, fairly short and somewhat
curved. Scales not regularly arranged. (Euplanktont).
Cells 7-8 IX broad, about 18 /a long.
Waupaca (rr).
WISCONSIN PHYTOPLANKTON
69
Mallomonas caudata Iwanoff. PI. 12, Fig. 6.
Bull, de I’Acad. Imp. d. Sc. de St. Pdtersbourg 5 Ser., 11: 250, PI. B, iigs. 1-8.
1899.
Cells broadly ovoid, with posterior end narrower than the anterior.
Scales oval, arranged in transverse series. Setae long, covering the
entire surface of the cell and frequently with minute teeth-like projec-
tions at the distal end. Cells with two long, parietal, laminate, chro-
inatophores. (Euplanktont).
Cells 12-30 fi broad, 40-85 long.
Beasley (rr), Birch (1) (rrr), Browns (rr), Carson (rrr), Catherine (rr),
Clare (r), Clear Crooked (rr), Crab (rr). Crawling Stone (rrr). Diamond
(rrr). Hill (ss), Jennie (rr). Kitten (sss). Lac la Belle (ss). Long (3) (ss),
Long (4) (rr). Lynx (rr). Mud (2) (ss). No Mans (s), North Turtle (r),
Okauchee (rr). Otter (sss), Pokegama (1) (rr), Pokegama (2) (r). Red Basa
(s), Rock (cc), Round (1) (sss), Rudolph (sss), St. Croix (rrr). Sand (4)
(sss), Sanford (sss). South Crab (rr). Wildcat (sss). Wild Goose (rr). Wolf
(rr).
CHRYSOSPHAERELLA Laut^rborn 1896.
Cells ellipsoid to pyriform, in spherical colonies of microscopic size
tliat are partially embedded in a spherical, hyaline, gelatinous envelope
containing numerous, tangentially placed, minute plates of silica. An-
terior ends of cells with two short, vase-shaped projections, each bear-
ing a single, long, straight, siliceous seta of some length. Cells with
one anterior flagellum ; two elongate, parietal, golden-brown chromato-
phores ; and several vacuoles.
Reproduction by vegetative cell division. Resting akinetes unknown.
Chrysosphaerella longispina Lauterborn. PI. 12, Figs. 7-8.
Zool. Anz. 19: 16. 1896; Zeits. f. wiss. Zool. 65: 381, pi. 18, figs. 12-16. 1899.
Speciflc characters as described above. (Euplanktont).
Average breadth of cells 9 /a, average length 15 fi. Colonies 50-250 /u
in. diam.
Bettine (rr), Blue Gill (ss), Boulder (rrr). Canteen (r), Elizabeth (rr).
Hill (aa). Lac la Belle (rr). Long (4) (rr), Lynx (r). Marl (rr), Mary (ss).
No Mans (rr), Oconomowoc (ss), Okauchee (s). Otter (ss). Rainbow (ss).
Round (4) (rr), Rudolph (sss), Silver (2) (ss). South Turtle (cc), Upper
Nemahbin (ss). Wild Goose (ccc).
Order ISO CHRYSID ALES.
Cells free-floating or sessile, solitary or colonial, naked or with a
definite homogeneous or sculptured periplast. Motile phase always
present, palmella or rhizopodial phase lacking. Cells variously shaped,
70
WISCONSIN PHYTOPLANKTON
always with two apical cilia of equal length ; generally with two lami-
nate, parietal, golden-brown chromatophores and without an eyespot.
The only family represented in the flora of the state is that of the
Euhymenomonadaceae.
Family EV HYMEN OMON AD ACE AE.
Differing from other families of the order in having a definite sculp-
tured periplast and an anterior vacuolar system. Synura the sole
representative.
SYNURA Ehrenberg 1838.
Cells radially arranged in spherical to oblong-ovoid free-swimming
colonies that are not enclosed by a gelatinous sheath. Individual cells
broadly pyriform, with the narrower end towards the center of the
colony. Outer portion of cells firm, with small spines, reticulations,
or combinations of the two. Cells with two long anterior cilia of equal
length, several vacuoles, two long laminate parietal chromatophores,
and without an eyespot.
Reproduction by division of cells and liberation of cell contents to
form amoeboid cells. Akinete formation also known.
Synura uvella Ehrenberg. PI. 12, Figs. 9-10.
Infusionsthierchen 61, pi. 3, figs. 9^-9®. 1838.
Exterior of cells covered with fine spines that are generally limited
to the anterior portion. (Facultative Planktont).
Cells 8-17 broad, 20-35 fi broad. Colonies up to 350 /a in diam.
Camp (ss), Canteen (cc). Crawling Stone (rrr), Fowler (cc), Jenny (rr),
Kawaguesaga (rr), Little Bear (rrr). Little Crooked (rr). Long (3) (r),
Lower Nemahbin (rr). Lynx (r), Mendota (ss), Mercer (rr). Mill (ccc), Mud
(2) (rr), Nagawicka (cc), Nancy (cc), Nicaboyne (rr). No Mans (cc), North
Turtle (rr), Oconomowoc (s). Palmer (c), Pardee (sss), Pewaukee (sss),
Pope (rrr). Rainbow (1) (rr). Red Bass (ss). Round (1) (sss), Rudolph (sss).
Sand (4) (rr), Sanford (ss), South Turtle (rr).
Order OCHROMONADALES.
Cells solitary or colonial, free-swimming or sessile, not forming pal-
mella or rhizopodial stages. Cells naked, or with a definitely shaped re-
ceptacle ; two lateral or apical cilia of unequal length, one or two golden-
brown disciform to laminate chromatophores ; contractile vacuoles ; and
an eyespot.
WISCONSIN PHYTOPLANKTON
71
KEY TO THE FAMILIES.
Cells naked, at times in a gelatinous envelope but never a
definite receptacle Ochbomonadageae
Cells within a definite receptacle Dinobryaceab
Family OCHROMONADACEAE.
Cells solitary or in colonies, always free-swimming, not enclosed by
a definite receptacle but at times with a hyaline, homogeneous, gelat-
inous envelope. Cells with two apical cilia of unequal length, one or
two golden-brown chromatophores, an eyespot and contractile vacuoles.
Uroglenopsis is the only representative in the local flora.
UROGLENOPSIS Lemmermann 1899.
Colonies free-swimming, with the cells embedded in a single layer at
the periphery of a copious, hyaline, homogeneous, gelatinous matrix of
spherical to broadly ellipsoid shape. Arrangement of cells radial or
somewhat irregular. Cells spherical to narrowly ellipsoid; with two
cilia of unequal length; two vacuoles at the anterior end; one or two
laminate to disciform, parietal, golden-brown chromatophores ; and with
or without an eyespot.
Reproduction by vegetative cell division.
Uroglenopsis Americana (Calkins) Lemmermann. PI. 13, Figs. 1-4.
Forschungsbr. a. d. Biol. Stat. zu Plbn 7: 107. 1899; Kryptogamenfl. d. Mark
Brandenburg 3, Algen 1 : 449, 444, figs. 1-3, 4-6. 1908.
Vroglena americana Calkins, Ann. Kept. Mass. State. Bd. of Health 23 : 655,
Vl. 4, figs. 1-4. 1892; Moore, Bot. Gaz. 23; 105, pi. 10, figs. 1-11. 1897.
Colonies free-swimming, generally spherical. Cells ellipsoid, with
one basal or lateral, parietal, disciform to laminate chromatophore. Eye-
spot single. Cilia of unequal length, with the longer 2-3 times the
length of the cell, the shorter %-i/2 the length of the ceU. (Euplank-
tont).
Cells 3-7 [ 1 . broad, 5-10 long. Colonies up to 500 fi in diam.
Beasley (cc), Bettine (ss). Browns (ss), Camp (ss), Carson (rrr). Diamond
(rr). Eagle (sss), Fowler (cc), Howey (rr), Lac la Belle (ss). Long (3) (ss).
Long (4) (rr). Lower Nemahbin (rr), Lynx (rr), Mendota (ss). Mill (ss).
Mud (4) (cc), Nancy (rr), Oconomowoc (ss), Okauchee (rrr), Otter (ss),
Paddock (s), Pewaukee (rr). Rainbow (1) (ss). Round (4) (rr), Taylor (ss).
Wildcat (ss), Wolf (rr), Youngs (cc).
72
WISCONSIN PHYTOPLANKTON
Family DINOBRYONACEAE.
Cells solitary or in colonies, free-floating or sessile. Always attached
to the base of a conical to vase-like, colored or hyaline, smooth or sculp-
tured receptacle. Cells with one or two laminate chromatophores, con-
tractile vacuoles, an eyespot, and two cilia of unequal length.
KEY TO THE GENERA.
Receptacles homogeneous, without growth rings Dinobryon
Receptacles with successive growth rings Hyalobryon
DINOBRYON Ehrenberg 1835.
Cells free-floating, sessile, or epiphytic; solitary or in colonies; at-
tached to the bottom of conical, campanulate, or cylindrical receptacles
with open apices and pointed bases. Colonial species arbuscular, each
receptacle with the pointed ends of 1-4 other receptacles in its mouth.
Development of branching indefinite. Protoplast spindle-shaped, coni-
cal, or ovoid ; attached by a stalk to the base of the receptacle. Anterior
end of protoplast with two cilia of unequal length that project beyond
the open end of the receptacle. Cells with one or two laminate, elon-
gate, parietal, golden-brown chromatophores; several apical, lateral, or
basal contractile vacuoles; and one apical eyespot. Assimilation pro-
duct generally leucosin.
Reproduction by longitudinal division of cell contents to form ovoid
daughter cells that migrate to the mouth of the old receptacle or leave
it entirely before developing new receptacles. Akinetes known.
The specific limits of colonial plankton species of this genus are very
poorly defined and it is almost impossible to draw a sharp line of de-
marcation between the various species. I have indicated as species the
centers around which the variations seem to occur.
KEY TO THE SPECIES.
Cells solitary.
Cell shape conical, elongate D. CAijoiFOBMa
Cells broadly spindle-shaped D. Tabellabiae
Cells in colonies.
Branching of cells markedly divergent D. Diveegens
Branching of cells not sharply divergent.
Cells elongate conical.
Sides of receptacles straight D. Stipitatum
Sides of receptacles undulate D. Bavaricum
Cells campanulate D. SEn'ULARiA
WISCONSIN PHYTOPLANKTON
73
Dinobryon caliciforme Bachmann. PL 13, Figs. 5-6.
Arch. f. Hydrob. u. Planktonkde. 3: 82, fig. 1908.
Cells solitary; epiphytic upon the gelatinous envelope of various
colonial Myxophyceae. Receptacles elongate conical, with a sharply
pointed base. Protoplast the same shape as the lower two-thirds of re-
ceptacle. Chromatophores two, laminate, parietal, and golden-brown
in color, Eyespot single. Cilia not as long as the cell. (Euplank-
tont) .
Receptacles 5-6 fx broad at apex, 30^0 fx long.
Embedded in or on gelatinous envelope of Coelosphaerium Naegeli-
anum and Microcystis aeruginosa.
Browns (sss).
Dinobryon tabellariae (Lemmermann) Pascher. PL 13, Figs. 7-9.
Siisswasserfl. Deutschl., osterr. u. d. Schw. 2, Flagellatae 2: 66, figs. 105»-105b.
1913.
Dinobryon utriculus var. tabellariae Lemmermann, Arkiv for Botanik 2,
No. 2: 119, pi. 1, fig. 19. 1904.
Cells solitary; epiphytic upon filaments of Tahellana. Receptacle
broadly spindle-shaped, with the base produced into a short stipe. Pro-
toplast attached to side of lower portion of receptacle, ovoid in shape
and with the usual contents of the genus. (Euplanktont).
Receptacles 7-10 fx broad at center, 4-5 at apex ; 18-22 fx long.
Crawling .Stone (r). Long (3) (rr). Sand (4) (s).
Dinobryon bavaricum Imhof. PL 13, Fig. 10.
Zool. Anz. 13: 484. 1890; Lemmermann, Bot. Not. 1903 : 78, pi. 3, figs. 3-4.
1903.
Cells in free-floating compact colonies. Receptacles of individual
cells elongate-conical. Base of receptacle very much produced with
sides almost parallel; expanded portion of receptacle with undulate
sides. Seasonal variation pronounced, the receptacles being much
longer during the summer. (Euplanktont).
Receptacles 6.5-8. 5 fx broad ; 45-100 long.
George (ss), Harris (rr), Marl (ss), Oconomowoc (ss), Speese (ss), Tied
Canoe (ss). White Sand (s).
74
WISCONSIN PHYTOPLANKTON
Dinobryon stipitatum Stein. PI. 13, Fig. 11.
Der Organismus der Infusionstiere 3: pi. 12, iig. 5. 1878; Pascher, D. Suss-
wagserfl. Deutschl. osterr. u. d. Schw. 2 , Flagellatae 2 : 73, -fig. 118. 1913.
Cells always in narrow, fairly dense, free-floating colonies. Recep-
tacles of individual cells elongate-conical, with bases produced into stipes
with nearly parallel sides. Sides of receptacle not undulate. Indi-
vidual receptacles of colony not divergent from one another. Seasonal
variation chiefly in elongation of apical cells of colony. (Facultative
Planktont) .
Receptacles 6-8 /a broad ; 56-96 fi long.
Marl (ss), Oconomowoc (cc). Round (4) (sss), iSouth Turtle (rr).
Dinobryon sociale Ehrenberg. PI. 13, Fig. 12.
Abh. d. k. Ak. d. Wiss. Berlin 1833; 279. 1835; Die Infusionsthiercben 125,
pi. 8, fig. 9. 1839; Pascher, Siisswasserfl. Deutschl. osterr. u. d. Schw. 2 ,
Flagellatae 2: 73, figs. 116-117. 1913.
Cells in free-floating colonies. Individual receptacles somewhat di-
vergent from one another and producing a fairly loose colony. Recep-
tacles conical, sometimes slightly constricted below the open mouth, with
bases gradually tapering to a sharp point that is not extended to form
a process. (Facultative planktont).
Receptacles 7-8 /t broad, 30-70 fi long.
Beasley (ss), Green (1) (ss). Green (2) (cc), Mill (c). North Turtle (rr),
Oconomowoc (cc). Silver (2) (s). Trout (rr).
Dinobryon setularia Ehrenberg. PI. 13, Fig. 13; PI. 14, Fig. 1.
Abh. d. k. Ak. d. Wiss. Berlin 1833: 280. 1835; Die Infusionsthiercben 124,
pi. 8, fig. 8. 1838.
Cells in free-floating, densely branching colonies. Receptacles cylin-
drical-campanulate, with the convex bases tapering abruptly to a sharp
point. Cells with shorter and broader receptacles than the other species.
Seasonal variation not so pronounced as in other species. (Facultative
Planktont) .
Receptacles 10-14 ja broad, 30^4 fi long.
Devils (1) (ccc), Kawaguesaga (ss). Long (4) (ss). Lost (ss). Lower
Nemahbin (ss). Rock (ss), Round (3) (ss), Winnebago (rr).
WISCONSIN PHYTOPLANKTON
75
Dinobryon divergens Imhof. PI. 14, Fig. 2.
Jahresbr. d. Naturf. Ges. Graubiindens N. P. 30: 134. 1887.
Dinotryon cylindricum var. divergens (Imhof) Lemmermann, Ber. d. D. Bot.
Ges. 18: 517, pZ. 19, /Zfirs. 15-20. 1900.
Cells in free-floating densely or openly branched colonies. Recep-
tacles with conical bases and the upper portion cylindrical or with
slightly flaring mouths. The axis of the upper portion of receptacle
forming an angle of 45—90 degrees with that of the basal portion. Sides
of receptacle sometimes undulate. Seasonal variation confined to dense-
ness of branching in colony rather than changes in receptacle shape.
(Facultative Planktont).
Receptacles 7-8 {x broad, 35-50 ix long (2(4-27 p, in upper portion and
15-20 in basal portion).
Beasley (s), Boulder (cc). Browns (cc), Center (ss). Devils (1) (ss),
Elizabeth (cc), George (r). Green (2) (rr). Hill (cc). Lac la Belle (ss),
Long (2) (rr). Marl (ss), Mary (cc), Meta (r). Mill (cc), Mud (1) (ss),
Nagawicka (cc). North Turtle (ss), Oconomowoc (cc). Otter (ss). Rock (ss).
Round (4) (rrr). Silver (2) (cc), Speese (cc), Tamarack (ss), Taylor (ss),
Tied Canoe (ss).
HYALOBRYON Lauterborn 1896.
Cells solitary or in branching colonies, free-floating or epiphytic.
Receptacle shape and cell contents as in Dinobryon but with the wall
of the receptacle containing a number of successive growth rings instead
of homogeneous. Wall of receptacle more delicate than Dmohryon.
Hyalobryon mucicola (Lemmermann) Pascher. PL 14, Figs. 3-4.
D. iSiisswasserfl. Deutschl., osterr. u. d. Schw. 2, Plagellatae 2: 81, fig. 131. 1913.
Hyalohryon Lauter'bornei var. mucicola Lemmermann, Ber. d. D. bot. Ges.
19: 340. 1901; Bachmann, Arch. f. Hydrob. u. Planktonkde. 8: 81, figs. XP*-
XI”. 1908.
Cells solitary, epiphytic upon gelatinous envelope of colonial Myxo-
phyceae, Chlorophyceae and Phaeophyceae. Receptacle delicate, upper
portion cylindrical and with a flaring mouth, lower portion conical and
with a short stipe. Growth rings of receptacle numerous. Protoplast
ovoid, attached to base of receptacle, with two golden-brown chromato-
phores, two cilia of unequal length and an eyespot. (Euplanktont).
Receptacles 4-6 ix broad, 25-45 fx long ; stipe 4-12 ix long.
Crawling Stone (r), Lac du Flambeau (sss), Long (3) (c), Mud (2) (rr),
Round (1) (rr).
76
WISCONSIN PHYTOPLANKTON
Division HYDRURINEAE.
Cells free-floating or sessile, usually in palmella-like colonies and
motile only at the time of reproduction; rarely solitary, generally in
gelatinous colonies of microscopic to macroscopic size that have a
definite to indefinite shape. Colony capable of growth in all parts or
with growing region restricted to apex. Gelatinous sheath of cells hya-
line, homogeneous or lamellated. Cells ovoid to spherical, with one or
two golden-brown parietal chromatophores and with or without a
definite wall.
Reproduction by pyramidate, spherical, or ovoid zoospores with one
or two cilia.
The members of this division are the connection between the normally
motile and the highly differentiated sessile Phaeophyceae.
Order PHAEO CAPS ALES.
Cells generally organized into free-floating, spherical, ellipsoid, or
elongate colonies. Growth of colony taking place in all parts and not
restricted to the apical region. Cells variously shaped and with one or
two golden-brown chromatophores.
Reproduction, aside from vegetative cell division, by the formation
of spherical to ovoid zoospores.
The order contains the single family of the Phaeocapsaceae and only
one member of the family, Phaeococcus, is found in the local flora.
PHAEOCOCCUS Borzi 1892.
Cells in spherical, ovoid, or irregularly shaped free-floating colonies
enclosed by a copious, hyaline, homogeneous or slightly lamellated,
gelatinous envelope. Cells ellipsoid to sub-spherical or spherical. Cell
number a multiple of two in young colonies, indefinite in older colonies.
Cells containing one or more golden-brown chromatophores, sometimes
with a red pigment spot.
Reproduction by vegetative cell division or direct metamorphosis of
cell contents into biciliate ovoid to pyriform zoospores.
Phaeococcus planctonicus W. & G. S. West. PI. 14 , Fig. 6.
Trans. Roy. Soc. Edinb. 41; 496, pi. 6, figs. 15-16. 1905.
Cells spherical to sub-spherical, generally distributed in small clumps
within a copious, hyaline, homogeneous or radially fibrillar, gelatinous
envelope. Number of cells in colony generally 16-64. Cells contain-
WISCONSIN PHYTOPLANKTON
'll
ing 1-2 parietal, disciform to bell-shaped, golden-brown chromatophores
with smooth or irregular margins. (Euplanktont).
Cells T.2-9.6 in diam. ; colonies 50-250 ft in diam.
Carson (ss), Clear Crooked (c), Crawling Stone (rr), Devils (1) (ss), Hill-
man (rr), Jennie (r), Mary (s), Mendota (sss), Pokegama (1) (rr), Sand
(4) (rr), Shell (ss), Silver (2) (s). White Sand (rr).
Division RHIZOCHRYSIDINAE.
Algae that are known in the rhizopodial stage only, although the
power to form a motile phase is presumed to be present. Cells solitary
or in small colonies, always free-floating. Cells with rhizopodial pro-
cesses and with or without a differentiated periplast. Cells with 1-2
golden-brown chromatophores, and with or without numerous vacuoles.
Reproduction by vegetative cell division.
This is an entirely artificial group where rhizopodial forms are placed
pending further elucidation of their life histories. Since the group
contains such doubtful forms no attempt has been made to differentiate
the orders and families.
KEY TO THE GENERA.
Cells solitary or in irregular colonies Rhizochrysis
Cells joined in a linear series to form colonies Chrysidastrum
RHIZOCHRYSIS Pascher 1913.
Cells free-floating, solitary or in colonies that are naked or enclosed
by a gelatinous sheath. Cells without a differentiation of the periplast
but with few or numerous, delicate, pseudopodial processes. Cells with
one or two golden-brown chromatophores and numerous vacuoles, of
small size when united in colonies.
Rhizochrysis limnetica sp. nov. PI. 14, Fig. 6.
Cells solitary, free-floating, without a differentiation of the periplast
but with numerous spicule-like processes extending in all directions.
Cells approximately spherical, with one golden-brown chromatophore
and numerous vacuoles. (Euplanktont).
Diam. cells (without processes) 35-45 ft.
Beasley (sss), Birch Island (rr), Crawling Stone (rr), Deer (rr), Diamond
(rrr), Half Moon (rr). Horse (rr), Kitten (sss), Lac du Flambeau (r). Long
(3) (sss). Marl (rrr), Nemahbin (ss), Oconomowoc (rr), Okauchee (rrr),
78
WISCONSIN PHYTOPLANKTON
Otter (rrr), Pokegama (2) (r), Rainbow (1) (r), Round (3) (rr), Sand (4)
(sss), Taylor (r), Upper Nashotah (r), Wildcat (sss).
This species is quite unlike other members of the genus since the
processes are much more delicate and the cells larger.
CHRYSIDASTRUM Lauterborn 1913.
Cells joined to one another by pseudopodial processes and arranged
to form free-floating linear colonies of 2-16 cells that are not enclosed
by a gelatinous envelope. Cells spherical, with the periplast undiffer-
entiated but extending into several long, delicate, pseudopodia-like pro-
cesses. Chromatophore single, central, and laminate to band-shaped.
Reproduction unknown.
Chrysidastrum catenatum Lauterborn. PI. 14 , Figs. 7 - 8 .
in Pascher, D. Siisswasserfl. Deutschl., dsterr. u. d. Schw. *2, Flagellatae 2: 91,
f.cj. 144. 1913.
Specific characters the same as those of the genus. (Euplanktont).
Diam. cells (without processes) 12-15 /a; (with processes) 45-60 fi.
Kitten (rr), Mud (2) (rr), Wildcat (rrr).
The cell shape is quite like that of Chrysamoeha but the definite or-
ganization into a linear colony and the single laminate chromatophore
are points of difference. The alga should also be compared with RMzo-
chrysis planctonica Pascher.
WISCONSIN PHYTOPLANKTON
79
Class HETEROKONTEAE.
Cells microscopic or macroscopic; free-floating, sessile, or epiphytic.
Cell shape spherical, ovoid, pyriform, cylindrical or irregular. Cells
solitary, in colonies of regular to irregular shape, or united to form
simple filaments. Colonies or individual cells with or without a gelat-
inous envelope. Chromatophores one to many, parietal, generally disci-
form, rarely laminate, yellowish- green in color and without a pyrenoid.
Assimilation product oil, never starch. Cells uninucleate or multinu-
eleate.
Asexual reproduction by vegetative cell division and a formation of
zoospores. Zoospores ovoid to pyriform, with two cilia of unequal
length and generally more than one yellowish-green chromatophore.
Sexual reproduction, insofar as known, isogamous, by zoogametes that
are similar in structure to the zoospores.
The various genera of the Heterokontae were formerly scattered
throughout the different families of the Chlorophyceae. The distinguish-
ing characteristics of this class are the yellowish-green chromatophores
without pyrenoids, with oil not starch the assimilation product; and
zoospores with two cilia of unequal length. There are three orders in
the class and representatives of all three are found in Wisconsin lakes.
KEY TO THE ORDERS.
V'egetative cells motile Heteeochloridales
Vegetative cells immobile.
Cells solitary or in colonies, never in filaments Heteeococcales
Cells united to form simple filaments Heteeotrichales
Order HETEROCHLORIDALES.
Cells solitary, free-swimming, ovoid to pyriform in shape. Motile
phase dominant, rarely metamorphosing over into an amoeboid or pal-
mella phase. Cells with two cilia of unequal length, one or more chro-
matophores of a yellowish-green color and without an eyespot. Assimi-
lation product leucosin or fat, never starch.
Asexual reproduction by vegetative division of cells.
Sexual reproduction unknown.
The order has but one family, the Chloramoebaceae, whose characters
are those of the order.
80
WISCONSIN PHYTOPLANKTON
CHLOROCHROMONAS Lewis 1913.
Cells solitary, generally free-swimming, very rarely amoeboid, some-
times attached to substratum by a posterior pseudopodia-like structure.
Cell shape pyriform to sub-ovoid, with an oblique depression at the
anterior end. Cilia two, at the anterior end of the cell and of unequal
length. Chromatophores two, yellowish-green in color, oblong with
rounded ends in front view, somewhat flattened in side view. Cells
with a single anterior vacuole, one nucleus, and without an eyespot.
Nutrition holophytic or saprophytic.
Reproduction by longitudinal fission when in the motile phase.
Chlorochromonas minuta Lewis. PI. 15, Figs. 1-3.
Arch. f. Protistenkunde 32: 254, ph 12, figs. 1-24. 1913.
Characters as described above. (Euplanktont).
Cells 4.5-9.5 (av. 6.3) p, long, with an average breadth of 4.7 p.
Average length of longer cilium 12.5 p, of the shorter 2.9 p.
Mendota.
This organism was first found by Lewis in a dish containing sections
of basswood {Tilia americana) that had been standing for some time in
a dish of tap water, which is drawn directly from Lake Mendota. I
have never noted the alga in plankton collections but have no doubt
but that a continued search will demonstrate its presence in Lake Men-
dota. During the past winter (1917-18) the alga appeared in an in-
fusion of fern leaves which had been standing for some time in tap
w^ater. This shows that the original source of the alga was the water
with which the sections were moistened and not the Tilia.
Order HETEROCOCCALES.
Cells spherical, ovoid, saccate, or elongate cylindrical ; solitary or in
colonies of definite or indefinite shape; free-floating or sessile. Cells
of colonies embedded in a hyaline, gelatinous envelope or a tough elastic
membrane. Chromatophores one to many, yellowish-green to nearly
grass-green in color and with oil not starch the assimilation product.
Asexual reproduction by vegetative cell division and a formation of
zoospores with cilia of unequal length.
Sexual reproduction by a fusion of zoogametes that are similar in
stT'ucture to the zoospores is known in certain genera.
WISCONSIN PHYTOPLANKTON 81
KEY TO THE FAMILIES.
Cells epiphytic Chlobosaccaceab
Cells free-floating.
Length of cells several times the diameter Ophiocytiaceae
Length of cells less than twice the diameter.
Cells irregularly distributed throughout an ovoid
gelatinous envelope Chlorobotrydaceae
Cells arranged about a common center within an
irregular gelatinous envelope Botryococcaceae
Family CHLOROSACCACEAE.
Cells epiphytic, solitary, gregarious, or embedded in an amorphous
gelatinous matrix. Chromatophores one to several, parietal, of a yel-
lowish-green color, with oil not starch the assimilation product.
Asexual reproduction by a formation of zoospores that presumably
have two cilia of unequal length.
Sexual reproduction by the fusion of isogamous zoogametes.
PERONIELLA Gobi 1887.
Cells epiphytic upon other algae, solitary or gregarious. Shape of
mature cells globular to ovoid, of young cells pyriform to ovoid. Cells
attached to substratum by a delicate hyaline stipe that is usually some-
what longer than the cell. Chromatophores one to two, pale yellowish-
green, without pyrenoids or starch and with oil as the assimilation
product.
Asexual reproduction by the division of cell contents into 2-4-8 uni-
ciliate ( ?) zoospores that are liberated by a lateral rupture of mother
cell wall. Zoospores swarming a short time and then coming to rest
upon substratum and developing into vegetative cells.
Peroniella planctonica G. M. Smith. PI. 15, Fig. 4.
Bull. Torr. Bot. Cl. 43: 476, pi. 25, M- 15. 1916.
Cells broadly ovoid to pyriform, with a long, delicate, hyaline stipe
that is without a disc or other enlargement at the base. Chromato-
phores usually single, rarely two, pale yellowish-green, without pyre-
noids or starch. (Euplanktont).
Cells (without stipe) 6-9.5 /a long; (with stipe) 15-18 /a. Stipe 8-10 /a
long, 1.2 /A broad.
In gelatinous envelope of SpJiaerozosma filaments.
Devils (1) (rr).
6
82
WISCONSIN PHYTOPLANKTON
Family CHLOROBOTRYDACEAE.
Cells solitary or in free-floating colonies enclosed by a copious, homo-
geneous, gelatinous envelope. Colony generally with a small number
of cells and with cell number a multiple of two. Cells spherical, ovoid,
angular, or cylindrical j with a firm cell wall that is sometimes impreg-
nated with a slight trace of silica ; and with one to many parietal, disci-
form, yellowish-green chromatophores without pyrenoids.
Asexual reproduction by vegetative cell division or a formation of
zoospores with two cilia of unequal length.
CHLOROBOTRYS Bohlin 1901.
Cells rarely solitary, generally in colonies of 2-4r-8-16 or more em-
bedded in a copious, homogeneous, hyaline, gelatinous envelope. Cells
spherical to broadly ovoid, with a heavy wall that sometimes contains
a small amount of silica. A conspicuous red pigment spot present in
cells at times.
Reproduction by vegetative division of cells in three directions.
KEY TO THE SPECIES.
Cells ovoid, with few chromatophores C. Limneticus
Cells spherical, with numerous chromatophores C. Reguiabis
Chlorobotrys regularis (W. West) Bohlin. PI. 15 , Fig. 10 .
Bih. kgl. Sv. Vet.-Ak. Handl. 27, Afd. 3, No. 4: 34. 1901; W. & G. S. West,
Jour, of Bot. 41 : 78, pi. 447, figs. 7-10. 1903.
Chlorococcum regulare W. West, Jour. Roy. Micr. Soc. 1892: 737, pi. 10,
fig. 55. 1892.
Cells spherical to subspherical ; rarely solitary, generally in colonies
of 2-4-8-16 enclosed by a copious, hyaline, homogeneous, gelatinous
envelope. Cell wall thick, sometimes containing a trace of silica.
Chromatophores yellowish-green, disciform, parietal, 6-30 in each cell.
Cells at times containing a single conspicuous red pigment spot. (Ty-
choplanktont).
Diam. cells 10-27 p. Diam. colonies 35-90 p.
North Turtle (rrr).
Chlorobotrys limneticus G. M. Smith. PI. 15, Fig. 9.
Trans. Wis. Acad. Sci., Arts, & Lett. 19^: 653, pi. 14, fig. 10. 1918.
Cells ovoid, irregularly distributed within a homogeneous, hyaline,
gelatinous envelope. 10-30 cells in a colony. Chromatophores 3-4,
WISCONSIN PHYTOPLANKTON
83
pale yellowish-green, disciform, parietal, and without pyrenoids. (Eu-
planktont) .
Cells 5-6 broad, 6-8 fx long. Diam. colonies 40-200 /x.
Camp (rr).
Family BOTRYOCOCCACEAE.
Cells always in free-floating colonies of deflnite or indefinite shape.
Number of cells in colony generally indefinite, few or many. Colony
enclosed by an envelope that may be hyaline or colored, gelatinous or
leathery. Cells usually ovoid, rarely spherical; with 1-2 parietal,
laminate to disciform, yellowish-green to nearly grass-green chromato-
phores without pyrenoids and with oil as the assimilation product.
Asexual reproduction by vegetative cell division. Zoospore forma-
tion or sexual reproduction unknown.
BOTRYOCOCCUS Kiitzing 1849.
Cells in free-floating colonies of indefinite shape. Cells closely ap-
posed to one another and enclosed by a gelatinous or tough membrane
that is sometimes wrinkled and folded. Colonies generally with cells
in several aggregates that are connected by broad or delicate strands
of the colonial integument. Cell shape spherical, ovoid, or cuneate.
Groups of cells arranged in a single layer around a common center, or
irregular in arrangement. Chromatophore single, parietal, laminate
to disciform, yellowish-green to nearly grass-green in color and without
a pyrenoid.
Reproduction by vegetative division of cells.
KEY TO THE SPECIES.
Cells held together by a thin gelatinous envelope B. Sudeticus
Cells held together by an irregular tough membrane.
Membrane completely enclosing cells B. BRAmm
Membrane covering base only of cells B. Peotuberans var. Minor
Botryococcus sudeticus Lemmermann. PI. 15, Fig. 8.
Forschungsbr. a. d. Biol. Stat. zu Plon. 4: 111, figs. 6-7. 1896.
Botryococcus Braunii G. S. West non Kiitzing, Brit. Freshw. Algae 237, figs.
106A-106B. 1904; G. M. Smith, Trans. Wis. Acad. Sci., Arts, & Lett. 18 ": 545
1916.
Colonies free-floating ; spherical or irregular ; with cells held in botry-
oidal clusters by a hyaline gelatinous envelope and frequently joined
10 one another by broad or narrow strands of the gelatinous envelope.
Cells spherical to subspherical, 16-32 or more in each botryoidal group.
84
WISCONSIN PHYTOPLANKTON
and arranged around a common center. Chromatophore single, cup-
shaped to disciform, without a pyrenoid. (Euplanktont).
Diam. cells 6-13 fx.
Clear (rr), Waubesa (rrr).
This is the B. Braunii Ktz. of the preliminary list, the identification
being based upon G. S. West’s description of B. Braunii in his British
Freshwater Algae. Dr. West has since informed me that the Ineffigiata
neglecta of that work is B, Braunii Ktz. and the B. Braunii described
therein is B. sudeticus Lemm.
Botryococcus Braunii Kiitzing. PL 15, Fig. 5.
Species algarum 892. 1849; Presenius, Abh. Senckenb. Naturf. Ges. 2: 239,
pi. 11, figs. 27-33. 1858.
Ineffigiata neglecta W. & G. S. West, Jour. Roy. Micr. Soc. 1897 : 503. 1897;
Jour, of Bot. 41 : 80, pi. 447, figs. 1-6. 1903.
Cells joined in small free-floating colonies of irregular shape that are
without a conspicuous gelatinous envelope but completely enclosed by
a tough, elastic, hyaline to orange colored membrane that is pro-
duced into irregular wrinkles, folds, and spines. Colonies frequently
united to form compound colonies by long delicate projections of the
colonial envelope. Cells ovoid or ellipsoid in shape and forming a
single layer around a central cavity. Chromatophore single, cup-shaped
to laminate, yellowish-green to nearly grass-green in color, without a
pyrenoid. Assimilation product a reddish oil that may color the whole
colony a brick red. (Facultative planktont).
Cells 3.5-5.5 fx broad, 5.7-10.5 fx long. Simple colonies up to 100 g.
in diam. ; compound colonies up to 1.5 mm.
Balsam (rr). Bear (3) (rr). Bear Trap (rrr), Beaver (2) (rr), Beaverdam
(ss), Birch Island (rrr), Birch (2) (rr), Boulder (rrr). Browns (sss). Camp
(rrr), Carson (r). Center (r). Chain (rrr), Chetac (rr). Clam (rrr), Clare
(r), Cochrane (rrr). Crawling Stone (rr). Crooked (sss). Deer (rr), Delavan
(rrr), Des Moines (rr). Devils (1) (r). Devils (2) (r). Devils (3) (rrr),
East (rr), Elizabeth (rr). Green (1) (rr). Green (2) (rrr). Grindstone (r).
High (rr). Horse (rrr). Horseshoe (1) (rr), Island (rr), Jennie (rr), Jones
(rrr), Kawaguesaga (rrr), Kegonsa (r), Kimball (rrr). Kitten (rrr). Lac
Court Oreilles (sss). Lac du Flambeau (rrr), Little Bass (1) (rrr). Little
Butternut (rrr). Little Crooked (rrr). Little Doctor (rr). Little Rice (1) (rr).
Long (1) (rrr). Lower Nashotah (r). Lynx (rr), Mary (sss), Mendota (ss),
Mercer (rrr). Mill (rrr), Monona (sss). Mud (3) (rrr). Mud Hen (sss), Nancy
(r), Nicaboyne (rrr). No Mans (rr). Paddock (r). Palmer (rrr), Pardee (sss).
Pike (rrr), Pokegama (1) (rrr), Pokegama (2) (rrr). Poor Farm (rrr). Re-
serve (rr). Rice (1) (rr). Round (2) (rrr), St. Croix (rrr). Sand (1) (r).
Sand (2) (rr). Sand (3) (rr), Sand (4) (rrr), Shell (rr). Silver (2) (r),
Sishebogema (rr). South Turtle (rr). Spirit (rrr). Tied Canoe (rrr), Travis
(rrr). Upper Nashotah (sss), Wapagossett (rr), Waubesa (r). White Ash
(rrr), Whitefish (rrr), Wildcat (rrr), Winnebago (rrr). Wolf (rrr).
WISCONSIN PHYTOPLANKTON
85
Botryococcus protruberans var. minor G. M. Smith. PI. 15, Figs. 6-7.
Trans. Wis. Acad. Sci., Arts, & Lett. 19': 652, pi. 14, figs. 6-7. 1918.
Cells in colonies of 4-8-16 or more held together by a tough gelat-
inous membrane. Colonies frequently joined to one another by long
hyaline strands of the colonial envelope. Cells ovoid to cuneate-ovoid,
with their bases embedded in the colonial envelope and their apices
not enclosed by the envelope. Cells arranged in a single layer around
a central cavity. Chromatophores single, yellowish-green, laminate,
occupying the median portion of the cell. (Euplanktont).
Cells 8-9.5 /A long, 5-6.5 fi broad at the widest part.
Diamond (rrr), George (aa), Hillman (rr), Lindy (rr). Oak (ss), Pardee
(rr), Sanford (rr), South Crab (s).
This species is distinguished from the foregoing by the smaller num-
ber of cells in the colony and the projection of the apex of the cells
through the colonial integument.
Family OPHIOCYTIACEAE.
Cells sessile or free-floating, solitary or colonial. Length of cells
generally several times the breadth. Cells straight, curved, sigmoid, or
spiral; with or without terminal spines. Chromatophores yellowish-
green ; annular, parietal and few in number ; or disciform, parietal and
numerous ; without pyrenoids and with oil as the assimilation product.
Asexual reproduction by division of cell contents to form 4-16 aplano-
spores or 2-8 biciliate zoospores with cilia of unequal length.
Sexual reproduction unknown.
OPHIOCYTIUM Nageli 1849.
Cells free-floating or epiphytic, solitary or colonial ; straight, arcuate,
sigmoid, or spiral elongate cylinders with rounded or capitate ends
that may be apiculate or attenuated into a single spine. Chromato-
phores pale yellowish-green, H-shaped in optical cross section, without
pyrenoids and with oil as the assimilation product. Cells coenocytic.
Cell wall consisting of a homogeneous cap at one end and with the re-
maining portion of the wall composed of a number of laminate layers.
Asexual reproduction by division of cell contents to form 4-16 aplano-
spores or 2-8 biciliate zoospores with cilia of unequal length.
86
WISCONSIN PHYTOPLANKTON
KEY TO THE SPECIES.
Poles of cells without spines O. Pabvulum
Poles of cells with spines O. Capitatum
Ophiocytium parvulum (Perty) A. Braun. PI. 15, Fig. 11.
Alg. unicell. 55. 1855; Lemmermann, Hedwigia 38; 33, pT. 4, figs. 30-'33. 1899.
Cells cylindrical, several times as long as broad; straight, arcuate, or
spiral; poles rounded and without spines. Chromatophores several,
H-shaped in cross section, pale yellowish-green. Oil droplets rarely
present. ( Tychoplanktont) .
Cells 3-9 fi broad.
Fishtrap (rrr).
Ophiocytium capitatum Wolle. PI. 15, Figs. 12-13.
Freshw. Algae of U. S. 176, pi. 158, figs. 3-7. 1887.
Cells solitary ; arcuate, sigmoid, or spiral cylinders with poles rounded
and the same size as or slightly larger than the median portion of the
cell. Length of cell 5-10 times the breadth. Poles of cells with a
single short, straight, or slightly curved spine. (Tychoplanktont).
Cells 5-10 /X broad, up to 85 fx long. Spines 5-7 /x long.
Tied Canoe (rrr).
var. LONGiSPiNUM (Mobius) Lemmermann. PI. 15, Figs. 14^16.
Hedwigia 38 : 32, pi. 4, figs. 21-25. 1899.
Cells cylindrical ; straight, arcuate, or spirally twisted, with a single
long spine at each pole that is nearly as long as the cell. (Euplank-
tont).
Diam. cells 4.5-6 fx. Length of spines 16-50 fx.
George (rr), Loon (rr).
Order HETEEOTRICHALES.
Cells in simple, unbranched filaments; with or without a gelatinous
envelope. Cell wall firm, fairly thick, lamellated in structure and
breaking down into H-shaped pieces at the time of reproduction. Chro-
inatophores few to several, yellowish-green, disciform, and parietal.
Cells usually uninucleate. Assimilation product oil, not starch.
Asexual reproduction by the formation of aplanospores or by zoo-
spores with two cilia of unequal length.
WISCONSIN PHYTOPLANKTON
87
Sexual reproduction by the fusion of isogamous zoogametes.
There is but one family in the order, the Tribonemaceae, whose char-
acters are the same as those of the order.
TRIBONEMA Derbes and Solier 1856.
Cells in simple unbranched filaments destitute of an enveloping gelat-
inous sheath. Cells cylindrical or barrel-shaped, with flattened end
walls. Cell wall frequently of considerable thickness and laminate in
structure. Chromatophores two to several, yellowish-green, disciform,
parietal, without starch and with oil as the assimilation product.
Asexual reproduction by aplanospores and biciliate zoospores that
have cilia of unequal length. The cell wall pulling apart and breaking
down into H-shaped pieces at the time of reproduction.
Sexual reproduction by the fusion of isogamous zoogametes.
Tribonema minus (Wille) Hazen. PI. 15, Figs. 17-18.
Mem. Torr. Bot. Cl. 11: 185, pi. 25, figs. 7-8. 1902.
Filaments generally forming a floccose yellowish to greenish mass.
Cells cylindrical or slightly swollen in the median portion, generally
2-4, rarely 6, times as long as broad. Chromatophores 2-4, yellowish-
green, disciform, parietal, generally in pairs. (Facultative planktont).
Cells 5-6 /A broad, 10-35 fi long.
Green (1) (rrr), Mendota (s).
Members of this genus are frequently found in ditches but seldom in
lakes. During the past season T. minus has appeared in considerable
quantity in the plankton of Lake Mendota, although previous to this
time the alga has not been found in the plankton. A similar sudden
appearance of T. homhycina forma depauperata Wille, a form closely
related to T. minus, has been noted in the plankton of Danish lakes by
Wesenberg-Lund (Studier over de danske soers Plankton p. 100.
Kjobenhavn, 1904).
88
WISCONSIN PHYTOPLANKTON
Class CHLOROPHYCEAE.
