(26765— 5m— 10-IV) ILLINOIS STATE NATURAL HISTORY SURVEY LIBRARY 5 5 0 It 7 5^ » M o. 51 ' 'JATURAL history SURVE’' 557 \M75t \ v.O f ,co| p.O 1 1 APR 2 1941 Digitized by the Internet Archive in 2016 https://archive.org/details/phytoplanktonofi5711smit 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 \'7 75t ^ V, ST ' Ccr^ , 6 r), w. 'T 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) . 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. 4-5t, 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 COCKAYNE, BOSTON 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 BULLETIN 57, PLATE 5 SMITH — ALGAE COCKAVNe, BOSTON WISCONSIN SURVEY BULLETIN 57, PLATE 6 I SMITH— ALGAE COCKAYNE, BOSTON 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 WISCONSIN SURVEY BULLETIN 57, PLATE 7 SMITH — ALGAE COCKAYNE. BOSTOI WISCONSIN SURVEY BULLETIN 57, PLATE 8 SMITH — ALGAE COCKAYNE. BOSTON 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 COCKAYNE, BOSTO* WISCONSIN SURVEY BULLETIN 57, PLATE lO SMITH — ALGAE COCKAYNE. BOSTON WISCONSIN PHYTOPLANKTON 195 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 ® 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