Nnrtlf (Earoltna g'tatf Initirraitg JiV This book was presented by Bernard S. Martof D8 S00564875 Z BERNARD MARTOF THIS BOOK IS DUE ON THE DATE INDICATED BELOW AND IS SUB- JECT TO AN OVERDUE FINE AS POSTED AT THE CIRCULATION DESK. mi 1 2 1975 FEB 28 1977 JU^f 29 1977 DEC 5 1979 HOW TO KNOW THE MOSSES HOW TO KNOW THE MOSSES A POPULAR GUIDE TO THE MOSSES OF THE NORTHEASTERN UNITED STATES Containing keys to eighty genera and short descriptions of over one hundred and Jifty species with special reference to tJie disti}2gnishing characteristics tJiat are apparent zvithout tJie aid of a le?is BY ELIZABETH MARIE DUNHAM MEMBER OF THE SULLIVANT MOSS SOCIETY With Illustrations by the Author BOSTON AND NEW YORK HOUGHTON MIFFLIN COMPANY COPYRIGHT, I916, BY ELIZABETH MARIE DUNHAM ALL RIGHTS RESERVED INCLUDING THE RIGHT TO REPRODUCE THIS BOOK OR PARTS THEREOF IN ANY FORM Published May iqib TO MY HUSBAND Meek creatures! the first mercy of the earth, veiling with hushed softness the dintlcss rocks; creatures full of pity, cover- ing with strange and tender honor the scarred disgrace of ruin, — laying quiet fingers on the trembling stones to teach them rest. ... No words that I know of will say what these mosses are. None are dehcate enough, none perfect enough, none rich enough. How is one to tell of rounded bosses of furred and beam- ing green, — the starred divisions of rubied bloom, fine filmed as if the Rock Spirits could spin porphyry as we do glass, — the tracery of intricate silver, and fringes of amber, lustrous, ar- borescent, burnished through every fiber into fitful brightness and glossy traverses of silken change, yet all subdued and pen- sive, and framed for simplest, sweetest offices of grace. They will not be gathered, like the flowers, for chaplet or love-token, but of these the wild bird will make its nest, and the wearied child his pillow. John Ruskin, Modern Painters, PREFACE The object of this book is to present mosses in a simple, non-technical way, so that the student may recognize at least their genera and in some cases their species without depending upon the use of a lens. The books on mosses that have been published up to the present time have required the use of a hand-lens or microscope in order to follow either the Keys or the descriptions. Wonderful and interesting detail in structure is revealed by this higher method of study, but mosses would remain unknown to many if no simpler and quicker way of learning them was pre- sented. When urged to undertake the work of thus simplify- ing the study of mosses, the author, together with most moss students, held the idea that microscopic examina- tion was necessary in order to know mosses. It was pointed out that, while a thorough knowledge of the different species must be obtained from microscopic study and technical books, the people who are content to recognize violets, asters, and goldenrods, without knowing the specific names, would be equally inter- ested to know the generic names of mosses. A Key only to the genera of mosses, therefore, seemed perfectly feasible, as in nearly every case there is some family or X PREFACE generic character that is recognizable in the field with- out the aid of a lens. In the descriptions of a few gen- era some additional characteristics visible with a hand- lens are given. These are not necessar}^ for the use of the Keys, but are of interest in bringing out some special points. In arranging the Keys it seemed best not to carry them out under many headings to a single genus, but to keep them as simple as possible and group even several genera under one head. This plan requires the student to refer constantly to the illustrations and descriptions and in this way to become familiar with the names and appearances of the different mosses. The Keys have been tested satisfactorily by several people. When they did not work out correctly, it was usually found that the trouble lay in failure either to read the explanatory chapters, to follow the Keys care- fully, or to study the descriptions thoroughly. The mosses included in the Keys are those that are commonly or occasionally collected in the northeastern part of the United States. But the Keys really cover a much