Cells with the coloring matter restricted to definite bodies that are
grass-green in color (chloroplasts). Cells free-floating, sessile, epi-
phytic, epizootic, or endophytic ; solitary, in microscopic to macroscopic
colonies of definite or indefinite shape that are naked or enclosed by a
hyaline to colored, homogeneous or lamellated, firm or gelatinous en-
velope. Colonies with all of the cells morphologically alike or differen-
tiated. Colonies growing in all directions; forming simple, laminated,
or parenchymatous plates; or developing into simple or branched fila-
ments. Cells motile throughout the whole life history, for a portion
of it, or immobile at all times. Cells variously shaped ; spherical, hemi-
spherical, ovoid, ellipsoid, spindle-shaped, acicular, reniform, angular,
irregular, cylindrical, conical, simple to branching tubular, or con-
stricted to form two symmetrical halves of various shapes. Cells con-
taining one or more disciform, laminate, cup-shaped, astral, ribbon-like,
or reticulate chloroplasts that are parietal, axial, or central in position
and have one or more centers for the synthesizing of starch (pyrenoids) .
Assimilation product oil in a few cases. Cells uninucleate or multinu-
cleate (coenocytic) ; containing a central vacuole, numerous small vacu-
oles, or without vacuoles. Contractile vacuoles chiefly confined to the
motile genera.
Asexual reproduction by vegetative cell division, aplanospores, zoo-
spores, or akinetes.
Sexual reproduction by isogamous or heterogamous zoogametes, isoga-
mous aplanogametes, or heterogamous motile antherozoids and immobile
oospheres. Zygotes germinating immediately, or after a period of rest ;
with a direct or an indirect germination into the plant bod}".
KEY TO THE DIVISIONS
Sexual or asexual reproductive bodies with 2-4 cilia of equal length. . I sokontak
Sexual or asexual reproduction by non-ciliate reproductive bodies Akontae
Division ISOKONTAE.
Cells solitary or in colonies and showing the same great range of
variation in shape, organization of the colony, interior structure, and
method of reproduction noted in the description of the class.
Included in this division is the important plankton family of the
Autosporaceae where no motile phase of reproduction is known. The
WISCONSIN PHYTOPLANKTON
89
close phylogenetic connection between the Autosporaceae and the other
members of the Protococcales is, however, perfectly evident.
KEY TO THE ORDERS.
Cilia normally present throughout the whole life cycle Volvocalks
Cilia present at time of reproduction only.
Cells in simple or branched filaments.
Cells uninucleate, with a single laminate chloroplast. . . .Ulotrichalxs
Cells multinucleate, with one or more chloroplasts. .Siphonooladiales
Cells solitary or in simple colonies, generally of microscopic
size Protococcales
Order VOLVOCALES.
Cells normally ciliate and motile during the vegetative phases of the
life cycle. Solitary or organized into colonies of definite form that
generally contain a definite number of cells. Protoplasts rarely naked,
usually with a differentiated outer cellulose covering that may be par-
tially gelatinized. Shape of protoplast spherical, ovoid, disciform,
pyramidate, or irregularly radiate. Cells with a single cup-shaped to
irregular chloroplast, with or without pyrenoids ; with 2-4 cilia at the
anterior end; generally with a disciform to bacilliform eyespot, two to
several contractile vacuoles, and one nucleus. Palmella stages fre-
quently arising in the unicellular members.
Asexual reproduction by division of cell contents into 2-16 zoospores ;
or a development of special, or all cells of the colony into autocolonies.
Sexual reproduction by isogamous zoogametes; heterogamous zoo-
gametes; or small motile antherozoids and large immobile oospheres.
Many hold with G. S. West (Algae 151, 1916) ^‘that it is very doubt-
ful if the Volvocineae have sufficient claims to be removed from the
Protococcales and elevated to a group of equal rank (the ‘ Volvocales’)
There is a very close relationship between the ‘‘palmella^’ stage of
various unicellular Volvocales and the family Palmellaceae of the Pro-
tococcales. This represents to me, however, a close phylogenetic rela-
tionship between the two and not a justification for uniting in the same
order forms with mobile vegetative cells and those which are immobile.
KEY TO THE FAMILIES.
2 cilia at the anterior end of cells.
Cells solitary CnLAMYDOMOif adaceae
Cells in definite coenobia Volvocaceae
4 cilia at the anterior end of cells Carteriaceae
90
WISCONSIN PHYTOPLANKTON
Family CHLAMYDOMONADACEAE.
Cells normally solitary and motile during the vegetative phases of
the life history. Spherical, ovoid, cylindrical, sub-acicular, compressed,
or quadrately projected. Chloroplast cup-shaped to laminate, lateral
or posterior in position, with or without pyrenoids. Cells uninucleate,
with or without an eyespot, with two cilia of equal length that generally
have two contractile vacuoles at their base. Cells at times becoming
immobile and developing into amorphous colonies enclosed by a wide
gelatinous envelope.
Asexual reproduction by the division of cell contents to form 2-16
biciliate zoogametes.
Sexual reproduction by the fusion of isogamous zoogametes.
CHLAMYDOMONAS Ehrenberg 1832.
Cells normally solitary and motile ; though capable of coming to rest,
losing the cilia, developing a gelatinous envelope and dividing vegeta-
tively to form colonies containing an indefinite number of cells. Cells
spherical, fusiform, ovoid, pyriform, or ellipsoid ; with two cilia of equal
length at the anterior end. Chloroplast typically cup-shaped, posterior,
and with one pyrenoid. Cells uninucleate, generally with two con-
tractile vacuoles at the base of the cilia; with or without an eyespot
which, when present, lies in the anterior portion of the cell.
Asexual reproduction by division of cell contents to form 2-16 bicili-
ate zoospores.
Sexual reproduction isogamous, by the division of cell contents into
8-64 zoogametes that fuse in pairs to form smooth-walled or sculptured
zygotes.
KEY TO THE SPECIES.
Cells spherical.
Anterior end without a beak C. Globosa
Anterior end with a pronounced beak C. Epiphytica
Cells ovoid.
Chloroplast cup-shaped and basal C. Snowti
Chloroplast laminate, lateral, or basal C. Dhtobryonj
Chlamydomonas globosa Snow. PI. 16, Fig. 8.
Bull. U. S. Fish Comm. 22: 389, pi. 1, figs. IIP-III®. 1903.
Cells spherical or slightly ellipsoid, without an anterior beak. Chloro-
plast cup-shaped, occupying the greater portion of the cell, with one
pyrenoid at the posterior end. Eyespot present, small, generally in the
middle third of the cell. Cilia slightly longer than the cell and with a
WISCONSIN PHYTOPLANKTON
91
single contractile vacuole at their base. Palmella stages frequent and
usually containing 4-8 cells. (Euplanktont).
Cells 5-10 fji broad.
Crawling Stone (rr).
Chlamydomonas epiphytica sp. nov. PI. 16, Figs. 11-13.
Cells spherical to pyriform, with a very pronounced anterior beak.
Chloroplast cup-shaped, forming a thin layer next to the cell wall, with
a single pyrenoid at the posterior end. Eyespot conspicuous, disciform,
at the anterior end of the cell. Cilia more than twice as long as the
cell. Cells frequently coming to rest in the gelatinous envelope of
Microcystis colonies but not losing the eyespot and usually retaining
the cilia. (Euplanktont).
Cells 7-8 broad, 8-9 fi long ; cilia 20-25 fi long.
Elizabeth (s), Mary (sss).
The alga is frequently found in the gelatinous envelope of Microcystis
colonies and suggests an epiphytic CJiaracmm but the presence of cilia
shows that it is a ChlaniydomoTias.
Chlamydomonas Snowh Printz. PI. 16, Figs. 9-10.
Skr. Vidensk.-Selsk. i Kristiana, Mat.-Naturv. Kl. 1913': No. 6: 18. 1914.
Chlamydomonas communis Snow, Bull. U. S. Fish Comm. 22: 388, pi. 1,
figs. ir-IP. 1903.
Cells motile but frequently forming palmella stages containing a
considerable number of cells. Cell shape ovoid to ellipsoid, with a very
inconspicuous anterior beak. Chloroplast cup-shaped, massive in the
posterior portion, with one pyrenoid at the center of the cell. Cilia
slightly longer than the cell; eyespot inconspicuous, variable in posi-
tion. (Facultative planktont).
Cells 6.5-8 fi broad, 10-15 y. long.
Nancy (rr).
Chlamydomonas dinobryoni sp. nov. PI. 16, Pigs. 5-7.
Cells rarely free-swimming, generally in large numbers and filling
the empty receptacles of Dinohryon colonies. Cells small, ovoid to pyri-
form in shape, without an anterior beak; with two short cilia at the
anterior end. Chloroplast disciform to hemispherical, basal or lateral
in position, containing a p 3 rrenoid. Eyespot and contractile vacuoles
not observed. (Euplanktont).
Cells 2-3 y broad, 3.5-5 y long; cilia 6-8 y long.
Lac du Flambeau (ss), Long (3) (s), Pokegama (2) (r).
92
WISCONSIN PHYTOPLANKTON
Many of the empty Dinohryon receptacles in these three connecting
lakes were filled with a minute green organism. These had cilia, even
when in the receptacle, and on the slightest crushing of the receptacle
began swimming around outside of it. Since cilia are constantly pres-
ent the alga is a CMamydomonas and not one of the Palmellaceae col-
lected at the time of reproduction.
Family CARTERIACEAE.
Cells normally motile and with four cilia of equal length at the an-
terior end. Solitary, or in coenobia containing a definite number of
cells. Cell shape spherical, ovoid, ellipsoid, cardioid, pyriform, or
lenticular. Cells enclosed by a definite wall, and with or without a
cup-shaped to lenticular chloroplast that is with or without pyrenoids.
Eyespot generally present, conspicuous, and at the anterior end of the
cell. Cells frequently with contractile vacuoles at the base of the
cilia. Palmella stages known in the solitary members of the family.
Asexual reproduction by the division of cell contents into 2-16 tetra-
ciliate zoospores or into autocolonies.
Sexual reproduction isogamous, by a fusion of tetraciliate zoogametes.
CARTERIA Diesing 1866.
Cells solitary, generally motile throughout the vegetative phases of
the life cycle. Spherical, ovoid, ellipsoid, or cardioid in shape; with
four cilia of equal length at the anterior end. Cell contents consisting
of a single cup-shaped chloroplast that contains a pyrenoid; one eye-
spot; and two contractile vacuoles at the base of the cilia. Palmella
stages containing an indefinite number of cells are found at times.
Asexual reproduction by division of cell contents to form 2-8 tetra-
eiliate zoospores.
Sexual reproduction by the division of cell contents to form 4-64
tetraciliate zoogametes that fuse in pairs to form zygotes with smooth
or sculptured walls.
KEY TO THE SPECIES.
Cells ellipsoid C. Klebsh
Cells cardioid C. Cobdiformis
Carteria cordiformis (Carter) Diesing. PI. 16 , Fig. 1 .
Sitzbr. d. k. Ak. d. Wiss. Wien, Mat.-Naturw. Kl. 52?: 356. 1866; Dill, Jahrb. f.
wlss. Bot. 28 : 353, pi. 5, figs. 42-44. 1895.
Cells cardioid in shape with four cilia at the base of the apical de-
pression. Chloroplast cup-shaped, fairly massive, with a single pyre-
WIBC0N8IN PHYTOPLANKTON
93
noid in the posterior region. Cells with two contractile vacuoles at
the base of the cilia and with a disciform eyespot in the upper third
of the cell. (Tychoplanktont).
Cells 9-16 broad, 12-20 /t long.
Crawling Stone (rrr).
Carteria Klebsii (Dangeard) Dill. PI. 16, Figs. 2-4.
Jahrb. f. wiss. Bot. 28 : 353. 1895; Printz, Skr. Vidensk.-Selsk. Kristiana, Mat.-
Naturv. Kl. 1913': No. 6: 13. 1914.
Pithiscus Klebsii Dangeard, Ann. Sci. Nat. 7 Ser. Bot. 7: 137, pi. 12, figs.
1-6. 1888.
Cells solitary, ellipsoid to ellipsoid-cylindrical, Avith a more or less
prominent beak at the anterior end. Chloroplast cup-shaped, massive,
with a large pyrenoid at the posterior end. Cells without an eye-spot
and with two contractile vacuoles at the base of the cilia. Cilia about
twice as long as the cells. Palmella stages containing many cells at
times. ( Tychoplanktont ) .
Cells 5-10 fi broad, 8-16 fi long.
Pokegama (1) (r).
Family VOLVOCACEAE.
Cells always motile and in coenobia of definite shape that contain a
definite or an indefinite number of cells. Colonies enclosed in a homo-
geneous, hyaline, gelatinous envelope. Cells of colony all alike or dif-
ferentiated into vegetative and reproductive cells. Vegetative cells
spherical, ellipsoid, pyriform or disciform ; with or without connecting
cytoplasmic processes; always biciliate. Chloroplasts generally cup-
shaped and containing one pyrenoid. Vegetative cells usually with an
eyespot and two contractile vacuoles.
Asexual reproduction by the division of all or certain of the cells in
the colony to form autocolonies.
Sexual reproduction by a division of all cells in the colony to form
isogamous zoogametes or heterogamous zoogametes of slightly different
size; or the formation of motile antherozoids from certain cells and
large immobile oospheres from others. Zygotes with smooth or sculp-
tured walls.
94 :
WISCONSIN PHYTOPLANKTON
KEY TO THE GENERA.
Colony with cells in a flat plate Gonitjm
Colony with cells forming a hollow sphere.
Cells mutually compressed Pandobina
Cells some distance from one another.
Asexual reproduction by division of all cells in colony Eudobina
Asexual reproduction by division of special cells.
At least half of cells capable of forming autocolonies. . .PLEonoEmA
Only a few cells capable of forming autocolonies Volvox
GONIUM Mueller 1773.
Colonies of 4^8-16 cells arranged in a flat quadrangular plate and
embedded in a common gelatinous matrix or connected by broad gelat-
inous strands. Cells ovoid to pyriform, with a single cup-shaped chlor-
oplast containing one pyrenoid. Each cell with two cilia of equal
length, contractile vacuoles at the base of the cilia, and an eyespot.
Four- and eight-celled colonies with the cilia on the same side ; sixteen-
celled colonies with the four central cells having their cilia on the same
side and the twelve marginal cells with radially arranged cilia.
Asexual reproduction by simultaneous division of all cells in the
colony to form autocolonies, or by a formation of 2-4 zoospores in each
cell.
Sexual reproduction isogamous, by a fusion of biciliate zoogametes.
Gonium pectorals Mueller. PI. 16 , Figs. 14 - 15 .
Vermium terrestrium et fluviatilium etc. 1: 60. 1773; Migula, Bot. Cent. 44:
72, pi. 2, figs. 1-8. 1890; Harper, Trans. -Am. Micr. Soc. 31: 65, pi. 5, figs. 1-19,
23. 1912.
Colonies containing 4-8-16 cells. Usually with 16 cells arranged in
two concentric series in a flat plate with truncate corners. Cells con-
nected with one another by broad, hyaline, gelatinous processes and
with open spaces between the processes; or with processes indistinct
and the whole colony embedded in a homogeneous, gelatinous matrix.
Outer ring with twelve cells whose long axes lie parallel to the plane
of the coenobe. Inner ring of four cells with a large open space at the
center and their long axes perpendicular to plane of the coenobe. Cells
ovoid to pyriform, with two cilia at the anterior end ; a posterior massive
cup-shaped chloroplast ; an anterior eyespot ; and two contractile vacu-
oles at the base of the cilia. (Tychoplanktont) .
Cells 7-11 fjL broad, 10-25 fi long.
Beaverdam (rrr), Clam (rrr), Duck (rr), Fowler (rrr), Island (r), K»-
consa (rrr), Long (1) (rrr), Mendota (rrr), Number One (rr). Pike (rrr),
Poplar (rrr).
WISCONSIN PHYTOPLANKTON
9S
PANDORINA Bory 1824.
Colonies always motile, spherical to snbspherical, containing 4-8-16-
32 cells mutually compressed to form a hollow sphere with a small
open space at the center. Colony enclosed by a fairly copious, firm,
hyaline, homogeneous, gelatinous envelope. Cells pyriform to angular
by mutual compression, with pointed ends toward the center of the
colony; biciliate at the fiattened distal end, the two cilia lying close
together while passing through the colonial envelope and then becom-
ing markedly divergent. Chloroplast single, massive, cup-shaped, with
one pyrenoid at the base. Eyespot single, generally on distal face of
the cell. Cells with a definite wall and two contractile vacuoles at the
base of the cilia.
Asexual reproduction by simultaneous division of all cells of the
colony to form autocolonies that are liberated by a gelatinization of the
colonial envelope.
Sexual reproduction by a division of each cell of the colony into
16-32 zoogametes. Zoogametes showing indications of heterogamy in
the slight difference in size and motility of the pairs that fuse to form
the smooth walled zygote.
Pandorina morum Bory. PI. 16, Figs. 16-17.
Encyc. meth. hist. nat. de Zoophytes 2: 600. 1824; G. S. West, Brit. Freshw.
Algae 193, figs. 76a-76h. 1904.
Colonies generally 16-celled and as described above. (Facultative
Planktont) .
Cells 8-16 fx broad ; colonies 20-^5 ju, broad.
Bear Trap (rrr), Blake (rrr), Camp (rr), Center (cc), Chetac (rr), Chetek
(ss). Deer (rrr)/. Duck (ss). East (rrr), Fowler (rr). Grindstone (s), Hillman
(rr). Hooker (s), Kegonsa (sss). Lac Court Oreilles (ss), Lindy (rr). Little
Bass (2) (rr). Little Butternut (rr). Little Rice (1) (r). Little Wood (rrr).
Long (1) (rrr), Loveless (rr), Lower Nashotah (rr). Lower Nemahbin (rr).
Lower Turtle (sss), Mendota (ss), Monona (s). Mud (1) (rrr), Nagawicka
(as), Nicaboyne (r), No Mans (rr), Number One (rr), Oconomowoc (rrr),
Okauchee (rrr), Pokegama (3) (r). Prairie (r). Rice (1) (r), St. Croix (rr),
Sishebogema (rr). South Turtle (sss), Upper Nashotah (rr),, Upper Nemahbin
(rr). Upper Turtle (rr), Waubesa (ss), Whitefish (rr), Winnebago (rr).
EUDORINA Ehrenberg 1832.
Colonies always motile, spherical or slightly elongate, of 16-32-64
cells lying some distance from one another and arranged to form a
hollow sphere near the periphery of the homogeneous, hyaline, gelat-
inous envelope. Cells spherical, with or without a beak at the point
of origin of the two cilia. Cilia parallel while passing through the
96
WISCONSIN PHYTOPLANKTON
colonial envelope and then widely divergent. Chloroplast single, cup-
shaped, filling practically the whole cell and generally with several pyre-
noids. Cells with a firm wall, one or two anterior contractile vacuoles,
and a single conspicuous eyespot near the base of the cilia.
Asexual reproduction by a simultaneous division of all cells to form
autocolonies which are liberated by a rupture of the colonial envelope.
Sexual reproduction heterogamous, dioecious, with all cells of a col-
ony developing into large immobile oospheres or plate-like masses of
32-64 fusiform antherozoids ; or monoecious with four cells forming
antherozoids and the remainder oospheres. Zygote smooth-walled.
Eudorina elegans Ehrenberg. PI. 19, Pig. 1.
Abh. d. kgl. Ak. d. Wiss. zu Berlin 1831: 78, pi. 2, 10j^-10d. 1832; G. S.
West Brit. Freshw. Algae 194, figs. 77a-77f. 1904.
Colonies generally 32-celled and as described above. (Facultative
planktont) .
Cells 12-24 jx in diam. ; colonies 50-200 fi in diam.
Balsam (rrr), Bear (3) (ss), Bear Trap (r), Beaverdam (sss). Big Butter-
nut (rr), Birch (2) (ss), Birch Islanjd (rr), Boulder (cc), Bryer (rr). Camp
(cc), Catherine (ss). Center (sss), Chetac (ss), Chetek (s), Clam (rr), Crawl-
ing Stone (rrr), Delavan (sss). Devils (1) (aa). Diamond (sss), Duck (ss),
Dunham (ss), Dutchmans (rrr), Elizabeth (rr). Pish (sss), Fowler (rr).
Granite (ss). Green (2) (rr), Grindstone (rrr), Hillman (rr). Hill (rrr).
Hooker (rr). Horseshoe (1) (rr). Horseshoe (2) (rrr), Howey (rrr). Island
(ss), Jennie (r), Kawaguesaga (rr), Kegonsa (ss). Lac Court Oreilles (rr).
Lac la Belle (rr). Lake of the Woods (S), Lindy (rr). Little Butternut (rr).
Little Wood (rrr). Long (3) (rrr). Loon (rr). Lower Nemahbin (rrr). Lower
Turtle (r). Lynx (rr), Meronk (rrr). Middle McKenzie (rr), Nancy (rr),
Nicaboyne (ss), No Mans (rr). North Turtle (ss). North Twin (rr). Number
One (rr), Okauchee (rr). Paddock (cc). Pine (2) (rrr). Pike (r), Pokegama
(2) (rr), Pokegama (3) (ss). Poplar (rr). Prairie (ss). Reserve (rr). Rain-
bow (rrr). Rice (1) (ss), Rooney (rr). Round (1) (r). Round (2) (rr).
Round (3) (sss). Sand (1) (sss). Sand (4) (rr). Silver (2) (c), Sishebogema
(ss). South Crab (rr). South Turtle (sss). Spirit (sss). Squirrel (ss), Tender-
foot (rrr), Travis (rrr). Vermilion (rr), Waubesa (sss). White Sand (rrr).
PLEODORINA Shaw 1894.
Colonies always motile; spherical to sub-spherical, with 32-128 cells
lying some distance from one another just within the periphery of the
homogeneous, hyaline, gelatinous, colonial envelope and not connected
by cytoplasmic strands. Cells differentiated into those that are purely
vegetative in character and those capable of dividing to form daughter
colonies. All but four cells of the colony reproductive or about half
reproductive and half vegetative. Cells spherical to ovoid in shape.
Vegetative cells with a cup-shaped chloroplast containing one pyrenoid;
WISCONSIN PHYTOPLANKTON
97
a large anterior eyespot ; two cilia of equal length, with two contractile
vacuoles at their base. Reproductive cells at first like the vegetative
cells, later with a more massive chloroplast that eventually contains
several pyrenoids. The eyespot and cilia of reproductive cells disap-
pearing when they are mature.
Asexual reproduction by a simultaneous division of all reproductive
cells to form autocolonies.
Sexual reproduction (which has been observed in one species only)
heterogamous, dioecious, by a division of all reproductive cells to form
plates of 64-128 biciliate, fusiform antherozoids ; or a development of
reproductive cells into oospheres. Zygotes smooth-walled.
The validity of this genus has been questioned by many and the view
put forward that the alga is but a stage in the life history of Eudorina.
Grove (New Phytol. 14; 169-182. 1915) gives a full discussion of the
literature of Pleodorina. Although Eudorina elegans is found in a
large number of Wisconsin lakes, Pleodorina has been found in but
three of them. If Pleodorina is a developmental stage of Eudorina, it
is strange that the ‘‘Pleodorina^’ stage has not been observed with
greater frequency. The young colonies look very much like those of
Eudorina and it is probably on this account that the two have been
confused.
Pleodorina californica Shaw. PI. 17, Figs. 1-3.
Bot. Gaz. 19 : 279, pi. 27, figs. 1-9. 1894.
Colonies containing 64-128 cells. Cells usually spherical and about
half vegetative and half reproductive. Reproductive cells becoming
4-5 times broader than the vegetative cells. (Facultative planktont).
Vegetative cells 6-14 fi in diam. ; reproductive cells 6-34 p. in diam.
Colonies 40-400 p in diam.
Clam (ss). Mud (1) (cc). Sand (1) (r).
VOLVOX L. 1758.
Colonies always motile, spherical to ovoid, containing a large number
of cells arranged in a single layer just within the periphery of the
homogeneous, hyaline, gelatinous, colonial envelope. Cells differen-
tiated into those for vegetative purposes, asexual, and sexual repro-
duction. Vegetative cells close together or some distance from one
another, with or without cytoplasmic connections of varying thickness.
Cell shape spherical, ovoid, or disciform. Individual cells or groups
of cells sometimes enclosed by their own gelatinous envelope. Celk
with two cilia of equal length, 2-6 contractile vacuoles, one nucleus.
7
98
WISCONSIN PHYTOPLANKTON
one eyespot, and a cup-shaped to disciform chloroplast that contains
one pyrenoid. Number of cells in a colony varying from 200-22,000.
Asexual reproductive cells few in number (rarely more than 20) and
forming autocolonies by repeated division, the young colonies migrat-
ing to the center of the coenobe at a certain stage in their development.
Sexual reproduction heterogamous, monoecious or dioecious, with a
development of 6-400 cells into spherical oospheres and few or many
of the cells into antheridia that contain 16-256 biciliate fusiform anther-
ozoids. Zygote with a smooth or stellate wall.
KEY TO THE SPECIES.
Cells with cytoplasmic connections.
Cytoplasmic connections heavy V. Globator
Cytoplasmic connections delicate V. Aureus
Cells without cytoplasmic connections V. Mononae
VOLVOX GLOBATOR L. PI. 18, Figs. 3-5.
Systema natura, Ed. 10: 820. 1758; Cohn, Beitr. z. Biol. d. Pflanzen 1, Heft 3:
93, vl. 2, -figs. 1-6. 1875.
'Colonies large, with many (1,000-22,000) cells that are flattened and
pentagonal to octagonal in surface view. Cells connected to one an-
other by stout cytoplasmic strands. Chloroplast of cells single, flat-
tened and angular, with one pyrenoid. Cells with 2-6 contractile vacu-
oles at the base of the two cilia and with an eyespot. Gelatinous sheaths
of individual cells sharply defined and (in surface view) pentagonal
to octagonal by mutual compression. Generally with 8 asexual repro-
ductive cells giving rise to autocolonies. Colonies commonly monoe-
cious, with 12-40 (generally 20-30) oospheres enclosed by large gelat-
inous vesicles. Antherids a flat plate of 64-256 fusiform antherozoids
with laterally attached cilia. Zygote verrucose, with conical warts.
( Tychoplanktont) .
Cells 2-7.5 (generally 3-5) /a in diam. Colonies 400-800 ^ in diam.
Center (s). Hooker (rr), Kegonsa (rr), Monona (r). Soft (rrr), Wauhesa
(rrr).
VoLvox AUREUS Ehrenberg. PI. 18, Fig. 2.
Die Infusionsthierchen 71, pi. 4, fig. 2. 1838; Klein, Jarhb. f. wiss. Bot. 20:
138, pi. 12, figs. 26-33. 1889.
Colonies spherical, containing a comparatively small (200-4,000)
number of cells. Cells circular in surface view, connected with one
another by very fine cytoplasmic strands. Individual gelatinous sheaths
of cells confluent with the colonial envelope. Cells containing a spheri-
WISCONSIN PHYTOPLANKTON
99
eal chloroplast, one eyespot, and a pair of contractile vacuoles at the
base of the two cilia. 4-14 asexual reproductive cells giving rise to
autocolonies. Colonies generally dioecious, with 3-9 oospheres and
about half of the cells developing into antherids that contain 16-32
fusiform antherozoids with two terminal cilia. Zygote smooth-walled.
(Facultative Planktont).
Cells 5-9 fi in diam. ; colonies 200-680 in diam.
Beaverdam (rrr), Camp (sss), Center (ss), Delavan (ss), Eagle (rr), Eliza-
beth (rrr), Fowler (rrr), Jennie (rrr), Kawaguesaga (rrr), Lac du Flam-
beau (rr). Lac la Belle (rr). Mill (rrr), Oconomowoc (rrr). Paddock (r),
Pokegama (1) (rr), St. Croix (rrr). Silver (2) (rr).
' Volvox mononae sp. nov. PI. 18, Fig. 1.
Colonies spherical, containing a comparatively small (400-2500)
number of cells. Cells spherical, not connected with one another by
cytoplasmic processes. Individual sheaths of cells confluent with colon-
ial envelope. Cells containing a single bell-shaped chloroplast with
one pyrenoid, an eye spot, and two cilia whose length is 2-3 times the
diameter of the cell. 3-10 asexual colonies formed inside the coeno-
bium and these daughter colonies in turn frequently containing young
colonies. Asexual reproductive cells becoming much larger than vege-
tative cells before division commences. Colonies dioecious, with oogonia
and antheridia in young daughter colonies only. 20-60 cells of a
young colony formng typical Volvox antheridia that generally contain
64 antherozoids. Female colonies with 6-10 oospheres. Zygote smooth
walled.
Vegetative cells 5-8 /x in diam. Colonies 50-350 /x in diam.
Monona (aaa).
Order PROTOCOCCALES.
Vegetative cells immobile; free-floating, sessile, or epiphytic; solitary
or in colonies. Colonies amorphous and frequently embedded in a
gelatinous envelope ; or of deflnite shape and with or without a gelati-
envelope. Colonies capable or incapable of increasing the number of
their cells after they are formed. Cells variously shaped, generally
with one chloroplast and pyrenoid.
Asexual reproduction by zoospores, fragmentation of the colony, auto-
spores, or autocolonies. Resting akinetes known in some species.
Sexual reproduction by isogamous zoogametes known but not found
in a majority of the genera.
100
WI8C0N8IN PHYTOPLANKTON
KEY TO THE FAMILIES.
Asexual reproduction by zoospores.
Cells epiphytic or endophytic Planospobaceiab
Cells or colonies free-floating.
Colonies capable of growth by cell division Palmeuaceae
Colonies incapable of growth by cell division Hydeodictyaceai:
Asexual reproduction by autospores or division of cells.
Cells capable of vegetative division.
Solitary, in regular masses, or in strata Pbotoooccaceae
In colonies held together by remains of old cell walls . . Dictyosphaeriaceae
Cells incapable of division except to form autospores Autospoeaceak
Family PALMELLACEAE.
Cells spherical, ovoid, or reniform; rarely solitary, generally united
to form colonies which are at times of macroscopic size. Colonies al-
ways embedded in a gelatinous matrix. Colonies capable of an in-
crease in size by the vegetative division of the constituent cells. Chloro-
plasts generally single, cup-to disc-shaped and parietal ; or star-shaped
and central ; with or without pyrenoids.
Keproduction by the fragmentation of the colony or by zoospores.
Sexual reproduction known in certain genera.
KEY TO THE GENERA.
Chloroplast star-shaped and central Asterococcus
Chloroplast cup- to disc-shaped and parietal.
Cells with pseudocilia Teteaspoea
Cells without pseudocilia.
Gelatinous envelope of colony lamellated Gloeocystis
Gelatinous envelope of colony homogeneous.
Cells spherical.
Chloroplast of old cells cup-shaped Sphaerocystis
Chloroplast of old cells disciform Planktosphaeeia
Cells ovoid to reniform Gloeooystopsis
GLOEOCYSTIS Nageli 1849.
Cells spherical; solitary or in small colonies of eight cells or less.
Each cell and the whole colony surrounded by a hyaline, lamellated,
gelatinous sheath. Chloroplast of young cells cup -shaped, parietal, and
with one pyrenoid; generally diffuse and rich in starch in old cells.
Asexual reproduction by a fragmentation of the colony through the
softening of the gelatinous envelope, or by zoospores. Akinetes known.
WISCONSIN PHYTOPLANKTON
101
Gloeocystis gigas (Kiitzing) Lagerheim. PL 19, Fig. 2.
ofvers. kgl. Vet-Ak. Fork. 40: No. 3: 63. 1883; G. S. West, Brit. Freshw.
Algae 245; figs. 113f-H3h. 1904.
Cells spherical; solitary or in families of 2-8; enclosed by a thick,
distinctly lamellated, gelatinous envelope. Chloroplast of young cells
cup-shaped, of older cells diffuse. (Tyehoplanktont).
Cells 9-17 /A in diam. ; colonies 45-95 /jl in diam.
Mendota (rr), Oconomowoc (rr).
SPHAEROCYSTIS Chodat 1897.
Colonies spherical with the cells in groups of 4-8-16-32 and disposed
towards the periphery of a hyaline, homogeneous, gelatinous envelope
and with the envelope surrounding each group of cells distinct or con-
fluent with the colonial envelope. Colonies sometimes forming palmella
stages where the cells are irregularly disposed. Cells spherical ; chloro-
plast cup-shaped or filling the entire cell, with one pyrenoid.
Reproduction by the liberation of a group of cells through the soften-
ing of the colonial envelope. Zoospores of two sizes have been observed,
Sphaerocystis Schroeteri Chodat. PI. 19, Figs. S-4.
Bull. Herb. Boiss. 5: 119, ph 9, figs. 1-12. 1897; G. <S. West, Jour. Linn. Soc.
Bot. 39: 76, figs. 9a-9f. 1909.
Characters the same as those of the genus. (Euplanktont).
Diam. cells 6-22 ^ ; diam. colonies 50-500 fi.
Balsam (rr), Bear (2) (ss), Bear Trap (sss), Beasley (rr). Big (sss). Big
Butternut (rr), Birch (1) (rr), Birch (2) (ss), Birch Island (rr), Boulder
(ss), Browns (rr). Camp (rr), Carson (rr). Catfish (rr). Center (rr), Chetac
(ss), Chetek (cc). Clam (rrr). Clear Crooked (s). Crab (r). Cranberry (rr).
Deer (rr). Devils (1) (sss). Eagle (rr). East (rr), Elizabeth (sss). Found (r)
Fowler (rr), Green (1) (rr). Half Moon (rr), Hillman (rr). Hooker (rr),
Kimball (rr). Kitten (rr). Lac Court Oreilles (rr). Lac du Flambeau (r).
Lac la Belle (ss). Little Bass (1) (ss). Little Butternut (r). Little Doctor
(rr). Little Wood (rr). Long (1) (ss). Long (2) (rr), Long (3) (rrr). Love-
less (rr). Lower Nashotah (rr). Lower Nemahbin (cc). Lower Turtle (r),
Mary (ss), Mendota (r), Meta (ccc). Mill (sss), Monona (r). Mud (1) (rr),
Mudhen (sss), Nicaboyne (r). No Mans (rr). North Turtle (rr). North Twin
(rr). Number One (cc), Oconomowoc (ss), Okauchee (ss). Old Taylors (rr).
Pike (rr). Pine (2) (rr). Pine Tree (rr), Pokegama (1) (ss), Pokegama (3)
(sss). Poplar (ss). Prairie (ss). Rainbow (rr), Rice (1) (ss). Rock (r).
Round (1) (rrr). Round (2) (rr), Rudolph (rr). Sand (3) (rr). Sand (4)
(rrr). Shell (ccc). Silver (2) (r). South Turtle (r). Tamarack (rr). Upper
Nemahbin (rr). Upper Turtle (rr), Waubesa (rr), Winnebago (r).
102
WISCONSIN PHYTOPLANKTON
Lemmermann follows Wille in placing the alga as a synonym of
Braun’s old genus Gloeococcus but I prefer to follow G. S. West’s
practice and consider the two genera distinct. The ordinary vegetative
condition is easily recognized but the rather rare palmella stage may be
mistaken for one of the limnetic Tetraspora species.
TETRASPOBA Link 1809.
Colonies macroscopic or microscopic ; attached or free-floating ; gelat-
inous ; spherical, cylindrical, expanded, or variously lobed. Cells spher-
ical, generally in groups of four towards the periphery of the homo-
geneous, hyaline, gelatinous colonial envelope. Sometimes irregularly
distributed within the gelatinous colonial envelope. Chloroplast cup-
shaped, parietal ; sometimes diffuse ; with one pyrenoid. Each cell with
two or four long, hyaline, gelatinous bristles (pseudocilia).
Asexual reproduction by the direct metamorphosis of vegetative cells
into biciliate zoospores.
Sexual reproduction by a division of vegetative cells to form 4-8
bilciliate zoogametes that fuse in pairs.
Tetraspora lacustris Lemmermann. PI. 19, Figs. 5-6.
Bot. Cent. 76: 152. 1898; Forschungsbr. a. d. Biol. Stat. zu Plon 7: 118, pi. 1,
fig. 13. 189’9.
Colonies microscopic; spherical, elongate, or irregular in shape; al-
ways free-floating. Cells spherical, generally in groups of four and
with pseudocilia 6-8 times as long as the diameter of the cell. Chloro-
plast single, cup-shaped, and parietal ; with or without pyrenoids. (Eu-
planktont).
Diam. cells 7-10 /x; diam. colonies up to 300 /x.
Crawling Stone (sss), Fence (rrr), Long (3) (sss), Mud (2) (sss), Pike
(rrr).
Small colonies frequently resemble palmella stages of Sphaerooystis
Schroeteri but Tetraspora may be recognized by the pseudocilia. In
case of doubt it is always advisable to stain with safranin to bring out
the pseudocilia.
GLOEOCYSTOPSIS G. M. Smith 1916.
Cells elongate-cylindrical, with rounded ends and more or less curved.
Cells aggregated in fours or eights within a homogeneous gelatinous
sheath. Colonies spherical to ovoid and composed of an indefinite num-
ber of these aggregates. Colony not enclosed by a gelatinous sheath.
WISCONSIN PHYTOPLANKTON
103
Chloroplast of young cells single, laminate, parietal, with one pyrenoid ;
diffuse in old cells.
Reproduction, aside from vegetative cell division, unknown.
Gloeocystopsis limneticus G. M. Smith. PI. 20, Figs. 1-2.
Bull. Torr. Bot. Cl. 43: 475, pi. 24, fig- 12. 1916.
Cells 4-6 fji broad, 10-15 fx long. Cell aggregates 25-30 fi in diam. ;
colonies up to 125 /a in diam. (Euplanktont).
Bear Trap (rr), Beaverdam (rrr). Catfish (rr), Harris (rrr). Little Bass
(2) (rrr).
A species that combines the general external morphological character-
istics of Gloeocystis and the cell shape of N ephrocytium.
PLANKTOSPHAERIA G. M. Smith 1918.
Cells spherical, embedded in a copious, homogeneous, hyaline, gelat-
inous envelope. At first solitary, later irregularly distributed within
tiie gelatinous envelope. Mature cells with several parietal, polygonal,
flattened chloroplasts each of which contains a single pyrenoid.
Reproduction by liberation of daughter colonies through the breaking
down of the gelatinous colonial envelope.
PLANKTOSPHAERIA GELATINOSA G. M. Smith. PI. 20, FigS. 3-6.
Trans. Wis. Acad. Sci., Arts, & Lett. 19^: 627, pi. 10, figs. 8-11. 1918.
Specific characters as described above. (Euplanktont).
Diam. cells 4.5-25 fx ; colonies up to 150 fx in diam.
Browns (rr), Mendota (r).
The general appearance of the colony suggests SpJiaerocystis
Schroeteri but P. gelatinosa differs in the numerous parietal chloroplasts
of each cell.
ASTEROCOCCUS Scherffel 1908.
Cells spherical or sub-spherical, solitary or in colonies, with a wide,
homogeneous or lamellated, gelatinous envelope. Chloroplast single,
central, star-shaped, the astral radiations ending in a disc at the cell
wall. Pyrenoid single, at the center of the chloroplast. Certain species
with two peripheral vacuoles and an eyespot.
Asexual reproduction by vegetative cell division and biciliate sub-
spherical zoospores.
Sexual reproduction unknown.
104
WISCONSIN PHYTOPLANKTON
Asterococcus limneticus G. M. Smith. PI. 20, Figs. 7-10.
Trans. Wis. Acad. Sci., Arts, & Lett. 19^: 627, vl. 10, figs. 3-6. 1918.
Colonies spherical, rarely ovoid, of 4-8-16 spherical cells widely
separated from one another and lying within a hyaline, homogeneous,
gelatinous matrix. Chloroplast single, star-shaped, with 4 or 8 (rarely
16) rays coming from a central mass and ending in a disc at the cell
wall. Pyrenoid single, at the center of the chloroplast. (Euplanktont).
Diam. cells 7.5-35 /a; colonies up to 125 /a in diam.
Chain (r), Clam (sss). Crooked (rrr). Deer (rrr), Des Moines (rr). Dummy
(ss). Fish (sss). Half Moon (rr), Hillman (rrr). Horseshoe (1) (ss), Horse-
shoe (2) (rr), Howey (rr). Lac Court Oreilles (ss). Lake of the Woods (rr),
Long (1) (r), Nancy (r). North Twin (rrr), Owen (cc). Reserve (r), Rooney
(rr). Sand (1) (r). Sand (3) (r), Shell (cc), Whitefish (sss). Wild Goose
(rrr).
The shape and cellular arrangement in colonies of this species is
quite similar to that of Sphaerocystis, but a sharp distinction exists in
its star-shaped chloroplast, a type of chloroplast that is very uncommon.
The alga is widely distributed in the lakes of northwestern Wisconsin.
Family DICTYOSPHAERIACEAE.
Cells in spherical or ovoid colonies, the number in young colonies a
multiple of two, in older colonies indefinite. Colonies with or without
a gelatinous envelope. Cells held together in fours or eights by the
persistence of the old mother cell wall in repeatedly branching four-
armed thongs or irregular threads. Chloroplast single; cup-shaped,
or filling the entire cell ; with one pyrenoid.
Keproduction by the division of cells into autospores which remain
attached to mother colony until accidentally broken away.
KEY TO THE GENERA.
Colony enclosed in a gelatinous sheath Dictyosphaebium
Colony not enclosed in a gelatinous sheath.
Cells spherical Westella
Cells ovoid to reniform Dimobphococcus
DICTYOSPHAERIUM Nageli 1849.
Cells spherical, ovoid, or reniform, connected with one another by
cruciately or dichotomously branching threads. Colony enclosed by a
hyaline, homogeneous, gelatinous envelope that is spherical or ovoid in
shape. Chloroplast single, parietal, cup-shaped, with one pyrenoid.
WISCONSIN PHYTOPLANKTON
105
Eeproduction by tbe division of the cell into 2 or 4 daughter cells
which remain connected to the colony by the old mother cell wall that
divides into 2 or 4 parts to form the branching thread system connect-
ing the cells. Zoospores reported but their existence is very doubtful.
Resting akinetes known.
KEY TO THE SPECIES.
Mature cells ovoid D. Ehrenbergianum
Mature cells spherical D. Ptjlchellxjm
Dictyosphaerium Ehrenbergianum Nageli. PI. 20, Figs. 11-12.
Gatt. einz. Algen, 73, pJ. 2, figs. Ea-ES 1849.
Colonies spherical to ovoid, rarely containing more than 30 cells.
Cells ovoid to ellipsoid when mature. Chloroplasts 1-2, parietal, lami-
nate, generally with a single pyrenoid. (Facultative Planktont).
Cells 4-7 jw. broad ; 6-10 ja long.
Clear (rr), Kegonsa (rrr>. Mendota (rr).
Dictyosphaerium pulchellum Wood. PI. 20, Fig. 13; PI. 21, Fig. 1.
Smithsonian cont. to knowl. 19 , No. 241 : 84, pZ. 10, fig. 4. 1872.
Colonies spherical to broadly ovoid, of 4-8-16-32 or many cells lying
near the periphery of the hyaline, homogeneous, gelatinous envelope.
Cells spherical when mature, spherical to ovoid when young ; generally
in fours at the ends of a repeatedly branching system of threads. Chloro-
plast single, parietal, cup-shaped, with one pyrenoid. (Facultative
pJanktont).
Diam. cells 3-10 /t.
Amicoy (ss). Balsam (rrr). Bear (1) (ss). Bear (2) (r), Bettine (s). Big
Butternut (r), Birch (1) (r), Birch (2) (rrr), Blake (ss). Bone (r), Boulder
(rrr). Canteen (rr), Carson (sss). Catfish (r), Catherine (rrr). Center (r).