larger field, many of the mosses being widely distributed, as will be seen by reading the range given with each genus or species. Four full pages of illustrations of terms used in de- scribing mosses accompany the chapters on ''Habit and Manner of Growth," "Leaves," and ''Capsules." Other illustrations occurring throughout the text, with the exception of a few in the Introduction, are drawn PREFACE xi natural size with an occasional enlarged plant, leaf, or capsule. Average specimens were selected for the illustrations, but allowances must be made for varia- tions in size and branching. The nomenclature given is that used by Dr. Bro- therus in Engler and Prantl's Die Natiirlichen Pflanzenfamilien, Teil i, Abteilung iii. As the Latin name of mosses in some cases is still a matter of dis- pute, synonyms are given in italics where the name has recently been changed. English names are usually lacking, but in most cases the Latin names are no longer than geranium or rhododendron, and when one becomes familiar with them they will seem no harder. The generic and specific names have been accented and the former divided into syllables. The grave accent C) indicates the long English sound of the vowel, the acute accent (0 shows the shortened sound. It is the custom in EngHsh-speaking countries to pronounce the botanical names according to the EngKsh method of pronouncing Latin. In the preparation of this book, the following books have been used for reference : Mosses with a Hand-Lens and Microscope, A. J. Grout; Mosses of Western Penn- sylvania, 0. E. Jennings; The Bryophytes of Connecticut, Evans and Nichols; Handbook of British Mosses, Dixon and Jameson; British Moss Flora, Braithwaite; and various other sources for derivations of generic names and explanation of abbreviations of author's names not found in the books mentioned. xii PREFACE I wish to take this opportunity to express my appre- ciation to the many friends who have assisted in the preparation of this book. Grateful acknowledgment is due to Mr. Hey ward Scudder for the suggestion of making a Key to the genera of mosses to be used with- out a lens, for testing the Keys, for much advice in writing the preliminary chapters, for reading and cor- recting the manuscript, and for many valuable sugges- tions. Mrs. Frank E. Lowe, Mr. H. Donald Kemp, and my sister, Miss Ethel A. Pennell, have read the preliminary chapters, tested the Keys, and given help- ful advice. I am indebted to Mrs. Lowe for collecting fresh mosses for study and comparison. Among others who have also patiently tried the Keys are Miss Georgia H. Emery, Miss Jane M. Furber, Miss Marie R. Felix, Miss Elizabeth A. Dike, Mrs. Frank C. Smith, Mrs. John L. Wright, and Miss Margaret Kemp. I am indebted to Mrs. Elizabeth G. Britton and Mr. Edward B. Chamberlain for answering many questions regarding nomenclature, authorities, and synonyms. Dr. A. J. Grout kindly gave me the deri- vation of Cirriphyllum and Miss Furber and Mr. Chamberlain assisted in looking up some of the other derivations. I am indebted to my husband, Mr. Horace C. Dunham, for helpful suggestions in drawing the illustrations. While recognizing its limitations and imperfections, I trust the book will accomplish much toward introduc- ing the mosses to those who have not known them, and PREFACE xlli in this way partly repay Mr. Charles J. Maynard and Mr. Walter Gerritson for their kind instruction when I began to study mosses, and all other friends for their assistance, interest, and encouragement while the work was in progress. CONTENTS ABBREVIATIONS OF NA]\IES OF AUTHORS . . xxiii INTRODUCTION i HABIT AND MANNER OF GROWTH 12 LEAVES 15 CAPSULES 20 THE KEYS EXPLAINED 23 HOW TO USE THE KEYS 26 HELPFUL SUGGESTIONS 32 KEY TO DISTINGUISH MOSSES FROM COMIMON HEPATICS AND LICHENS 39 LEAF KEY TO GENERA 41 CAPSULE KEY TO GENERA 53 LIST OF GENERA 70 Class BRYOPHYTES — Sub-Class MUSCI Order I. SPHAGNALES Family SPHAGNACEAE 73 Order IL ANDREAEALES Family ANDREAEACEAE 75 Order III. BRYALES ACROCARPI Family DICRANACEAE 77 Family LEUCOBRYACEAE 95 Family FISSIDENTACEAE 97 xvi CONTENTS Family POTTIACEAE loo Family GRIMMIACEAE iii Family ORTHOTRICHACEAE ii6 Family FUNARIACEAE 122 Family BRYACEAE 