Chain (rr), Chetac (ss), Chetek (ss). Crab (s). Cranberry (rr). Crawling
Stone (rrr). Deer (rr), Diamond (rr). Duck (cc). Dummy (sss). Eagle (rr),
Elizabeth (rrr), Pishtrap (rr). Granite (ss). Grassy (rr). Grindstone (rr).
Half Moon (rr). High (rr), Hillman (ss). Horse (rr). Horseshoe (1) (rrr).
Horseshoe (2) (ss), Howey (rr), Jag (rr), Kawaguesaga (rr), Kegonsa (r).
Kitten (rrr). Lac Court Oreilles (ss). Lac du Flambeau (rr), Lindy (rr).
Little Bass (1) (rr), Little Bass (2) (rr). Little Butternut (rr). Little Crooked
(rrr). Little Bice (2) (sss). Little Wood (sss). Long (1) (rrr). Long (3)
(rrr). Loon (r). Loveless (rr). Lower Turtle (r). Lynx (rrr), Mendota (ss),
Mercer (rrr), Middle McKenzie (rrr), Monona (ss). Mud (2) (rr), Mudhen
(rr), Nagawicka (rrr), Nancy (r), Nicaboyne (rr). North Turtle (r), Ocono-
mowoc (r), Okauchee (rr). Old Taylors (rr), Owen (rrr). Palmer (rr), Pe-
waukee (rr). Pine Tree (sss), Pokegama (1) (r), Pokegama (3) (c). Poor
106
WISCONSIN PHYTOPLANKTON
Farm (rrr), Prairie (c), Reserve (rr), Rice (ss), Rock (rr), Rooney (rr),
Rose (sss), Rozen (rr), St. Croix (rrr), Sand (3) (rrr). Shell (cc), Sishe-
bogema (rr), (South Turtle (rr). Spirit (r). Tamarack (sss). Tenderfoot (rr).
Tied Canoe (rrr), Travis (rr). Upper Nashotah (sss). Upper Nemahbin (rr).
Vermilion (r), Wapagossett (rrr), Waubesa (ss). White Ash (sss), Whitefish
(rr). White Sand (rr), Wild Goose (s), Winnebago (sss).
DIMORPHOCOCCUS A. Braun 1855.
Ceils in groups of four and held in an irregular free-floating colony
by the branching remains of the old mother cell wall. Colony not en-
closed by a gelatinous envelope. Each aggregate of four cells lying in
one plane with two cells ovoid to cylindrical with rounded ends, and two
cells reniform to cardioid. Chloroplast of young cells single, parietal,
laminate, with one pyrenoid; chloroplast of old cells occupying the
entire cell.
Reproduction by the division of any cell into four daughter cells
which remain attached to the colony by the threadlike remains of old
cell wall until accidentally broken away.
Dimorphococcus lunatus a. Braun. PI. 21, Fig. 5.
Alg. Unicell. 44. 1855; Rabenhorst, FI. Bur. Algarum 3: 3G, figs, a-c (p. 6).
1868; G. S. West, Brit. Freshw. Algae 221, figs. 93a-93b. 1904.
Cells of each group of four alternately arranged (in vertical view)
the central cells cylindrical with rounded ends, the terminal cells reni-
form to cardioid. (Facultative planktont).
Cells 4-15 fi broad, 9-25 /x long. Colonies up to 150 /x in diam.
Bear (2) (rr). Bear (3) (rr), Beaver dam (rrr), Blue Gill (rrr), Catfish
(rr), Des Moines (rrr). Devils (2) (rr). Horseshoe (1) (rr), Horseshoe (2)
(rrr), Kegonsa (rrr), Lindy (rr), Minocqua (rrr). Mud (1) (rr), Pike (rr),
Pine (1) (rr). Pine Tree (rrr), St. Croix (rrr). Shell (rrr).
WESTELLA de Wildeman 1897.
Cells small, spherical to sub-spherical, grouped in fours (rarely
eights) in irregular, free-floating colonies containing 30-100 cells; the
colony being held together by the non-gelatinizing remains of the old
mother cell walls. Colonies without a gelatinous envelope. Chloro-
plast cup-shaped and parietal, or entirely filling the cell, with or with-
out a pyrenoid.
Reproduction by the division of any cell to form 4^S autospores that
remain connected with the mother colony until accidentally broken
away.
WISCONSIN PHYTOPLANKTON
107
KEY TO THE SPECIES.
Groups with cells quadrate or pyramidate W. Botryoides
Groups with cells in a linear series W. Linearis
Westella botryoides (W. West) de Wildeman. PL 21, Fig. 4.
Bull. Herb. Boiss. 5: 532. 1897.
Tetracoccus 'botryoides W. West, Jour. Roy. Micr. Soc. 1892: 735, pi. 10,
ags. 43-48. 1892.
Colonies irregularly shaped, without a gelatinous envelope, generally
containing 40-80 cells. Cells spherical, pyramidately or quadrately
arranged in groups of four (rarely eight). Chloroplast single, cup-
shaped or entirely filling the cell; with or without a pyrenoid. (Facul-
tative Planktont).
Diam. cells 3-9 /a.
Blake (rrr), Fishtrap (rr), Hillman (rrr), Horse (rrr), Horseshoe (1) (rr),
Jag (r), Little Bass (2) (rr), Little Butternut (rrr). Little Crooked (rr),
Mendota (rrr). Mill (rrr), Nancy (rr). Pine Tree (rr). Round (3) (rr),
Sishebogema (rr).
var. MAJOR G. M. Smith.
Trans. Wis. Acad. Sci., Arts, & Lett. 19^: 628. 1918.
Cells larger than the typical form, otherwise the same.
Diam. cells 8-13 /a.
Whitefish (rr).
Westella linearis sp. nov. PI. 21, Figs. 2-3.
Colonies of irregular shape, rarely containing more than 40 cells.
Cells spherical, always in groups of four and arranged in a linear
series. Kemains of old mother cell walls that hold the colony together
very inconspicuous. Colony without a gelatinous envelope. Chloro-
plast single, parietal, without a pyrenoid. (Euplanktont ?).
Diam. cells 3-6 /a.
Pine Tree (rr).
In the arrangement of the cells this species is quite unlike the other
members of the genus but since the cells are in groups of four that are
held together by the remains of old mother cell walls it seems better
to place it in this genus than in Crucigenia.
108
WISCONSIN PHYTOPLANKTON
Family PROTOCOCCACEAE.
Cells solitary and spherical; or in colonies containing an indefinite
number of cells that are spherical and mutually compressed or in very
short irregular filaments. Cell wall delicate to heavy, smooth or vari-
ously sculptured. Chloroplast single, parietal and disciform, with or
without pyrenoids. Cells capable of vegetative division.
Reproduction, aside from vegetative division of cells, by zoospores or
aplanospores.
KEY TO THE GENERA.
Cell wall thin, smooth Chlorella
Cell wall thick, sculptured Teochiscia
CHLORELLA Beyerinck 1890.
Cells small, spherical ; solitary or in small colonies of indefinite shape.
Chloroplast disciform to cup-shaped, with or without a pyrenoid.
Reproduction by the division of cell contents into 2-4-8 daughter
cells. Resting akinetes known.
Chlorella vulgaris Beyerinck. PI. 22, Fig. 1.
Bot. Ztg. 48: 758, pi. 7, figs. 2a-2b. 18'90.
Cells spherical, generally solitary. Chloroplast parietal, cup-shaped,
with or without a pyrenoid. Cell wall smooth and delicate. (Faculta-
tive Planktont).
Diam. cells 5-10 /a.
Mendota (rr).
C. vulgaris is a minute alga and one that is easily overlooked. The
record of its occurrence in Lake Mendota is based upon its isolation by
pure culture methods from a plankton catch. It is very probable that
it is present in other lakes but has been overlooked.
TROCHISCIA. Kiitznig 1845.
Cells spherical to sub-spherical, solitary or in small clumps. Cell
wall fairly heavy, areolate or ornamented vdth spines, denticulations,
ridges, or other projections. Cells generally containing several parietal
disciform chloroplasts each with a pyrenoid.
Reproduction by vegetative cell division or the formation of -4-16
aplanospores that are liberated by the dissolution of the old mother
cell wall.
WISCONSIN PHYTOPLANKTON
109
Trochiscia reticularis (Reinscli) Hansgirg. PI. 22, Fig. 2.
Hedwigia 27: 129. 1888.
Acanthococcyiis reticularis Reinsch, Ber. d. D. bot. Ges, 4: 242, pZ. 12, figs.
24a-24b. 1886.
Cells generally solitary, spherical. Cell wall fairly thick and covered
with linear ridges that intersect to form 50-70 polygons on the surface
of the cell. (Tychoplanktont).
Diam. cells 24-32 /x.
Wildcat (rrr).
Family AUTOSFOEACEAE.
Cells solitary or in colonies that are generally of a definite shape and
without a gelatinous envelope. Cells variously shaped; with a single
chloroplast and pyrenoid as a rule. Cells incapable of vegetative divi-
sion to form two similar daughter cells.
Reproduction by division of cell contents into 2-4r-8-l 6-32-64 cells
which assume the shape of the mother cell before their liberation (auto-
spores). In the colonial species the autospores from any one cell are
organized to form the new colony (autocolony) before their liberation.
Motile asexual reproductive bodies or sexual reproduction unknown.
KEY TO THE SUBFAMILIES.
Cells solitary.
Cells angular Tetraedreae
Cells not angular.
Ornamented with long spines or setae Micractinieae (p. p.)
Not ornamented with spines or setae.
Length of cells several times the diameter Selenastreae (p. p.)
Length of cells not more than twice the diameter Oocysteae (p. p.)
Cells in colonies.
Ornamented with long setae or spines.
Coenohe capable of growth in three directions Micractinieae (p. p.)
Coenobe a flat plate Crucigenieae (p. p.)
Not ornamented with setae or spines.
Number of cells in coenobe always a multiple of two.
Coenobe flat Crucigenieae (p. p )
Coenobe spherical or cells radiating from a common
center > Coelastreak
Number of cells not a multiple of two in every case.
Cells elongate, straight or curved Selenastreae (p. p.)
Cells spherical, ovoid, or reniform Oocysteae (p. p.)
110
WISCONSIN PHYTOPLANKTON
Subfamily OOCYSTEAE,
Cells spherical, ovoid, or renif orm ; solitary or in temporary colonies.
Daughter cells retained within old mother cell wall for some time after
their formation. Walls generally thick and cells with one to many
chloroplasts.
KEY TO THE GENERA.
Cells within old mother cell wall separated by a dark gelatinous
mass Gloeotaenium
Cells within old mother ceil wall not separated by a dark gelat-
inous mass.
Cells ovoid to elliptic, never curved Oocystis
Cells ovoid to reniform, frequently curved Nepheooytium
OOCYSTIS Nageli 1845.
Cells ovoid, ellipsoid, or cylindrical with rounded to somewhat pointed
ends, generally symmetrical but never curved. Cell wall smooth, with-
out spines, frequently with nodular thickenings at the poles. Chloro-
plasts one to many; parietal, disciform, stellate, or reticulate; with or
without pyrenoids. Cells solitary or in temporary colonies of 2-4-8-16
or more enclosed by the partially gelatinized and greatly swollen old
mother cell wall.
Reproduction by a formation of 2-4^8-16 autospores that remain
within the old cell wall for some time. Three to four cell generations
sometimes enclosed by the same wall. Tetraedron-YAiQ resting spores
with granulate walls have been observed.
The genus differs from others in the expanded cell wall that encloses
the cells in temporary colonies. Printz (Nyt. Mag. f. Naturvidensk.
1913, p. 165) has recently monographed the genus and cleared up many
points by collecting the published descriptions of species; but there is
great need of a series of cultural studies to determine the range of
variation within the so-called “species” that are recognized at the
present time.
KEY TO THE SPECIES.
Cbloroplast stellate O. Natans
Cbloroplast disciform to laminate.
Cells with polar nodules.
Sides of cells concave O. Pandubifobmis
Sides of cells convex.
4 or more chloroplasts in each cell.
Cells with 40-60 chloroplasts O. Ebemosphaebia
WISCONSIN PHYTOPLANKTON
111
Cells with 6-25 chloroplasts.
Polar nodules conspicuous, 12-25 chloroplasts O. Solitaria
Polar nodules not prominent, 4-10 chloroplasts O. Crassa
1-2 (rarely 4) chloroplasts in each cell.
Cells elliptic, length ll^ times breadth O. Lacustris
Cells oblong-cylindrical, length 2-3 times breadth O. Submaeina
Cells without polar nodules.
Poles of cells rounded.
Length of cells less than 12 /x O. Pusilla
Length of cells more than 12 /x.
1-4 chloroplasts in each cell O. Bobgei
8-10 chloroplasts in each cell O. Elliptica
Poles of cells pointed.
Old cell wall enclosing colonies rounded 0. Parva
Old cell wall enclosing colony sharply pointed.. 0. Gloeocystiformis
OocYSTis PusiLLA Hansgirg. PL 22, Fig. 3.
Sitzbr. d. k. bohm. Ges. d. Wiss. in Prag, Jahrgang 1890: 9. 1890; Printz, Nyt.
Mag. f. Naturvidensk. 51: 181, pi. 4, figs. 31-32. 1913.
Cells cylindrical, poles rounded and without nodules. Chloroplasts
2-3, parietal, laminate, without pyrenoids. Temporary colonies con-
taining 2-^L-8 cells. (Tychoplanktont).
Diam. cells 4. 5-6. 5 /x ; length 8-12 fx.
Tied Canoe (rr).
OocYSTis Borgei Snow. PL 22, Fig. 4.
Bull. U. S. Fish Comm. 22: 379, pi. 2, figs. VIP-VIP. 1903.
Cells broadly elliptic, length 1% times the breadth; poles rounded
but without nodules. Chloroplasts 1^, parietal, laminate, each con-
taining a single pyrenoid. Cells solitary or in families of 2-4-8 within
an old mother cell wall. (Euplanktont).
Cells 9-13 broad, 9-17 fi long.
Big (rr), Birch (1) (sss). Camp (r), Catfish (r). Devils (1) (rr). Duck
(r). Found (rr). Green (2) (rr), Kawaguesaga (rr). Kitten (rrr). Long (2)
(rr), Mendota (r). North Turtle (r), Pardee (rr). Rock (r), Winnebago (rr).
OocYSTis ELLIPTICA W. West. PL 22, Pig. 5.
Jour. Roy. Micr. Soc. 1892: 736, pi. 10, fig. 56. 1892.
Cells oblong-elliptic, with poles rounded and without nodules. Chlor-
oplasts 10-20, disciform, parietal, without ( ?) pyrenoids. Cells rarely
solitary, generally in families of 4-8 within an old mother cell wall.
( Tychoplanktont) .
Cells 11-12.5 /X broad, 20-25 /x long.
Amicoy (rr).
112
WISCONSIN PHYTOPLANKTON
OocYSTis PARVA W. & G. S. West. PL 22, Fig. 6.
Jour, of Bot. 36: 335. 1898; G. S. West, ibid. 37: 223, pi. 394, iigs. 14-17. 1899.
Cells broadly fusiform to elliptic, ends pointed but without polar
nodules. Each cell with 1-3 parietal, laminate to disciform chloro^
plasts, with or without pyrenoids. Cells solitary or in families of 2-^r-8.
(Facultative Planktont).
Cells 4-7 ft broad ; 6-12 ft long.
Beaver (1) (rr), Bettine (rr). Clear Crooked (rr), Cochrane (rrr). Crab
(rrr). Deer (rr), George (rr). Half Moon (rr). Hooker (rr). Little Bass (2)
(rr). Lynx (rr), Mendota (rr), Muskallonge (rr). Palmer (rr), Pine (1) (rr),
Rudolph (rr). Sand (1) (rrr). Stone (rr), Wolf (rr).
OocYSTis GLOEOCYSTiFORMis Borge. PL 22, Fig. 7.
Botaniska Studier till. F. R. Kjellman 23, pi. 1, figs, la- lb. 1906.
Cells narrowly elliptic with ends pointed. Chloroplast single, pari-
etal, without a pyrenoid. Cells in families of 2-4 within the old cell
wall, several cell generations frequently forming a single colony. Wall
enclosing colony with pointed ends but no polar nodules. (Tychoplank-
tont).
Breadth of cell 3-5.5 ft ; length 8-15 ft.
Lac Court Oreilles (sss).
The old mother cell wall does not gelatinize as readily in this species
as in others so that several cell generations are generally found in the
same colony. The species is best recognized, however, by the sharply
pointed ends of the colony waU.
OocYSTis LAcuSTRis Chodat. PL 22, Figs. 8-9.
Bull. Herb. Boiss. 5: 119, pi. 10, figs. 1-7. 1897.
Cells elliptic to broadly fusiform, somewhat pointed and with a
nodule at the poles. Chloroplasts 1-3, laminate, parietal, with or with-
out pyrenoids. Margins of chloroplasts sometimes irregular. Cells
rarely solitary, generally in families of 2-4-8 within the old mother
cell wall. (Euplanktont).
Cells 8-22 fi broad, 14-32 ft long.
Big Butternut (rr), Bone (rr). Center (r). Chain (rr), Chetek (r). Devils
(2) (ss). Dummy (rr), Fowler (rr), Hillman (rr), Little Bass (2) (rr).
Little Butternut (rrr). Long (2) (rrr), Long (3) (rrr), Mary (r), Mercer
(rr), Palmer (rr), Pokegama (3) (rr). Prairie (rr), Reserve (rr). Sand (4)
(rr), Sishebogema (rrr), Upper Nashotah (rrr), Upper Turtle (sss). White
Sand (rr).
WISCONSIN PHYTOPLANKTON
113
OocYSTis SUBMARINA Lagerheim. PI. 22, Fig. 10.
Bot. Not. 1886 : 45, iig. 1. 1886.
Cells oblong-cylindrical, 2-3 times as long as broad, somewhat pointed
and with a nodule at each pole. Chloroplasts 1-2, laminate, parietal,
usually with a pyrenoid. Cells rarely solitary, generally in families
of 2-d^8-16 within the old mother cell wall. (Tychoplanktont).
Cells 3-9 IX broad, 7-20 /x long.
Camp (sss), Upper Nemahbin (rr).
OocYSTis SOLITARIA Wittrock. PL 22, Fig. 11.
Bot. Not. 1879: 24, figs. 1-5. 1879.
Cells ovoid to ellipsoid, solitary or in families of 2-4r-8. Cell wall
fairly thick and with conspicuous polar nodules. Chloroplasts numer-
ous (generally 12-25), parietal, disciform to polygonal, with or with-
out pyrenoids. (Facultative Planktont).
Cells 7-20 /X broad, 14-35 /x long.
Hooker (r). Sand (1) (rr).
OocYSTis CRASSA Wittrock. PL 22, Figs. 12-13.
Bot. Not. 1880: 117. 1880.
Cells ovoid, length 1% times the breadth, with a nodule at each pole.
Chloroplasts 4-10 in number, fairly large, parietal, disciform to angu-
lar, generally with a pyrenoid. Cells solitary or in families of 2-4-8.
Old cell wall enclosing the colony greatly distended. (Tychoplanktont) .
Cells 10-20 /X broad, 11^26 fx long.
St. Croix (rr).
OocYSTis EREMOSPHAERiA G. M. Smith. PL 23, Figs. 1-2.
Trans. Wis. Acad. Sci., Arts, & Lett. 19^: 630, pi. 14, figs. 8-9. 1918.
Cells ovoid, 1% to 2 times as long as broad. Solitary or in families
of 2-4. Chloroplasts numerous (40-60), parietal, lenticular, each con-
taining a single pyrenoid. Cell wall thick, with a conspicuous polar
nodule. (Facultative Planktont ?).
Cells 23-31 fx broad, 35-45 /x long.
Beaverdam (rr). Shell (sss).
8
114
WISCONSIN PHYTOPLANKTON
OocTSTis PANDURiFORMis YSiT. MINOR G. M. Smith. PI. 23, Fig. 3.
Bull. Torr. Bot. Cl. 43: 471, pi. 24, fig. 2. 1916.
Cells oblong-ovoid, 2 to 2% times as long as broad, sides slightly
concave and poles with a conspicuous nodule. Chloroplasts numerous
(15-25), parietal, disciform, and each containing a pyrenoid. Cells
solitary or in families of 2-4r-8. (Tychoplanktont).
Greatest diameter of cells 12-15 /t, median diameter 11-14; length
30-35
Star (rr).
This is the only species of the genus where the sides of the cells are
concave.
Oocystis natans var. major var. nov. PI. 23, Figs. 4-5<i
Cells ovoid, without a conspicuous polar nodule. Chloroplasts 4^8,
parietal, star-shaped or irregular, each chloroplast with a pyrenoid.
More than two cell generations rarely found within the same mother
cell wall. (Facultative Planktont).
Cells 16-25 broad, 31-38 /a long. Families up to 90x120 fx.
Birch (2) (sss), Chetac (s). Rice (1) (rr).
Lemmermann founded the genus Oocystella upon this stellate nature
of the chloroplast (Zeits. f. Fischeri u. d. Hilfsw. 11 : 103. 1903) but
the genus has not been recognized and the single species is placed in
Oocystis.
NEPHROCYTIUM Nageli 1849.
Cells ovoid, reniform, or oblong-elliptic; generally in colonies of
2-4—8-16 cells within the partially gelatinized remains of the old mother
cell wall. Arrangement of cells in young colonies spiral, in old colonies
irregular. Chloroplast single and expanded at first, later fragmenting
and becoming diffuse ; pyrenoid single.
Reproduction by the formation of 2-4-8-16 autospores in each cell.
Nepiirocytium Agardhianum Nageli. PI. 23, Pigs. 6-7.
Gatt. elnz. Algen 79, pi. 3, figs. Ca-CP. 1849.
Cells reniform, generally spirally arranged in young colonies. Chlor-
oplast single, parietal, laminate, and with one pyrenoid in young cells ;
diffuse in old cells. (Tychoplanktont).
Cells 2-12 fx broad, 6-28 jx long ; colonies up to 60 fx long.
Bear (3) (rrr). Bear Trap (rrr). Camp (rr), Hillman (rr). Little Bass
(rrr), Mendota (rr). Mill (rrr).
WISCONSIN PHYTOPLANKTON
115
GLOEOTAENIUM Hansgirg 1890.
Cells spherical, ovoid, or variously flattened; solitary or united in
colonies of 2-4r-8 cells enclosed by a non-expanded mother cell wall and
separated from one another by a dark colored gelatinous mass that lies
between the cells. Colonies rectangular, with rounded corners in front
view ; oblong with sharp corners in side view. Cell wall thick, distinctly
lamellated ; old cell wall enclosing the colony frequently with folds and
gelatinous discs opposite the cells. Chloroplast entirely Ailing cells;
with or without a pyrenoid.
Reproduction by autospores and aplanospores.
Gloeotaenium Loitlesbergerianum Hansgirg. PI. 23, Pigs. 8-9.
Sitzbr. d, k. bohm. Ges. d. Wiss. in Prag, Jabrgang 1890: 10. 1890; Transeau,
Bot. Gaz. 55: 66, pi. 3, figs. 1-24. 1913.
Cells spherical to ovoid, completely filling the space inside of old
mother cell wall. (Tychoplanktont).
Diam. cells 20-30 fi; length 2-celled colonies 40-70 fi breadth 22-40 fi;
thickness 20-30 /i. 4-celled colonies 40-70 fi broad, 40-80 ^ long.
Big Butternut (rrr).
Sub-family TETRAEDREAE.
Cells always solitary, without a gelatinous envelope, flattened or
isodiametric, triangular, quadrangular, or polyangular; angles simple
or produced into spines or long hyaline setae.
KEY TO THE GENERA.
Cells simple or with fairly stout spines at angles Tetraedron
Cells with long hyaline setae at angles Polyedbiopsis
TETRAEDRON Kiitzing 1845.
Cells solitary, free-floating, flattened or isodiametric, triangular,
quadrangular, or polyangular. Angles simple or produced into simple
or furcate spines. Cell wall smooth or verrucose. Chloroplasts one to
many, parietal, disciform to angular ; or completely filling the cell ; with
or without pyrenoids.
Reproduction by division of cell contents into 1^8 autospores that
are liberated by the rupture of the old mother cell wall.
116
WISCONSIN PHYTOPLANKTON
KEY TO THE SPECIES.
Angles of cells never produced into processes.
Corners of cells without spines.
Cells triangular T. Muticum
Cells quadrangular T. Minimum
Corners of cells with spines.
All cell corners in the same plane.
Cells triangular T. Trigonum
Cells with more than three angles.
Cells with four angles T. Reguu\re v. Incus (p. p.)
Cells with five angles T. Caudatum
All cell corners not in the same plane.
Cells quadrangular.
Pyramidal cells T. Regulabe
Halves of cells twisted over one another.
Wall smooth.
Angles delicately tapering T. Victorieae var. Major
Angles strongly convex T. Regulars var. Torsum (p. p.)
Wall verrucose T. Verrucosum
Cells five-angled T. Pentaedricum
Angles at corners produced into processes.
Processes always unbranched T. Hastatum
Processes always branched.
Cells flattened and processes in the same plane.
General outline of cell H-shaped T. Constricum
General outline of cell not H-shaped.
Processes long, conspicuously branched T. Gracilb
Processes short, not conspicuously branched. .. .T. Lobulatum (p. p.)
Cells isodiametric and processes not in the same plane.
Processes short T. Enorme
Processes long.
With 3-5 series of branchings T. Lobulatum var. Polyfuroatum
Never more than three series of branchings.
Diameter of cells always greater than the length
of the processes T. Planotonicum
Diameter of cell always less than the length of
the processes T. Limneticum
Tetraedron muticum var. punctulatum (Reinseh) de Toni. PI. 23,
Figs. 10-13.
Sylloge algarum 1 : 600. 1889.
Polyedrium muticum var. punctulatum Reinseh, Notarisia 3: 498, pi. 4,
flg. 6. 1888.
Cells small, triangular, somewhat flattened. Sides of cells convex in
front view. Corners sharp but without spines. Cell wall covered with
small granules. (Tychoplanktont).
Diam. cells 15-20 fx; thickness 8-10 /x.
Beaverdam (rr). Deer (rrr), Sand (2) (rr).
WISCONSIN PHYTOPLANKTON
117
Tetraedron trigonum (Nageli) Hansgirg. PI. 23, Figs. 14-16.
Hedwigia 27: 130. 1888.
Polyedrium trigonum Nageli, Gatt. einz. Algen 84, pi. 4, ^gs. Bla-Blb. 1849.
Cells medium sized, triangular, flattened. Sides of cells generally
concave, rarely straight. Corners with a single, stout, straight or curved
spine. (Facultative Planktont).
Diam. cells (without spines) 20-30 ix \ length spines 8-10 /x.
Crawling stone (rrr). High (r), Pokegama (1) (rr). Rice (1) (rrr). Ten-
derfoot (rr). Tied Canoe (rrr).
var. SETiGERUM (Archer) Lemmermann. PI. 24, Figs. 1-4.
Arkiv. for Botanik 2, No. 2: 110. 1904.
Tetrapedia setigera Archer, Quart. Jour. Micr. Sci. N. S. 12: 365, pi. 21,
figs. 14-17. 1872; Grevillea 1: 46, pi. 3, figs. 14-17. 1872; G. S. West, Brit.
Freshw. Algae 349. 1904; de Toni, Sylloge algarum 5: 113. 1907.
Polyedrium trigonum var. setigerum (Archer) Schroder, Forschungsbr. a. d.
Biol. Stat. zu Plon 6: 23, pi. 1, fig. 6. 1898.
Cells small, triangular, flattened, with a conspicuous emargination
on each side in front view. Comers of cells rounded and produced into
a long delicately tapering spine. Chloroplast single. Ailing the entire
cell ; with one pyrenoid. (Facultative Planktont).
Diam. cells (without spine) 7-9 /x; length of spines 12-15 /x.
White Ash (r).
G. S. West and de Toni follow Archer in considering this organism
a member of the Myxophyceae West stating; setigera Archer is a
beautiful little species known from N. W. Scotland and W. Ireland,
which has been erroneously referred by some authors to the chlorophy-
ceous genus Tetraedron. The cell contents of Tetrapedia setigera are
homogeneous and of a pale blue-green color.” The cell contents of the
individuals that I have observed are distinctly grass green in color
and contain a single pyrenoid. This pyrenoid has not been noted
by ell her Archer or Schroder. Since the shape and dimensions of
the cel's that I have found are exactly the same as those given by
Archer I believe that I am dealing with the same organism that he
described and one which is a member of the Chlorophyceae and not
the Myxophyceae.
var. GRAciLE (Reinsch) de Toni. PI. 24, Figs. 5-9.
Sylloge algarum 1: 598, 1889; Printz, Kgl. Norske Vidensk. Selsk. Skr. 1915,
No. 4: 29, pi. 3, figs. 167-169. 1916.
Polyedrium trigonum var. gracile Reinsch, Die Algenfl. d. mitt. Th. v.
hh-anken 75: pi. 3, figs, la-lb. 1867.
Tetraedron proteiforme G. M. Smith non (Turner) Brunnthaler, Trans. Wis.
Acad. Sci., Arts, & Lett, 19': 632, pi. 15, figs. 4-5. 1918.
118
WISCONSIN PHYTOPLANKTON
Cells triangular, flattened, concavity of sides very marked. Angles
of cells ending in short spines. Several parietal, disciform chloroplasts
without pyrenoids. (Facultative Planktont).
Cells 23-50 fx broad ; 6-10 fi thick.
Blake (rr), Chain (r), Cochrane (r), Fishtrap (rr), Horse (r), Lac Court
Oreilles (rr), Little Bear (rr), Little Crooked (rrr). Loon (rr), Paddock (rrr).
Palmer (rrr), Rice (1) (rr), Tenderfoot (r). Tied Canoe (rrr). White Ash
(rr), Wolf (rr).
In the second list of Wisconsin algae this alga was given as T. pro-
teiforme but I am now convinced that it is T. trigonum var. gracUe.
The cells reach a much larger size than that given by Reinsch and the
excavation of the sides may be very much greater ; in fact the cells are
at times so delicate that they might be placed as Cerasterias species had
not other individuals in the same collection the ordinary cell shape of
T. trigonum var. gracUe,
Tetraedron minimum (A. Braun) Hansgirg. PI. 24, Figs. 10-13.
Hedwigia 27: 131. 1888; G. S. West, Brit. Freshw. Algae 231, fig. 101a. 1904.
Cells small, flattened, front view square or oblong with slightly
rounded corners and concave sides. Side view fusiform-elliptic. Wall
smooth or finely granulate. Chloroplast single, parietal, with one
pyrenoid. (Facultative Planktont).
Cells 6-20 fi long, 5-8 fx thick.
Beaver (2) (rrr). Camp (rr), Deer (rrr), Hillman (rrr), Horse (rr), Little
Bass (2) (rrr). Little Doctor (rr), Mendota (rrr), Okauchee (rrr), Paddock
(rrr). Round (3) (rrr).
Tetraedron regulare Kiitzing. PI. 24, Fig. 14.
Phycol. germanica 129. 1845.
Polyedrium tetraedricum Nageli, Gatt. einz. Algen 84, pi. 4, figs. B3a-B3b.
1849.
Cells medium sized, tetragonal, generally pyramidal, sides concave,
straight, or slightly convex. Angles with a single, heavy, short, blunt,
spine. ( Tychoplanktont ) .
Diam. cells (with spines) 14-45 fx.
Blake (rr).
var. INCUS Teiling. PI. 24, Figs. 15-16.
Sv. Bot. Tids. 6: 277, 274, fig. 12. 1912.
Polyedrium regulare Chodat non Kiitzing, Mater, pour la flore crypt. Suisse
V: 220, fig. 146. 1902.
Cells small, tetragonal, flattened or pyramidal, sides slightly concave.
Angles produced into a single short delicate straight or curved spine.
( Tychoplanktont) .
WISCONSIN PHYTOPLANKTON
119
Diam. cells (without spine) 13-18 /a; length of spines 7-8 /a.
Poor Farm (rr).
This is probably what Chodat has figured as T, regulare. It differs
from the typical form in the smaller size, constantly concave sides of
the cell, and the delicate spines at the cell angles.
var. TORSUM (Turner) Brunnthaler. PI. 24, Figs. 17-18.
in Pascher, Siisswasserfl. Deutschl., osterr. u. d. Schw. 5^: 150, fig. 169. 1915.
Cells medium sized, tetragonal, with the two halves of the cells
cruciately arranged. Sides of cells straight or convex. Angles of cells
with a single short stout spine (Facultative Planktont).
Diam. cells 25-40 /a.
Horse (sss).
Over a hundred individuals were observed in the plankton catch
from this lake and the twisting of the cell halves was a very constant
character.
Tetraedron victorieae var. major var. nov. PI 24, Figs. 19-22;
PI. 25, Fig. 1.
Cells medium sized, four-sided, with two deeply emarginate sides
dividing the cell into two cruciately arranged halves. Sides of cells,
in vertical view, broadly fusiform with acute apices. All angles of
cells with a single heavy straight spine (Euplanktont).
Cells (with spines) 30-60 /a long; 15-20 /a broad.
Chain (r).
The cell shape and the peculiar twisting of the two halves is identical
with that of T. victorieae Woloszynska (Hedwigia 55: 203, pi. 6, jigs.
1-A:. 1914) which is known from the plankton of Lake Victoria
Nyanza, Africa. Measurement of about 25 Wisconsin individuals give
the following variation in size, length 30-60 /a, breadth 15-20 ; whereas
the length of the African individuals varies from 20 to 30 /a and the
breadth 10-15 /a.
Tetraedron verrucosum G. M. Smith. PI. 25, Pigs. 2-3.
Trans. Wis. Acad. Sci., Arts, & Lett. 19^: 632, pi. 15, figs. 1-2. 1918.
Cells large, tetragonal, pyramidate, or with the halves cruciate. Sides
convex. Angles of cell terminating in a very heavy, blunt spine. Cell
wall thick, verrucose. (Euplanktont).
Diam. cells (with spines) 65-80 /a; length of spines 13-18 /a.
Bear (1) (rr).
120
WISCONSIN PHYTOPLANKTON
Tetraedron caudatum (Corda) Hansgirg. PI. 25, Figs. 4-7.
Hedwigia 27: 131. 1888; G. iS. West, Brit. Freshw. Algae 231, fig- 101®. 1904.
Cells small, flattened, flve-sided; four of the sides concave and the
fifth deeply incised. Angles rounded and produced into a single
straight spine that lies parallel with the flat side of the cell. (Tycho-
planktont) .
Diam. cells 6-22 fx ; length of spines 1-3.5 /x.
Ctiain (rrr). East (rrr), Dutchmans (rrr). Horse (rr). Lake of the Woods
(rrr), Mendota (rrr), Palmer (rrr). Reserve (rrr). Wild Goose (rrr).
The notch at one side of the cell varies considerably in depth but
is always deeper than the incurving of the other four sides.
var. LONGispiNUM Lemmermann. PI. 25, Pigs. 8-12.
Bot. Cent. 76: 151. 1898; Forschungsbr. a. d. Biol. Stat. zu Flon 7: 117, ph 1,
figs. 8-9. 1899.
Spines on corners at right angles to the flat side of the cell, generally
two pointing in one direction and three in the other. Spines much
longer than in the typical form. (Euplanktont).
Diam. cells (without spines) 8-18 /a; length of spines 3-8 fi.
Pine Tree (r), Travis (sss)
This is a sharply defined variety, differing from the typical form in
the bending of the spines so that they lie at right angles to the plane
of the cell. Lemmermann ’s figure 9 shows this very well but for some
reason the cell in his figure 8 has no spines and so is not at all charac-
teristic.
Tetraedron pentaedricum W. & G. S. West. PI. 25, Figs. 13-17.
Trans. Linn. Soc. 2nd iSer. Bot. 5: 84, pi. 5, figs. 15-16. 1895.
Cells small, five-cornered, with four corners in one plane and the fifth
lying at an angle of 30-90 degrees. Corners subacute, each with a
single, short, curved spine. Chloroplast single, parietal, with one pyre-
noid. (Facultative Planktont).
Diam. cells (without spines) 5.5-14 fi, (with spines) 9-20 fx.
Soft (rr).
T. pentaedricum has not been observed since it was described from
Madagascar by the Wests. Chodat considers it a synonym of T. cau-
datum (Corda) Hansg. erroneously citing it as Tetrapedia pentaedri-
cum (Mater, pour la fl. crypt. Suisse 1^: 219. 1902). Isolation of this
WISCONSIN PHYTOPLANKTON
121
alga in pure culture with the retention of its distinguishing character
shows that the Wests are correct in considering it a distinct species.
It resembles T. caudatum in the size, number of corners, character of
spines at the corners, and the concave sides ; but differs in having four
corners in approximately the same plane and the fifth at an angle with
the plane of the other four. There is considerable variation in the
angle at which this fifth corner lies but it is never in the same plane as
the other corners. The Wests (1. c. fig. 17) also describe a variety
minima which, as the name implies, is smaller. I find that the variations
in size of cells of the typical form in a pure culture include the dimen-
sions set for the variety minima so that this variety cannot be recognized.
Tetraedron hastatum (Reinsch) Hansgirg. PI. 25, Fig. 18.
Hedwigia 27: 132. 1888.
Polyedrium tetraedricum var. hastatum Reinsch, Die Algenfl. d. mitt. Th. t.
Franken 77, pi. 5, iigs. 3a-3b. 1867.
Cells medium sized, pyramidate, with the angles produced into long
tapering and somewhat concave processes. Processes unbranched but
having 2 or 3 short spines at the tip. (Tychoplanktont).
Diam. cells (with processes) 28-36 /a; diam. base of process 8 /jl.
Horse (rrr).
The general shape of the cell is similar to that of T. limneticum but
there is no branching of the processes.
var. PALATiNUM (Schmidle) Lemmermann. PI. 25, Figs. 19-21.
Ber. d. D. hot. Ges. 20: (247). 1902.
Polyedrium hastatum var. palatinum Schmidle, Ber. d. D, hot. Ges. 18: 148,
149, pi. 6, figs. 4-5. 1900.
Cells pyramidal, with convex sides, angles produced into fairly deli-
cate non-tapering processes about as long as the diameter of the cells.
Processes unbranched but with three short spines at the apex. (Ty-
choplanktont) .
Diam. cells (without processes) 4^14 y.; length processes about 10 fi.
Horse (rr).
The processes at the angles of the cell do not seem as much a part
of the cell as in the typical form. Although both the typical form
and the variety palatinum were found at the same station the two seem
distinct and without transition forms.
122
WISCONSIN PHYTOPLANKTON
Tetraedron constrictum nom. nov. PI. 25, Figs. 22-24.
Tetraedron arthrodesmiforme var. lohulatum Woloszynska, Hedwigla 55:
203, pi. 6, fig. 11. 1914.
Cells medium sized, tetragonal, flattened, two sides straight and two
opposite sides concave. Angles produced into narrow slightly taper-
ing processes which give the cell a decided H-shape. Ends of proc-
esses generally dichotomously branched the branchlets ending in two
short spines. (Euplanktont).
Diam. cells (without processes) 5-8 /a; length 18-25 fi; thickness 8 fx.
licngth of processes 10-15 (i.
Bone (rr).
Woloszynska has found these peculiar H-shaped cells in the plankton
of Lake Victoria Nyanza, Africa and placed them among other varieties
of T. arthrodesmiforme described at the same time. The variety lohu-
latum is, however, sufficiently different from the other varieties to war-
rant raising it to speciflc rank. Bone lake is the only station where it
has been found but several individuals were seen in the catch from
this lake.
Tetraedron gracile (Reinsch) Hansgirg. PI. 26, Figs. 1-5.
Hedwigia 28: 19. 1889.
Polyedrium gracile Reinsch, Notarisia 3: 502, pi. 7, figs, la-lc. 1888.
Cells medium size, conspicuously flattened, rectangular, with flattened
sides. Angles of cells produced into narrow processes that generally
branch twice and end in minute spines. The primary branchings of
the processes are at an angle of 90 degrees with one another and always
parallel with a side of the cell. Each cell containing several, parietal
disciform to laminate chloroplasts without pyrenoids. (Euplanktont).
Diam. cells (without processes) 15-30 /a; (with processes) 35-80 fx)
thickness of cells 6-12 /a.
Bear (1) (rr). Bear Trap (rrr), Blake (rr). Chain (rr), Elizabeth (rrr),
Hillman (sss). Loon (rrr). Pine (2) (rr), Poor Farm (rr). Round (rr), Travis
(r), Wapagossett (rr).
Tetraedron lobulatum (Nageli) Hansgirg. PI. 26, Figs. 6-7.
Hedwigia 27: 132. 1888.
Polyedrium lohulatum Nageli, Gatt. einz. Algen 84, pi. 4, figs. B4a-B4b. 1849.
Cells medium sized, tetragonal, flattened, or pyramidal. Processes
of angles with one or two short dichotomous branchings that generally
do not end in spines. Sides of cells distinctly concave. Cells contain-
WISCONSIN PHYTOPLANKTON
123
ing several parietal disciform chloroplasts without pyrenoids. (Tycho-
planktont) .
Diam. cells (with processes) 30-40 fi.
Birch Island (rrr), Long (3) (rrr), Sand (2) (rr).
The specimens from Sand lake were of particular interest since three
showed the production of autospores (fig. 6). The chloroplast of old
cells are frequently indistinct but they can be seen quite readily in
young cells.
var. POLYFURCATUM G. M. Smith. PI. 26, Fig. 8.
Bull. Torr. Bot. Cl. 43: 480, pi. 26, figs. 21-22. 1*916.
Cells tetragonal, flattened or pyramidal; with concave, straight, or
slightly convex sides. Processes at angles somewhat tapering, 3-5 times
dichotomously branching, the ultimate branchlets with 2-3 minute
spines. (Facultative Planktont).
Diam. cells (without processes) 15-25 fi, (with processes) 35-70 /x.
Beaverdam (r), Blake (rr). Bone (rr), Clare (rr), Fish (rr). Loon (rr),
Muskallonge (rrr). Palmer (r), Pardee (r), Pine Tree (rr), Rice (1) (rr).
Shell (rr). Wild Goose (rrr).
Differing from the typical form in the greater branching of the
processes and from T. enorme (Ralfs) Hansg. in the much longer proc-
esses.
Tetraedron limneticum Borge. PI. 27, Figs. 1-3.
Bot. Not. 1900: 5, pi. 1, fig. 2. 1900; W. & G. S. West, Trans. Roy. Soc. Edin-
burgh 41: 507, pi. 6, figs. 10-11. 1905.
Cells of medium size, tetragonal, pyramidal, the four angles being
produced into one or two dichotomous branchings. Terminal branch-
lets with 2-3 short spines. (Euplanktont).
Diam. cells (with processes) 45-85 p.; diam. base of processes 8-12 p.
Chain (rr), Chetek (r). Clear (r). Crawling Stone (rrr). Deer (rr). Diamond
(rrr). Island (rr). Kitten (rr), Little Butternut (rr). Little Crooked (rrr),
Mud (2) (r), Nancy (rr). Palmer (rr). Pine Tree (rr). Poplar (rr). Spirit
(rrr). Squirrel (rr). Wildcat (rr). Wild Goose (rrr). Wolf (rr).
Tetraedron planctonicum G. M. Smith. PI. 27, Figs. 4-5.
Bull. Torr. Bot. Cl. 43 : 479, pi. 26, figs. 19-20. 1916.
Cells medium-sized, four to five sided, sides concave to convex. Angles
of cells produced into narrow, once to twice dichotomously branched
processes. Ultimate branchlets with 2-3 short spines. Processes broad
in front view, narrow in side or vertical view. (Euplanktont).
124
WISCONSIN PHYTOPLANKTON
Diam. cells (without processes) 18-30 /x; (with processes) 45-60 /x.
Cranberry (rr), Cochrane (rr), Devils (2) (sss), Granite (rr), Horseshoe
(1) (rr), Lindy (rrr), Lost (rr), No Mans (rr), Prairie (rr). Rock (rr). Ver-
milion (r).
The chief difference between this species and T. Umneticum is the
greater size of the cells in proportion to the length of the processes.
Tetraedron enorme (Ralfs) Hansgirg. PI. 27, Fig. 6.
Hedwigia 27: 132. 1888; G. S. West, Brit. Freshw. Algae 231, fig. IOId. 1904.
Cells irregularly tetrahedric, angles produced into short processes
and sides emarginate. Processes generally bilobed and ending in short
spines. ( Tychoplanktont ) .
Diam. cells 25-45 fx.
Carson (rr), Cochrane (rr), Devils (2) (r). Horse (rrr). Horseshoe (2)
(rrr). Lake of the Woods (rrr), Okauchee (rrr). Pine (2) (rr).
POLYEDRIOPSIS Schmidle 1899.
Cells solitary, generally tetragonal, flattened; rarely pyramidal cr
with sides cruciate. Corners truncate and with 3-10 long, hyaline,
slightly tapering setae. Chloroplast parietal or entirely Ailing the
cell, pyrenoid single.
Reproduction by the formation of 2-4-8 autospores through the divi-
sion of the cell contents.
PoLYEDRiOPSis SPiNULOSA Schmidle. PI. 27, Figs. 7-8,
Allg. Bot. Zeitschr. 5: 17. 1899.
Tetraedron spinulosnm Schmidle, ibid. 2: 193, fig. 2. 1896.
Characters the same as those of the genus. (Euplanktont).
Greatest diameter of cells 12-25 fi ; length of setae about 40 fi.
Horse (rr). Prairie (rrr).
The general tendency among phycologists is to follow Wille’s prac-
tice and place the alga in a special sub-genus of Tetraedron. The
setae on the cell angles are of the same type as those found on Lager-
heimia and Micractinium so that Polyedriopsis forms, in my opinion,
a genus parallel with Tetraedron just as Lagerheimia does with Oocystis.
WISCONSIN PHYTOPLANKTON
125
Sub-family MICEACTINIEAE.
Cells solitary or in colonies; spherical or ovoid; with long hyaline
setae or spines completely covering or restricted to certain parts of the
cell wall. Chloroplast single and cup-shaped ; or laminate to disciform
and from one to several in each cell. Chloroplasts generally with pyrv3-
noids.
KEY TO THE GENERA.
Cells spherical.
Cells organized into definite colonies Micractinium (p.p.)
Cells solitary.
Wall covered with fine hair-like setae.
Setae thickened in lower third Acanthospheaeba
Setae not thickened in lower third Golenkinia
Wall covered with delicately tapering spines Echinosphaerella
Cells ovoid.
Cells organized into definite colonies Micractinium: (p.p.)
Cells solitary.
Setae somewhat tapering Lagerheimia
Setae not tapering Franceia
MICRACTINIUM Fresenius 1858.
Cells spherical or ovoid, in colonies of 4-32 or more, generally quad-
rately arranged in one plane but sometimes tetrahedrically disposed.
Cell wall delicate, with 1-7 long hyaline setae that are not thickened
at the base lying on the free surface of the cells. Chloroplast single,
parietal, cup-shaped ; with one pyrenoid.
Reproduction by the division of contents of any cell to form a 4- or
8-celled autocolony, the young colony being liberated by a rupture of
the mother cell wall into four parts. Young coenobia frequently re-
maining attached to the parent coenobe for some time.
KEY TO THE SPECIES.
Cells spherical M. PusiixuM
Cells ovoid M. Quadrispenum
Micractinium pusillum Fresenius. PL 28, Figs. IS.
Abh. Senckenb. Naturf. Ges. 2: 236, pi. 11, figs. 46-49. 1858; G. M. Smith, Bull.
Torr. Bot. Cl. 43: 477, pi. 25, fig. 18. 1916.
Richteriella hotryoides (Schmidle) Lemmermann, Hedwigia 37: 307, pi. 10,
figs. 1-6. 1898.
Richteriella hotryoides forma fenestrata Chodat, Mater, pour la flore crypt.
Suisse V: 194, fig. 110. 1902.
126
WISCONSIN PHYTOPLANKTON
Richteriella lotryoides forma tetraedrica Lemmermann, Arch. f. Hydrobiol.
u. Planktonkde. 5: 307. 1910.
Colonies of 4-8-16 or more cells in groups of four and disposed in a
quadrate or pyramidate manner with the groups of four in turn pyra-
midately or quadrately arranged. Cells spherical, with 1-5 long, hya-
line, delicately tapering setae on the face not adjacent to other cells.
Chloroplast single, parietal, cup-shaped; with one pyrenoid. (Eu-
planktont).
Diam. cells (without setae) 3-7 /x; length of setae 20-35 /x.
Blake (rrr), Bone (sss), Chain (sss), Chetek (rr), East (rr), Green (1)
(rr), Hooker (rr), Horse (rr), Horseshoe (2) (rrr). Island (rrr), Little Bass
(2) (r). Little Crooked (rrr). Loveless (r), Mendota (rr), Monona (cc). North
Turtle (rr), Pokegama (3) (rr). Poor Farm (rr). Pope (rr), Prairie (rr),
Round (1) (rr). Tenderfoot (rrr). Tied Canoe (rr). Wolf (rrr).
Flat sixteen-celled colonies with a central open space are the most
common. Such colonies have been given the form name fenestrata but
both it and the form tetraedrica are unworthy of recognition. On rare
occasions large colonies are found; colonies containing over 750 cells
having been collected from the plankton of Lake Monona.
var. ELEGANS G. M. Smith. PI. 29, Pig. 1.
Trans. Wis. Acad. Sci., Arts, & Lett. 19h 631, pi. 12, fig. 4. 1918.
Cells with 5-7 setae on the exposed face. Dimensions as in the
typical form. (Euplanktont).
Rice (1) (rr).
This seems to be a distinct variety since the cells of colonies from
this lake all bore the large number of setae.
Micractinium quadrisetum (Lemmermann) G. M. Smith. PI. 28,
Fig. 4 .
Bull. Torr. Bot. Cl. 43: 479, pi. 25, fig. 17. 1916.
Cells ovoid, with 1-4 long, delicately tapering setae on the exposed
faces. Chloroplast single, parietal, cup-shaped; with one pyrenoid.
(Euplanktont).
Diam. cells (without setae) 4-7 fi, length 8-10 /x; length of setae
23-40 fx.
Bear Trap (rrr). Camp (rr). Cranberry (rrr). Eagle (rrr).
The cells of this species are somewhat larger than those of M. pusil-
lum and are distinctly ovoid. The character upon which the specific
WISCONSIN PHYTOPLANKTON
127
name is based is quite misleading since the number of setae may vary
from one to four. Colonies containing more than sixteen cells have
not been observed and the cell arrangement has been quadrate in every
case.
GOLENKINIA Chodat 1894.
Cells spherical, normally solitary; occasionally forming temporary
colonies. Cell wall thin, sometimes enclosed in a thin gelatinous en-
velope. Surface of cell covered with hyaline setae that are slightly
tapering but not conspicuously thickened in the lower third. Chloro-
plast single, parietal and cup-shaped or entirely filling the cell; pyre-
noid single.
Keproduction by the formation of autospores. Zoospores have been
reported but their formation is doubtful.
KEY TO THE SPECIES.
Setae 25-45 long G. Radiata
Setae 12-18 long G. Patjcispina
Golenkinia radiata Chodat. PI. 29, Figs. 2-3.
Jour, de Bot. 8: 305, 2 )Z. 3, figs. 1-24. 1894.
Cells spherical, solitary, sometimes in temporary colonies of four
cells. Entire cell wall covered with long, delicate, hyaline setae. Chlor-
oplast single, cup-shaped, parietal ; with one pyrenoid. (Euplanktont) .
Diam. cells (without setae) 7-15 /x; length setae 25-45 /x.
Green (2) (rrr), White Ash (rr).
This and the following Golenkinia species have been made a sub-
genus of Micractinium by Wille and that terminology followed in the
second list but the colonial and solitary habit seem to me sufficiently
diverse to v/arrant generic distinction.
Golenkinia paucispina W. & G. S. West. PI. 29, Figs. 4-5.
Trans. Roy. Irish Acad. 32, Sec. B: 68, pi. 1, fig. 18. 1902.
Cells solitary, spherical, with few to fairly numerous, short, delicately
tapering, hyaline or dark setae. Chloroplast single, completely filling
the cell, with one pyrenoid. (Euplanktont).
Diam. cells (without setae) 15-18 /x; length setae 12-18 /x.
Prairie (rr).
The setae of the cells in Prairie lake were more numerous than the
Wests found them in individuals from the plankton of Lough Neagh,
128
WISCONSIN PHYTOPLANKTON
Ireland. They were also dark colored and are more conspicuous than
in other members of the Micractineae.
ACANTHOSPHAERA Lemmermann 1899.
Cells spherical, solitary, with a single cup-shaped chloroplast con-'
taining one pyrenoid. Cell wall thin, without a gelatinous sheath;
covered with many long hyaline setae that are thicker in the lower
third and then abruptly diminish to a very fine hair.
Method of reproduction unknown.
Acanthosphaera Zachariasi Lemmermann. PI. 29, Figs. 6-8.
Forschungsbr. a. d. Biol. Stat. zu Plon 7: 118, pi. 1, figs. 10-11. 1899.
Characters as those of the genus. (Euplanktont).
Diam. cells (without setae) 9-14.5 /x; length setae 30-35 /x.
Horse (rr).
The chief distinction between this genus and Golenkinia is the thick-
ening of the lower part of the setae.
Echinosphaerella gen. nov.
Cells spherical, solitary. Cell wall thin, completely covered with
heavy, long, hyaline, delicately tapering and slightly concave, homo-
geneous spines. Chloroplast single, parietal, cup-shaped; with one
pyrenoid.
Reproduction unknown.
Echinosphaerella limnetica sp. nov. PI. 29, Figs. 9-11.
Characters as described above. (Euplanktont).
Diam. cells (without spines) 9-12 fi. Spines 2.5-3 /x broad at base,
20-25 fjL long.
Horse (rr).
The alga at once suggests a desmid zygospore, especially those of
certain Staurastrum species. In all desmid zygospores the chloroplast
is not definite and since the alga collected from Horse Lake has a
single, well defined, cup-shaped chloroplast with one pyrenoid the pre-
sumption is that it is a vegetative cell and not a zygospore. The
nearest genus is Echinosphaeridium Lemmermann where the setae
covering the wall have a broad tapering gelatinous sheath at the base.
In Echinosphaerella there is not a central hair-like seta with a gelati-
nous covering, but a homogeneous spine of considerable thickness at the
WISCONSIN PHYTOPLANKTON
129
base. Although the genus is provisionally placed in the Micractinieae
its spines are quite different from those of other genera of the sub-
family.
LAGERHEIMIA Chodat 1895.
Cells solitary; ovoid, ellipsoid, or citriform. Cell wall firm, without
a gelatinous sheath; with long tapering setae that lie a short distance
back from the poles or cover the entire wall. Chloroplasts 1-4, pari-
etal, laminate; with or without pyrenoids.
Reproduction by autospores that are generally liberated at once but
which may remain inside the old mother wall a short time.
KEY TO THE SPECIES. _
Setae covering entire cell wall L. Droescheri
Setae confined to poles of the cell.
Cells lemon-shaped L. Citriformis
Cells ovoid.
Length of setae more than double that of cell L. Longiseta
Length of setae less than double that of cell.
2- 4 setae at each pole L. Subsalsa
3- 8 (generally 6) setae at each pole L. Ciliata
Lagerheimia ciliata (Lagerheim) Chodat. PI. 31, Figs. 1-2.
Nuova Notarisia 10: 90. 1895.
Oocystis ciliata Lagerheim, ofvsers Kgl. Vet.-Ak. Porh. 39, No. 2: 76, pi. 3,
figs. 33-37. 1882.
Chodatella ciliata (Lag.) Lemmermann, Hedwigia 37: 310. 1898.
Cells oblong-ovoid, with 3-7, hyaline, delicately tapering setae at
each pole. Chloroplasts 1-4, parietal, laminate; each with a single
pyrenoid. ( Euplanktont) .
Breadth of cells (without setae) 6-18 ja; length (without setae) 10-
• 21 fi. Setae 15-20 fx long.
Kegonsa (rr), Mendota (sss).
The setae of this species are not in definite whorls but distributed over
the entire polar region.
var. minor (G. M. Smith) comb. nov. PI. 31, Fig. 3.
Chodatella ciliata var. minor G. M. Smith. Bull. Torr. Bot. Cl. 43: 477,
pi. 25, fig. 16. 1916.
Cells ovoid, with 6-8 setae at each pole. (Euplanktont).
Diam. cells (without setae) 6-7.5 /x; length (without setae) 8-10 fx.
Setae about 20 /t long.
Muskallonge (rr).
9
130
WISCONSIN PHYTOPLANKTON
Lagerheimia subsalsa Lemmermann. PI. 30, Figs. 3-4.
Forschungsbr. a. d. Biol. Stat. zu Plon 6: 193, pi. 5, figs. 2-6. 1898.
Chodatella subsalsa Lommermann, Hedwigia 37: 310. 1898.
Cells ovoid, with 2-4 delicate setae at each pole. Chloroplast single,
laminate, parietal; with one pyrenoid. (Euplanktont).
Diam. cells (without setae) 2.5-8 /x; length (without setae) 5-12 fi.
Setae 7.5-26 /x long.
Deer (rrr), Geneva (rr).
Lagerheimia longiseta (Lemmermann) Printz. PI. 30, Figs. 8-9.
Skr. Vidensk. i Kristiania, Mat.-Naturv. Kl. 1913% No. 6: 60. 1914.
Chodatella longiseta Lemmermann, Hedwigia 37: 310, pi. 10, figs. 11-18.
18’98.
Cells ellipsoid, with a whorl of 4-10 long, hyaline, delicately tapering
setae a short distance from each pole. Chloroplast single ( ?), parietal;
without a pyrenoid (?). (Euplanktont).
Breadth of cells (without setae) 5-8 fi; length (without setae) 9-13 ju.
Setae 40-55 /x long.
White Sand (sss).
The exceedingly long setae at once distinguish the species from all
others. The arrangement of the setae in a whorl is best seen in an end
view of a cell.
var. major var. nov. PI. 30, Figs. 10-12.
Cells ovoid, with somewhat pointed ends. With a whorl of 4-7 setae
a short distance from each pole. Cells containing 1-2 laminate pari-
etal chloroplasts each with a single pyrenoid. (Euplanktont).
Breadth of cells (without setae) 12-15 /x; length (without setae)
15-22 fx. Setae 45-60 fi long.
Blake (rr). Little Bass (2) (rrr).
The variety is distinguished from the typical form by the more
pointed and larger cells.
Lagerheimia citriformis (Snow) comb. nov. PI. 30, Pigs. 1-2.
Chodatella citriformis Snow, Bull. U. S. Pish Comm. 22: 389, pi. 2, figs.
8^-8’. 1903.
Cells ovoid to ellipsoid, with a small obtuse projection at each pole.
Poles with a whorl of 4-8 long, hyaline, delicately tapering setae at the
WISCONSIN PHYTOPLANKTON
131
base of the polar projections. Chloroplast single, parietal; with one
pyrenoid. ( Euplanktont) .
Breadth cells (without setae) 8-20 fi; length (without setae) 13-23 fj..
Setae 25-35 fi long.
Horse (rrr), Kegonsa (rrr).
This is the only species with polar projections that resemble the
polar nodules of Oocystis.
Lagerheimia Droescheri (Lemmermann) Printz. PI. 30, Figs. 5-7.
Skr. Vidensk. i Kristiania Mat.-Naturv. Kl. 1913% No. 6: 60. 1914.
Chodatella Droescheri Lemmermann, Ber. d. D. Bot Ges. 18: 98, ph 3, fig. 12.
1900.
Cells ovoid to ellipsoid; with numerous hyaline delicately tapering
setae covering the entire wall. Cells with 2-A parietal, laminate
chloroplasts ; each with a single pyrenoid. (Euplanktont).
Breadth of cells (without setae) 5-12 fi; length (without setae) 9-16
fi. Setae 15-22 long.
Horse (rrr), Travis (r). Upper Nashotah (rr).
FEANCEIA Lemmermann 1898.
Cells ovoid, solitary or in colonies of 2-4; free-floating. Cells en-
closed in a delicate gelatinous sheath (?). Entire cell wall covered
with delicate hyaline setae that do not taper. Chloroplasts 1-3, pari-
etal, laminate, with or without pyrenoids.
Eeproduction by autospores.
Franceia ovalis (France) Lemmermann. PI. 31, Fig. 4.
Hedwigia 37: 308. 1898.
Phythelios ovalis Franc6, Notarisia 1894: 2, figs. 1-5. 1894.
Cells ovoid to elliptic; with two chloroplasts. (Euplanktont).
Breadth of cells (without setae) 7-10 /x; length (without setae) 13-
17 fx. Setae 15-23 fx long.
Pine Tree (rr).
The minimal dimensions given above are somewhat smaller than those
given by France but I feel that the Wisconsin organism should not be
considered a distinct variety until the variation in size of the typical
form has been determined -more fully.
The recognition of the genus Franceia is open to question since the
characters upon which Lemmermann bases the genus (number of
132
WISCONSIN PHYTOPLANKTON
chloroplasts, presence of a vacuole, and cell division in one plane) are
ones which might be found in any Lagerheimia species. The setae,
however, are very delicate and do not taper so that the genus is pro-
visionally considered distinct from Lagerheimia.
Sub-family SELENA8TREAE.
Cells elongate, straight or curved; with finely pointed ends or with
ends rounded. Solitary or associated in colonies containing an indefi-
nite number of cells. Colonies with or without a gelatinous envelope.
Cells generally with one parietal chloroplast that is with or without
pyrenoids.
KEY TO THE GENERA.
Cells solitary.
Ends of cells produced into setae Schroedebia
Ends of cells not produced into setae.
Chloroplast with an axial row of pyrenoids Closteriopsis
Chloroplast never with more than a single pyrenoid . Ankistrodesmus (p. p.)
Cells in colonies.
Colonies not enclosed in a gelatinous sheath.
Cells straight, in loose fasiculate bundles or spirally
twisted around one another Ankistrodesmus (p. p.)
Cells curved, with convex faces towards one another Selenastbum
Colonies enclosed in a gelatinous sheath.
Cells curved Kirchneriella
Cells straight.
Colonies with cells in groups of two Elaktothrix
Colonies with cells in groups of 2-4-8 Quadrigula
SELENASTRUM Reinseh 1867.
Cells broadly to narrowly acicular, semilunar; joined by their con-
vex faces into colonies of 4^8-16 or more cells without a gelatinous en-
velope. Chloroplast single, parietal, laminate, on convex side of young
cells ; entirely filling older cells ; with one pyrenoid.
Reproduction by any cell forming 2-4-8 autospores which, when
liberated, have the arrangement of the cells in an adult colony. Auto-
spores remaining attached to parent colony for some time.
The statement is generally made that there are not more than six-
teen cells in a colony but I have found that in the plankton of Wiscon-
sin lakes the colonies sometimes contain over a hundred cells.
WISCONSIN PHYTOPLANKTON
133
KEY TO THE SPECIES.
Cells arcuate, never sickle-shaped S. Westh
Cells arcuate to sickle-shaped.
Diameter of cells not exceeding 5 ai S. Geacile
Diameter of cells 5-8 S. Bibbaianum
Selenastrum gracile Keinsch. PI. 31, Fig. 5.
D. Algenfl. d. mitt. Th. v. Franken 65, pi, 4, figs. 3a-3b. 1867.
Cells lunate to sickle-shaped, quite narrow in proportion to their
length. Apices of cells acute. Chloroplast single, laminate, parietal,
on convex side of cell. Without a pyrenoid. (Facultative Planktont).
Diam. cells 3-5 p , ; length 15-30 fx. Distance between apices 8-20 p.
Bear (3) (rr), Chain (rr), Hillman (rrr). Horse (rr), Monona (r),
Pokegama (1) (rr), Prairie (rr). Upper Turtle (rrr), Whitefish (rr).
Differs from the next species in the more delicate cells. Possibly it
should be considered a variety of S. Bihmianum and not a distinct
species.
Selenastrum Bibraianum Reinsch. PI. 31, Figs. 6-7.
D. Algenfl. d. mitt. Th. v. Franken 64, pi. 4, figs. 2a-2b. 1867.
Cells in spherical to ovoid colonies of 4-8-16 or more with their con-
vex sides facing the center of the colony. Cells crescent-shaped lo
sickle-shaped, gradually tapering to a fairly sharp apex. Chloroplast
parietal, on convex side of and almost filling the cell ; pyrenoid single.
(Facultative Planktont).
Diam. cells 5-8 p ; length 20-38 p. Distance between apices 5-25 p.
Beaverdam (rr), Blake (rrr). Bone (rr), Deer (rrr), Little Bass (2) (rrr),
Loveless (rr), Mendota (rrr), Meta (r), Nancy (rr), Pewaukee (rr), Pine
Tree (rr). Poor Farm (rr). Rice (1) (rr). Spirit (rrr). Squirrel (rrr), Ten-
derfoot (rr), Travis (rr). White Ash (sss), Wolf (rr).
All descriptions of S. Bibraianum state that there are but four or
eight cells in the colony but I have found that in Wisconsin lakes there
may be over a hundred cells in the colony, the number of cells usually
ceasing to be a multiple of two after there are more than sixteen cells
in the colony.
Selenastrum Westii sp. nov. PI. 31, Figs. 8-10.
Selenastrum acuminatum G. S. West non Lagerheim, Jour, of Bot. 50 : 88,
figs. 5a-5&. 1912.
Colonies of 2-4-8 cells irregularly arranged with their convex sides
in apposition. Frequently dissociating into the individual cells when
WISCONSIN PHYTOPLANKTON
.r.ature. Ceils innate to arcuate, never sickle-shaped; gradually taper-
ing to a shaj’p point. Chloroplast single, parietal on convex side of cell ;
without a pyrenoid. (Facultative Planktont).
Diam. cells 1. 5-2.5 /a. Distance between apices 15-18 /x.
Devils (1) (rr).
The cells of this species are quite like those of Scenedesmus acumi-
natus (Lagerheim) Chodat but their organization in the colony is quite
different. West has recently investigated an organism which he con-
siders identical with the Selenastrum acuminatum described by Lager-
heim. I have obtained West’s organism in pure culture and find that
the cell shape and colony organization is as he describes. The fortunate
rediscovery of Lagerheim ’s species from the plankton of Horse Lake
shows that in the organization of the colony it is a Scenedesmus and
that Chodat is entirely correct in removing the species from Selenast-
rum. The organism that West found is, on the other hand, a true
Selenastrum but is not the species which Lagerheim erroneously re-
ferred to Selenastrum.
ANKISTRODESMUS Corda 1838.
Cells acicular to fusiform ; straight, lunate, or sigmoid ; ends of cells
gradually tapering to a point; solitary or loosely aggregated without
order in temporary colonies that are not embedded in a gelatinous en-
velope. Chloroplast single, parietal, sometimes fragmented into small
pieces ; with or without a pyrenoid.
Reproduction by the formation of several autospores in any cell.
KEY TO THE SPECIES.
Cells twisted around one another A. Spiralis
Cells not twisted around one another A. Falcatus
Ankistrodesmus falcatus (Corda) Ralfs. PL 32, Pig. 1.
Brit. Desmidieae 180, pi. 34, figs. 3a-3b. 1848; G. S. West, Brit. Freshw. Algae
223, fig. 94a. 1904.
Cells acicular to narrowly fusiform, tapering very gradually to acute
apices, lunate or slightly arcuate. Length 12-24 times the diameter.
Seldom solitary, generally loosely associated in fasiculate bundles.
Chloroplast single, generally without pyrenoids. (Facultative Plank-
tont) .
Diam. cells 1.5-3. 5 fx; length 20-80 fx.
Fence (rrr). Half Moon (rrr), Horse (rr), Kawaguesaga (rrr), Lac du
Flambeau (rrr). Little Crooked (rr). Lost (rr), Oconomowoc (rrr), Pine
WISCONSIN PHYTOPLANKTON
135
Tree (rr), Poor Farm (rr), Poplar (rr), Rock (1) (rr), Tenderfoot (rr),
White Ash (rr).
var. ACicuLARis (A. Braun) G. S. West.
Brit. Freshw. Algae 223, figs. 94b-94o. 1904.
Cells usually solitary, straight or slightly curved, apices acutely at-
tenuated. Chloroplast single, parietal, with or without a pyrenoid.
Cells 2.5-4 fi broad, 36-65 /x long.
Beaverdam (rr), Little Bass (1) (rrr), Mendota (rr). Rice (1) (rr), Wau-
besa (rrr).
var. TUMiDus (W. & G. S. West) G. S. West. PI. 32, Fig. 2.
Brit. Freshw. Algae 224, fig. 94d. 1904.
Cells solitary or in small aggregates, straight or curved, inflated at
the middle and with acute apices. Chloroplast single, parietal, with
or without pyrenoids. (Tychoplanktont).
Cells 4.5-6.S /a broad; 61-73 fi long.
Devils (1) (rrr), Mendota (rr).
var. MiRABiLis (W. & G. S. West) G. S. West. PI. 32, Figs. 3-5.
Brit. Freshw. Algae 224, fig. 94b. 1904.
Cells solitary, straight, lunate, or sigmoid; with acute apices; much
longer and narrower than the typical form. Chloroplast single, com-
monly fragmented by large vacuoles in the cytoplasm; without pyre-
noids. ( Euplanktont ) .
Cells 2-3.5 /A broad ; up to 150 /a long.
Bear (3) (rr), Bryer (rr), Chain (sss). Crab (rrr). Devils (1) (sss).
Devils (2) (rr). Dummy (rr), High (rr). Horseshoe (1) (rr). Reserve (rr).
Squirrel (rr), Travis (rrr), Whitefish (rr).
Ankistrodesmus spiralis (Turner) Lemmermann. PI. 32, Figs. 6-7.
Arch. f. Hydrobiol. u. Planktonkde. 4: 176. 1908.
Raphidium spirals Turner, Kgl. Sv. Vet.-Ak. Handl. 25, No. 5: 156, pi. 20,
fig. 26. 1892.
Ankistrodesmus falcatus var. spiralis (Turner) G. S. West, Brit. Freshw.
Algae 224. 1904.
Cells acicular, attenuated to acute apices ; in colonies of four or eight
and spirally twisted around one another in the middle of the cell but
with the extremities free. Chloroplast single, completely filling the
cell; without a pyrenoid ( ?). (Tychoplanktont).
136
WISCONSIN PHYTOPLANKTON
Cells 1-2.5 ^ broad ; 20-40 long.
Grassy (rr), Silver (2) (rrr).
G. S. West places the alga as a variety of A. falcatus but the twist-
ing of the cell seems to be such a constant character that I have fol-
lowed Lemmermann’s practice in considering it a distinct species.
CLOSTERIOPSIS Lemmermann 1898.
Cells solitary, acicular, with ends produced into very acute apices,
without a gelatinous envelope. Chloroplast single, not interrupted
at the center of the cell, occupying the greater portion of the cell and
containing a single axial row of about a dozen pyrenoids.
The genus is very closely related to Ankistrodesmus, differing onh^
in the greater length of the cells and the axial row of pyrenoids. It
also resembles certain Closteriwn species but the chloroplast of Closter-
ium is always interrupted at the center of the cell. Many feel that the
single species is not sufficiently differentiated to warrant its separation
from Ankistrodesmus,
CLOSTERIOPSIS LONGissiMA var. TROPICA W. & G. S. West. PI. 32, Fig. 8.
Trans. & Proc. Bot. Soc. Edinb. 23: 31, pi. 1, fig. 1. 1905.
RhapTiidium longissimum var. tropicum W. & G. S. West, Trans. Linn. Soc.
2nd. Ser. Bot. 6: 198. 1902.
Cells acicular, poles acute but not ending in a point of hair-like fine-
ness. (Facultative Planktont).
Cells 6-7.5 fx broad ; 225-370 /a long.
North Turtle (rr).
The dimensions of specimens that I have found agree with those given
for individuals from Ceylon but not with those from the Scotch plank-
ton.
SCHROEDERIA Lemmermann 1898.
Cells solitary, straight or curved, acicular; with one apex produced
into a fine seta tapering to a point, the other with a slightly broader
projection terminating in a small disc. Cells without a gelatinous en-
velope. Chloroplast single, parietal, laminate; with one pyrenoid.
Method of reproduction unknown.
WISCONSIN PHYTOPLANKTON
137
ScHROEDERiA SETiGERA (Schroder) Lemmermann. PI. 32, Fig. 12.
Hedwi^ia 37: 311. 1898; G. M. Smith, Bull. Torr. Bot. Cl. 43: 473, pZ. 24,
fig. 8. 1916.
Length of cells 15-20 times breadth. (Enplanktont).
Cells 3-6 fi broad, 60-85 /a long (with spines). Length of spines
13-27 fi.
Chain (sss). Devils (1) (c). Long (2) (rr). Sand (1) (rr).
This peculiar alga has the general appearance of a Characium. Al-
though hundreds of individuals have been found, it has never been
found attached to other algae or to crustaceans so that it seems safe
to assume that it leads a free-floating and not an epiphytic existence.
The disc at one end of the setae described above has not been observed
by other investigators, possibly because the alga is very minute.
Reproductive stages have never been found so that the systematic
position of the genus is doubtful. Judging by the cell shape it is a
close relative of Ankistrodesmus, a genus to which it has been referred
by some.
ScHROEDERiA JuDAYi G. M. Smith. PI. 32, Figs. 9-11.
Bull. Torr. Bot. Cl. 43: 474, pZ. 24, Ms. 9-11. 1916.
Cells smaller than the foregoing. (Euplanktont).
Cells 2.5-6 II broad, 45-63 /t long (with spines). Length of spines
10-16 /X.
Amicoy (rr), Birch (rrr), Camp (rr), Delavan (rr), Kawaguesaga (rr),
Mendota (sss), Prairie (rr). Round (1) (rrr), St. Croix (rr).
QUADRIGULA Printz 1915.
Cells generally in groups of 2-4-8 with their long axes parallel to
the long axis of the colony and enclosed by a hyaline, homogeneous,
gelatinous sheath. Colonies ellipsoid, 2-5 times as long as broad. Cells
cylindrical to fusiform, A-1 times as long as broad, straight or slightly
curved. Chloroplast single, filling most of the cell; with or without
pyrenoids.
Reproduction by 2-4-8 autospores from each cell, the fasiculate group
of autospores frequently remaining within the envelope of the mother
colony for some time.
138
WISCONSIN PHYTOPLANKTON
KEY TO THE SPECIES.
Ends of cells rounded Q. Pfitzeri
Ends of cells pointed.
Chloroplast notched at the center Q. Chooati
Chloroplast not notched at the center Q. Lacustbis
Quadrigfula Pfitzeri (Schroder) comb. nov. PL 33, Figs. 1-2.
Rhaphidium Pfitzeri Schroder, Verb. d. Nat.-Med. Ver. zu Heidelberg N. F.
7: 152, pi. 6, fig. 6. 1902.
Ankistrodesmus Pfitzeri (Schroder) G. S. West, Brit. Freshw. Algae 224,
figs. 94g-94h. 1904.
Cells about 7 times as long as broad, central portion cylindrical with
ends slightly tapering and rounded. Chloroplast generally filling the
entire cell, with or without a pyrenoid. (Euplanktont).
Breadth of cells 3-6 /x, length 22-45 (generally about 35) p..
Bear (1) (rr), Beaver dam (rr), Blake (rr). Chain (rr). Clear (rr),
Cochrane (sss). Devils (1) (s), Fishtrap (rrr), Found (r), Fowler (rr),
Harris (rr), Hillman (ss), Jennie (rr). Lac Court Oreilles (rr), Lindy (rr).
Long (2) (rrr). Little Wood (rr). Mud (1) (rr), Mudhen (rr), Oconomowoc
(rr), Okauchee (rr). Palmer (sss), Pardee (rr). Pine Tree (r), Poplar (r).
Reserve (rr). Rice (1) (rr). Sand (1) (rr). Shell (rr), tSishebogema (rr),
Travis (rr). White Ash (r), Whitefish (rr). Wild Goose (rrr).
The chief characteristic of the genus is the arrangement of the cells
in groups of 2-4-8 with their long axes parallel to the long axis of the
colony, together with the gelatinous envelope that surrounds the colony.
Admitting the generic validity of Quadirigula, Ankistrodesmus Chodati
and A. lacustris are in a much more natural position when placed with
Quadrigvla species.
Quadrigula Chodati (Tanner-Fullman) comb. nov. PL 33, Fig. 3.
Raphidium Chodati Tanner-Fullman, Bull. Herb. Boiss. 2 Ser. 6: 156, figs.
1-11. 1906.
Ankistrodesmus Chodati (Tanner-Fullman) Brunnthaler, in Pascher, Siiss-
wasserfl. Deutschl., osterr. u. d. Schw. 5": 193, fig. 306. 1915.
Cells linear, arcuate, or lunate ; fusiform and tapering to sharp ends.
Longitudinally arranged in a gelatinous colony of 4-8-16 or more cells.
Cells with a single, parietal, laminate chloroplast that is notched at
the center and contains two pyrenoids. (Euplanktont).
Breadth of cells 3.5-7 p, length 30-80 p. Colonies up to 50x250 p.
Boulder (r). Little Bass (2) (rrr). Lac du Flambeau (rr). Sand (3) (ss).
Tanner-Fullman states that the cells are always lunate but those that
T have observed were always straight or slightly curved. The notching
of the chloroplast together with the two pyrenoids is such a distinct
WISCONSIN PHYTOPLANKTON
139
feature that there can be no doubt of the identity of the Wisconsin alga
with his species.
Quadrigula lacustris (Chodat) comb. nov. PL 33, Figs. 4-6.
Raphidium Braunii var. lacustre Chodat, Bull. Herb. Boiss. 5: pi. 11, figs.
9-10. 1897; Mater, pour la fl. crypt. Suisse 1^: 200, fig. 117. 1902.
AnTcistrodesmus lacustre (Chodat) Ostenfeld, Hedwigia 46: 384. 1907.
Cells spindle-shaped, straight, with pointed ends. Cells rarely soli-
tary, generally irregularly distributed throughout, or in groups with
their long axes parallel to the long axis of the fusiform gelatinous
colonial envelope. Chloroplast single, parietal, laminate, at one side
of the cell or spirally twisted; generally with a single pyrenoid. (Eu-
planktont).
Cells 3-5 fjL broad, 20-25 /a long.
Blue Gill (rr). Browns (rr). Clear Crooked (cc). Green (2) (rr). Horseshoe
(1) (rr). Lynx (rr), Pokegama (2) (rr). Round (1) (rrr).
ELAKTOTHRIX Wille 1898.
Cells fusiform when mature, longitudinally arranged in pairs within
a fusiform homogeneous gelatinous matrix. Chloroplast single, laminate,
parietal, with one or two pyrenoids. Colonies epiphytic when young
and free-floating when mature; or free-floating throughout the life of
the plant.
Reproduction by a transverse division into two daughter cells which
remain unchanged for some time. Akinetes known.
Wille first placed the alga as a close relative of Actinastrum Hantz-
schi Lagerheim, but later thought it a relative of Coccomyxa Schmidle
(Wille, in Engler & Prantl, Nat. Pflanzenfam. V (Nachtr.) : 36, figs.
18^-18®. 1909) ; Pascher (Susswasserfl. Deutschl., Osterr. u. d. Schw.
5^: 220, figs. 25-26. 1915) places it among the algae of doubtful sys-
tematic position; while G. S. West (Algae 1: 202. 1916) thinks it
closely allied to Ankistrodesmus, a view which seems to me most logical
since Ankistrodesmus, Quadrigtda and Elaktothrix form a very natural
evolutionary series.
KEY TO THE SPECIES.
Both poles of cells acute E. Viridis
One pole of cell acute, the other generally rounded E. Gelatinosa
Elaktothrix gelatinosa Wille. PI. 34, Figs. 1-3.
Biol. Cent. 18: 302. 1898; in Engler & Prantl, Nat. Pflanzenfam. 1* (Nachtr.) :
36, figs. 18a-18b. 1909; W. & G. S. West, The Naturalist, 1909: 291, figs. 6a-6d.
1909.
Colonies free-floating, elongate fusiform to somewhat irregular ; with
140
WISCONSIN PHYTOPLANKTON
the long axes of the cells parallel to the long axis of the colony. Cells
lying in pairs, spindle-shaped; generally with one pole rounded and
the other pointed. The rounded ends of a pair of cells in apposition.
Chloroplast single, parietal, laminate; with one pyrenoid. Colonies
rarely containing over fifty cells. (Euplanktont).
Cells 3-6 fx broad; 15-25 /a long. Colonies 10-30 fx broad; 70-160
fi long.
Crooked (rrr), Deer (rrr), Hillman (rr), Jag (rrr), Jennie (rr), Long (2)
(rrr), Long (3) (rr), Loon (rrr), Mudhen (rr). Pine (2) (rrr). Sand (2)
(rrr), Streitor (sss).
The dimensions of the cells and the general appearance of the colony
in individuals that I have found is more like the Wests’ description of
the alga as found in England. Wisconsin colonies rarely contain more
than sixteen cells.
Elaktothrix viridis (Snow) Printz. PI. 33, Fig. 7.
Skr. Vidensk. i Kristiania Mat.-Naturv. Kl, 1913^: No. 6: 31, pi. 1, figs. 9-12.
1914.
Fusola viridis Snow, Bull. U. S. Fish Comm. 22 : 389, pi. 2, figs. VP-VP. 1903.
Colony free-floating or epiphytic, fusiform or irregular; gelatinous
sheath of colony sharply defined, frequently showing remains of old '
cell wall at apex. Cells broadly fusiform, straight or sigmoid, with
acute apices. Chloroplast single, completely filling the cell; with one
or two pyrenoids. (Tychoplanktont) .
Cells 6-15 II broad, 12-35 /x long.
Soft (rr).
KIRCHNEKIELLA Schmidle 1893.
Cells lunate to sickle-shaped with their apices almost touching; or
elongate, vermiform, arcuate, or spiral cylinders with rounded ends.
Associated without definite arrangement in colonies enclosed by a hya-
line, homogeneous, gelatinous envelope. Number of cells in young
colonies a multiple of two, in older colonies indefinite but rarely more
than seventy-five. Chloroplast single, parietal, on convex side of or
entirely filling the cell ; generally with a single pyrenoid.
Reproduction by the division of any cell to form four or eight auto-
spores that are liberated by a rupture of the old mother cell wall but
remain within the gelatinous envelope of the colony.
■^WISCONSIN PHYTOPLANKTON
141
KEY TO THE SPECIES.
Cells lunate to sickle-shaped.
Ends of cells pointed K. Lunaris
Ends of cells rounded K. Obesa
Cells arcuate, spiral, or vermiform cylinders.
Breadth of cells 2 /a or less K. Contorta
Breadth of. cells over 2 /a K. Elongata
Kirchneriella lunaris (Kirchner) Mobius. PL 34, Fig. 4.
Abh. d. Senckenb. Naturf. Ges. 18: 331. 1894; Chodat, Mater, pour la fl. crypt.
Suisse 1®: 202, figs. 12r-12V. 1902.
Cells flattened, crescent-shaped, with apices some distance apart,
about twice as long as broad, ends tapering to a blunt point; irregu-
larly arranged in groups of four to eight within the gelatinous colonial
envelope. Chloroplast single, filling the entire cell with the exception
of a small part on the concave side; pyrenoid single. (Facultative
Planktont) .
Cells 3-8 fji broad, 6-15 /a long ; colonies up to 250 fx in diam.
Bear (3) (rr), Beaverdam (rr), Birch Island (rrr), Blake (rr). Chain (ss),
Chetek (rr), Cochrane (rr). Crab (rrr). Deer (rr), Devils (2) (rr). Duck
(rr), Dummy (sss), Elizabeth (rr). Green (2) (rr). High (rr), Hillman (r),
Horseshoe (1) (rr), Jag (rr), Lindy (rrr). Little Crooked (rrr). Little Doc-
tor (rr). Long (3) (rrr). Loveless (rr). Lower Turtle (rrr). Lynx (rrr), Men-
dota (rr), Meta (rr). Mud (2) (rr), Nancy (sss). North Twin (rrr). Paddock
(rr), Pardee (rr). Pine Tree (rr), Pokegama (1) (r), Pokegama (3) (sss),
Poplar (rr). Prairie (sss). Round (3) (rrr), St. Croix (r). Shell (r). Spirit
(rrr). Squirrel (rr). Upper Turtle (rrr). White Ash (rr).
The species differ from K.- obesa in the pointed ends of the cells. The
two are widely distributed plankton organisms but have never been
found in quantity in any lake of the state.
var. Dianae Bohlin. PL 34, Fig. 5.
Bih. Kgl. Sv.‘Vet.-Ak. Handl. 23, Afd. 3, No. 7: 20, pi. 1, figs. 28-30. 1897.
Cells curved until the apices are almost touching, apices more pointed
and frequently slightly twisted. (Facultative Planktont).
Cells 3-5 fl broad, 10-21 fi long.
Hillman (rr). Pine (2) (rr). White Ash (r).
The cell shape of this variety resembles that of Selenastrum but the
colony differs in being enclosed by a gelatinous envelope. The apices
are much sharper than in the typical form.
142
WISCONSIN PHYTOPLANKTON
var. irregularis var. nov. PI. 35, Fig. 1.
Apices of cells twisted and frequently not pointing in the same direc-
tion. (Facultative Planktont).
Cells 4r-6 broad, 6-13 fi long.
Cochrane (rr), Pokegama (1) (r), Tenderfoot (rr).
Although the cell apices of K. lunaris var. dianae are sometimes not
in the same plane, they never exhibit the twisting found in this variety.
The twisting of the cells of this variety is similar to that of K. contorta
but they have the shape and pointed ends that characterize K, lunaris.
Kirchneriella obesa (W. West) Schmidle. PI. 35, Figs. 2-3.
Ber. d. Naturf. Ges. zu Freiburg i. B. 7: 16 (83). 1893; G. S. West, Brit.
Freshw. Algae 226, figs. 96a-96e. 1904.
Cells flattened with outer side markedly convex and inner sides
parallel, ends rounded and tapering slightly. Chloroplast single, fill-
ing the entire cell with the exception of a small portion on the con-
cave side; with one pyrenoid. (Facultative Planktont).
Cells 3-8 broad, 6-16 fx long.
Bear (2) (rr). Bear Trap (rr). Camp (rr), Catherine (rr), Center (r).
Chain (rr), Chetac (r). Crawling Stone (rrr). Devils (1) (rrr), Hillman (rr),
Kitten (rr). Lac Court Oreilles (ss), Lac du Flambeau (rr), Mendota (r).
Palmer (rrr). Pine Tree (rr), Pokegama (2) (rr). Poor Farm (rr). Reserve
(rr). Rice (1) (rr). Rock (rrr). Sand (4) (rr). South Turtle (rr). White-
fish (rrr). Wildcat (rr), Winnebago (rr).
The cells of this species might be described as thick discs incised a
third to a half the width of the cell did not other members of the genus
show that this effect is produced by a curving of the cell.
var. MAJOR (Bernard) G. M. Smith. PI. 35, Fig. 4.
Trans. Wis. Acad. Sci., Arts, & Lett. 19^: 636, pi. 10, fig. 7. 1918.
Inner face between cell apices curved; apices not close together,
rounded and slightly tapering. (Facultative Planktont).
Cells 3-5 fi broad, 8-21 /x long.
Carson (rr). Lac Court Oreilles (r). Wolf (rr).
This variety has a large open space between the apices whereas in
the typical form this space is narrow and with parallel sides. The cells
are also much narrower in proportion to their length. Brunnthaler
(in Pascher, Siisswasserfl. Deutschl. Osterr. u. d. Schw. 5^: 180. 1915)
has placed the alga as a form of K. lunaris var. dianae but the cell apices
are too rounded to consider it a variety of K. luTiaris.
WISCONSIN PHYTOPLANKTON
143
Yar. APERTA (Teiling) Briinntlialer. PI. 35, Figs. 5-6.
in Pascher, Siisswasserfl. Deutschl. osterr. u. d. Schw. 5^: 182, iig, 268. 1915.
Kirchneriella aperta Teiling, Sv. Bot. Tids. 6; 276, fig. 9. 1912.
Cells with blunt, rounded apices, concave side between apices broadly
V-sbaped. (Facultative Planktont).
Diam. cells 6-12 fx.
Diamond (rr), Palmer (ss).
Kirchneriella contorta (Schmidle) Bohlin. PI. 35, Fig. 7.
Bih. Kgl. Sv. Vet.-Ak. Handl. 23, Afd. 3, No. 7: 20. 1897.
Kirchneriella obesa var. contorta Schmidle, Flora 78: 44, pi. 7, fig. 2. 1894.
Cells cylindrical, arcuate or in spirals that never make more than
iy 2 turns; ends rounded, not tapering. Cells generally lying some
distance from one another within the homogeneous colonial envelope.
Chloroplast single, filling the entire cell, without a pyrenoid. Cells
sometimes spirally arranged in the colony; rarely more than sixteen
cells in a colony. (Facultative Planktont).
Cells 0.7-2.0 fi broad, 8-14 /x long ; colonies up to 60 ^ in diam.
Chain (rrr), Clear (rr), Cochrane (rr), Fowler (rrr), Mendota (rrr), Par-
dee (rr), Pine Tree (rrr). Poor Farm (rrr).
A species which at first glance does not appear related to K. lunaris
and K. obesa, but which at times shows a certain resemblance to
K. obesa var. major. It and the following species are rare algae in
Wisconsin. They are closely related, the chief difference being the
smaller size and fewer number of cells in the colony of K. contorta.
Kirchneriella elongata G. M. Smith. PI. 36, Figs. 1-2.
Bull. Torr. Bot. Cl. 43 : 473, pi. 24, fig. 7. 1916.
Cells elongate-cylindrical with rounded ends; spirally or irregularly
twisted. Colonies of 4-8-16 or more cells arranged in a snarl at the
center of a copious homogeneous gelatinous sheath. Chloroplast single,
parietal; without a pyrenoid. (Facultative Planktont).
Cells 2-3 fx broad, 15-25 fx long ; colonies up to 100 fx in diam.
Devils (2) (rrr). Horse (rrr), Lac Court Orellles (rr). No Mans (rr).
Palmer (rr). White Ash (sss).
Sub-family CRUCIGENIEAE.
Cells acicular, fusiform, ovoid, triangular, or trapezoidal; in fiat
eoenobia with the number of cells always a multiple of two. Cells
quadrately arranged in coenobe or in a linear series. Coenobe gener-
ally without a gelatinous envelope. Chloroplasts 1-4, parietal, disci-
form or laminate ; generally with one pyrenoid.
144
WISCONSIN PHYTOPLANKTON
KEY TO THE GENERA.
Cells quadrately arranged.
Quadrate arrangement apparent in front view of cells.
Outer face of cells without spines Crucigenia
Outer face of cells with spines Tetrastrum
Quadrate arrangement apparent in end view of cells Tetradesmus
Cells arranged in a linear series Scenedesmus
CRUCIGENIA Morren 1830.
Coenobe free-swimming, of four cells quadrately arranged with a
quadrangular open space at the center and frequently connected to
other eoenobia by a gelatinous envelope or the remains of the old mother
cell walls. Multiple eoenobia forming a flat plate one cell in thickness
and containing 4, 16, 32, 64 or more cells. Cells flattened; ovoid, tri-
angular, trapezoidal, or semicircular in front view ; with a smooth cell
wall. Chloroplasts 1-4, parietal, disciform to laminate, with or with-
out pyrenoids.
Reproduction by autocolony formation, the four cells of the coenobe
generally producing autocolonies at the same time.
KEY TO THE SPECIES.
Cells apiculate C. Apiculatum
Cells not apiculate.
Coenobe with a large rectangular open space at the center.
Front view of cells trapezoidal C. Fenestrata
Front view of cells semicircular C. Lauterbornei
Coenobe with a small open space at the center.
Length of coenobe greater than the breadth.
Wall of cell the same thickness throughout.
Outer face of cells concave C. Cruciata
Outer face of cells convex.
Cells of coenobe regularly arranged C. Rectangularis
Cells of coenobe irregularly arranged C. Irregularis
Wall of cell thicker at the poles C. Truncata
Length of coenobe the same as the breadth.
Cells triangular, with fairly acute corners C. Tetrapedia
Cells spherical to triangular, with rounded corners C. Quadrata
Crucigenia rectangularis (Nageli) Gay. PI. 36, Fig. 3.
Recherches sur le. dev. et la class, de quelques algues vertes 100, pi. 15, fig. 151.
1891.
Coenobe four-celled, cells in mutual contact at the poles and sides
and with a small rectangular open space at the center. Generally
united in compound eoenobia containing an indefinite number of coen-
WISCONSIN PHYTOPLANKTON
145
obes. Cells ovoid to elongate-ovoid, with 1-4 parietal, disciform chloro-
plasts, each with a single pyrenoid. Old mother cell wall frequently
enclosing young coenobia for some time. (Facultative Planktont).
Cells 4r-7 /X broad, 5-10 /x long.
Bear (2) (rr), Beaverdam (rr), Big (rrr), Birch Island (rrr), Devils (1)
(r), Fowler (rrr), Half Moon (rr), Hillman (rr), Kegonsa (rr). Lac Court
Oreilles (rr), Lindy (rr). Little Bass (2) (rr). Little Doctor (rr). Mill (rrr),
Nancy (rr), Nicaboyne (rr), Okauchee (rrr). Old Taylors (rr). Pine Tree
(rr). Sand (1) (rr). Upper Nashotah (rrr), Winnebago (rr).
Crucigenia irregularis Wille. PI. 36, Figs. 4-5.
Biol. Cent. 18: 302. 1898; Nyt. Mag. f. Naturvidensk. 88: 10, pZ. 1, -fig. 15,
1900; W. & G. S. West Trans. & Proc. Bot. Soc. Edinburgh 23: 29, pi. 1, iig$.
6-7. 1905.
Coenobia four-celled, with cells in contact at sides and poles, at other
limes without a definite arrangement. Coenobia irregularly combined
into multiple coenobia. Cells ovoid ; with 1-4 parietal, disciform chloro-
plasts; with or without pyrenoids. (Facultative Planktont).
Cells 4-9 /X broad, 6-14 /x long. Coenobia 8-14 «, broad, 15-30 /x long.
Browns (rr). Camp (rr). Fish (rr). Horseshoe (2) (rr), Mudhen (rr).
Reserve (rr), Sand (3) (sss).
The cell shape is quite similar to that of C. rectangularis but the ar-
rangement of cells within the coenobe is very irregular in about half
the colonies one meets with. This irregular cellular arrangement coup-
led with the larger cell size warrants the separation of the alga from
C. rectangularis. The alga is generally reported to be without pyre-
noids but I have frequently found them in the chloroplasts of C. irregu-
laris.
Crucigenia crucifera (Wolle) Collins. PI. 36, Fig. 6.
Tufts, coll, studies 2: 170. 1909.
Staurogenia crucifera Wolle, Bull. Torr. Bot. Cl. 6: 140. 1877.
Staurogenia cruciatum Wolle, Freshw. Algae of U. S. 171, pi. 157, figs. 9-11.
1887.
Coenobia four-celled, rhomboidal, with rounded ends, slightly con-
cave sides, and a small rectangular open space at the center. Cells
elongate, outer face concave, inner and those in contact with other cells
straight. Chloroplast single, parietal, laminate; without a pyrenoid.
(Facultative Planktont).
Cells 3.5-5 /X broad, 5-7 /x long. Coenobia 9-11 /x broad, 14^16 fx long.
Hillman (rr). Tenderfoot (rr).
The arrangement of the individual coenobia into compound coenobia
is generally that which Wolle gives in his figure 9 of Staurogenia cruci-
10
146
WISCONSIN PHYTOPLANKTON
atum. Collin’s surmise that the reported cruciform marking of the
cell wall is probably due to a division of the cell contents is correct and
what Wolle calls the cell is in reality the coenobe. The remains of the
old cell walls play an important part in binding together the various
coenobia of the multiple coenobe.
Crucigenia truncata sp. nov. PI. 36, Figs. 7-9.
Coenobe four-celled, with a small rectangular space at the center and
held in compound coenobia of indefinite size by the remains of old
mother cell walls. Cells quadrately arranged with bases and middle
third of inner sides in mutual contact but with apices and outer faces
free. Cells elongate, ovoid, with free ends truncate. Cell wall at free
apex thicker than in other parts. Chloroplasts 1-4, parietal, disci-
form, without pyrenoids. ( Euplanktont ) .
Cells 4-6 fi broad, 6-10 fi long. Coenobia 6-12 broad, 12-20
fi long. Compound coenobia up to 50x75 fi.
Chain (rr), Hillman (rr), Pine Tree (rr), Travis (rr).
The species is differentiated by its flattened cell apices and the thicker
walls at the apices. The cells are always regularly arranged within the
coenobe, but when in compound coenobia the arrangement is frequently
irregular.
Crucigenia apiculata (Lemmermann) Schmidle. PI. 37, Fig. 1.
Allg. Bot. Zeitschr. 6: 234. 1900.
Staurogenia apiculata Lemmermann, Bot. Cent. 76: 151. 18'98; For-
Bchungsbr. a. d. Biol. Stat. zu Plon 7: 119, pi. 1, fig. 14. 1899; Snow, Bull.
U. S. Fish Comm. 22: 376, pi. 1, figs. V^V«. 1903.
Tetrastrum apiculatum (Lemmermann) Brunnthaler, in Pascher, Siisswas-
serfl. Deutschl., Osterr. u. d. Schw. 5^: 177, fig. 258. 1915; G. M. Smith, Bull.
Torr. Bot. Cl. 43 : 472, pi. 24, fig. 3. 1916.
Coenobia four-celled, embedded in a delicate gelatinous sheath. Cells
quadrately arranged with their long axes parallel and a small rectangu-
lar space at the center. Coenobia generally in multiple coenobia which,
when containing large numbers of coenobia, are frequently irregular.
Cells ovoid to triangular, with a short conical projection at the free
apex and frequently another one at the side of the base away from the
center of the coenobe. Each cell containing 1-4 parietal disciform
chloroplasts with one pyrenoid. (Euplanktont).
Cells 3-7 /A broad, 5-10 fi long. Coenobia 6-12.5 fx broad, 9-18
/i long. Compound coenobia up to 150 p, broad.
Mendota (rrr). Palmer (rrr), South Crab (rr).
The cells of 16-celled multiple coenobia are regularly arranged but
when multiple coenobia contain 150-200 cells the arrangement is fre-
WISCONSIN PHYTOPLANKTON
147
quently irregular. The gelatinous sheath enclosing the colony is very
delicate and can only be seen when properly stained. This species was
placed in the genus Tetrastrum in a preliminary list, but it is more
closely related to Crucigenia than to Tetrastrum.
Crucigenia quadrata Morren. PI. 36, Figs. 10-14.
Ann. Sci. Nat. 20: 415, pi. 15, figs. 1-5. 1830.
Staurogenia triangularis Chodat, Mem. Herb. Boiss. 1, No. 17 : 7, figs. 14-19.
1900.
Crucigenia triangularis (Chodat) Schmidle, Allg. Bot. Zeitschr. 6: 234. 1900.
Staurogenia multiseta var. punctata Schmidle, Ber. d. D. bot. Ges. 18: 157,
pi. 6, figs. 13-14. 1900.
Coenobia four-celled, circular in outline. Cells in mutual contact at
or with very small rectangular openings at center of the coenobe.
Four coenobia compressed to form rectangular multiple coenobia which
in turn are joined to other sixteen-celled multiple coenobia. Cells
spherical to triangular; with a smooth wall or with 1-6 minute knob-
like projections on the wall. Chloroplasts 1-4, parietal, disciform, with
or without pyrenoids. (Facultative Planktont) .
Cells 2.5-6 fL broad, 3-7 p, long. Coenobia 5.5-17 /x in diam. 16-
celled compound coenobia 12-30 /x in diam.
Carson (rrr). Chain (rr), Hillman (sss). Kitten (rrr), Lac du Flambeau
(rr). Palmer (sss), Pardee (rr). Tenderfoot (rrr). White Sand (rrr).
Pyrenoids are very prominent in the chloroplasts of certain colonies
while other colonies collected from the same station show no trace of
them. In some of the colonies from Hillman lake small, globular, but-
ton-like structures were observed on the cell walls. Such structures
have been noted by Schmidle and form the distinctive character of his
variety punctata of Staurogenia multiseta [Tetrastrum multisetum
(Schmidle) Chodat]. If the variety is to be recognized it should be
called C. quadrata var. punctata (Schmidle) but I am of the opinion
that it is not a sufficiently constant character to warrant recognition.
There is likewise no justification for considering C. triangularis (Cho-
dat) Schmidle a distinct species since it does not differ in any respect
from C. quadrata.
Crucigenia tetrapedia (Kirchner) W. & G. S. West. PI. 37, Fig. 2.
Trans. Roy. Irish Acad. 32, Sec. B: 62, pi. 1, figs. 11-12. 1902.
Staurogenia tetrapedia Kirchner, Jahreshefte d. Ver. f. Vaterl. Naturk. i.
Wiirttemberg 1880, pi. 2, fig. 1.
Tetrapedia emarginata Schroder, Ber. d. D. bot. Ges. 15: 492, pi. 25, figs.
6a-6c. 1897.
Lemmermannia emarginata (Schroder) Chodat, Mem. Herb. Boiss. 1, No.
IT; figs. 1-^. 1900.
148
WISCONSIN PHYTOPLANKTON
Lemmermannia tetrapedia (Kirchner) Lemmermann, Arkiv. for Botanik 2,
No. 2: 157. W04.
Coenobia four-celled, with a very small rectangular open space at
the center. Frequently joined in multiple coenobia of sixteen -cells that
may be connected in turn to other 16-celled multiple coenobia. Cells
flattened, triangular, with rounded corners. Cell contents homogeneous,
or with a single parietal chloroplast, with or without pyrenoids. (Fac-
ultative Planktont).
Diam. cells 4.8-9.5 /x; diam. coenobia 8-15 /x; diam. 16-celled multiple
coenobia up to 40 /x.
Palmer (rr).
Certain investigators have noted that the cell contents are at times
absolutely homogeneous. This has caused Schroder to consider the alga
a species of Tetrapedia, one of the Myxophyceae, but the Wests have
given cogent reasons for considering it a Crucigenia. 1 have found a
distinct parietal chloroplast and pyrenoid in the cells whereas Chodat
states that there is a chloroplast but no pyrenoid. His founding of the
genus Lemmermannm upon this single character (lack of a pyrenoid)
has rightly been called by G. S. West (Brit. Freshw. Algae 217. 1904)
‘‘the climax of absurdity.”
Crucigenia fenestrata Schmidle. PI. 37, Fig. 3.
Allg. Bot. Zeitschr. 6: 234. 1900.
Staurogenia fenestrata Schmidle, Allg. Bot. Zeitschr. 3: 107, fig. 1. 1897.
Coenobia four-celled, rectangular, with a medium-sized opening at
tile center; with an inconspicuous gelatinous sheath. Frequently in
multiple coenobia with the component coenobia lying close together.
Cells trapezoidal, with the longest face at the outside of the coenobe.
Chloroplast single, except just before division, parietal, without a pyre-
noid ( ? ) . ( Euplankt ont ) .
Cells 3-5 fx broad, 5-12 /x long ; coenobia 8-14 /x broad.
Bettine (rr). White Sand (rr).
The specimens that I have found do not agree in all respects with
Schmidle ’s description since there was no gelatinous sheath surround-
ing the coenobe and filling the central space.
Crucigenia Lauterbornei Schmidle. PI. 37, Fig. 4.
Allg. Bot. Zeitschr. 6: 234. 1900.
Staurogenia Lauterbornei Schmidle, Allg. Bot. Zeitschr. 2: 192, fig. 1. 1896.
Coenobia four-celled, cells in contact with one another at their apices
only and with a large square open space at the center of the coenobe.
WISCONSIN PHYTOPLANKTON
149
Coenobia joined in multiple coenobia of at least sixteen cells by the re-
mains of old cell walls and a gelatinous envelope. Cells flattened, sub-
hemispherical in front view with the flattened side towards the center
of the coenobe. Chloroplast single, parietal, on the outer face of the
cell; with one pyrenoid. (Euplanktont).
Cells 4.5-9 fx broad, 8-15 /x long. Coenobia 15-25 /x in diam ; multiple
coenobia up to 150 fx in diam.
Kegonsa (r), Fokegama (rr), Rice (1) (r), Upper Turtle (r).
A very distinct species and one that is readily recognized by the large
opening at the center of the colony. C. fenestrata also has a large, rec-
tangular open space at the center of the coenobe but the two species
have quite differently shaped cells ; those of C, Lauterhornei being semi-
circular in front view, and those of C. fenestrata trapezoidal.
TETKASTRUM Chodat 1895.
Coenobia four-celled, with cells cruciately arranged in a flat plate;
at times embedded in a thin gelatinous envelope. Cells triangular to
ovoid, with several spines or setae on the free face. Chloroplasts 1-4,
parietal, disciform, with or without pyrenoids.
Reproduction by autocolony formation in any cell.
The genus is closely related to Crucigenia, differing only in the spines
on the margins of the cells and an absence of an association in multiple
coenobia.
Tetrastrum staurogeniaeforme (Schroder) Lemmermann. PI. 37,
Figs. 5-6.
Ber. d. D. bot. Ges. 18: 95. 1900.
Cohniella Staurogeniaeformis Schroder, Ber. d. D. bot. Ges. 15: 373, pZ. 17,
ftg. 5. 1897.
Coenobia four-celled, with a very minute open space at the center
of the colony. Coenobe embedded in a very delicate gelatinous envelope.
Cells cruciately arranged, triangular, with 5-6 very delicate setae on
the free surface. Chloroplasts 1-4, parietal, disciform, with or without
pyrenoids. ( Euplanktont) .
Diam. cells (without setae) 3-6 fx; diam. coenobia (without setae)
7-15 /X. Setae 4-8 fx long.
Horse (rr), Mendota (rrr).
The setae on the outer face of the cells are very delicate and easily
overlooked. If the setae are not taken into consideration the alga looks
exactly like Crucigenia quadrat a.
150
WISCONSIN PHYTOPLANKTON
TETRADESMUS G. M. Smith 1913.
Colonies free-floating, four-celled, rarely two- or three-celled. Cells
in two planes with two cells in each plane and joined along the long
axes when the colony is viewed from the side. Viewed from the top
cells quadrately arranged. Cells elliptic-fusiform to broadly elliptic,
with outwardly divergent or straight apices. Chloroplast single, pari-
etal and laminate or completely filling the cell ; pyrenoid single, central
or eccentric.
Reproduction by autocolony formation in any cell of the colony, the
young coenobia being liberated by a rupture of the mother cell wall.
Tetradesmus wisconsinensis G. M. Smith. PI. 37, Figs. 7-11.
Bull. Torr. Bot. Cl. 40: 76, pi. 1, figs. 1-2, 3-20. 1913.
Cells elliptic-fusiform, apices attenuated and outwardly divergent.
Pyrenoids eccentric. (Facultative Planktont).
Cells 4^6 fji broad, 12-14.5 fx long.
Blake (rrr), Mendota (rr), Nancy (rrr).
SCENEDESMUS Meyen 1829.
Coenobe a flat (rarely curved) plate of ellipsoidal, ovoid, or acicular
cells with cell number always a multiple of two. Cells in lateral con-
tact and in one or two rows. Cell wall smooth, corrugated, granulate,
or spicate ; with or without marginal or lateral teeth or spines. Chloro-
plast single, parietal, and laminate in young cells; frequently filling
entire cell in older colonies ; pyrenoids single, central or eccentric.
Reproduction by autocolonies from any or all cells of the coenobe,
the number of cells in the colony not necessarily the same as that of
the mother colony.
KEY TO THE SPECIES.
Walls smooth, without granulations, lateral ridges, terminal teeth or spines.
Cells acicular to broadly elliptic, with pointed ends.
Colony a flat plate.
All cells in colony erect S. Obliqutjs
Median cells erect, terminal cells lunate S. Dimoephus
Colony a curved or twisted plate.
Cells forming a curved surface S. Acuminatus
Cells alternately arranged with terminal cells not in the
same plane as the others S. Beenardu
Cells ovoid to cylindrical, with rounded ends.
Arrangement of cells a single linear or subalternating but
never a double series S. Bijuoa
Arrangement of cells a double linear series S. Arcuatus
WISCONSIN PHYTOPLANKTON
151
Wall variously sculptured or ridged, at times with terminal teeth or spines.
Longitudinal ridges on sides of the cells.
Without terminal teeth or spines S. Acutiformis
With terminal teeth or spines.
Terminal cells with long spines at poles S. Aematus
All cells with short teeth at poles S. Brasiliensis
Longitudinal ridges not present on sides of the cells.
Teeth-like spines covering entire wall S. Hystrix
Teeth or spines confined to poles, outer face of terminal
cells, or middle of all cells.
Cells with short teeth at poles S. Denticulatus
Cells with long spines.
Spines on both median and terminal cells.
Poles of cells only region bearing spines.
Cells ovoid to ovoid-cylindrical S. Longus
Cells naviculoid S. Opoliensis
Poles and median part of cells bearing spines S. Abundans
Spines confined to terminal cells.
Cells ovoid to ovoid-cylindrical S. Qtjadricauda
Cells naviculoid S. Opoliensis
SCENEDESMUS OBLIQUES (Turpin) Kiitzing. PI. 37, Figs. 12-14.
Linnaea 8: 609. 1833; G. S. West, Brit. Freshw. Algae 220, fig. 92a. 1904.
Cells of 2-4-8 cells arranged in a single linear or sublinear series.
Cells fusiform, with acute apices ; interior cells with straight sides, outer
face of terminal cells slightly concave, straight, or convex. Cell wall
smooth, without terminal teeth or spines. (Tychoplanktont).
Cells 3-9 /X broad, 10-21 /x long. 4-celled coenobia 10-21 /x broad,
12.5-24 fjL long.
Balsam (rrr). Bear (1) (rrr), Blake (rr). Bone (rr). Grassy (rr), Hill-
man (rrr). Horseshoe (2) (rrr), Lindy (rr). Little Bear (rrr). Little Doctor
(rr). Little Rice (2) (rrr). Loon (rr), Mendota (rrr), Pewaukee (rrr). Poor
Farm (rrr). Pope (rrr). Rice (2) (rr). Sand (3) (rrr). Sand (4) (rrr). Up-
per Nemahbin (rrr). White Ash (rrr).
ScENEDESMUS DiMORPHUS (Turpin) Kiitzing. PI. 37, Figs. 15-17.
Linnaea 8 : 608. 1833; G. M. Smith, Trans. Wis. Acad. Sci., Arts, & Lett. 18 ' :
434, pi. 32, figs. 185-189; pi. 33, figs. 190-195. 1916.
Coenobia of four or eight cells arranged in a linear or alternating
series. Cells fusiform with apices attenuated to delicate points. In-
terior cells erect, outer erect or markedly lunate. Cell wall smooth,
without terminal teeth or spines. (Facultative Planktont).
Cells 2-5 /X broad, 18-23 /x long. 4-celled coenobia 18-23 fx broad,
12-25 fx long.
Dunham (rrr). Horse (r), Pine Tree (sss), Poor Farm (ss), Travis (sss).
152
WISCONSIN PHYTOPLANKTON
The outwardly turned lunate terminal cells, together with the pro-
nounced alternate arrangement distinguishes this species from the fore-
going. I have given elsewhere (1. c.) the reasons for considering this
a distinct species and not a variety of S. obliquus,
SCENEDESMUS ACUMiNATus (Lagorheim) Chodat. PI. 38, Figs. 1-4.
Mater, pour la fl. crypt. Suisse 1": 211. 1902.
Selenastrum acuminatum Lagerheim dfvers. Kgl. Vet.-Ak. Forh. S9: No. 2:
71, pi. 3, figs. 27-30. 1882.
Coenobia curved, of 4 or 8 (generally 4) cells. All of the cells of a
colony arcuate or lunate, fusiform, with the ends gradually tapering
to a fine point. Cell wall smooth, without teeth, granulations or spines.
(Facultative Planktont).
Cells 3-7 fjL broad, 30-40 fi between apices.
Horse (sss).
This species should not be confused with Selenastrum acuminatus
G. S. West non Lagerheim, a species which I have already discussed
in connection with Selenastrum Westii G. M. Smith.
ScENEDESMUS Bernardii G. M. Smith. PI. 38, Figs. 5-9.
Trans. Wis. Acad. Sci., Arts, & Lett. 18^: 436, pi. 33, figs. 196-208. 1916.
Colonies of 2-4-8 cells. Interior ceils fusiform, lunate or sigmoid,
with acute apices; alternately arranged with apices in contact with
apices or median portion of adja.cent cells. Terminal cells fusiform to
lunate, frequently at an angle to the plane of the coenobe, in contact
Avith the interior cells by the apex only. Cell wall smooth, without
terminal spines or teeth. ( Tychoplanktont ?).
Cells 3-6 fl broad, 8-17 /x long.
Monona (rrr).
ScENEDESMUS BiJUGA (Turpin) Lagerheim. PI. 37, Pigs. 18-20.
Nuova Notarisia 1893: 158. 1893.
Scenedesmus hijugatus (Turpin) Kiitzing. G. S. West, Brit. Freshw. Algae
220, fig. 92c. 1904.
Coenobes flat, of 2^r-8 cells in a single (rarely subalternate) series.
Cells oblong-elliptic to ovoid, with broadly rounded ends. Cell wall
smooth, Avithout teeth or spines. (Tychoplanktont).
Cells 4-7 fl broad, 7-18 fi long. 4-celled colonies 7-18 fi broad, 16-25
fl long.
Fowler (rrr), Lindy (rr), Little Bice (2) (rr). Mill (rr). Poplar (rrr),
Silver (2) (rr), Streitor (rr). Upper Turtle (rrr). Wolf (rr).
WISCONSIN PHYTOPLANKTON
153
var. ALTERNANs (Reinsch) Borge. PI. 38, Figs. 10-11.
Ai-kiv. for Botanik 6, No. 1: 57. 1906.
Scenedesmus alternans Reinsch, Abh. Senckenb. Naturf. Ges. 6: 135, pi. 20,
ng. D‘. 1866.
Colonies flat, generally 8-celled, with a very marked alternate ar-
rangement of the component cells. Cells ovoid to elliptic. (Tycho-
planktont).
Cells 4-8 fjL broad, 6-15 /x long. 8-celled coenobia 12-30 /x broad,
22^5 /X long.
Blake (rr). Devils (1) (rrr), Muskallonge (rr).
Since cultural studies have shown that the alternate arrangement of
cells is a constant character it is proper to consider this a distinct vari-
ety. The variety has also been found in lakes where the typical form
is absent.
Scenedesmus arcuatus Lemmermann. PI. 38, Figs. 12-14.
Forscbungsbr. a. d. Biol. Stat. zu Plon 7: 112, pi. 1, figs. 2-4. 1899.
Colonies always curved, of 4r-8-16 (generally 8) cells arranged in a
double row. Cells ovoid, sometimes angular by mutual compression
at the base. -Coenobia with small interstices between the cells. Cell
wall smooth, without spines or teeth. (Euplanktont).
Cells 3-9 /X broad, 9-17 /x long. 8-celled coenobia 15-25 /x broad,
15-40 /X long.
Beaverdam (rr), Blake (rrr), Camp (rrr). Center (ss). Chain (rr),
Cochrane (rr), Cranberry (rr), Hillman (r). Lac Court Oreilles (rr). Lac du
Flambeau (rr). Little Bass (2) (rr). Little Crooked (rr). Long (1) (rrr).
Long (3) (rr). Lower Turtle (rr), Mendota (sss), Meta (rrr). North Turtle
(rr), Owen (rrr). Paddock (rrr). Palmer (rrr), Pardee (rr), Pokegama (2)
(rr). Reserve (rr). Round (1) (rrr). Sand (1) (rrr). Sand (4) (rrr). Shell
(rrr), Sishebogema (rr). Tied Canoe (rr). Upper Turtle (rr). Wolf (r).
One of the few species of the genus that is exclusively confined to
the plankton. The curving of the coenobe and the double series of
ovoid cells at once separates it from all other species.
var. CAPiTATUS G. M. Smith. PI. 38, Figs. 15-16.
Trans. Wis. Acad. Sci., Arts, & Lett. 19^: 637, pi. 11, figs. 4-5. 1918.
Cells with nodular thickenings at the poles. (Euplanktont).
Cells 5-11 /X broad, 11-23 /x long. 8-eelled colonies 22-27 /x broad,
20-35 /X long.
Center (rr).
154
WISCONSIN PHYTOPLANKTON
var. PLATYDISCA G. M. Smith. PL 39, Figs. 1-3.
Trans. Wis. Acad. Sci., Arts, & Lett. 18*: 451, pZ. 30, figs. 101-105. 1916.
Colonies always flat, generally 8-celled. Cells oblong-elliptic and
arranged in a double series. Coenobia with small interstices between
the cells. (Facultative Planktont).
Cells 4.5-T.5 ix broad, 8-17 fx long. 8-celled coenobia 11-30 fx broad,
18-30 [X long.
Camp (rrr). Eagle (rr), Fowler (rr), George (rr). Horse (rrr), Kegonsa
(ss). Paddock (rr). Pine (1) (rr).
An alga that has been considered a normal variation of S. hijuga but
one which, as stated elsewhere (1. c.), seems more closely related to
S. arcxmtus.
ScENEDESMus ACUTiFORMis Schroder. PL 39, Figs. 4-6.
Forschungsbr. a. d. Biol. Stat. zu Plon 5: 45, pZ. 2, figs. 4a-4b. 1897.
Coenobia flat, of 2-4-8 (generally 4) cells arranged in a linear series.
Cells fusiform, with acute apices. Cell wall of interior cells with a
single ridge that extends from pole to pole on each side ; wall of termi-
nal cell with 2-4 ridges. Poles of cells without spines or teeth. (Fac-
ultative Planktont).
Cells 5-8 ix broad, 16-22 fx long. 4-celled colonies 16-22 fx broad,
20-25 fx long.
Mendota (rr). Rice (1) (rrr).
Only a single longitudinal ridge can be seen in a front view of the
cell but the number of ridges is readily ascertained in an end view of
cells. The presence of these ridges without accompanying spines or
teeth separates this from other species.
ScENEDESMUs ARMATUS (Chodat) G. M. Smith. PL 39, Figs. 7-10.
Trans. Wis. Acad. Sci., Arts, & Lett. 18*: 460, pi. 29, figs. 90-93. 1916.
Coenobia of 2-4^8 cells arranged in a linear or subalternating series.
Cells ovoid to oblong-ellipsoid; with rounded apices. Terminal cells
with a single long spine at each pole. Both sides of cells with a longi-
tudinal ridge that may extend from pole to pole but is generally indis-
tinct in the median portion of the cell. (Facultative Planktont).
Cells 4-7 fx broad, 7-16 fx long. 4-celled coenobia (without spines)
7-16 fx broad, 16-25 fx long. Spines 5-7 /a long.
Bear (2) (rr). Bear Trap (rrr). Bone (rr). Browns (rr), Carson (rr). Fish-
trap (rrr). Horseshoe (2) (rr). Lac Court Oreilles (rr). Little Butternut (rrr),
Little Crooked (rr). Loveless (rr). Lynx (rrr), Mendota (rrr), Pardee (rrr).
Pine Tree (rr), St. Croix (rrr), Silver (rr). Upper Turtle (rrr). Wolf (rr).
WISCONSIN PHYTOPLANKTON
155
var. major var. nov. PI. 39, fig. 11.
Cells up to 9 broad and 25 /i long. Spines 15 long. (Facultative
Planktont ?).
Palmer (rr).
ScENEDESMUS BRASiLiENSis Bohlin. PI. 39, Figs. 12-14.
Bill. Kgl. Sv. Vet.-Ak. Handl. 23, Afd. 3, No. 7: 22, pi. 1, figs. 36-37. 1897.
Coenobia flat, of 2^:-8 (generally 4) cells arranged in a single linear
series. Cells cylindrical to ovoid-ellipsoid, with a single longitudinal
ridge extending from pole to pole on each side of the cell. Poles with
1-4 small teeth. (Facultative Planktont).
Cells 3-6 fi broad, 11-24 fi long. 4-celled coenobia 11-24 p. broad,
12-25 long.
Bear (2) (r), Beaverdam (rrr), Chain (rrr), Clare (rrr), Deer (rrr), Jag
(rr), Lac du Flambeau (rrr). Lake of the Woods (rrr), Lindy (rr). Little
Doctor (rr). Old Taylors (rr). Pine (2) (rr). Rice (1) (rr). White Sand (rrr).
The species may be distinguished from S. denticuLatus by the linear
ridges on the sides of the cells.
ScENEDESMUS HYSTRix Lagerheim. PI. 39, Figs. 15-16.
dfvers. Kgl. Vet.-Ak. Porh. 39, No. 2: 62, pi. 2, fig. 18. 1882.
Coenobia flat, of 2-4^8 cells joined in a single linear series. Cells
oblong-cylindrical, with blunt conical apices. Entire surface of cells
covered with minute spines. (Tychoplanktont).
Cells 3-5 IX broad, 8-18 [x long. 4-celled coenobia 8-18 fx broad, 12-
25 fx long.
Rudolph (rrr).
ScENEDESMUS DENTICULATUS Lagerheim. PI. 39, Figs. 17-19.
Ofvers. Kgl. Vet.-Ak. Forh. 39, No. 2: 61, pi. 2, figs. 13-17. 1882.
Coenobia flat, generally four-celled. Cells ovoid to ovoid-ellipsoid,
arranged in a linear or subalternating series. Poles of cells without
ridges but with 1-4 short spines. (Facultative Planktont).
Cells 5-11 fx broad, 7-15 fx long. 4-celled coenobia 7-15 fx broad,
15-22 fx long.
Amicoy (rr). Bear (2) (rr). Browns (rr). Chain (rr). Deer (rrr). High (r),
Hillman (rr). Horse (rrr). Horseshoe (2) (rr). Lac du Flambeau (rrr), Lit-
tle Doctor (rrr). Silver (3) (rr). White Ash (rr). Wolf (rr).
156
WISCONSIN PHYTOPLANKTON
ScENEDESMUs LONGUS Meyen. PI. 39, Figs. 20-22.
Nova Acta Phys.-Med. Acad. Caes. Leop. Nat. Cur. 14: 774, pi. 43, fig. 28.
1829. G. M. Smith, Trans. Wis. Acad. Sci., Arts, & Lett. 18": 469, pi. 31, figs.
156-158. 1916.
Scenedesmus quadricauda var. setosus (Kirchner) Lagerheim, 5fvers. Kgl.
Sv Vet.-Ak. Forh. 39, No. 2: 63. 1882.
Coenobe flat, of 2-4-8 (generally 4) cells arranged in a single linear
series. Cells ovoid to oblong-cylindrical, with rounded poles. Poles
of all cells with 1-2 spines. Cell wall destitute of spines except at the
poles. ( Tychoplanktont) .
Cells 4-5 fi broad, 8-11 long. 4-celled coenobia 8-11 fx broad, 16-
20 jx long.
Rock (rr).
var. Naegelii (Brebisson) comb. nov. PL 40, Figs. 1-2.
Scenedesmus Naegelii de Brebisson, Mem. de la soc. Imp. de Sc. Nat. de
Cherbourg 4: 158. 1856.
Scenedesmus eaudatus Nageli non Corda, Gatt. einz. Algen 91, pi. 5, figs.
2c-2d. 1849.
Colonies flat, always eight-celled. Cells cylindrical, with rounded
poles. Terminal cells with spines at both poles, interior cells with
spines at one pole, rarely at both poles. (Facultative Planktont).
Cells 6.6-11 /X broad, 18-33 /x long. 8-celled colonies 18-33 /x broad,
50-85 /X long.
Blake (rr). Camp (rrr). Poor Farm (rrr). White Ash (rr).
This alga was described by de Brebisson from the drawings of
/S». quadricauda by Nageli. In my monograph of Scenedesmus I in-
cluded it as a synonym of S. longus (Trans. Wis. Acad. Sci., Arts, &
Lett. 18^: 469. 1916) but am now convinced that it should be con-
sidered a distinct variety. The cells are much larger than the typical
form but unfortunately Nageli gives neither measurements for the cells
nor an indication of the scale of magnification of his drawings. The
measurements stated above are those of cells from Wisconsin lakes.
The peculiar arrangement of the spines that Nageli figures, where three
adjacent interior cells have spines on the same end and none on the
other with the reverse condition in the remaining interior cells, was
found to be a common but not a constant character since specimens were
found with spines at both poles of interior cells.
WISCONSIN PHYTOPLANKTON
157
ScENEDESMUs ABUNDANS (Kirchner) Chodat. PI. 39, Figs. 23-25.
Mater, p. la fi. crypt. Suisse. 4*: 77. 3913; G. M. Smith, Trans. Wis. Acad. Sci.,
Arts, & Lett. 18^: 465, pi, 31, /ips. 137-140, 1916.
Scenedesmus quadricauda var. ahundans (Kirchner) Lagerheim, 5fvers.
Kgl. Vet.-Ak. Forh. 39, No. 2: 64, pi. 2, fig. 20. 1882.
Coenobe flat, generally 4-celled. Cells ovoid to oblong-ellipsoid.
Terminal cells with 1-2 spines at poles and additional spines on outer
face between the poles. Interior cells with 1-2 spines at each pole.
(Facultative Planktont).
Cells 4r-7 /A broad, 7-12 ix long. 4-celled coenobia 7-12 fx broad,
15-30 fx long. Spines 4r-7.5 {x long.
Beaver (2) (rr), Cochrane (rr). Diamond (rr). Grassy (rr), Horse (rr),
Long (1) (rrr), Nancy (rrr). Palmer (rr). Poor Farm (ss).
var. LONGiCAUDA G. M. Smith. PI. 39, Figs. 23-27.
Trans. Wis. Acad. Sci., Arts, & Lett. 18^: 467, pi. 30, -figs. 121-125. 1916.
Cells smaller, ovoid. Spines much longer in proportion to the size
of the cells. (Facultative Planktont).
Cells 3-6 fx broad, 7-9 fx long. 4-celled coenobia 7-9 fx broad, 10-15
fx long. Spines 6-10 (x long.
Camp (rr), Chain (rrr). Horse (rr). White Ash (rr).
var. BREViCAUDA G. M. Smith. PI. 40, Figs. 3-5.
Trans. Wis. Acad. Sci., Arts, & Lett. 18': 468, pi. 30, figs. 126-132. 1916.
Cells ovoid, smaller. Spines much shorter and never more than
three between the polar spines of terminal cells. (Facultative Plank-
tont).
Cells 2.5-5 fx broad, 5-8 fx long. 4-celled coenobia 5-8 fx broad,
10-13 fx long. Spines 1.5-3 .5 fx long.
Mendota (rr).
var. ASYMMETRiCA (Schroder) G. M. Smith. PL 40, Figs. 6-8.
Trans. Wis. Acad. Sci., Arts, & Lett. 18': 468, pi. 27, figs. 45-46. 1916.
Scenedesmus quadricauda var. asymmetrica Schroder, Forschungsbr. a. d.
Biol. Stat. zu Plon 5: 45, pi. 2, figs. 5a-5c. 1897.
Coenobia generally 4-celled, with oblong-ellipsoid cells. Poles of
terminal cells with a single spine. All cells of coenobe with a single
median spine perpendicular to the plane of the coenobe and at one
side of cell only. (Facultative Planktont).
Cells 2.5-4.5 y. broad, 12-15 y long. 4-celled coenobia 12-15 y broad,
13-18 y long. Spines 7-10 y long.
Blue Gill (rr). Wild Goose (rrr).
158
WISCONSIN PHYTOPLANKTON
ScENEDESMUS QUADRicAUDA (Turpin) de Brebisson. PI. 40, Figs. 9-11.
Mem. de la Soc. Ac. de Falaise 1835: 66. 1835; G. S. West, Brit. Preshw. Algae
220, -figs. 92D-92F. 1904.
Coenobia flat, of 2-4-8-16 (generally 4) cells in a simple linear or
snbalternating series. Cells cylindrical-ovoid, with rounded poles. Poles
of terminal cells with a single long straight or curved spine. Poles of
interior cells without spines. (Facultative Planktont).
Cells 3.5-6 [X broad, 11-16 /a long. 4-celled coenobia 11-16 /a broad,
12-23 /A long. Spines 10-12 /a long.
Beaverdam (rr). Big Butternut (rrr), Blake (rr). Browns (rr). Camp (rr),
Cketek (rr). Clam (rr). Clear (rr). Eagle (rr). East (rrr), Fislitrap (rr).
Green (1) (rr), Hillman (rr). Horseshoe (2) (rr). Lac du Flambeau (rr),
Lindy (rr). Little Rice (2) (r). Lost (rr), Loveless (rr), Lower Nashotah
(rr). Lower Nemahbin (rr), Mary (rr), Meta (rr). Mud (1) (rr). Mud (2)
(rr), Muskallonge (r), Nancy (rr), Okauchee (rrr). Old Taylors (rr) Poke-
gama (1) (rr),Pope (rr). Poplar (rr). Poor Farm (sss), Rice (1) (rr). Round
(3) (rr), Sand (1) (rrr). Sand (4) (rr), Travis (ccc). White Ash (rr), Wild
Goose (rrr), Winnebago (rr).
The most ubiquitous species of the genus. The presence of spines
on the poles of the terminal cells only is the distinguishing feature of
the species. Cultural work has shown that it is possible to recognize
several distinct varieties of this species.
var. PARVUS G. M. Smith. PI. 40, Fig. 17.
Trans. Wis. Acad. Sci., Arts, & Lett. 18": 480, pZ. 31, Ms. 162-166. 1916.
Cells ovoid-cylindrical. Length of cells 2-2.5 times the breadth and
equal to the length of the spines. (Tychoplanktont).
Cells 3-4 IX broad, 5.5-8 /a long. 4-celled coenobia 5.5-8 /a broad,
12-15 IX long. Spines 4.5-8 /a long.
Deer (rrr).
var. QUADRisPiNA (Chodat) G. M. Smith. PI. 40, Figs. 15-16.
Trans. Wis. Acad. Sci., Arts, & Lett. 18": 479, pi. 31, figs. 167-171. 1916.
Cells broadly ovoid, about twice as long as broad. Spines short,
about as long as the diameter of the cell. (Tychoplanktont).
Cells 3.5-8 fx broad, 8.5-15 /a long. 4-celled coenobia 8.5-15 ^ broad,
16-32 fx long. Spines 2.5-5.5 /a long.
Mill (rrr). Pine (rr), Pokegama (1) (rrr), Round (1) (rr). Tied Canoe
(rrr).
WISCONSIN PHYTOPLANKTON
159
var. LONGiSPiNA (Chodat) G. M. Smith. PI. 40 , Figs. 12 - 14 .
Trans. Wis. Acad. Sci., Arts, & Lett. 18 ": 480, pi. 31, figs. 159-161. 1916.
Cells ovoid-cylindrical. Length of cells 2.5 times the breadth. (Fac-
ultative Planktont).
Cells 3.5-5 p, broad, 8-11 jx long. 4-celled coenobia 8-11 /x broad,
12-20 fx long. Spines 7.5-10 fx long.
Horse (rr). Lost (rr), Mendota (sss). Palmer (r).
var. Westii G. M. Smith. PI. 41, Pigs. 3-7.
Trans. Wis. Acad. Sci., Arts, & Lett. 18 ": 480, pi. 32, figs. 177-180. 1916.
Cells 4.5-8 fx broad, 16-22 p. long. 4-celled coenobia 16-22 p broad,
25-35 p long. Spines 12-16 p long. (Facultative Planktont).
Bear Trap (rrr), Blake (rr). Camp (rr), Cochrane (rr), Crawling Stone
(rr), Grassy (rr). Horse (rrr), Lac Court Oreilles (rr). Loon (rrr), Meta
(rr), Silver (2) (rr).
var. MAXIMUS W. & G. S. West. PI. 41 , Figs. 1 - 2 .
Trans. Linn. Soc. 2 Ser. Bot. 5: 83, pi. 5, figs. 9-10. 1895.
Cells much larger and spines proportionally longer. (Facultative
Planktont).
Cells 9-11.5 p broad, 27-36 p long. 4-celled coenobia 27-36 p broad,
35^0 p long. Spines 20-30 p long.
Eagle (rr), Nicaboyne (rr). Pine Tree (rr). Poor Farm (rr). Tenderfoot'
(rrr), Travis (r).
SCENEDESMUS OPOLiENSis P. Kichter. PI. 41 , Figs. 8 - 11 .
Zeits. f. angw. Mikr. 1: 7, figs. A-E. 1896.
Coenobia flat, of 2-4-8 (generally 4) cells in a single linear series.
Interior cells naviculoid, outer margin of terminal cells straight or
slightly convex. Cells in lateral contact in median third only. Termi-
nal cells with a long spine at each pole ; interior cells with or without
long or short spines. Polar spines greatly reduced at times. (Faculta-
tive Planktont).
Cells 5-8 p broad, 12-28 p long. 4-celled coenobia 12-28 p broad,
15-30 p long. Spines 5-28 p long.
Palmer (rr).
The navicular shape of the cells, their lateral contact in the median
third only, together with the beak-like instead of rounded apex sepa-
rates this species from S. quadricauda.
160
WISCONSIN PHYTOPLANKTON
Sub-family C0ELA8TREAE.
Coenobia forming a sphere with the cells radially arranged in a single
layer around a common center. The number of cells in a coenoba al-
ways a multiple of two. Cells spherical, polygonal, or elongate cylindri-
cal.
KEY TO THE GENERA.
Cells spherical, polygonal, or flattened; length never more than twice the
breadth.
Cells without spines on the outer face Coelastrum
Cells with spines on outer face Sorastrum
Cells 3-7 times as long as broad Actinastrum
COELASTRUM Nageli 1849.
Coenobe a hollow sphere of 2-4-8-16-32-64-128 cells. Cells spheri-
cal, ovoid, or pyramidal ; compressed or with large intercellular spaces ;
enclosed in a very delicate gelatinous sheath. Daughter coenobia some-
times remaining joined in multiple coenobia by the remains of the old
mother cell wall.
Reproduction by autocolony formation in any cell of the coenobe.
Liberation of young coenobia by a rupture of old mother cell wall.
KEY TO THE SPECIES.
Cells spherical.
Processes uniting the cells long C. Reticulatxjm
Processes uniting the cells short.
External face of cells without projections C. Microporum
External face of cells with short truncate projections. . .C. Cambricum
Cells truncate cones ....C. Proboscideum
Coelastrum microporum Nageli. PI. 41, Figs. 12-13; PI. 42, Fig. 1.
in Braun, Alg. unicell. 70. 1855; Senn, Bot. Ztg. 57: 53, pi. 2, iigs. 11-17. 1899.
Coenobia spherical to ovoid ; with 8-16-32-64 cells. Cells spherical,
enclosed by a delicate gelatinous sheath and connected to one another
by short, stout, gelatinous processes. Intercellular interstices smaller
than the diameter of the cells. (Facultative Planktont).
Diam. cells (without sheath) 3-20 p,; (with sheath) 4-23 p,. Diam.
coenobia 20-90 p.
Balsam (rrr). Bear (1) (rr), Bear (2) (rr). Bear Trap (rrr), Big Butter-
nut (rrr), Blake (rrr). Bone (rrr), Boulder (rrr). Browns (rr). Center
(rr), Chetac (rr), Cochrane (rr). Deer (rrr). East (rrr), Elizabeth (rr),
Fishtrap (rrr), Granite (rr). Hill (rr), Hillman (rrr). Horseshoe (2) (rrr),
WISCONSIN PHYTOPLANKTON
161
Island (rr), Lac du Flambeau (sss), Little Bass (2) (rr), Little Butternut
(rr), Little Crooked (rrr), Little Doctor (rr). Loveless (rrr), Lower Naah-
otah (rrr). Lower Turtle (rr), Mary (rr), Mendota (sss), Mill (rrr), Mud (2)
(rr), Nancy (rrr), Oconomowoo (rr). Otter (rrr), Pewaukee (rrr). Pine Tree
(rrr), Pokegama (1) (rr), Pokegama (2) (rr). Poor Farm (rrr). Pope (rrr),
Prairie (rrr). Round (1) (rrr). Sand (1) (rr). Sand (4) (rr). Shell (rrr).
Silver (1) (rr). South Turtle (rr). Squirrel (rr). Tenderfoot (rr). Tied Canoe
(rrr), Travis (rrr). Vermilion (rr), White Ash (rrr), White Sand (rrr).
Wolf (rrr).
A species that is found in all types of lakes.
CoELASTRUM CAMBRicuM Archer. PL 42, Figs. 2-3.
Quart. Jour. Micr. Sci. N. S. 8: 65. 1868; W. West, Jour, of Bot. 31: 99, pZ.
333, lig. 14. 1893.
Coenobia spherical, of 8-16-32-64r-128 (generally 32) cells. Cells
spherical, with a single truncate projection on the outer face. Each
cell connected to adjacent ones by short, somewhat flattened, gelatinous
projections. Small circular or triangular interstices between the cells.
( Facultative Planktont ) .
Diam. cells (with sheath) 6-21 /a, (without sheath) 5-18 /a. Diam.
coenobia 20-100 /a.
Balsam (rrr). Bear (2) (rr), Beaverdam (rr), Birch Island (rrr). Blue
Gill (rrr). Catfish (rr), Cochrane (rrr). Cranberry (rr). East (rr). Found
(rr), Hillman (rrr), Jag (rr). Little Bass (2) (r), Mercer (rr). Middle Mc-
Kenzie (rrr), Minocqua (rr), Nancy (rrr), Nicaboyne (rr). Old Taylors (rrr),
Owen (rrr). Pine (1) (rr). Pine Tree (rr), Pokegama (1) (rr). Prairie (rr),
Rudolph (rrr), St. Croix (rr). Silver (1) (rr), Streitor (rr), Travis (r).
Wild Goose (rrr).
CoELASTRUM RECTicuLATUM (Dangcard) Senn. PI. 42, Figs. 4-6.
Bot. Ztg. 57: 66, pi. 2, figs. 1-10. 1899.
Coenobia spherical, of 8-16-32 cells ; generally held in multiple coe-
nobia by the remains of old mother cell walls. Cells spherical, enclosed
by a narrow gelatinous sheath and connected to adjacent cells by 6-9
long, slender, tough, gelatinous processes. (Facultative Planktont).
Diam. cells (with sheath) 6-24 fi. Diam. coenobia 10-65 /a.
Bear Trap (rrr). Bear (3) (rr), Beaverdam (rrr). Big McKenzie (rrr),
Birch (2) (rr), Blake (rrr). Browns (ss). Camp (rr). Fish (rr). High (rrr).
Island (rr). Lac Court Oreilles (rr). Little Bass (2) (rr), Mary (rr), Mendota
(rr). Mud (1) (rr), Mudhen (rr), Nancy (rr). North Twin (rrr). Palmer (rr).
The long processes connecting the cells distinguish this species from
all others. Solitary coenobia are rarely met with since the long proc-
esses hinder the escape of young coenobia.
11
162
WISCONSIN PHYTOPLANKTON
CoELASTRUM PROBOSCiDEUM Bohlin. PI. 42, Figs. 7-8 ; PI. 43, Figs. 1-2.
Bih. t. Kgl. Sv. Vet.-Ak. Handl. 23, Afd. 3, No. 7: 33, pi. 2, figs. 19-22. 1897.
Coenobia pyramidal or cubical, rarely polygonal; of 4^8-16-32 (gen-
erally 4 or 8) cells; frequently joined in compound coenobia of irregu-
lar shape. Cells truncate cones, at times with concave sides ; with base
of cone towards the center of coenobe. Interstices between cells large,
polygonal. Chloroplast single, parietal, with one pyrenoid. (Faculta-
tive Planktont).
Diam. cells 6.5-17 /x; diam. 4-celled coenobia 12-35 /x; compound
coenobia up to 350 /x in diam.
Bear Trap (rrr), Cochrane (rr), Durchmans (rrr), Pine Tree (aa). Round
(rrr).
The appearance of this alga as the dominant organism of the plankton
of Pine Tree lake is of particular interest since Coelastrum species have
not been reported as occurring in abundance by any student of the
phytoplankton. Compound coenobia were very common and it was not
at all unusual to find 50-80 four- or eight-celled coenobia joined in one
irregular mass. The cells of four-celled coenobia are tetrahedrically
arranged in the manner that G. S. West has described them for Coelas-
irum compositum (Jour. Linn. Soc. Bot. 38: 136, pi. 5, figs. 8-9. 1907)
and I believe that G. compositum should be considered a synonym of
C. prohoscideum. The cellular arrangment of eight-celled coenobia is
exactly as Bohlin and Senn describe. In the sixteen-celled coenobia,
which are of very rare occurrence, the cells form a hollow sphere so that
the general appearance of the colony resembles the other species of the
genus. This difference in ceU number is of minor significance, the
number of cells in a colony being dependent upon the vegetative vigor
of the mother cell at the time colony formation takes place.
SORASTRUM Kutzing. 1845.
Cells pyriform, semilunar, or reniform; united to form spherical
colonies of 8-16-32-64-128 cells. Center of colony a polyhedral body
from which gelatinous strands radiate to each cell. Distal side of cells
with 1, 2, or 4 spines. Chloroplast diffuse, with one pyrenoid.
Reproduction unknown ; presumably by autocolonies as in Coelastrum^
possibly by zoospores as in Pediastrum.
WISCONSIN PHYTOPLANKTON 163
KEY TO THE SPECIES.
Spines on outer face of cells short (4-8 /*) S. SpiNuiiOSUM
Spines on outer face of cells long (10-15 /*) S. Amebicanum:
SoRASTRUM SPINULOSUM Nageli. PL 44, Figs. 4-5.
Gatt. einz. Algen 99, pi. 5, -figs. Da-Dd. 1849; G. S. West, Brit. Preshw. Algae
215, figs. 89A-89B. 1904.
Coenobe of 4-8-16-32 cells. Cells broadly renifonn to cuneate, with
four short horns at the corners of the outer face. Stipe leading to
sphere at center of colony short. Chloroplast single, generally filling
the entire cell; pyrenoid single. (Tychoplanktont).
Cells 8-20 {X broad, 6-18 ix long, 5-8 fx thick. Horns of adult cells
4-8 fx long.
Hillman (rrr), Horse (rrr).
SoRASTRUM AMERiCANUM (Bohlin) Schmidle. PI. 44, Fig. 1.
Engl. Jahrb. 27: 230. 1900: Lemmermann, Arch. f. Hydrob. u. Planktonkde.
5: 310, fig. 5. 1910.
Selenosphaerium americanum Bohlin, Bib. t. Kgl. Sv. Vet.-Ak. Handl. 23,
Afd. 3, No. 7: 40, pi. 2, figs. 38-41. 1897.
Coenobia spherical, solitary, of 16-32-64-128 (generally 16 or 32)
cells. Cells cardiate to pyramidate, somewhat flattened, with the apex
towards the center of the coenobe and ending in a broad gelatinous
stalk as long as the cell. Stalk cylindrical, 5-6 faceted at the base;
with the facets in contact with those of other stalks and forming a hol-
low sphere. Outer face of cells emarginate, with a single long spine at
each of the four corners. (Facultative Planktont).
Cells 7-20 fx broad, 5-20 fx long (without stalk), 4^S fx thick. Spines
of adult cells 10-15 fx long.
Devils (1) (rr), Devils (2) (rrr), Nancy (rrr), Travis (rr).
The longer spines and stalk, together with the more prominent central
sphere, separates this species from the foregoing.
var. UNDULATUM G. M. Smith. PI. 44, Figs. 2-3.
Trans. Wis. Acad. Sci., Arts, & Lett. 19^: 640, pi. 13, fig- 7. 1918.
Sides of facets at base of stipe undulate. Dimensions as in the typi-
cal form. (Facultative Planktont).
Beaverdam (rrr).
164
WISCONSIN PHYTOPLANKTON
ACTINASTRUM Lagerheim 1882.
Coenobia free-floating, of 4-8-16 (generally 8), ovoid, cylindrical,
club-shaped, or drum stick shaped cells radiating from a common cen-
ter. Coenobia sometimes united to form multii^’e coenobia of irregular
shape. Each cell with a single, laminate, parietal chloroplast; with
or without pyrenoids.
Reproduction by longitudinal and transverse division of the contents
of any cell, the young autocolony being liberated by a rupture of the
mother cell wall.
KEY TO THE SPECIES.
Center of cell twice as broad as poles A. Hantzsc?hi
Center of cells about the same width as the poles A. Graciulimum
Actinastrum GRAciLLiMUM G. M. Smith. PI. 43, Figs. 3-5.
Bull. Torr. Bot. Cl. 43: 480, pi. 26, fig. 23. 1916.
Coenobia of 4 or 8 cells radiating from a common center. Cells elon-
gate-cylindrical, tapering but slightly to a truncate end, 7-10 times as
long as broad. Chloroplast single, parietal, laminate, with or without
a pyrenoid. (Euplanktont).
Cells 1.75-3 fx broad, 14-21 long; colonies 30-45 fi in diam.
Horse (rr), Kegonsa (rrr), Mendota (rr).
The species differs from the following in the very slight dilation of
the median portion of the cell and the greater proportional length.
Actinastrum Hantzschi Lagerheim. PI. 43, Figs. 6-7.
Ofvers. Kgl. Vet.-Ak. Porh. 39, No. 2: 70, pi. 3, figs. 25-26. 1882.
Coenobia of 4 or 8 cells radiating from a common center. Coenobia
sometimes united to form multiple coenobia. Cells 3-6 times as long
as broad, with truncate poles, ovoid-cylindrical. Diameter of middle
of cells twice that of poles. Chloroplast single, parietal, laminate ; with
one pyrenoid. (Euplanktont).
Cells 3-6 fi broad, 10-26 fx long ; coenobia up to 50 fx in diam ; com-
pound coenobia up to 200 fx in diam.
Chetek (rr), Kegonsa (r). Lower Turtle (rrr), Mendota (rr), Prairie (rr).
Upper Turtle (rr), Waubesa (rrr).
Multiple coenobia are of rare occurrence and have only been found
in the plankton of Chetek lake. This may be due to the fact that such
colonies readily fragment into the individual coenobia and the handling
incident to the collection of samples is sufficient to break up multiple
coenobia.
WISCONSIN PHYTOPLANKTON
165
var. ELONGATUM G. M. Smith. PI. 43, Fig. 8.
Trans. Wis. Acad. Sci., Arts, & Liett. 19^: 636, pi. 12, -fig. 3. 1918.
Colonies of 4 or 8 cells. Cells cylindrical, tapering but little towards
the poles. ( Euplanktont) .
Cells 4^5 II broad, 30-35 long.
Bear (3) (rr).
The cells of this variety are much longer than those of the typical
form.
Family HYDRODICTYACEAE.
Cells cylindrical, or flattened and hexagonal to trapezoidal with one,
two, or four projections. Coenobia of definite shape; cylindrical with
a large number of cells; or disciform with 2-4-8-16-32-64-128 cells.
Cells incapable of division after their formation. Chloroplast single,
parietal, laminate to reticulate, frequently filling the entire mature
cell ; with one to many pyrenoids.
Asexual reproduction by the divisioli of contents of any cell to form
zoospores that swarm within old cell wall or within a gelatinous vesicle
extruded from the cell. Zoospores becoming apposed in the shape of
the adult cell when they come to rest.
Sexual reproduction by isogamous zoogametes which fuse in pairs to
form angular resting cells which form colonies on their germination.
KEY TO THE GENERA.
Coenobe a hollow cylindrical tube with rounded ends Hydeodictyon
Coenobe a flattened disc one cell in thickness.
Number of cells in coenobe always 2 Etjasteopsis
Number of cells in coenobe 4-8-16-32-64-128, very
rarely 2 Pediastbum
HYDRODICTYON Roth 1800.
Cells macroscopic, oblong-cylindrical with rounded ends; united to
form a free-floating, reticulate, saccate coenobium. Meshes of nets
3-12 (generally 5-6) sided. Cells coenoeytic; chloroplast parietal,
reticulate at first, later diffuse; pyrenoids single in very young cells,
several hundred in mature cells.
Asexual reproduction by the division of cell contents into very many
biciliate zoospores which swarm about in and become arranged as in
the mature coenobe within the old mother cell wall. Liberation of the
young coenobe by a gradual gelatinization of the mother cell wall.
Sexual reproduction by zoogametes which are similar in structure to
166
WISCONSIN PHYTOPLANKTON
zoospores but smaller, the zoogametes fusing in pairs to form a spheri-
cal zygote after their liberation through a pore in the cell wall. Zygote
germinating, after a short period of rest, into 2-5 large uni- or biciliate
zoospores that form irregular polyhedral cells on coming to rest. Poly-
eders ultimately germinating into 200-300 zoospores that are liberated
in a vesicle and form a net as in asexual reproduction.
Hydrodictyon reticulatum (L) Lagerheim. PI. 44, Fig. 6; PI. 45,
Fig. 1 .
dfvers. Kgl. Vet.-Ak. Forh. 40, No. 2: 71. 1883; G. S. West, Brit. Freshw. Algae
208, figs. 84A-84F. 1904
Cells elongate cylindrical, forming a definite closed net. (Tycho-
pJanktont) .
Cells 5-250 ii broad, up to 1.5 cm. long. Coenobia up to 30 cm. long.
Little Bass (2) (rr), Mendota (rr), Monona (sss).
An alga that is in no sense a plankton organism but one which some-
times grows in abundance in shallow, well protected bays and so may,
at times, be found free-floating in large patches a considerable distance
from the shore.
PEDIASTKUM Meyen 1829.
Coenobia disciform to stellate, free-floating, of 2-4-8-16-32-64-128
cells arranged in a layer one cell in thickness. Coenobe entire, perfor-
ate, or clathrate. Marginal cells polygonal, with one, two, or four proc-
esses that sometimes terminate in a tuft of long hyaline setae. Interior
cells polygonal, without processes. Cell wall smooth, granulate, or
covered with a meshwork of fine ridges; without a gelatinous sheath.
Chloroplasts parietal and disciform at first, later filling the entire cell ;
with 1-4 pyrenoids. Cells coenoc 5 d;ic.
Asexual reproduction by the division of contents of any cell into
2-4-8-16-32-64-128 biciliate zoospores that are extruded in a gelatinous
vesicle and, after a short period of swarming, on becoming quiescent
appose themselves in the same position as the mature cells of the
coenobe.
A fusion of biciliate zoogametes into polyhedral resting cells has been
observed. On germination these zygospores form 8-16-32 zoospores
that behave as in asexual reproduction.
WISCONSIN PHYTOPLANKTON
167
KEY TO THE SPECIES.
Outer face of marginal cells without projections.
W all smooth p. Integrum
Wall reticulate P. Araneosum
Outer face of marginal cells with 1, 2, or 4 projections.
Marginal cells with more than one projection.
Cells on margin with four projections and a deep linear incision. .P. Tetras
Cells on margin with two projections.
Coenobe entire.
Cell wall smooth or punctate.
Projections side by side in front view of cell P. Boryanum
Projections above one another in front view P. Kawraiskyi
Cell wall reticulate.
Wall covered with coarse reticulations P. Araneosum
Wall covered with fine reticulations P. Sculptatum
Coenobe perforate.
Ends of projections truncate P. Duplex
Ends of projections incised P. Biradiatum
Marginal cells with one projection P. Simplex
Pediastrum simplex var. duodenarium (Bailey) Rabenhorst. PL 45,
Figs. 2-6.
Fl. Eur. Algarum 3: 72. 1868.
Monactinns duodenarius Bailey, Smithsonian cont. to knowl. 7, Art. 3: 14,
pi. 1, fig. 37. 1855.
Monactinus octonarius Bailey, iMd. p. 14, pi. 1, fig. 36. 1855.
Pediastrum simplex var. clatfiratum (Schroter) G. S. West, Jour. Linn. Soc.
Bot. 38: 134. 1907.
Coenobia circular to oval, of 4-8-16-32-64-128 (generally 8-16-32)
cells. Inner face of marginal cells concave, outer face produced into
a single, delicately tapering, concave process frequently furnished with
a tuft of delicate hyaline setae. Interior cells as those of the periphery
but with shorter processes. Interstices between cells large. Cell wall
smooth or finely punctate. (Facultative Planktont).
Cells 10-24 fl broad, 20-45 fi long.
Balsam (rr). Bear (1) (r). Bear Trap (rrr), Blake (r), Camp (rr). Green
(1) (rrr). High (rr), Hillman (rrr), Kegonsa (rr). Little Bass (rr), Little
Butternut (r). Little Crooked (rrr), Lost (rr). Loveless (rrr), Mary (rr),
Monona (r). Mud (2) (rr). Palmer (rrr), Pokegama (1) (sss). Rice (1) (r),
St. Croix (rr), Silver (1) (rr). Spirit (rr). Upper Turtle (r). Vermilion (cc),
Wapagossett (r). White Ash (rr), Winnebago (rr). Wolf (rrr).
This alga is one that has been given a number of names by various in-
vestigators, but for the reasons stated elsewhere (Trans. Wis. Acad. Sci.,
Arts, & Lett. 19^: 642. 1918) I consider the one given above the proper .
name.
168
WISCONSIN PHYTOPLANKTON
Pediastrum integrum Nageli, PI. 45, Fig. 7.
Gatt. einz. Algen 97, p?. 5, figs. B4a^B4r. 1849.
Coenobia 8-16-32-64-celled, circular or oval, without perforations.
Interior cells polygonal; marginal cells 5-6 sided, at times with rudi-
ments of two projections that are sometimes reduced to a single wart,
but generally without projections. Cell wall smooth or punctate.
( Tychoplanktont) .
Diam. cells 15-30 /x.
Soft (rrr).
var. PRiVA Printz. PI. 45, Pigs. &-10.
Skr. Vidensk. i Kristiana Mat.-Naturv. Kl. 1913': No. 6: 73, pi. 5, fig. 147.
1914.
Coenobia generally 8-celled. Marginal cells trapezoidal, without in-
cisions or processes. Interior cells polygonal, without incisions. Cell
wall smooth. (Facultative Planktont).
Diam. cells 8-10 /x. Diam. 8-celled coenobia 15-25 /x.
Palmer (rr).
The general shape of the cells is like that of P. tetras but since there
are no incisions in the cells they cannot be placed among the varieties
of P. tetras.
Pediastrum araneosum Raciborski. PI. 45, Fig. 11.
Mem. Acad. Imp. Sci. Cracow 20: 84. 1890.
Coenobia circular to oval, without perforations, of 8-16-32-64-128
cells. Interior cells in contact with 4^6 other cells, straight sided. In-
ner half of marginal cells similar to interior cells, outer half without
processes but with a deep emargination. Surface of cell covered with
a coarse reticulum of ridges. (Facultative Planktont).
Diam. cells 15-32 /x.
Birch Island (rr), Blue Gill (rrr), Boulder (rrr), Carson (rrr). Deer (rrr).
Devils (1) (rrr), Diamond (rrr), Dutchmans (rr). Horseshoe (1) (rr). Lake
of the Woods (rrr), Lindy (rr). Loon (rrr), Nicahoyne (rr), Nancy (r). Pine
Tree (rr), Pokegama (1) (rrr). Poor Farm (rrr). Sand (2) (rr), Wild
Goose (rr).
var. RUGULOSUM (G. S. West) G. M. Smith. PI. 45, Figs. 12-13.
Bull. Torr. Bot. Cl. 43: 476, pi. 25, fig. 14. 1916.
Sides of cells undulate where they are in contact with one another.
(Facultative Planktont).
Meta (r).
WISCONSIN PHYTOPLANKTON
169
Pediastrum sculptatum G. M. Smith. PI. 46, Fig. 1 .
Bull. Torr. Bot. Cl. 43: 475, pL 25, fig. 13. 1916.
Coenobia oval to circular, of 8-16-32 cells. Interior cells with 4-6
straight sides, with a few interstices between the cells. Marginal cells
bilobed, with the lobes produced into two short divergent or parallel
processes. Cell wall covered with a network of very fine ridges. (Fac-
ultative Planktont) .
Diam. cells 10-15 ju,. Diam. coenobia 80-150 /x.
South Turtle (rr).
Pediastrum Boryanum (Turpin) Meneghini. PI. 46, Figs. 2-7.
Linnaea 14: 210. 1840; G. S. West, Brit. Freshw. Algae 211, figs. 85 f- 85 h.
1904.
Coenobia circular to ovoid, of 4^8-16-32-64^-128-256 (generally 8-
16-32) cells that are normally compactly arranged in concentric rings.
Interior cells 4-6 sided, with straight sides. Inner half of marginal
cells similar to interior cells ; outer half produced into two short obtuse
processes ending in short spines, slightly to deeply emarginate between
the processes. Projections on outer face and their spines sometimes
greatly reduced. Wall smooth or granulate. (Facultative Planktont).
Diam. cells 7.5-30 /x. Diam. 16-celled coenobia 40-100 (i.
Balsam (rrr). Bear (1) (rrr), Bear (2) (rrr). Bear (3) (ss). Bear Trap
(rr), Beasley (rr), Beaver (rr), Beaverdam (ss). Big Butternut (rr), Birch
Island (rr), Blake (rr). Bloom (r), Boulder (rrr), Browns (rr). Camp (r),
Carroll (sss), Carson (rrr), Catherine (rr). Center (ss), Chetac (rr), Chetek
(rrr). Clear Crooked (rr), Cochrane (rrr). Crawling Stone (rr). Deer (r), Des
Moines (rr). Devils (1) (rr). Eagle (sss). East (rrr), Elizabeth (rrr). Fence
(rrr), Fishtrap (rr). Found (rr), Fowler (rrr), Geneva (rr), Granite (rr),
Grassy (rr). Green (2) (rrr). Grindstone (rr). Half Moon (rrr), Harris (rr).
High (rr), Hillman (rr). Hooker (rr). Horse (rrr). Horseshoe (1) (ss),
Kawaguesaga (r), Kegonsa (sss). Kitten (rr). Lac la Belle (rr). Lac Court
Oreilles (rr). Lac du Flambeau (r), Lindy (rr). Little Bass (2) (r). Little
Bear (sss). Little Butternut (rrr). Little Crooked (rr). Little Rice (2) (rr).
Little Wood (rrr). Long (2) (rr). Long (3) (rrr). Loveless (r). Lower Nash-
otah (rrr). Lower Nemahbin (rr). Lower Turtle (rr). Marl (rr), Mary (ss),
Mendota (ss), Monona (ss). Mud (1) (r). Mud (2) (r), Mudhen (rr), Muskal-
loDge (rr), Nagawicka (rr), Nancy (sss), Nicaboyne (rrr), Oconomowoc (rr).
Old Taylors (rr), Owen (r). Paddock (rrr), Pewaukee (rr). Pine (2) (rrr),
Pokegama (1) (sss), Pokegama (2) (r), Pokegama (3) (rr). Poor Farm (rr).
Poplar (rr). Prairie (rrr). Rainbow (rr). Reserve (rrr), Rice (1) (rr). Round
(1) (sss). Round (2) (rr), St. Croix (rr). Sand (1) (rrr). Sand (3) (rrr),
Sand (4) (sss). Silver (2) (r), Spirit (rr). Star (rr), Streitor (rr), Taylor
(r). Tenderfoot (rrr). Tied Canoe (rrr). Turtle [North and South] (rr), Up-
170
WISCONSIN PHYTOPLANKTON
per Turtle (r), Vermilion (rr), Waubesa (r), White Ash (sss), Whitefish (rr),
White Sand (rr). Wildcat (rrr), Winnebago (r), Wolf (s).
A species that is almost universally present and one which varies
greatly in the character of the marginal cells.
var. UNDULATUM Wille. PI. 46, Fig. 8.
Ofvers. Kgl. Vet.-Ak. Forh. 36, No. 5: 28. 187'9.
Sides of cells in contact with other cells undulate instead of straight.
( Tychoplanktont) .
Winnebago (rr).
var. LONGICORNE Kaciborski. PI. 46, Fig. 9.
Akad. Umiej. w. Krakowie 20: 13. 1889; Printz, Skr. Vidensk. i Kristiana
Mat.-Natury. Kl. 1913, No. 6: 74, pi, 5, fig^ 149. 1914.
Horns at the ends of processes much longer than typical form, some-
times swollen at apex. Cell wall smooth or granulate.
Diam. cells up to 40 fx. Horns 12-30 [x long.
Bone (rrr).
Raciborski recognizes the forms glabrum and granviatum but, judg-
ing by the variation in the nature of the wall in the typical form, these
forms should not be recognized.
Pediastrum Kawraiskyi Schmidle. PI. 46, Figs. 10-13.
Arb. d. Botan. Gartens zu Tiflis 2: 269. 1897; Nitardy, Beih. z. Bot. Cent. 32-:
164, pi. 5, fig. 6. 1914.
Coenobia of 16-32-64 cells that are compactly arranged. Interior
cells 4—6 sided, sides straight. Inner half of marginal cells as interior
cells, outer half with two short projections that lie one above the other
when the coenobe is seen in surface view. Cell wall smooth. (Eu-
pJanktont).
Diam. cells 9-22 fx. Diam. 32-celled coenobia 60-100 /a.
Big Bass (r). Palmer (rr). Tenderfoot (rrr), Winnebago (r).
The cell shape is quite similar to P. Boryanum but the peculiar posi-
tion of the processes on the marginal cells at once distinguishes this
species from all others. Some investigators are inclined to the view
that P. Kawraiskyi is but a passing condition of P. Boryanum that is
found for one generation only. I have grown P. Boryanum in pure
cultures for several years and have never seen a single coenobe with the
projections of marginal cells lying one above the other, and so feel con-
fident that P. Kawraiskyi is not a temporary growth condition of
P. Boryanum.
WISCONSIN PHYTOPLANKTON
171
Pediastrum duplex Meyen. PL 46, Figs. 14-16.
Nova Acta Phys. Med. Ac. Caes. Leop.-Carol. Nat. Cur. 14^• 772, pi. 43, figs.
6-20. 1829.
Coenobia of 8-16-32-61r-128 (generally 16-32) cells, with small lens-
shaped perforations between the cells. Interior cells more or less rec-
tangular, not in contact with one another in the central portion of the
side walls. Inner half of marginal cells similar to interior cells, outer
half prolonged into two short truncate processes. Cell wall smooth.
(Facultative Planktont).
Diam. cells 11-21 /a.
Balsam (rrr). Bear (2) (r), Birch Island (rr), Browns (rr), Catherine (rr).
Center (r). Clam (rrr), Cochrane (rr). Crawling Stone (r). Deer (rr), Des
Moines (rrr), Diamond (rrr). Eagle (r), Fishtrap (rr). Found (rr), Fowler
(rr), Helen (1) (rr). High (rr), Kawaguesaga (rr), Kegonsa (r). Kitten (r).
Lac la Belle (r), Lindy (rr). Little Bass (2) (rr), Little Bear (r). Little
Crooked (r). Little Rice (2) (rr). Long (3) (rrr). Lost (rr), Mendota (sss),
Mercer (rr), Meronk (rrr), Monona (c), Nagawicka (rr), Nancy (sss), Nica-
boyne (rrr). North Twin (rr), Oconomowoc (rr), Okauchee (rr), Pardee (rr),
Pokegama (1) (ss), Pokegama (2) (rr). Poor Farm (r). Poplar (rrr). Round
(1) (r). Round (2) (rr). Sand (4) (sss), Sishebogema (rr). Soft (r). South
Turtle (sss), Taylor (rr). Tenderfoot (r). Tied Canoe (rrr). Upper Nemahbin
(rr), Waubesa (ccc), White Sand (rrr). Wildcat (sss). Wild Goose (rrr),
Winnebago (ss),Wolf (sss).
In many cases the marginal cells of this species and the varieties
clathratum, reticulatum and graeilUmum have a tuft of long hyaline
setae at the apex of the projections. Their function is to give buoyancy
to the coenobe when living under pelagic conditions. Petersen (Bot.
Tids. 31: 161-176. 1911) has been able to demonstrate their presence
in other species by means of stains.
var. CLATHRATUM (A. Braun) Lagerheim. PL 47, Pigs. 1-3.
Ofvers. Kgl. Vet.-Ak. Forh. 39, No. 2: 56. 1882.
Cells more deeply emarginate and perforations of disc larger. (Fac-
ultative Planktont).
Diam. cells 12-22 ft.
Balsam (rr), Bear (3) (rr). Bear Trap (rr), Beaverdam (sss). Big Butter-
nut (rr), Blake (r). Bloom (rr). Camp (ss). Catfish (rr), Catherine (rr),
Chetek (s). Cranberry (rr). East (rrr). Fish (s). Horseshoe (1) (rr). Horse-
shoe (2) (rr). Lac du Flambeau (rrr). Lac la Belle (r). Little Bass (2) (sa).
Little Butternut (r). Little Wood (rrr). Long (1) (rrr), Loveless (sss).
Lower Turtle (r), Mary (r), Mendota (r). Middle McKenzie (s). Mud (2) (rr),
Mud (3) (sss), Nancy (r), Okauchee (rrr). Old Taylors (rrr), Pokegama (1)
(r). Rice (1) (ss). Round (2) (rr), Sand (3) (rr). Sand (4) (r). Spirit (sss).
Upper Turtle (sss), Wapagossett (rr). White Ash (r).
172
WISCONSIN PHYTOPLANKTON
var. RETicuLATUM Lagerheim. PI. 47, Figs. 4-7.
ofvers. Kgl. Vet.-Ak. Forh. 39, No. 2: 56, pi. 2, fig. 1. 1882.
Perforations of coenobe very large, oval. Interior cells sub-cruciate
to H-shaped. Sides of projections of marginal cells parallel, projec-
tions generally terminating in a tuft of delicate long hyaline setae.
(Euplanktont ?).
Cells 10-20 fi broad, 15-40 fi long.
Big (rr), Camp (s), Center (s), Clietek (b), Crab (rr), Hill (rr), Hooker
(rr), Horse (sss), Island (sss), Kawaguesaga (rr), Little Bear (rr). Little
Rice (1) (rr). Lost Bass (r), Loveless (r), Nancy (r), Paddock (rr), Palmer
(r), Pardee (r). Pine (2) (rrr), Pokegama (1) (r), Pokegama (3) (ss),
Prairie (ss). Reserve (rr). Rice (r), St. Croix (sss), Sisbebogema (r). South
Turtle (rr), Tenderfoot (rr), Waubesa (rr), Whitefish (rr), Winnebago (rr).
var. GRACiLLiMUM W. & G. S. West. PI. 47, Figs. 8-11 ; PI. 48, Figs. 1-2.
Jour, of Bot. 33: 52. 1895.
Cells very narrow, never wider than the processes. Body of margi-
nal cells curved outwards, with two long, somewhat converging processes
that have parallel or slightly convex sides. Interior cells like those of
margin but with somewhat shorter processes. Perforations of coenobe
very large. (Euplanktont).
Cells 10-22 fjL broad, 12-32 /a long. Diam. 16-celled coenobia 65-140 /x.
Clam (rr). Pine Tree (sss), Travis (r).
The perforations of the coenobe and the extension of the processes
are the greatest in this variety. The varieties clathratum, reticvlatum,
and gracillimum are not sharply defined and it is possible, taking the
collections as a whole, to arrange a series that grades almost impercept-
ibly from the typical form to the variety gracillimum. The individuals
from any one lake, however, generally vary within fairly narrow limits
so I feel that these varieties should be recognized instead of putting
them in one collective species without varieties.
var. ROTUNDATUM Lucks. PI. 46, Fig. 17.
Jahrb. d. Westpr. Lehrervereins f. Naturk. 2-3: 31. 1907; Nitardy, Beih. z.
Bot. Cent. 32=*: pi. 9, fig. 11. 1914.
Projections of marginal cells markedly convex and capitate instead
of parallel. (Tychoplanktont).
Oconomowoc (rrr). Horseshoe (1) (rr).
WISCONSIN PHYTOPLANKTON
173
var. coHAERENS Bohlin. PI. 48, Figs. 3-4.
Bih. t. Kgl. Sv. Vet.-Ak. Handl. 23, Afd. 3, No. 7: 31, pZ. 2, fig, 1. 1897.
Pediastrum duplex var. reticulatum forma coJiaerens (Bohlin) Brunnthaler,
in Pascher, D. Siisswasserfl. Deutschl., osterr. u. d. Schw. 5^: 95, fig. 57e. 1915.
Coenobia circular to oval, of 16-32-64 cells, with median-sized inter-
cellular spaces. Wall of cells covered with short, linear, concentrically
arranged granules. (Facultative Planktont).
Cells 12-22 fjL broad ; 13-24 fi long.
Pine Tree (r).
Pediastrum biradiatum Meyen. PI. 48, Figs. 5-8.
Nova Acta Phys.-Med. Ac. Caes.-Leop. Nat. Cur. 14^: 773, pi. 43, figs. 21-22. 1829.
Pediastrum rotula (Ehrenberg) A. Braun emend. Alg. unicell. 101, pi. 6,
figs. 2-3, 5-7, 10, 12-14. 1855.
Coenobia of 4-8-16-32-64 cells, with medium sized openings between
cells. Marginal cells in contact with one another at base only, with
two long projections that are dilate and incised at the apex. Interior
cells as those of the margin but apices of projections neither dilate nor
incised, in contact with other cells at base and ends of projections only.
Cell wall smooth. (Facultative Planktont).
Cells 10-22 broad, 15-30 fi long. Diam. 32-celled coenobia 80-150 /x.
Balsam (rrr). Bear (3) (rr), Big McKenzie (rr), Lac du Flambeau (rr),
Mud (2) (rr), Nancy (rrr), Pokegama (1) (rrr), Wolf (rrr).
This species resembles P. duplex var. reticulatum in the perforation
of the disc but differs in the deep incision of the marginal cell projec-
tions. Perfect colonies are seldom seen since apices of projections of
certain interior cells are free and have the same dilation and incision
that is found in the marginal cells. The number of ceUs in the colony
is generally stated as 8-16-32 but the coenobia in the plankton of Wis-
consin lakes are 32- or 64-celled except in very rare cases.
Pediastrum tetras (Ehrenberg) Ralfs. PL 48, Figs. 9-12.
Ann. & Mag. of Nat. Hist. 14: 469, pi. 12, fig. 4. 1844.
Coenobia rectangular, oval or circular; without perforations; of
4-8-16-32 (generally 4-8) cells. Outer face of marginal cells with a
single deep linear to cuneate incision, the halves of the outer face
slightly to deeply emarginate. Interior cells with a single deep linear
incision and 4-6 straight sides. Cell wall smooth. (Tychoplanktont).
Diam. cells 8-15 /x.
Blake (rrr). Browns (rrr). Chain (rrr), Chetek (rr), Cochrane (rrr), Hill-
man (rrr). Horse (rrr). Horseshoe (2) (rrr), Kimball (rrr), Lindy (rrr).
174
WISCONSIN PHYTOPLANKTON
Little Doctor (rr), Mendota (rrr), Palmer (rrr), Pewaukee (rrr), Pine (2)
(rr), Pokegama (1) (rr), Poor Farm (rr), Tied Canoe (rrr).
The four projections in the outer face of marginal cells are due to a
deep emargination of the two halves. This, coupled with the deep in-
cision of all cells, at once separates the species from others of the genus.
The alga does not thrive under plankton conditions although it is com-
mon in ditches and ponds of the state.
var. OBTUSATA Raciborski.
Akad. Umiej. w. Krakowie 20: 32. 1889; Printz, Skr. Vidensk. i Kristiana
Mat.-Naturv. Kl. 1913S No. 6: 78, pi. 6, fig. 153. 1914.
Cells larger than typical form, sometimes expanded at base. Halves
of outer face of marginal cells entire or very slightly emarginate.
( Tychoplanktont ) .
Diam. cells 14-18 p , ; length 18-22 p..
Beaverdam (rrr).
var. TETRAODON (Corda) Hansgirg. PI. 48, Figs. 13-14; PI. 49, Figs. 1-2.
Prodr. d. Algenfl. v. Bohmen 1: 112. 1888.
Euastrum tetraodon Corda, Almanach de Carlsbad 9: 238, pi. 2, fig. 9. 1839.
Coenobia generally 8-celled. Incision of cells deep, and with projec-
tions adjacent to incision very pronounced on marginal cells. (Facul-
tative Planktont).
Diam. marginal cells 8-15 ju,; length 12-18 fi.
Pine Tree (rr), Travis (r).
There is no question that my figures of the organism are identical
with the one that Nitardy (Beih. Bot. Cent. 32^ : 123, pi. 5, fig. 8. 1914)
has reproduced from Corda. The variety is sharply defined through
the greater development of the projections.
EUASTROPSIS Lagerheim 1894.
Coenobia free-floating, 2-celled. Cells flattened, approximated at the
bases, distal end free and deeply emarginate. Chloroplast single, pari-
etal, with one pyrenoid.
Asexual reproduction by division of cell contents into 2-4^8-16-32
zoospores which are extruded in a vesicle and on becoming quiescent
join in pairs to form the characteristic coenobe.
Sexual reproduction unknown.
WISCONSIN PHYTOPLANKTON
175
Euastropsis Richteri (Schmidle) Lagerheim. PI. 49, Fig. 3.
Tromso Museums Aarshefter 17 : 20, pi. 1, figs. 8-27. 1894.
Cells trapezoidal, outer face deeply emarginate. (Tychoplanktont).
Cells 4.5-25 /a broad, 5-20 /x long. Coenobia 4.5-25 fi broad, 10-40
(I long.
Kegonsa (rrr).
It is quite possible to mistake 2-celled Pediastrum colonies for
E. Richteri, but since such Pediastrum colonies are of very rare occur-
rence the similarity of the two is not apt to lead to confusion. '
Family PLAN 08P0R ACE AE.
Cells solitary or gregarious; ovoid, pyriform, fusiform, cylindrical,
or hemispherical ; epiphytic, endophytic, or epizootic. Cells capable of
growth but incapable of division after their formation. Generally with
a single chloroplast with one or more pyrenoids.
Asexual reproduction by division of cell contents to form many zoo-
spores.
Only one genus, Characium, is found in the plankton of the state.
CHARACIUM A. Braun 1849.
Cells sub-spherical, ovoid, pyriform, fusiform, or cylindrical; soli-
tary or gregarious; epiphytic or epizootic; generally attached to sub-
stratum by a more or less elongate stipe, rarely sub-sessile. Chloroplast
parietal and laminate to cup-shaped in young cells ; later expanded to
fill entire cell : with one or more pyrenoids. Cells at times with several
chloroplasts.
Asexual reproduction by repeated division of cell contents into 8-16-
32-64-128 zoospores that are liberated through a lateral or apical pore.
Zoospores swarming but a short time and then coming to rest on sub-
stratum and developing into vegetative cells.
Microgametes reported but doubtful.
KEY TO THE SPECIES.
Epiphytic upon other algae.
Cells ovoid C. Stipitattjm
Cells lunate C. Cubvatum
Epizootic upon crustaceans.
Apices of cells rounded C. Cylindbictjm
Apices of cells produced into a fine seta.
Stipe simple C. Limnetictjm
Stipe ending in filiform rhizoids C. Geachjpes
176
WISCONSIN PHYTOPLANKTON
Characium stipitatum (Bachmann) Wille. PL 49, Figs. 4-7.
in Engler & Prantl, Nat. Pflanzenfam. V (Nachtr.); 45. 1909; G. M. Smith,
Bull. Torr. Bot. Cl. 43: 472, pi, 24, figs. 4-6. 1916.
Cells spherical to pyriform, with a delicate hyaline stipe somewhat
longer than the cell. Chloroplast single, parietal, cup-shaped, always
on the side away from the stipe; pyrenoid single. Zoospores broadly
ovoid, biciliate, with a cup-shaped chloroplast at the posterior end.
(Euplanktont).
Epiphytic upon and embedded within the gelatinous envelope of
Coelosphaerium Naegelianwn Unger.
Cells 5-8 fx broad. Stipe 10-16 p. long.
Amicoy (r). Balsam (rr), Beartrap (rr), Beaverdam (s), Big (rr), Big
McKenzie (ss), Clam (ss), Devils (2) (ss). Horseshoe (1) (ss), Horseshoe
(2) (rr), Long (2) (ss), Kawaguesaga (ss). North Twin (sss), Pardee (r).
Pike (rr), Pokegama (1) (s), Pokegama (2) (r). Poplar (rrr), St. Croix (r).
Sand (4) (rr), Sishebogema (rr).
In one case the alga was found upon Oocystis but in all others it was
inside the gelatinous envelope of Coelosphaerium Naegelianwn Unger.
When the alga grows upon Coelosphaerium the colony is apt to be in-
fested with 50-100 individuals as a rule. The alga was originally des-
cribed as a Chlamydomonas species but since the sessile phase is the
dominant one of the life cycle it is better placed as a Characium species.
Although found at only one station in Europe it is widely distributed
in northern Wisconsin.
Characium curvatum G. M. Smith. PI. 49, Figs. 8-15.
Trans. Wis. Acad. Sci., Arts, & Lett. 19^: 641, pi. 11, figs. 6-13. 1918.
Cells lunate or recurved, with acute or sub-acute apices. Stipe hya-
line, thick, tubular or conical, sometimes irregular in outline. Chloro-
])last single, parietal, laminate to cup-shaped; with or without a pyre-
noid. ( Euplanktont) .
Epiphytic upon Coelosphaerium Naegelianum Unger, Bictyosphaer-
ium pulchellum Wood, and Phaeococcus planet onicus W. & G. S. West.
Cells 3-6 /A broad, 8-18 p long (without stipe), 13-22 /a long with
stipe.
Bear (1) (rr), Birch (2) (cc). Chain (rr), Chetac (aa), Chetek (rr), Clam
(sss). East (rr), Horseshoe (1) (ss), Lindy (rr). Mud (1) (rr). South Crab
(ss). Wild Goose (rr).
An alga that resembles C. stipitatum in the manner of growth but
one which is found upon a wider range of genera. It also differs in the
curved cells and the broader stipe.
WISCONSIN PHYTOPLANKTON
177
Characium cylindricum Lambert. PI. 49, Pigs. 16-19.
Rhodora 11 : 70, pi. 79, figs. 1-2, 7-8, 10-13, 23-25. 1909.
Cells cylindrical, with rounded apices, base tapering slightly into a
short stipe without a basal disc. Chloroplasts 1-16, parietal, disciform
to laminate, without pyrenoids. (Euplanktont).
On Diaphanosoma hrachyura and Branchipus vernalis.
Cells 8-20 fjL broad, 20-430 /a long.
Howey (cc).
- The lack of a pyrenoid suggests Characiopsis but the bright green
color of the chloroplast shows that the alga is one of the Chlorophyceae
and so is placed among Cho/racium species. Young cells contain a sin-
gle chloroplast but with growth there is an increase in the number of
chloroplasts and all stages between cells with a single chloroplast and
those with sixteen may be found on the same crustacean. Lambert
holds that this condition is a stage in the division into zoospores but
in my opinion it is the normal condition of the adult cell. Another
point of interest is the position of the alga upon the host since it is
only found on the tail of the crustacean.
Characium limneticum Lemmermann. PI. 49, Figs. 25-29.
Bot. Not. 1903: 81, pi. 3, figs. 7-10. 1903.
Cells broadly fusiform, lunate, rarely straight; apex produced into
a single delicate hyaline seta ; base a delicate stipe without basal discs.
1-8 parietal band-shaped chloroplasts, each containing 1-2 pyrenoids.
(Euplanktont).
Cells 5-14 /A broad, 25-110 /a long ; stipe 5-10 /a long.
On Diaphanosoma hrachyura.
Boulder (rr). Browns (rr), Delavan (rrr).
Lemmermann describes the chloroplast as single but reports a divi-
sion of the chloroplast prior to division. I have found that in all nor-
mal adult cells of C. limneticum, C. gracilipes, and C. cylindricum there
is more than one chloroplast.
The species is very closely related to C. gracilipes but is much
smaller, proportionally broader, and has a simple stipe. It is very
probable that Raphidium longissimum var. septatum Chodat {Ankistro-
desmus longissimum var. septatum (Chodat) Brunnthaler) is a cell of
C. limneticum broken off from the crustacean during collection.
12
178
WISCONSIN PHYTOPLANKTON
Characium gracilipes Lambert. PI. 49 , Figs. 20 - 24 .
Rhodora 11: 65, pi. 79, figs. 3-6, 9, 14-22. 1909.
Cells straight or curved with the median portion fusiform; apex
tapering into a long seta and base attenuated to a filiform stipe. Chloro-
plast parietal, band-shaped, 1-32 per cell; with one pyrenoid in each
chloroplast. ( Euplanktont) .
On Diaphanosoma hrachyura.
Cells 5-14 /X broad, 70-480 /x long.
Howey (cc).
This alga was found on the same organism and at the same time as
C. cylindricum. It was confined to the forward appendages while
C. cylindricum was found at the tail only.
Order ULOTMCHALES.
Cells usually in a simple or branched thallus, rarely forming disci-
form thalli one cell in thickness. Thallus generally attached, rarely
free-floating; naked, or enclosed by a tough and leathery or copious
and gelatinous, homogeneous or lamellated envelope. Cells generally
with a single parietal laminate to cup-shaped chloroplast with one or
more pyrenoids. Cell shape usually cylindrical with flattened ends,
rarely cylindrical with rounded ends, spherical or cubical.
Asexual reproduction by vegetative cell division, by a division of
vegetative or special cells to form 2-16 bi- or tetraciliate zoospores, and
by aplanospores.
Sexual reproduction either isogamous by a division of ceU contents
to form bi- or tetraciliate zoogametes ; or heterogamous by the fusion of
tetraciliate zoogametes of different size or the union of large non-motile
oospheres and small biciliate antherozoids.
KEY TO THE FAMILIES.
Cells united to form simple filaments Ulotbjchaoeab
Cells united to form branching filaments.
Sexual reproduction by isogamoua zoogametes Chaetophoraceae
Sexual reproduction by heterogamous zoogametes Aphanochaetaceae
Family ULOTRICHACEAE.
Cells united to form simple free-floating or sessile filaments which
are enclosed at times by a copious, hyaline, homogeneous or radially
fibrillar, gelatinous envelope. Cell shape spherical to cylindrical with
rounded or flattened ends. Walls of cells delicate or thick, homogen-
WISCONSIN PHYTOPLANKTON
179
ecus or lamellated. Cells containing a nucleus and one parietal, lami-
nate or cup-shaped chloroplast with one or more pyrenoids.
Asexual reproduction by vegetative cell division, aplanospores or
biciliate zoospores.
Sexual reproduction isogamous, by a fusion of bi- or tetraciliate zoo-
gametes.
ULOTHRIX Kiitzing 1833.
Filaments simple, free-floating or with the basal cell modified to form
a hold-fast. Cells cylindrical, with flattened end walls, united to form
simple filaments that are the same diameter throughout. Wall of cells
delicate or thick, homogeneous or lamellated, without a gelatinous outer
layer. Chloroplast single, parietal, laminate, with one or more pyre-
noids. Cells uninucleate.
Asexual reproduction by the division of cell contents to form 1-32 .
aplanospores and bi- or tetraciliate zoospores.
Sexual reproduction isogamous, by a fusion of biciliate zoogametes.
KEY TO THE SPECIES.
Filaments 11-45 fi in diameter U. Zonata
Filaments 5-7 in diameter U. Subconsteicta
Ulothrix zonata (Weber & Mohr) Kiitzing. PL 50, Fig. 6.
Flora 16: 519. 1833; Hazen, Mem. Torr. Bot. Cl. 11: 147, pi. 20, figs. 1-4. 1902.
Filaments attached or free-floating and forming greenish masses.
Cells disciform to cylindrical, % to V/2 times as long as broad. End
walls of cells straight, side walls straiglit or slightly convex in older
cells. Chloroplast forming a broad or narrow pariccal annular girdle
containing several pyrenoids. Wall of cell thick, generally homo-
geneous but at times lamellated in structure. (Tychoplanktont).
Mature cells 11-45 p in diameter.
Mendota (rrr).
Ulothrix subconstricta G. S. West. PL 50, Figs. 4r-5.
Jour, of Bot. 53 : 82, figs. 6a-6c. 1915.
Filaments free-floating, narrow, slightly constricted at cross walls of
cells, with or without a homogeneous gelatinous envelope. Cells elon-
gate, 2-6 times as long as broad, slightly inflated at the poles. Chloro-
plast single, parietal, laminate, with irregular edges and occupying
the median two thirds of the cell. With or without 1-2 pyrenoids.
Cell wall very delicate. (Facultative Planktont).
180
WISCONSIN PHYTOPLANKTON
Cells 5.7-9 broad.
The specimens that I have found in our lakes differ somewhat from
those described by West since the cells are not slightly dilate at the
poles and the chloroplasts usually contain pyrenoids. The Wisconsin
organism does not seem sufficiently differentiated, however, to warrant
the description of a new variety or species. This alga is of particular
interest since it is the only one of the order which has become established
as a true member of the plankton.
Family CHAETOPHORACEAE,
Cells united to form branching filamentous, discoidal or parenchyma-
tous thalli. Branches of thallus generally attenuated at apices and
sometimes ending in long hair-like processes. Thallus naked or en-
closed in a copious, hyaline, homogeneous, gelatinous envelope. Cell
shape ordinarily cylindrical with flattened ends. Chloroplast single,
parietal and laminate to girdle-shaped; with one or more pyrenoids.
Nucleus single.
Asexual reproduction by aplanospores and bi- or tetraciliate zoo-
spores.
Sexual reproduction isogamous, by a fusion of biciliate zoogametes.
STIGEOCLONIUM Kiitzing 1843.
Thallus free-floating or attached, with branches scattered and not
arising in dense tufts. Thallus without an appreciable difference in
size between the main stem and minor branches ; covered with a homo-
geneous, hyaline, gelatinous envelope. Cells cylindrical to disciform,
gradually decreasing in diameter towards the apex and with terminal
cells conical or elongated to hair-like unseptate processes. Chloroplast
single, parietal ; gridle-shaped and filling median portion of older cells ;
completely filling younger cells. Each chloroplast generally containing
several pyrenoids.
Asexual reproduction by aplanospores and tetraciliate zoospores.
Sexual reproduction isogamous, by the fusion of biciliate zoogametes.
Stigeoclonium lubricum (Dillwyn) Kiitzing. PI. 50, Fig. 7.
Phycol. germ. 189. 1845.
Myxonema liTbricum (Dillw.) Fries. Hazen, Mem. Torr. Bot. Cl. 11 : 195,
p/. 28, Ms. 1-2. 1902.
Filaments forming dark green tufts up to 30 cm. long. Filaments
much branched and branches usually opposite, rarely single. Cells of
main filament at base of branches sub-spherical, shorter than other cells.
WISCONSIN PHYTOPLANKTON
181
Branehlets abundant, opposite, scattered in basal portion, dense in dis-
tal, only slightly narrower than the branch from which they arise and
with terminal cell conical or setiferous. Lower cells of main branch
swollen, %-4 times as long as broad, with a girdle-like chloroplast in
median portion. (Tychoplanktont).
Main branches 14-16.5 fx broad; branehlets 6-7 fx broad.
Mendota (rrr), Wild Goose (rrr).
Family APHANOCHAETACEAE.
Thallus epiphytic, generally upon other algae, creeping in habit and
composed of simple or irregularly branching filaments that taper from
the center to short, narrow terminal cells that do not end in terminal
setae. Central cells of filament spherical to spherical-cylindrical ; those
towards the end cylindrical with straight or convex sides; terminal
cells conical. Cells generally bearing one or more long, hyaline, un-
septate setae with swollen bases. Chloropast parietal, completely fill-
ing the cell, or gridle-like and in the median portion; generally with
more than one pyrenoid.
Asexual reproduction by tetraciliate zoospores or aplanospores.
Sexual reproduction heterogamous, by the fusion of tetraciliate zoo-
gametes that are markedly different in size.
The family contains the single genus Aphanochaete whose characters
are those of the family.
Aphanochaete vermiculoides WoUe. PI. 50, Fig. 8.
Freshw. algae of U. S. 119, pi. 105, figs. 9-10. 1887.
Herposteiron hyalothecae Hansgirg, G. M. Smitli, Trans. Wis. Acad. Sci.,
Arts, & Lett. 18^: 560. 1916.
Filaments but slightly branched and confined to the peripheral por-
tion and twisted around or arched from the gelatinous envelope of
liyalotJieca filaments. Cells cylindrical, with straight or convex sides
and containing a single chloroplast with 1-A pyrenoids. Setae very
sparse, rarely more than five on any filament. (Tychoplanktont).
Cells 4^6 [I broad ; 5-12 p, long.
Beaverdam (rr).
All other species of the genus grow directly upon the cells of the
substratum but the wide gelatinous envelope of the Hyalotheca is in
this case sufficiently firm to support the Aphanochaete. The alga has
the appearance of an arching worm crawling along the filament.
182
WISCONSIN PHYTOPLANKTON
Order SIPHONOCLADIALES.
Cells multinucleate, generally cylindrical and united to form simple
or branched thalli that are, at times, quite complicated in structure.
Chloroplasts disciform, parietal and numerous, or united by strands
to form a single reticulate structure. Pyrenoids generally present.
Asexual reproduction by zoospores and aplanospores.
Sexual reproduction isogamous by means of zoogametes; or heter-
ogamous by large non-motile oospheres and small motile antherozoids.
The order is largely marine and only one representative, CladopJim'a,
has been found in the plankton.
Family CLADOPHORACEAE.
Filaments generally sessile, simple or branched, with septations be-
tween the cells complete. Walls of cells generally heavy, homogeneous
or lamellose, without a gelatinous envelope. Cells with numerous
parietal disciform chloroplasts or a single reticulate chloroplast ; multi-
nucleate ; with a single large central vacuole.
Asexual reproduction by zoospores and akinetes.
Sexual reproduction isogamous, by means of zoogametes.
CLADOPHORA Kiitzing 1843.
Filaments branched, with the component cells in a single linear series ;
lateral branches arising at distal part of main branch cells and gener-
ally with an abundantly developed system of branching. Growth of
filaments confined to the apical region. Cells cylindrical, several times
as long as broad; multinucleate; with numerous parietal disciform
chloroplasts or the chloroplasts united by processes to form a single
reticulate chloroplast; pyrenoids numerous.
Asexual reproduction by the formation of many biciliate zoospores in
any cell of the filament.
Sexual reproduction isogamous, by means of biciliate zoogametes.
Cladophora glomerata (L.) Kiitzing. PI. 50, Figs. 1-3.
Phycol. gener. 266. 1843; Collins, Tufts Coll. Studies 2: 350, pi. 13, fig- 124.
1909.
Branching of filaments fairly dense in lower portion and very dense
at the apex. Ultimate branchlets containing several cells, straight or
slightly incurved, with ends rounded but not markedly attenuated.
Cells of main branches 6-7 times as long as broad, 3-6 times as broad
WISCONSIN PHYTOPLANKTON
183
as branchlets. Zoospore formation confined to terminal and subtermi-
nal cells. (Tychoplanktont).
Diam. main cells 75-100 />t, branchlets 35-50 fi.
Mendota (rr).
Division AKONTAE.
Cells solitary or in filaments, variously shaped, with one or more
grass-green chloroplasts that usually contain more than one pyrenoid.
Asexual reproduction ordinarily by vegetative cell division, rarely by
aplanospores, never by zoospores.
Sexual reproduetion isogamous, always by aplanogametes, never by
ciliate zoogametes.
The lack of cilia in every type of reproduction is the great character-
istic of the division. It includes but one order, the Conjugates, which
forms a very homogeneous though diverse group.
Order CONJUGALES.
Cells solitary or in simple filaments; cell shape various, cylindrical
without median constrictions or bilaterally symmetrical and usually
with a median constriction dividing the cell into two symmetrical halves.
Cell wall smooth or variously ornamented, with an inner firm portion
and an outer gelatinous portion that is very copious at times. Chloro-
plasts 1-8, variously shaped, axial or parietal, with one to several pyre-
noids. Nucleus single, at the center of the cell.
Asexual reproduction by vegetative cell division or aplanospores.
Sexual reproduction isogamous, by aplanogametes.
KEY TO THE FAMILIES.
Cells cylindrical, without a median constriction, united to
form simple filaments Zygnemaceae
Cells solitary or in filaments, divided into two symmetri-
cal halves, generally with a median constriction Desmidiaceae
(See Fart II)
Family ZYGNEMACEAE.
Cells always cylindrical, with ends flattened or replicate, serially
arranged to form simple filaments that occasionally have simple lateral
outgrowths. Filaments generally free-floating though at times attached
by a modification of terminal cell into a basal cell with short rhizoidal
processes. Wall of cell firm, homogeneous, with a narrow or copious,
homogeneous or radially fibrillar, gelatinous covering. Cell contents
consisting of a single nucleus, and one to several chloroplasts that are
184
WISCONSIN PHYTOPLANKTON
either stellate or laminate and axial or parietal. Chloroplasts with one
to many pyrenoids.
Asexual reproduction by vegetative cell division or metamorphosis
of cell contents into a single large aplanospore.
Sexual reproduction isogamous, by metamorphosis of all or a part
of the cell contents into an aplanogamete which fuses with an aplano-
gamete from the same or another filament. Zygote with 2-3 layers,
sometimes germinating immediately but usually after a period of rest.
KEY TO THE GENERA.
Chloroplast stellate Zygnema
Chloroplast a longitudinal band.
Chloroplast axial Mougeotia
Chloroplast parietal Spieogyea
MOUGEOTIA C. A. Agardh 1824.
Cells cylindrical, generally several times as long as broad. Chloro-
plast single, forming an axial plate extending the whole length of the
cell and generally with several pyrenoids.
Conjugation generally scalariform and with the zygote formed in the
conjugation tube. Zygote at times occupying the median portion of
male and female gametangia as well as conjugation tube. Wall of
zygote of two layers the inner smooth, the outer smooth or sculptured,
hyaline or colored.
Mougeotia viridis (Kutzing) Wittrock. PI. 51, Fig. 1.
Bih. Kgl. Sv. Vet.-Ak. Handl. 1 , No. 1 : 39. 1872.
Staurospermum viride Kutzing. Cooke, Brit. Freshw. Algae 107, pi. 44,
figs. 2a-2c. 1882.
Cells 4-10 times as long as broad. Zygospores normally bounded by
four cells, quadrangular, with concave sides and truncate corners.
( Tychoplanktont) .
Cells 6-8 fi broad. Zygotes 22-32 p, broad.
Okauchee (rrr).
ZYGNEMA C. A. Agardh 1817.
Cells cylindrical, rarely more than twice as broad as long. Filaments
with a terminal cell at times modified to form a holdfast. Cells with
one nucleus and two axial stellate chloroplasts each of which contain
a single pyrenoid. Conjugation lateral or scalariform, with a forma-
tion of zygospores in the conjugation tube or the gametangia. Zygotes
ipherical to ellipsoid, wall with three layers.
WISCONSIN PHYTOPLANKTON
185
Zygnema pectinatum (Vauclier) C. A. Agardh. PI. 51, Fig. 2.
Synop. algarum Scand. 102. 1817; DeBary, Unters. u. d. Fam. d. Conjugaten.
77, pi, 1, figs. 15-19. 1858.
Vegetative cells 1-3 times as broad as long. Zygospore formed in
conjugation tube, with rounded ends. Middle layer of zygote wall
brown and scrobiculate. (Tychoplanktont).
Vegetative cells 30-40 fi broad. Zygote 35-40 fx broad.
Oconomowoc (rrr).
SPIROGYRA Link 1820.
Cells cylindrical, with end walls a flat plane or replicate; united to
form simple filaments that may be attached by a modification of the
terminal cell into holdfasts. Length of cells slightly greater than to
several times the breadth. Chloroplasts one to several, parietal, in
long ribbons that extend from end to end in the cell and generally
make several spiral turns. Nucleus single, moored in the center of the
central vacuole by cytoplasmic strands running to the pyrenoids. Chlor-
oplasts wdth several pyrenoids that are generally in a single median row.
Conjugation scalariform or lateral, with zygote formation in game-
tangia and never in the tube. Zygote spherical, ellipsoid, or cylindri-
cal with rounded ends. Middle layer of zygote hyaline or colored,
smC'Oth or sculptured.
Spirogyra porticalis (Muller) Cleve. PI. 51, Fig. 3.
Nova Acta Reg. Soc. Sci. Upsaliensis 3, Ser., 6: No. 11, 22, pi. 5, figs. 8-13.
1868.
Length of vegetative cells 2-6 times the breadth. Cells with plane
cross walls and containing a single chloroplast that makes 3-5 turns and
contains numerous conspicuous pyrenoids. Gametangia but little swol-
len when zygospore is mature. Zygospores broadly ovoid to sub-cylin-
drical, with a yellow membrane when mature. (Tychoplanktont).
Diam. cells 30-50 fi. Diam. zygospores 40-50 fx.
Mendota (rrr).
1S6
WISCONSIN PHYTOPLANKTON
PLATE 1.
Page
Fig. 1. Chroococcus minutus (x 825) 28
Fig. 2. Chroococcus dispersus (x 825) 28
Fig. 3. Chroococcus dispersus var. minor (x 825) 28
Fig. 4. Chroococcus limneticus (x 825) 29
Fig. 5. Chroococcus limneticus var. suhsalsus (x 825) 29
Fig. 6. Chroococcus limneticus var. carneus (x 825) 30
Fig. 7. Chroococcus limneticus var. distans (x 825) 30
Fig. 8. Chroococcus limneticus var. elegans (x *825) 30
Fig. 9. Chroococcus turgidus (x 1000) 31
WISCONSIN SURVEY
BULLETIN 57, PLATE 1
SMITH — ALGAE
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WISCONSIN SURVEY
BULLETIN 57, PLATE 2
1
0000 OB 00
OOQO OQ OQ
0000 00 00
OGOQ 00 i©
onno On nn
Q ©o© (f
SMITH— ALGAE
COCKAVNC, BOSTON
WISCONSIN PHYTOPLANKTON
187
PLATE 2.
Page
Fig. 1. CUroococcus giganteus (x 825) 30
Fig. 2. Merismopedia tenuissima (x 1000) 33
Fig. 3. Merismopedia punctata (x 1000) 33
Fig. 4. Merismopedia glauca (x 1000) 32
Fig. 5. Merismopedia elegans (x 1000) 32
Fig. 6. Merismopedia elegans var. major (x 1000) 32
Fig. 7. Aphanocapsa delicatissima (x 1000) 41
Fig. 8. Aphanocapsa elachista var. conferta. (x 1000) 42
Fig. 9. Aphanocapsa pulchra (x 825) 42
Fig. 10. Aphanocapsa endophytica (x 1000) 42
188
WISCONSIN PHYTOPLANKTON
PLATE 3.
Page
Fig. 1. Aphanocapsa Grevillei (x 825) 43
Pig. 2. Aphanocapsa rivularis (x 825) 43
Fig. 3. Aphanocapsa elachista var. planctonica (x 1000) 42
Pigs. 4-5. Coelosphaerium Kuetzingianum (x 825) 34
Fig. 6. Coelosphaerium Naegelianum (x 825) 35
Fig. 7. Coelosphaerium duhium (x 825) 35
WISCONSIN SURVEY
BULLETIN 57, PLATE 3
COCKAYNE. BOSTON
WISCONSIN SURVEY
BULLETIN 57, PLATE 4
SMITH — ALGAE
WISCONSIN PHYTOPLANKTON
189
PLATE 4.
Page
Fig. 1. Coelosphaerium Naegelianum (x 825) 35
Figs, 2-3. Gomphosphaeria aponina (x 825) 37
Fig. 4. Gomphosphaeria aponina var. cordiformis (x 825) 37
Fig. 5. Gomphosphaeria lacustris (x 825) 36
Fig. 6. Microcystis aeruginosa var. 'major (x 825) 40
190
WISCONSIN PHYTOPLANKTON
PLATE 5.
Page
Figs. 1-2. Microcystis aeruginosa (Pig. 1, x 825; fig. 2, x 180 39
Fig. 3. Microcystis fios-aquae (x 825) 39
Fig. 4. Microcystis incerta (x 825) 40
Fig. 5. ApTianothece prasina (x 825) 45
Fig. 6. Aphanothece nidulans var. endophytica (x 1000) 44
WISCONSIN SURVEY
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WISCONSIN SURVEY
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I
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WTBOONBIN PHYTOPLANKTON 191
PLATE 6.
Page
Fig. 1. Aphanothece nidulans (x 1000) 44
Fig. 2. Aphanothece stagnina (x 825) 45
Fig. 3. Aphanothece clathrata (x 1000) 44
Fig. 4. Rhahdoderma linear e (x 1000) 47
Fig. 5. Gloeothece linearis (x 1000) 46
Fig. 6. Gloeothece linearis var. composita (x 1000) v 46
Fig. 7. Dactylococcopsis raphidioides (x 825) 47
Figs. 8-10. Dactylococcopsis acicularis (x 1000) 48
192
WISCONSIN PHYTOPLANKTON
PLATE 7.
Page
Fig. 1. SpiruUna major (x 1000) 50
Fig. 2. SpiruUna princeps (x 1000) 50
Figs. 3-5. Oscillatoria proUfica (x 825) 51
Fig. 6. Oscillatoria tenuis (x 825) 52
Figs. 7-8. Oscillatoria tenuis var. tergestina (x 825) 52
Figs. 9-11. Lyngbya limnetica (x 1000) 52
Figs. 12-13. Lyngdya contorta (x 1000) 53
Figs. 14-15. Lyngdya Birgei (x 825) 54
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WISCONSIN SURVEY
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WISCONSIN PHYTOPLANKTON
193
PLATE 8.
Fig. 1. Trichodesmium lacustre (x 1000)
Fig. 2. Anahaena plantonica (x 825)
Fig. 3. Anahaena Bornetiana (x 825)
Figs. 4-5. Anahaena Levanderi (x 825)
Fig. 6. Anahaena macrospora var. rohusta (x 825) .
Fig. 7. Anahaena a3'^is (x 825)
Fig. 8. Anahaena limnetica (x 825)
Figs. 9-10. Anahaena augstumalis var. marcMca (x 825)
13
Page
54
56
58
58
57
57
57
58
194
WISCONSIN PHYTOPLANKTON
PLATE 9.
Page
Figs. l-i3. Anahaena spiroides var. crassa (Pig. 1, x 825, figs. 2~3, x 400) 59
Figs. 4-5. Anahaena circinalis (Fig. 4, x 825, fig. 5, x 400) 59
Fig. 6. Anahaena circinalis var. mao'ospora (x 825) 60
SMITH— ALGAE
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WISCONSIN PHYTOPLANKTON
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PJLATE 10.
Page
Fig. 1. Anabaena circinalis var. macrospora (x 400) 60
Figs. 2-4. Anabaena flos-aquae (Figs. 2-3, x 825; fig. 4, x 400) 60
Figs. 5-7. Anabaena fios-aquae var. Treleasii (x 825) 60
Fig. 8. Anabaena Lemmermanni (x 825) 61
196
WISCONSIN PHYTOPLANKTON
PLATE 11.
Page
Fig. 1. Anahaena Lemmermanni (x 400) 61
Figs. 2-4. Aphanizomenon flos-aquae (Fig. 2, x 400; figs. 3-4, x 1000).. 61
Figs. 5-6. OloeotricMa ecTiinulata (x 400) 63
WISCONSIN SURVEY
BULLETIN 57, PLATE 11
SMITH — ALGAE
COCKAYNE, BOSTON
WISCONSIN SURVEY
BULLETIN 57, PLATE 12
SMITH — ALGAE
COCKAYNE. BOSTON
WISCONSIN PHYTOPLANKTON 197
PLATE 12.
Page
Fig. 1. ChrysamoeM radians (x 1000) 67
Pig. 2. Mallomonas producta (x 500) 68
Fig. 3. Mallomonas producta var. marchica (x 500) 68
Fig. 4. Mallomonas alpina (x 500) 68
Fig. 5. Mallomonas tonsurata (x 500) 68
Fig. 6. Mallomonas caudata (x 500) 69
Pigs. 7-8. Chrysosphaerella longispina (Fig. 7, x 400; fig. 8, x 1000).. 69
Pigs. 9-10. Synura uvella (Pig. 9, x 1000, fig. 10, x 400) 70
198
WISCONSIN PHYTOPLANKTON
PLATE 13.
Page
Figs. 1-4. Uroglenopsis americana (Fig. 1, x 400; figs. 2-4, x 1000) .... 71
Figs. 5-6. Dinohryon caldformis (x 1000) 73
Figs. 7-9. DinoJ)ry on tabellariae (x 1000) 73
Fig. 10. Dinolryon davaricum (x 400) 73
Fig. 11. Dinohryon stipitatum (x 400) 74
Fig. 12. Dinohryon sociale (x 400) 74
Fig. 13. Dinohryon setularia (x 400) 74
WISCONSIN SURVEY
BULLETIN 57. PLATE 13
WISCONSIN SURVEY
BULLETIN 57, PLATE 14
SMITH — ALGAE
COCKAYNE, BOSTON
WISCONSIN PHYTOPLANKTON 199
PLATE 14.
Page
Pig. 1. DinoJ)ryon setularia (x 400) 74
Fig. 2. Dinobryon divergens (x 400) 75
Figs. 3-4. Hyalobryon mucicola (x 1000) 75
Pig. 5. Phaeococcus plantonicus (x 1000) 76
Fig. 6. Rhizochrysis limnetica (x 400) 77
Figs. 7-8. Chrysidiastrum catenulatum (Fig. 7, x 500, fig. 8, x 1000)... 78
200
WISCONSIN PHYTOPLANKTON
PLATE 15.
Page
Pigs. 1-3. Chlorochromonas minuta (x 1000) 80
Fig. 4. Peroniella planctonica (x 1000) 81
Fig. 5. Botryococcus Braunii (x 400) 84
Figs. 6-7. Botryococcus protuberans var. minor (Fig. 6 x 500, fig. 7 x
1000) 85
Fig. 8. Botryococcus sudeticus (x 400) 83
Fig. 9. Chlorobotrys limneticus (x 1000) 82
Fig. 10. Chlorolotrys regularis (x 1000) 82
Fig. 11. Ophiocytium parvulum (x 1000) 86
Figs. 12-13. Ophiocytium capitatum (x 1000) 86
Figs. 14-16. Ophiocytium capitatum var. longispinum (x 1000) 86
Figs. 17-18. Trihonema minus (x 1000) 87
WISCONSIN SURVEY
BULLETIN 57, PLATE 15
SMITH — ALGAE
COCKAYNE, BOSTON
WISCONSIN SURVEY
BULLETIN 57, PLATE 16
SMITH — ALGAE
COCKAVNC, BOSTON
WISCONSIN PHYTOPLANKTON
201
PLATE 16.
Page
Fig. 1. Carteria cordiformis (x 1000) 92
Figs. 2-4. Carteria Elehsii (x 1000) 93
Figs. 5-7. Chlamydomonas dinohryoni (x 1000) 91
Pig. 8. Chlamydomonas glohosa (x 1000) 90
Figs. 9-10. Chlamydomonas Snowii (x 1000) 91
Figs. 11-13. Chlamydomonas epiphytica (x 1000) - 91
Figs. 14-15. Gonium pectorale (x 500) 94
Figs. 16-17. Pandorina morum (x 400) 95
202
WISCONSIN PHYTOPLANKTON
PLATE 17.
Figs. 1-3. Pleodorina calif ornica (x 400) ,
Page
97
WISCONSIN SURVEY
BULLETIN 57. PLATE 17
SMITH — ALGAE
COCKAYNE. BOSTON
WISCONSIN SURVEY
BULLETIN 57, PLATE 18
H ^-#1^
W<>W
WWi
/q 0
J© K9
a ® ® ®
J Q 0 ■ © ® ®-
„ _,_. JV ®
<d-y9r
V ^ ® 7®
4>rt '■■■©
SMITH— ALGAE
COCKAYNK, BOSTON
WISCONSIN PHYTOPLANKTON
203
PLATE 18.
Page
Pig. 1. Yolvox mononae (x 266) 99
Fig. 2. Yolvox aureus (x 266) 98
Figs. 3-5. Yolvox fflodator (x 266) 98
204
WISCONSIN PHYTOPLANKTON
PLATE 19.
Page
Pig. 1. Eudorina elegans (x 500) 96
Fig. 2. Gloeocystis gigas (x 1000) 101
Figs. 3-4. Sphaerocystis Schroeteri (x 1000) 101
Figs. 5-6. Tetraspora lacustris (x 500) 102
WISCONSIN SURVEY
BULLETIN 57, PLATE 19
SMITH-
:0>~K N E , BOSTOM
WtSCONSIN SURVEY
BULLETIN 57. PLATE 20
SMITH— ALGAE
COCKAYNE. BOSTON
WISCONSIN PHYTOPLANKTON
205
PLATE 20.
Page
Figs. 1-2. Oloeocystopsis Umneticus (x 1000) 103
Figs. 3-6. Planktosphaeria gelatinosa (x 1000) 103
Pigs. 7-10. Asterococcus Umneticus (Fig. 7, x 500; figs. 8-10, x 1000) . 104
Figs. 11-12. DictyospJiaerium Ehrenhergianum (x 1000) 105
Fig. 13. Dictyosphaerium pulcTiellum (x 1000) 105
206
WISCONSIN PHYTOPLANKTON
PLATE 21.
Page
Fig. 1. Dictyosphaerium pulchellum (x 1000) 105
Figs. 2-3. Westella linearis (x 1000) 107
Fig. 4. Westella hotryoides (x 1000) 107
Fig. 5. Dimorpiiococcus lunatus (x 1000) 106
WISCONSIN SURVEY
BULLETIN 57, PLATE 21
SMITH — ALGAE
COCKAYNE. BOSTON
WISCONSIN SURVEY
BULLETIN 57, PLATE 22
SMITH— ALGAE
COCKAYNE, BOSTON
WISCONSIN PHYTOPLANKTON
207
PLATE 22.
Page
Fig. 1. Chlorella vutff.aris (x 1000) 108
Fig. 2. Trochiscia reticularis (x 1000) 109
Fig. 3. Oocystis pusilla (x 1000) Ill
Fig. 4. Oocystis Borgei (x 1000) Ill
Fig. 5. Oocystis clliptica (x 1000) Ill
Fig. 6. Oocystis parva (x 1000) 112
Fig. 7. Oocystis gloeocystijormis (x 1000) 112
Figs. 8-9. Oocystis lacustris (x 1000) 112
Fig. 10. Oocystis sulymarina (x 1000) 113
Fig. 11. Oocystis solitaria (x 1000) 113
Figs. 12-13. Oocystis crassa (x 1000) 113
208
WISCONSIN PHYTOPLANKTON
PLATE 23.
Page
Pigs. 1-2. Oocystis eremosphaeria (x 1000) 113
Fig. 3. OoXyystis panduriformis var. minor (x 1000) 114
Figs. 4-5. Oocystis natans var. major (Fig. 4, x 500; fig. 5, x 1000).. 114
Figs. 6-7. NepTirocytium Agardhianum (x 1000) 114
Figs. 8-9. Oloeotaenium Loitleshergerianum (x 400) 115
Pigs. 10-13. Tetraedron muticum var. punctulatum (x 1000) 116
Figs. 14-16. Tetraedron trigonum (x 1000) 116
WISCONSIN SURVEY
BULLETIN 57, PLATE 23
SMITH — ALGAE
COCKAYNE, BOSTON
WISCONSIN SURVEY
BULLETIN 57, PLATE 24
SMITH — ALGAE
COCKAYNE. BOSTON
WISCONSIN PHYTOPLANKTON 209
PLATE 24.
Page
Figs. 1-4. Tetraedron trigonum var. setigerum (x 1000) 117
Figs. 5-9. Tetraedron trigonum var. gracile (x 1000) 117
Pigs. 10-13. Tetraedron yninimum (x 1000) 118
Fig. 14. Tetraedron regular e (x 1000) 118
Figs. 15-16. Tetraedron regulare var. incus (x 1000) L18
Pigs. 17-18. Tetraedron regulare var. torsum (x 1000) 119
Figs. 19-22.. Tetraedron victorieae var. major (x 1000) 119
14
210
WISCONSIN PHYTOPLANKTON
PLATE 25.
Page
Fig. 1. Tetraedron victorieae var. major (x 1000) 119
Figs. ;2-3. Tetraedron verrucosum (x 1000) 119
Figs. 4-7. TetraMron caudatum (x 1000) 120
Figs. 8-12. Tetraedron eaudatum var. longispinum (x 1000) 120
Figs. 13-17. Tetraedron pentaMrieum (x 1000) 120
Fig. 1^. TetraMron hastatum (x 1000) 121
Figs. 19-21. Tetraedron hastatum var. palatinum (x 1000) 121
Figs. 22-24. Tetraedron constrictum (x 1000) 122
WISCONSIN SURVEY
BULLETIN 57, PLATE 25
SMITH — ALGAE
COCKAYNE
BOSTON
WISCONSIN SURVEY
BULLETIN 57, PLATE 26
SMITH — ALGAE
COCKAYNE. BOSTON
WISCONSIN PHYTOPLANKTON 211
PLATE 26.
Page
Figs. 1-5. TetraMron gracile (x 1000) 122
Figs. 6-7. Tetraedron lohulatum (x 1000) 122
Pig. 8. Tetraedron lolulatum var. polyfurcatum (x 1000) 123
212
WISCONSIN PHYTOPLANKTON
PLATE 27.
Page
Figs. 1-3. Tetraedron limneticum (x 1000) 123
Figs. 4-5. Tetraedron planctonicum (x 1000) 123
Fig. 6. Tetraedron enorme (x 1000) 124
Figs. 7-8. Polyedriopsis spinulosa (x 1000) 124
WISCONSIN SURVEY
BULLETIN 57. PLATE 27
SMITH — ALGAE
COCKAYNE, BOSTON
WISCONSIN SURVEY
BULLETIN 57, PLATE 28
SMITH— ALGAE
COCKAYNE. BOSTON
WISCONSIN PHYTOPLANKTON
213
PLATE 28.
Page
Figs. 1-3. Micractinium pusillum (x 1000) 125
Fig. 4. Micractinium quadrisetum (x 1000) 126
214
WI8G0N8IN PHYTOPLANKTOIi^
PLATS 29.
Page
Fig. 1. Micractinium pusillum var. elegans (x 1000) 126
Figs. 2-3. Golenkinia radiata (x 1000) 127
Figs. 4-5. Golenkinia paucispina (x 1000) 127
Figs. 6-8. Acanthosphaera Zachariasi (x 1000) 128
Figs. 9-11. E Chino spTiaerella limnetica (x 1000) 128
WISCONSIN SURVEY
BULLETIN 57, PLATE 29
SMITH — ALGAE
WISCONSIN SURVEY
BULLETIN 57, PLATE 30
SMITH — ALGAE
COCKAYNE. BOSTON
WISCONSIN PHYTOPLANKTON
215
PLATE 30.
Page
Figs. 1-2. Lagerheimia citriformis (x 1000) 130
Figs. 3-4. Lagerheimia suhsala (x 1000) 130
Figs. 5-7. Lagerheimia Droescheri (x 1000) 131
Figs. 8-9. Lagerheimia longiseta (x 1000) 130
Figs. 10-12. Lagerheimia longiseta var. major (x 1000) 130
216
WISCONSIN PHYTOPLANKTON
PLATE 31.
Page
Figs. 1-2. Lagerheimia ciliata (x 1000) 129
Fig. 3. Lagerheimia ciliata var. minor (x 1000) 129
Fig. 4. Franceia ovalis (x 1000) 131
Fig. 5. Selenastrum gracile (x 1000) 133
Figs. 6-7. Selenastrum Bihraianum (x 1000) 133
Figs. 8-10. Selenastrum Westii (x 1000) 133
WISCONSIN SURVEY
BULLETIN 57, PLATE 3!
SMITH — ALGAE
COCKAYNE, BOSTON
WISCONSIN SURVEY
BULLETIN 57, PLATE 32
COCKAYNE, BOSTON
WISCONSIN PHYTOPLANKTON
217
PLATE 32.
Page
Fig. 1. Ankistrodesmus falcatus (x 1000) 134
Fig. 2. Ankistrodesmus falcatus var. tumidus (x 1000) 135
Figs. 3-5. Ankistrodesmus falcatus var. miraMlis (x 1000) 135
Figs. 6-7. Ankistrodesmus spiralis i(x 1000) 135
Fig. 3. Closteriopsis longissima var. tropica (x 400) 136
Figs. 9-11. Schroederia Judayi (x 1000) 137
Fig. 12. Schroederia setigera (x 1000) 137
218
WISCONSIN PHYTOPLANKTON
PLATE 33.
Page
Figs. 1-2. Quadrigula Pfitzeri (x 1000) 138
Fig. 3. Quadrigula Chodati (x 1000) 138
Figs. 4-6. Quadrigula lacustris (Fig. 4, x 500; figs. 5-6, x 1000) 139
Fig. 7. Elaktothrix viridis (x 825) 140
WISCONSIN SURVEY
BULLETIN 57. PLATE 33
SMITH— ALGAE
COCKAYNE. BOSTON
WISCONSIN SURVEY
BULLETIN 57, PLATE 34
SMITH — ALGAE
COCKAVNC. BOSTON
WISCONSIN PHYTOPLANKTON
219
PLATE 34.
Page
Figs. 1-3. Elaktothrix gelatinosa (Figs. 1-2, x 500; fig. 3, x 1000) 139
Fig. 4. Kirchneriella lunaris (x 1000) 141
Fig. 5. Kirchneriella lunaris var. dianae (x 100 141
220
WISCONSIN PHYTOPLANKTON
PLATE 35.
Fig- 1. Kirchneriella lunaris var. irregularis (x 1000)
Figs. 2-3. Kirchneriella ohesa (x 1000)
Fig. 4. Kirchneriella ohesa var. major (x 1000)
Figs. 5-6. Kirchneriella ohesa var. aperta (x 1000)
Fig. 7. Kirchneriella contorta (x 1000)
Page
142
142
142
143
143
WISCONSIN SURVEY
BULLETIN 57, PLATE 35
SMITH — ALGAE
COCKAYNE. BOSTON
WISCONSIN SURVEY
BULLETIN 57, PLATE 36
SMITH — ALGAE
COCKAVNE. BOSTOf^
WISCONSIN PHYTOPLANKTON
221
PLATE 36.
Page
PMgs. 1-2. Kirchneriella elongata (x 1000) 143
Pig. 3. Crucigenia rectangularis (x 1000) 144
Figs. 4-5. Crucigenia irregularis (x 1000) 145
Fig. 6. Crucigenia crucifera (x 1000) 145
Figs. 7-9. Crucigenia truncata (x 1000) 146
Figs. 10-14. Crucigenia quadrata (x 1000) 147
222
WISCONSIN PHYTOPLANKTON
PLATE 37.
Page
Fig. 1. Crucigenia apiculata (x 1000) 146
Fig. 2. Crucigenia tetrap'-ciia (x 1000) 147
Pig. 3. Crucigenia fenstrata (x 1000) 148
Fig. 4. Crucigenia Lauterhornei (x 1000) 148
Pigs. 5-6. Tetrastrum staurogeniaeforme (x 1000) 149
Figs. 7-11. Tetradesmus wisconsinensis (x 1000) 150
Figs. 12-14. Scenedesmus oMiquus (x 1000) 151
Figs. 15-17. Scenedesmus dimorphus (x 1000) 151
Figs. 18-20. Scenedesmus Hjuga (x 1000) 152
WISCONSIN SURVEY
BULLETIN 57, PLATE 37
SMITH— ALGAE
COCKAYNE. BOSTOl
WISCONSIN SURVEY
BULLETIN 57, PLATE 38
SMITH — ALGAE
COCKAYNE, BOSTON
WISCONSIN PHYTOPLANKTON 223
PLATE 38.
Page
Figs. 1-4. Scenedesmus acuminatus (x 1000) 152
Figs. 5-9. Scenedesmus Bernardii (x 1000) 152
Figs. 10-11. Scenedesmus Mjuga var. alternans (x 1000) 153
Figs. 12-14. Scenedesmus arcuatus (x 1000) 153
Figs. 15-16. Scenedesmus arcuatus var. capitatus (x 1000) 153
224
WISCONSIN PHYTOPLANKTON
PLATE 39.
Page
Figs. 1-3. Scenedesmus arcuatus var. platydisca (x 1000) 154
Figs. 4-6. Scenedesmus acutiformis (x 1000) 154
Figs. 7-10. Scenedesmus armatus (x 1000) 154
Fig. 11. Scenedesmus armatus var. major (x 1000) 155
Figs. 12-14. Scenedesmus hrasiliensis (x 1000) 155
Figs. 15-16. Scenedesmus Tiystrix (x 1000) 155
Figs. 17-19. Scenedesmus denticulatus (x 1000) 155
Figs. 20-22. Scenedesmus longus (x 1000) 156
Figs. 23-25. Scenedesmus ahundans (x 1000) 157
Figs. 26-27. Scenedesmus ahundans var. longicauda (x 1000) 157
WISCONSIN SURVEY
BULLETIN 57. PLATE 39
SMITH — ALGAE
COCKAYNE. BOSTON
WISCONSIN SURVEY
BULLETIN 57. PLATE 40
COCKAYNE, OOSTOi
-WISCONSIN PHYTOPLANKTON
225
PLATE 40.
Page
Pigs. 1-2. Scenedesmus longus var. Naegelii (x 1000) 156
Figs. 3-5. Scenedesmus ahundans var. hrevicauda (x 1000) 157
Figs. 6-8. Scenedesmus ahundans var. asymmetrica (x 1000) 157
Figs. 9-11. Scenedesmus quadricauda (x 1000) 158
Figs. 12-14. Scenedesmus quadricauda var. longispina (x 1000) 159
Figs. 15-16. Scenedesmus quadricauda var. quadrispina (x 1000) 158
Fig. 17. Scenedesmus quadricauda var. parvus (x 1000) 158
15
226
WISCONSIN PITYTOPLANKTON
PLATE 41.
Page
Figs. 1-2. Scenedesmus quadricauda var. maximus (x 1000) 159
Figs. 3-7. Scenedesmus quadricauda var. Westii (x 1000) 159
Figs. 8-11. Scenedesmus opoliensis (x 1000) 159
Figs. 12-13. Coelastrum microporum (x 825) 160
WISCONSIN SURVEY
BULLETIN 57. PLATE 41
SMITH — ALGAE
COCKAYNE. BOSTON
WISCONSIN SURVEY
BULLETIN 57. PLATE 42
SMITH — ALGAE
COCKAVNC, BOSTON
WISCONSIN PHYTOPLANKTON
227
PLATE 42.
Page
Fig. 1. Coelastrum microporum (x 825) 160
Figs. 2-3. Coelastrum camT)ricum (x 825) 161
Figs. 4-6. Coelastrum reticulatum (x 825) 161
Figs. 7-8. Coelastrum prohoscideum (x 825) 162
228
WISCONSIN PHYTOPLANKTON
PLATE 43.
Page
Figs. 1-2. Coelastrum prohoscideum (x 825).. 162
Figs. 3-5. Actinastrum gracillimum (x 1000) 164
Figs. 6-7. Actinastrum HantzscM (Fig. 6, x 500; fig. 7, x 1000) 164
Fig. 8. Actinastrum HantzscM var. elongatum (x 1000) 165
WISCONSIN SURVEY
BULLETIN 57, PLATE 43
SMITH — ALGAE
COCKAYNE. BOSTON
WISCONSIN SURVEY
BULLETIN 57, PLATE 44
SMITH — ALGAE
COCKAVNC. BOSTOlM
WISCONSIN PHYTOPLANKTON
229
PLATE 44.
Page
Fig. 1. Sorastrum americanum (x 1000) 163
Figs. 2-3. Sorastrum americanum var. undulatum (x 1000) 163
PMgs. 4-5. Sorastrum spinulostim (x 1000) 163
Fig. 6. Hydrodictyon reticulatum (x 100) 166
{
r
230
WISCONSIN PHYTOPLANKTON
PLATE 45.
Page
Fig. 1. Hydrodictyon reticulatum (x 266) 166
Figs. 2-6. Pediastrum simplex var. duodenarium (x 333) 167
Pig. 7. Pediastrum integrum (x 333) 168
Figs. 8-10. Pediastrum integrum var. priva (x 666) 168
Fig. 11. Pediastrum araneosum (x 333) 168
Figs. 12-13. Pediastrum araneosum var. rugulosum (Fig 12, x 333,
fig. 13, X 666)
168
SMITH
WISCONSIN SURVEY
BULLETIN
57, PLATE 45
10
ALGAE
COCKAYNE, BOSTON
WISCONSIN SURVEY
BULLETIN 57, PLATE 46
SMITH — ALGAE
COCKAYNC, BOSTOi
WISCONSIN PHYTOPLANKTON
231
PLATE 46.
Page
Fig. 1. Pediastrum sculptatum (x 333) 169
Figs. 2-7. Pediastrum Boryanum (x 333) 169
Fig. 8. Pediastrum Boryanum var. undulatum (x 333) 170
Fig. 9. Pediastrum Boryanum var. longicorne (x 333) 170
Figs. 10-13. Pediastrum Eawraiskyi (x 33S; 170
Figs. 14-16. Pediastrum duplex (x 333) 171
Fig. 17. Pediastrum duplex var. roiundatum (x 333) 172
232
WISCONSIN PHYTOPLANKTON
PLATE 47.
Page
Figs. 1-3. Pediastrurti duplex var. clathratum (x 333) 171
Figs. 4-7. Pediastrum duplex var. reticulatum (x 333) 172
Figs. 8-11. Pediastrum duplex var. gracillimum (x 333) 172
WISCONSIN SURVEY
BULLETIN 57, PLATE 47
SMITH — ALGAE
COCKAYNE. BOSTON
WISCONSIN SURVEY
BULLETIN 57, PLATE 48
SMITH — ALGAE
COCKAVNK
BOSTOM
WISCONSIN PHYTOPLANKTON 233
PLATE 48.
Page
Pigs. 1-2. Pediastrum duplex var. gracillimum (x 333) 172
Pigs. 3-4. Pediastrum duplex var. cohaerens (x 333) 173
Pigs. 5-8. Pediastrum biradiatum (x 333) 173
Pigs. 9-12. Pediastrum tetras (x 666) 173
Figs. 13-14. Pediastrum tetras -var. tetrabdon (x 686) 174
234
WISCONSIN PHYTOPLANKTON
PLATE 49.
Page
Pigs. 1-2. Pediastrum tetras var. tetraodon (x 1000).... 174
Fig. 3. Eaustropsis RicJiteri (x 1000) 175
Figs. 4-7. Characium stipitatum (x 1000) 176
Figs. 8-15. Characium curvatum (x 1000) 176
Figs. 16-19. Characium cylindricum (Fig. 16, x 400; figs. 17-19, x
1000) 177
Figs. 20-24. Characium gracilipes (x 1000) 178
Figs. 25-29. Characium limneticum (x 1000) 177
COCKAYNE. BOSTON
WISCONSIN SURVEY
BULLETIN 57, PLATE 50
SMITH— ALGAE
n
COCKAVNC. BOSTON
WISCONSIN PHYTOPLANKTON 235
PLATE 50.
Page
Figs. 1-3. Cladophora glomerata (Figs. 1-2, x 50, fig. 3, x 300) 182
Figs. 4-5. Ulothrix suJ)constricta (x 1000) 179
Fig. 6. Ulothrix zonata (x 400) 179
Fig. 7. Stigeoclonium luhricum (x 300) 180
Fig. 8. Aphanochaete vermiculoides (x 400) 181
236
WISCONSIN PHYTOPLANKTON
PLATE 51.
Page
Fig. 1. Mougeotia viridis (x 400) 184
Fig. 2. Zygnema pectinatum (x 400) 185
Fig. 3. Spirogyra porticaUs (x 400) 185
WISCONSIN SURVEY
BULLETIN 57, PLATE 5
SMITH — ALGAE
COCKAYNE. BOSTON
\
OF THE
UNIVERSITY OF (LIINOIS
I
INDEX
Page
Acanthococcus reticularis Reinsch. .. 109
ACANTHOSPHAERA Lemm 128
A. ZACHARIASI Lemm. pi. 29, f. 6-8. . 128
ACTINASTRUM Lag 164
A. GRACILLIMUM G. M. Smith pi.
^3, f. S-5 164
A. HANTZSCHI Lag. pi. ^5, f. 6-7 164
V. ELONGATUM G. M. Smith pi. J,3,
f. 8 165
AKONTAE 183
ANABAENA Bory 55
A. AFFINIS Lemm. pi. 8, f. 7 57
A. AUGSTUMALIS v. MARCHICA
Lemm. pi. 8, f. 9-10 58
A. BORNETIANA Collins pi. 8, f. S. . 58
A. CIRCINALIS (Ktz.) Rab. pi. 9,
f. i-5 59
V. MACROSPORA (Wittr.) de Toni
pi. 9, f. 6; pi. JO, f. jf 60
A. FLOS- AQUAE (Lyng.) Breb. pi. 10,
f. 2-4 60
A. fios-aquae Klebh. non (Lyng.)
Breb 61
V. TRELEASII Born. & Flah. pi. 10,
f. 5-7 60
A. Hassallii (Ktz.) Wittr 59
V. macrospora Wittr 60
A. LEMMERMANNI P. Richt. pi. 10,
f. 8; pi. JJ, f. J Cl
A. LEVANDERI Lemm. pi. 8, f. 4-5. . 58
A. LIMNETIC A G. M. Smith pi. 8, f. 8 57
A. MACROSPORA v. ROBUSTA
Lemm. pi. 8, f. 6 57
A. mendotae Trelease 60
A. PLANCTONICA Brunnth. pi. 8, t. 2 56
A. SPIROIDES V. CRASSA Lemm.
pi. 9, f. 1-S 59
Anacystis pulverus Wood 40
ANKISTRODESMUS Corda 134
A. Chodati (Tanner-Fullman)
Brunnth 138
A. FALCATUS (Corda) Ralfs
pi. 32, f. J 134
V. ACICULARIS (A. Br.)
G. S. West 135
V. MIRABILIS (W & G. S. West)
G. S. West pi. 32, f. 3 — 5 135
V. spiralis (Turn.) G. S. West. . . 135
V. TUMIDUS (W. & G. S. West)
G. S. West pi. 32, f. 2 135
Page
A. lacustre (Chodat) Ostenfeld 139
A. longissimum v. septatum
(Chodat) Brunnth 177
A. Pfitzeri (Schrod.) G. S. West 138
A. SPIRALIS (Turn.) Lemm.
pi. 32, f. 6—7 135
APHANIZOMENON Morren 61
A. FLOS-AQUAE (L.) Ralfs
pi. 11, f. 2—4 61
APHANOCHAETACEAE 181
APHANOCHAETE A. Br 181
A. VERMICULOIDES Wolle
pi. 50, f. 8 181
APHANOCAPSA Nag 41
A. DELICATISSIMA W. &. G. S.
West pi. 2, f. 7 41
A. ELACHISTA v. CONFERTA
W. & G. S. West pi. 2, f. 8 42
V. PLANCTONICA G. M.
Smith pi. 3, f. 3 42
A. ENDOPHYTICA G. M. Smith
pi. 2, f. JO 42
A. GREVILLEI (Haas.) Rab.
pi. 3, f. J 43
A. PULCHRA (Ktz.) Rab. pi. 2, f. 9. 42
A. RIVULARIS (Carm.) Rab.
pi’. 3, f. 2 43
APHANOTHECE Nag 43
A. CLATHRATA W. & G. S. West
pi. 6, f. 3 44
A. NIDULANS P. Richt. pi. 6, f. J 44
V. ENDOPHYTICA W. & G. S.
West pi. 5, f. 6 44
A. PR A SIN A A. Br. pi. 5, f. 5 45
A. STAGNINA (Spreng.) A. Br.
pi. 6, £. 2 45
ASTEROCOCCUS Scherffel 103
A. LIMNETICUS G. M. Smith
pi. 20, f. 7— JO 104
Autocolony 109
AUTOSFORACEAE 109
Autospore 109
BOTRYOCOCCACEAE 83
BOTRYOCOCCUS Ktz 83
B. BRAUNII Ktz. pi. J5, f. 5 84
B. Braunii G. S. West non Ktz 83
B. PROTUBERANS v. MINOR
G. M. Smith pi. 15, f. 6—7 85
B. SUDETICUS Lemm. pi. 15, t. 8 83
CARTERIA Diesing 92
238
INDEX
Page
C. CORDIFORMIS (Carter) Diesing
pi, 16, f. 1 92
C. KLEBSII (Dang.) Dill
pi. 16, f. 2 — If 93
CARTERIACBAE 92
CHAETOPHORACEAE 180
CHARACIUM A. Br 175
C. CURVATUM G. M. Smith
pi. Jfi, f. 8 — 15 176
C. CYLINDRICUM Lamb.
pi. ^9, f. 16—19 177
C. GRACIDIPES Lamb. pi. J,9, f. 20—24 178
C. LIMNETICUM Lemm.
pi. 49, f. 25 — 29 177
C. STIPITATUM (Bachman) Wille
pi. 49, f. 4—7 176
CHLAMYDOMONADACEAE 90
CHLAMYDOMONAS Ehr 90
C. communis Snow 91
C. DINOBRYONI G. M. Smith
pi. 16, f. 5—7 91
C. EPIPHYTICA G. M. Smith
pi. 16, f. 11— IS 91
C. GLOBOSA Snow pi. 16, f. 8 90
C. SNOWII Printz pi. 16, f. 9 — 10. ... 91
CHLORAMOEBACEAE 79
CHLORELLA Beyerinck 108
C. VULGARIS Beyerinck pi. 22, f. 1 .. . 108
CHLOROBOTRYDACEAE 82
CHLOROBOTRYS Bohlin 82
C. LIMNETICUS G. M. Smith
Page
C. MINUTUS (Ktz.) Nag. pi. 1 , f. 1 . . . 28
C. TURGIDUS (Ktz.) Nag. pi. 1 , f. 9 . 3 i
CHRYS AMOEBA Klebs 67
C. RADIANS Klebs pi. 12 , f. 1 67
CHRYSIDASTRUM Lauterborn 78
C. CATENTATUM Lauterborn
pi. 14, f. 7—8 78
CHRYSOMONADINEAE 65
CHRYSOSPHAERELLA Lauterborn 69
C, LONGISPINA Lauterborn
pi. 12, f. 7—8 69
CLADOPHORA Ktz 182
C. GLOMERATA (L.) Ktz.
pi. 50, f. 1 — S 182
CLADOPHORACEAE 182
Clathrocystis aeruginosa (Ktz.)
Henfrey 39
CLOSTERIOPSIS Lemm 136
C. LONGISSIMA v. TROPICA W.
& G. S. West pi 32, f. 8 136
COCCOGONEALES 26
COCCOMYXA Schmidle 139
COELASTREAE I 6 O
COELASTRUM Nag ] 160
C. CAMBRICUM Arch, pi, 42, f. 2 — 3 . 161
C. compositum G. S. West 162
C. MICROPORUM Nag. pi. 41, f.
12— IS; pi. 42, t. 1 160
C. PROBOSCIDEUM Bohlin pi. 42, f.
7—8; pi. 43, f. 1—2 162
C. RETICULATUM (Dang.) Senn
pi. 15, f. 9 82
C. REGULARIS (W. West) Bohlin
pi. 15, f. 16 82
CHLOROCHROMONAS Lewis 80
C. MINUTA Lewis pi. 15, f. 1—S 80
Chlorococcus regulare W West 82
CHLOROPHYCEAE 88
CHLOROSACCACEAE 81
Chodatella ciliata (Lag.) Lemm 129
V. minor G. M, Smith 129
C. citriformis Snow 130
C. DroescTieri Lemm 131
C. longiseta Lemm 130
G. subsala Lemm 130
CHROMULINALES 66
CHROOCOCCACEAE 27
CHROOCOCCUS Nag 27
C. DISPERSUS (V. Keiss.) Lemm.
pi. 1 , f. 2 28
V. MINOR G. M. Smith pi. 1, f. 3. 28
C. GIGANTEUS W. West, pi. 2, f. 1. .. 30
C. LIMNETICUS Lemm. pi. 1, t. 4- ... 29
V. CARNEUS (Chod.) Lemm.
pi. 1, f. 6 30
V. DI STANS G. M. Smith
pi. 1, f. 7 30
V. ELEGANS G. M. Smith
pi. 1, f. 8 30
V. SUBSALSUS Lemm. pi. 1, f. 5. 29
Chroococcus minor var dispersus
V. Keiss 28
pl. 42, f. 4—6 161
COELOSPHAERIUM Nag 33
C. DUBIUM Grunow pl, 3, f. 7 35
C. KUETZINGIANUM Nag,
pl. 3, f. 4—5 34
C. NAEGELIANUM Unger
pl. 3, f. 6 ; pl. .J, f. 1 35
Coenocyte 88
Cohniella staurogeniae forme SchrOder 149
Collection methods 10
Conferva echinulata J. E. Smith 63
CONJUGALES 183
CRUCIGENIA Morren 144
C. APICULATA (Lemm.) Schmidle
pl. 37, f. 1 146
C.CIRUCIFERA (Wolle) Collins
pl. 36, f. 6 145
C. FENESTRATA Schmidle pl. 37, f. 3. 148
C. IRREGULARIS Wille pl. 36, f. f— 5. 145
C. LAUTERBORNEI Schmidle
pl. .37, f. .J 148
C. QUADRATA Morren pl. 36, f. 10— 14. 147
V. punctata (Schmidle) 147
C. RECTANGULARIS (Nag.) Gay
pl. .36, f. 3 144
C. TETRAPEDIA (Kirchner) W & G.
S. West pl. 37, f. 2 147
G. triangularis (Chodat) Schmidle.... 147
C. TRUNCATA G. M] Smith
pl. 36, f. 7—9 146
CRUCIGENIEAE 14-3
INDEX
239
Pag-e 1
DACTYLOCOCCOPSIS Hansg 47
D. ACICULARIS Lemm. pi. 6, f. 8—10 48
D. RHAPHIDIOIDES Hansg.
pi. 6, f. 7 47
DICTTOSPHAERIACEAE 104
DICTYOSPHAERIUM Nag 104
D. EHRENBERGIANUM Nag.
pi. 20, f. 11—12 105
D. PULCHELLUM Wood pi. 20,
f. 13; pi. 21, f. 1 105
DIMORPHOCOCCUS A. Br 108
D. LUNATUS A. Br. pi. 21, t. 5 106
DINOBRYON Ehr 72
D. BAVARICUM Imhof pi. 13, t. 10. . . 73
D. CALICIFORME Bachm.
Page
GLOEOTRICHIA J. G. Ag 63
I G. ECHINULATA (J. E. Smith) P.
i Richt. pi. 11, f. 5 — 6 63
! G. visum Born, et Flah. non Thur. ... 63
iGOLENKINIA Chodat 127
I G. PAUCI SPINA W. & G. S. West
pi. 29, f. Jf—5 127
G. RADI AT A Chodat pi. 29, f. 2—3. . . 127
GOMPHOSPHAERIA Ktz 36
G. AFONINA Ktz. pi. k, t 2—3 37
V. CORDIFORMIS Wolle pi. !,, t. It 37
G. LACUSTRIS Chodat pi. 4. f. 5 36
G. Naegeliana (Unger) Lemm 35
i GONIUM Mueller 94
I G. PECTORALE Mueller
pi. 13, f. 5—6 73
D. DIVERGENS Imhof pi. 1^, f. 2 75
D. SETULARIA Ehr. pi. 13, f. 13;
V\. lit, i. 1 74
D. SOCIALE Ehr. pi. 13, f. 12 74
D. STIPITATUM Stein pi. 13, f. 11. .. . 74
D. TABELLARIAE (Lemm.) Pascher
pi. 13, f. 7 — 9 73
D. utriculus var. tabellariae Lemm. .. 73
DINOBRYONACEAE 72
ECHINOSPHAERELLA G. M. Smith 128
E. LIMNETICA G. M. Smith
pi. 29, f. 9—11 128
ECHINOSPHAERIDIUM Lemm 128
ELAKTOTHRIX Wille 139
E. GELATINOSA Wille pi. 3!,, t. 1—3 139
E.VIRDIS (Snow) Printz pi. S3, f. 7. 140
EUASTROPSIS Lag 174
E. RICHTERI (Schmidle) Lag.
T>1. If9, t. 3 175
Euastrum tetraodon Corda 174
EUCHROMULINACEAE 66
EUCHRYSOMONADINAE 66
EUDORINA Ehr 95
E. ELEGANS Ehr. pi. 19, /. 1 96
EUHYMENOMONADACEAE 70
Euplankton 1
Facultative plankton 1
FRANCEIA Lemm 131
F. OVALIS (Franck) Lemm. pi. 31, f. /, 131
Fusola virdis Snow 140
pi. 16, f. U — 15
Heleoplankton
Ilerposteiron hyalothecae Hansg
HETEROCHLORIDALES
IlETEROCOCCALES
Hormogones
I-IETEROKONTAE
PIETEROTRICHALES
HORMOGONEALES
Hormogones
HYALOBRYON Lauterborn
H. Lauterhornei var mucicola Lemm.
H. MUCICOLA (Lemm.) Pascher
pi. Ilf, f. 3 — ^
KYDRODICTYACEAE
HYDRODICTYON Roth
H. RETICULATUM (L.) Lag.
pi. f. 6; Pl. 45, f. 1
HYDRURINEAE
Ineffigiata neglecta W. & G. S. West
ISOCHRYSIDALES
ISOKONTAE
Key to the genera
KIRCHNERIELLA Schmidle
K. aperta Teiling
K. CONTORTA (Schmidle) Bohlin
pi. 35, f. 7
K. ELONGATA G. M. Smith
pi. 36, f. 1 — 2
K. LUNARIS (Kirchner) Mobius
pi. 3//, f. 4
94
5
181
79
80
26
79
86
48
48
75
75
75
165
165
166
76
84
21
140
143
143
143
141
Gas vacuoles 33
Geography of Wisconsin 5
Geology of Wisconsin 5
GLOEOCOCCUS 102
GLOEOCYSTIS Nag 100
G. GIGAS (Ktz.) Lag. pi. 19, f. 2 101
GLOEOCYSTOPSIS G. M. Smith 102
G. LIMNETICUS G. M. Smith
pi. 20, f. 1—2 103
GLOEOTHECE Nag 45
G. LINEARIS Nag. pi. 6, f. 5 46
V. COMPOSITA G. M. Smith
V. DIANAE Bohlin pi. 34, f. 5. ... 141
V. IRREGULARIS G. M. Smith
pi. 35, f. i 142
K. OBESA (W. West) Schmidle
pi. 35, f. 2—3 142
V. APERTA (Teiling) Brunnthaler
pi. 35, f. 5—6 143
V. contorta Schmidle 143
V. MAJOR (Bernard) G. M.
Smith pi. 35, f. 4 142
LAGERHEIMIA Chodat 129
L. CILIATA (Lag.) Chodat
pi. 6, f. 6 46
GLOEOTAENIUM Hansg 115
G. LOITLESBERGERIANUM Hansg.
pi. 23, f. 8 — 9 115
pi. 31, f. 1 — 2 129
V. MINOR G. M. Smith pi. 31, f. 3. 129
L. CITRIFORMIS (Snow) G. M.
Smith pi. 30, f. 1—2 130
240
INDEX
Page
L. DROESCHERI (Lemm.) Printz
pi. 30, f. 5 — 7 131
L. LONGISETA (Lemm.) Printz
pi. 30, f. 8—9 130
V. MAJOR G. M. Smith
pi. 30, f. 10 — 12 130
L. SUBSALSA Lemm. pi. 30, f. 3—1 . . 130
Lake areas of Wisconsin 6
Lakes
Altitude 6
Chemical composition of water . . 8
Formation of Wisconsin Lakes . . 5
Hard water 7
Medium water 7
Origin of Names 11
Size 5
Soft water 7
Temperature 6
Lemmermannia emarginata
Pago
M. octonarius Bailey 167
MOUGEOTIA C. A. Ag 184
M. VIRIDIS (Ktz.) Wittr. pi. 51, f. 1. 184
Myxonema lubricum (Dillw.) Fries... 180
MYXOPHTCEAE 26
OCHROMONADACEAE 71
OCHROMONADALES 70
OOCTSTEAE 110
Oocystella Lemm 114
OOCYSTIS Nag 110
O. BORGEI Snow pi. 22, f. Ill
O. ciliata Lag 129
O. CRASS A Wittr. pi. 22, f. 12—13 113
O. ELLIPTICA W. West pi. 22, f. 5. . . Ill
O. EREMOSPHAERIA G. M. Smith
pi. 23, f. 1-2 113
O. GLOEOCYSTIFORMIS Borge pi. 22,
f. 7 112
O. LACUSTRIS Chodat pi. 22, f. 8—9. 112
(Schroder) Chodat 147
Lemmermannia tetrapedia (Kirch-
ner) Lemm 148
List of Lakes studied 13-19
LYNGBYA C. A. Ag 52
L. BIRGEI G. M. Smith pi. 7, f. U — 15. 54
L. CONTORT A Lemm. pi. 7, f. 12—13. 53
L. LIMNETIC A Lemm. pi. 7, f. 9—11. 52
L. Wollei Farlow 54
L. Wollei Trelease non Farlow 54
MALLOMONADACEAE 67
MALLOMONAS Perty 67
M. ALPINA Pascher & Ruttner
O. NATANS V. MAJOR G. M. Smith
pi. 23, f. 4-5 114
O. PANDURIFORMIS v. MINOR G.
M. Smith pi. 23, f. .3 114
O. PARVA W. & G. S. West pi. 22, f. 6 112
O. PUSILLA Hansg. pi. 22, i. 3 Ill
O. SOLITARIA AVittr. pi. 22, f. 11 113
O. SUBMARINA Lag. pi. 22, f. 10 113
OPHIOCYTIACEAE 85
OPHIOCYTIUM Nag 85 ^
O. CAPITATUM Wolle pi. 15, f. 12-13. 86
V. LONGISPINUM (Mobius) Lemm.
pi. 15, f. U-16 86
pi. 12, f. 4
M. CAUDATA Iwanoff pi. 12, f. 6. . . .
M. PRODUCTA (Zach.) Iwanoff
68 O. PARVULUM (Perty) A. Br. pi. 15,
69 t. 11 86
OSCILLATORIA Vaucher 50
pi. 12, f. 2 68
V. MARCHICA Lemm. pi. 12, f. 3. 68
M. TONSURATA Telling pi. 12, f. 5. . . 68
MERISMOFEDIA Meyen 31
M. ELEGANS A. Br. pi. 2, f. 5 32
V. MAJOR G. M. Smith pi. 2, f. 6. 32
M. GLAUCA (Ehr.) Niig. pi. 2, f. 4 ‘12
M. PUNCTATA Meyen pi. 2, f. 3 33
M. TENUISSIMA Lemm. pi. 2, f. 2. . . 33
MICRACTINIEAE 125
MICRACTINIUM Fresenius 125
M. PUSILLUM Fresenius
pi. 28, f. 1—3 125
V. ELEGANS G. M. Smith
pi. 29, f. 1 126
M. QUADRISETUM (Lemm.) G. M.
Smith pi. 28, f. 4 126
MICROCYSTIS Ktz 38
M. AERUGINOSA Ktz. pi. 5, f. 2—3. 39
V. MA.lOR (Wittr.) G. M. Smith
pi. 4, f. 6 40
M. FLOS-AQUAE (Wittr.) Kirchner
pi. .5, f. 1 39
M. ICHTHYOBLABE Ktz 38
M. INCERTA Lemm. pi. 5, f. 4 40
M. PULVERA (Wood) Migula 40
Monaciinus duodcnarius Bailey 167
O. PROLIFICA (Grev.) Gom. pi. 7,
f. 3-5 51
O. RUBESCENS D. C 51
O. TENUIS C. A. Ag. pi. 7, f. 6 52
V. TERGESTINA (Ktz.) Rab. pi. 7,
f. 7-8 52
OSCILLATORIACEAE 49
PALMELLACEAE 100
PANDORINA Bory 95
P. MORUM Bory pi. 16, f. 16-17 95
PEDIASTRUM Meyen 166
P. ARANEOSUM Racib. pi. 45, f. 11.. 168
V. RUGULOSUM (G. S. West) G. M.
Smith pi. 45, f. 12-13 168
P. BIRADIATUM Meyen pi. 48, f. 5-8 173
P. BORYANUM (Turp.) Menegh. pi.
46, f. 2-7 169
V. LONGICORNE Racib. pi. 46, f. 9. 170
y. longicorne forma glabrum Racib. 170
V. longicorne forma granulatum
Racib 170
V. UNDULATUM Wille pi. 46, f. 8. . 170
P. DUPLEX Meyen pi. 46, f. U-16 171
V. CLATHRATUM (A. Br.) Lag.
pi. 47, f. 1-3 171
V. COHAERENS Bohlin pi. 48, f. 3-4 173
INDEX
241
V. GRACILLIMUM W. & G. S. West
pi. JfT, f. 8-11; pi. 172
V. RETICULATUM Lag. pi. ^7, f . 4-7 172
V. reticulatum forma cohaerens
(Bohl.) Brunnth 173
V. ROTUND ATUM Lucks pi. 1,6, t. 17 172
P. INTEGRUM Nag. pi. 45, f. 7 168
V. PRIVA Printz pi. 45, f. 8-10 168
P.rotula (Ehr.) A. Br 173
P. SCULPTATUM G. M. Smith pi. 46,
t. 1 169
P. SIMPLEX V. DUODENARIUM
(Bailey) Rab. pi. 45, f. 2-6 167
V. clathratum (Schroter) G. S. West 167
P. TETRAS (Ehr.) Ralfs pi. 48, f. 9-12 173
V. OBTUSATA Racib 174
V. TETRAODON (Corda) Hansg.
Page
Relative abundance of different species 28
RHABDODERMA Schmidle & Lauter-
born 46
R. LINEARE Schmidle & Lauterborn
pl. 6 , f. 4 47
Bhaphidium Braunii var. lacustre
Chodat 139
R. Chodati Tanner-Fullman 138
R. longissimum var. septatum Chodat 177
V. tropicum W. & G. S. West 136
B. Pfitsieri SchrOder 138
B. spirale Turner 135
RHIZOCHRYSIDINAE 77
RHIZOCHRTSIS Pascher 77
R. LIMNETIC A G. M. Smith pl. 14 , t. 6 77
R. PLANCTONICA Pascher 78
Bichteriella botryoides (Schmidle)
pl. 48, f. IS-IJ, ; pl. 1,9, t, 1-2 174 Lemm
PERONIELLA Gobi 81 I forma fenestrata Chodat
P. PLANCTONICA G. M. Smith pl. > forma tetraedrica Lemm.
15. f. 4 81
PHAEOCAPSACEAE 76 '
PHAEOCAPSALES 76
PHAEOCOCCUS Borzi 76 '
P. PLANCTONICUS W. & G. S. West 1
pl, 14 , f. 5 76 :
PHAEOPHYCEAE 65
Phythelois ovalis France 131
Phytoplankton 1
Pithiscus Klebsii Dangeard 93
PLANKTOSPHAERIA G. M. Smith.. 103
P. GELATINOSA G. M. Smith pl. 20,
f. 3-6 103
PLANOSPORACEAE 175
PLECTONEMA WOLLEI Farlow 54 '
PLEODORINA Shaw 96 ’
P. CALIFORNICA Shaw pl. 17, f. 1-S 97
Polycystis ichthyohlabe Ktz 88
POLYEDRIOPSIS Schmidle 124
P. SPINULOSA Schmidle pl. 27, f. 7-8 124
Polyedrium gracile Reinsch 122
P. hastatum var. palatinum Schmidle 121
P. lobulatum Nag 122
Bivularia echinulata J. E. Smith
RIVULARIACEAE
SCENEDESMUS Meyen
S. ABUNDANS (Kirchner) Chodat pl.
SO, f. 23-26
V. ASYMMETRICA (Schrdder) G.
M. Smith pl. 46, f. 6-8
V. BREVICAUDA G. M. Smith pl.
46, f. 3-5
V. LONGICAUDA G. M. Smith pl.
39, f. 26-27
S. ACUMINATES (Lag.) Chodat pl.
58, f. i-4
S. ACUTIFORMIS SchrOder pl. 39, f.
4-6
S. alternans Reinsch
S. ARCUATUS Lemm. pl. 58, f. 12-11,. .
V. CAPITATUS G. M. Smith pl. 38,
f. 15-16
V. PLATYDISCA G. M. Smith pl. 39,
f . 1 — 3
S. ARMATUS (Chodat) G. M. Smith
pl. 39, f . 7-10
P. muticum v. punctulatum Reinsch.. 116
P. tetraedricum Nag 118
V. hastatum Reinsch 121
P, trigonum Nag 117
V. gracile Reinsch 117
V. setigerum (Arch.) SchrOder 117
PROTOCOCCACEAE 108 i
PROTOCOCCALES 99
Protococcus mmutus Ktz 28
Pseudocilia 102
Pseudovacuoles 33
Pyrenoids 88
QUADRIGULA Printz 137
Q. CHODATI (Tanner-Fullman) G.
M. Smith pl. 35, f. 3 138
Q. LACUSTRIS (Chodat) G. M.
Smith pl. 33, f. 4-6 139
v.MAJOR G. M. Smith pl. 39, f. 11..
S. BERNARDII G. M. Smith pl. 38, f.
5-9
S. BIJUGA (Turpin) Lag. pl. 37, f.
18-20
V. ALTERNANS (Reinsch) Borge
pl. 38 , f. 10-11
S. bijugatus (Turpin) Ktz
S. BRASILIENSIS Bohlin pl. 39, f.
12-14
B. caudatus Nag. non Corda
S. DENTICULATUS Lag. pl. 39, f.
17-19
S. DIMORPHUS (Turpin) Ktz. pl. 37,
f. 15-17
S. HYSTRIX Lag. pl. 39, f. 15-16
S. LONGUS Meyen pl. 39, f. 20-22
125
125
126
6 S
62
150
157
157
157
157
152
154
153
153
153
154
154
155
152
152
153
152
155
156
155
151
155
156
Q. PFITZERI (Schrdder) G. M. v. NAEGELII (Breb.) G. M. Smith
Smith pl. S3, f. 1-2 138 ; pl. 46, f. 1-2 156
242
INDEX
Page !
S. Naegeln Breb 156
S. OBLIQUUS (Turpin) Ktz. pi. 37,
f. 72-74 151
S. OPOLIENSIS P. Kichter pi. 41 , f.
8-77 159
S. QUADRICAUDA (Turpin) Breb.
pi. JfO, f. 9-11 158
V. ahundans (Kirchner) Lag 157
V. asymmetrica SchrOder 157
V. LONGISPINA (Chodat) G. M.
Smith pi. JfO, f. IS-U 159
V. MAXIMUS W. & G. S. West pi.
47 . f. 1-2 159
V. PARVUS G. M. Smith pi. J,0, f. 17 158
V. QUADRISPINA (Chodat) G. M.
Smith pi. 40 . f. 15-16 158
V. setosus ( Kirchner ■> Lag 156
V. WESTII G. M. Smith pi. 47, f.
5-7 159
SCHROEDERIA Lemm 136
S. JUDATI G. M. Smith pi. 52, f. 9-11 137
S. SETIGERA (SchrOder) Lemm. pi.
52, f. 72 137
SELENASTREAE 132
SELENASTRUM Relnsch 132
S. acuminatum G. S. West non Lag. 133
8. acuminatum Lag 152
S. BIBRAIANUM Reinsch
Page
TETRADESMUS G. M. Smith 150
T. WISCONSINENSIS G. M. Smith
pi. 57, f. 7—11 150
TETRAEDREAE I 15
TETRAEDRON Ktz II 5
T. arthrodesmiforme v. lohulatum
Wolosz 122
T. CAUDATUM (Corda) Hansg.
pi. 25, f. 4 — 7 120
V. LONGISPINUM Lemm. pi. 25,
f. 8-12 120
T. CONSTRICTUM G. M. Smith
pi. 25, f. 22—24 122
T. ENORME (Ralfs) Hansg. pi. 27, t. 6. 124
T. GRACILE (Reinsch) Hansg.
pi. 25, f. 7 — 5 122
T. HASTATUM (Reinsch) Hansg.
pi. 25, f. 78 121
V. PALATINUM (Schmidle)
Lemm. pi. 25, f. 19—21 121
T. LIMNETICUM Borge pi 27, f. 7—5. 123
T. LOBULATUM (Nag.) Hansg.
pi. 26, f. 6—7 122
V. POLTFURCATUM G. M.
Smith pi. 26, £. 8 123
T. MINIMUM (A. Br.) Hansg.
pi. 24 , f. 10— IS 118
T. MUTICUM V. FUNCTULATUM
pi. 57, f. 6 — 7
S. GRACILE Reinsch pi. 57, f. 5
S. WESTII G. M. Smith pi. 37, f. 8—10
Selenosphaerium americanum Bohlin.
SIPHONOCLADIALES
SORASTRUM Ktz
S. AMERICANUM (Bohlin) Schmidle
pl. 44, f. 7
UNDULATUM G. M. Smith
pi. 44 , f. 2—5
S. SPINULOSUM Nag. pi. 44, f. 4—5.
SPHAEROCTSTIS Chodat
S. SCHOETERI Chodat pi. 19, f. 3—4.
SPIROGYRA Link
S. PORTICALIS (Mueller) Cleve
pi. 51, f. 3
SPIRULINA Turpin
S. MAJOR Ktz. pi. 7, f. 7
S. FRINCEPS (W. & G. S. West)
G. S. West pi. 7, £. 2
Staurogenia apiculata Lemm
8. cruciatum Wolle
8. crucifera Wolle
8. fenestrata Schmidle
8. Lauterhomei Schmidle
8. multiseta v. punctata Schmidle . . .
8. tetrapedia Kirchner
8. triangularis Chodat
STIGEOCLONIUM Ktz
S. LUBRICUM (Dillwyn) Ktz.
pi. 50, £. 7
SYNURA Ehr
S. UVELLA Ehr. pi. 12, f. 9—10
Tetracoccus botryoides W. West
133
133
133
163
182
162
163
163
163
101
101
185
185
49
50
50
146
145
145
148
148
147
147
147
180
180
70
120
121
123
(Reinsch) de Toni pi. 23, f. 10—13. 116
T. PENTAERUICUM W. & G. S.
West pi. 25, f. 75—77
V. minimum W. & G. S. West
T. PLANCTONICUM G. M. Smith
pi. 27, f. 4—5
r. proteiforme G. M. Smith non (Turn.)
Brunnthaler
T. REGULARE Ktz. pi. 24, f. 74 H8
T. regulare Chodat non Ktz 119
V. INCUS Telling pi. 24, f. 15—76. 118
V. TORSUM (Turner) Brunn-
thaler pi. 24, f. 77—78 119
T. spinulosum Schmidle 124
T. TRIGONUM (Nag.) Hansg.
pi. 23, f. 74 — 16 117
V. GRACILE (Reinsch) de Toni
pi. 24 , f. 5—9 117
V. SETIGERUM (Archer) Lemm.
pi. 24 , f. 7—4 117
T. VERRUCOSUM G. M. Smith
pi. 25, f. 2—3
T. VICTORIEAE Wolos
V. MAJOR G. M. Smith pi. 24,
f. 79 — 22; pi. 25, f. 7 H9
Tetrapedia emarginata SchrOder 147
T. pentaedricum Chodat 129
T. setigera Archer H7
TETRASPORA Link 192
T. LACUSTRIS Lemm. pi. 79, f. 5 — 6 . 102
TETRASTRUM Chodat 149
70 jr. wpiculatum (Lemm.) Brunnthaler. . 146
197 T. mwZtisetwm (Schmidle) Chodat ....147
119
119
INDEX
243
Page
T. STAUROGENIAEFORME
(Schroder) Lemm. pi. S7^ f. 5 — 6. 149
TRICHODESMIUM Ehr 64
T. LACUSTRE Klebahn pi. 8, f. 1 54
TRIBONEMA Derbes et Sober 87
T. BOMBYCINA v. DEPAUPERATA
Wille 87
T. MINUS (Wille) Hazen
pi. 15, f. n — 18 87
TRIBONEMACEAE 87
Triehomes 48
TROCHISCIA Ktz 108
T. RETICULARIS (Reinsch) Hansg.
pi. 22, f. 2 109
Tychoplankton 1
ULOTRICHACEAE 178
ULTRICHALES 178
ULOTHRIX Ktz 179
U. SUBCONSTRICTA G. S. West
pi. 50, f. -J— 5 179
U. ZONATA (Weber & Mohr) Ktz.
pi. 50, f. 6 179
Page
XJroglena americana Calkins 71
UROGLENOPSIS Lemm 71
U. AMERICANA (Calkins) Lemm.
pi. 18, f. 1—4 71
VOLVOCACEAE 93
VOLVOCALES 89
VOLVOX L 97
V. AUREUS Ehr. pi. 18, f. 2 98
V. GLOBATOR L. pi. 18, f. 3—5 98
V. lMONONAE G. M. Smith, pi. 18, f. 1 99
WESTELLA de Wildeman 106
W. BOTRYOIDES (W. West) de
Wildeman pi. 21, f. ^ 107
V. MAJOR G. M. Smith 107
W. LINEARIS G. M. Smith
pi. 21, f. 2—3 107
Zooplankton 1
ZYGNEMA C. A. Ag 184
Z. PECTINATUM (Vaucher) C. A.
Ag. pi. 51, f. 2 185
ZYGNEMACEAE 183