126 Family MNIACEAE 134 Family AULACOMNIACEAE 139 Family BARTRAMIACEAE 143 Family TIMMIACEAE 148 Family WEBERACEAE 150 Family BUXBAUMIACEAE 152 Family GEORGIACEAE 154 Family POLYTRICHACEAE 156 PLEUROCARPI Family HEDWIGIACEAE 172 Family FONTINALACEAE 175 Family CLIMACIACEAE 179 Family LEUCODONTACEAE 182 Family NECKERACEAE 185 Family ENTODONTACEAE 189 Family LESKEACEAE 195 Family HYPNACEAE 208 Family BRACHYTHECIACEAE 243 APPENDIX Helps to Identification of the Most Common and Con- spicuous Mosses 261 GLOSSARY 269 INDEX .275 ILLUSTRATIONS PLATES Plate I. Illustrations of Terms .... facing 12 Plate II. Illustrations of Terms .... facing 14 Plate III. Illustrations of Terms .... facing 18 Plate IV. Illustrations of Terms .... facing 22 Plate V. Dicranum facing 88 Plate VI. Mnium facing 134 Plate VII. Polytrichum facing 162 FIGURES IN THE TEXT Reindeer Moss (Cladonia rangiferina) 4 Red-tipped Moss (Cladonia cristatella) 4 Beard Moss (Usnea barbata) 4 Lycopodium lucidulum 5 Lycopodium obscurum 5 Long Moss (Tillandsia) 6 Flowering Moss (Pyxidanthera) 6 Liverwort (Marchantia) 7 Scale Moss (Bazzania) 7 Ceratodon purpureus 26 Sphagnum cymbifolium 73 Andreaea petrophlla 75 Trematodon ambiguus 77 Ditrichum tortile 79 Ditrichum pallidum 80 xviii ILLUSTRATIONS Saelania glaucescens 8i Ceratodon purpureus 82 DlSTICHlUM CAPILLACEUM 84 Dicranella heteromalla 8.5 Oncophorus Wahlenbergii 86 Leucobryum glaucum 95 FlSSmENS ADIANTOIDES 97 Weisia viridula 100 Hymenostylium CURVIROSTRE lOI tortella tortuosa io3 tortella caespitosa i03 didymodon rubellus . i04 Barbula unguiculata 105 pottia truncatula i06 tortula muralis i08 tortula papillosa i08 Encalypta ciliata 109 GRIMMIA APOCARPA 112 Rhacomitrium aciculare 114 Drummondia clavellata 116 Orthotrichum sordidum 118 Orthotrichum anomalum 118 Orthotrichum Braunii ii8 Ulota ulophylla 120 PhYSCOMITRIUM TURBINATUM 122 FUNARIA HYGROMETRICA 1 24 Leptobryum pyreforme 126 Pohlia nutans 128 Bryum caespiticium 129 ILLUSTRATIONS xix Bryum argenteum 130 Rhodobryum ontariense 132 aulacomnium heterosticiium i40 aulacomnium palustre 141 Plagiopus Oederi 143 Bartramia pomiformis 144 Philonotis fontana 146 TiMMIA CUCULLATA I48 Webera sessilis 150 Buxbaumia apiiylla 152 Georgia pellucida 154 Catharinaea undulata 157 Catharinaea angustata 158 POGONATUM BREVICAULE l6l Pogonatum capillare 162 Hedwigia albicans 173 FONTINALIS antipyretic A VAR. GIGANTEA 1 75 Fontinalis novae-angliae 175 DiCHELYMA CAPILLACEUM I77 Climacium dendroides 179 Leucodon julaceus 183 Leucodon brachypus 183 Neckera pennata 185 Homalia Jamesii 186 Thamnium alleghaniense 188 Entodon cladorrhizans 190 Entodon seductrix 190 Platygyrium repens 192 Pylaisia Sciiimperi 193 XX ILLUSTRATIONS Thelia HIRTELLA IQS Myurella gracilis 197 Anomodon rostratus 199 Anomodon minor 199 Anomodon attenuatus 200 Leskea polycarpa 201 Thuidium abietinum 202 Thuidium delicatulum 202 Helodium lanatum 206 Helodium paludosum 206 Amblystegium serpens 208 Amblystegium riparium 209 HoMOM ALLIUM ADNATUM 2IO HyGRO amblystegium IRRIGUUM 212 HyGRO AMBLYSTEGIUM FLUVIATILE 212 Drepanocladus uncinatus . , , 214 Drepanocladus fluitans 215 Calliergon cordifolium 216 Acrocladium cuspid atum 218 Hygrohypnum dilatatum 219 Hygrohypnum eugyrium var. Mackayi 219 CtENIDIUM MOLLUSCUM 222 Rhytidiadelphus triquetrus 223 Hylocomium proliferum 225 Hylocomium umbratum 227 Hypnum Schreberi 229 Ptilium crista-castrensis 230 Stereodon reptilis .233 Stereodon imponens 234 ILLUSTR.\TIONS xxi Stereodon arcuatus 236 Stereodon Haldanianus 237 isopterygium turfaceum 238 Plagiotiiecium denticulatum 240 Plagiothecium striatellum 242 Camptothecium nitens 243 Brachythecium salebrosum 244 Brachythecium rivulare 247 cirriphyllum boscii 250 oxyrhynchium rusciforme 25 1 eurhynchium strigosum var. robustum 253 Bryhnia novae-angliae 254 Rhynchostegium serrulatum 256 ABBREVIATIONS OF NAMES OF AUTHORS Note. The abbreviations, or in a few cases the full names, given after the generic or specific names of the mosses refer to the botanists who named the plants. When the same botanical name was used earlier by another author in a different connection, the name of the earlier author is given in parentheses. Aust. Austin, Coe F. Banks Banks, George Bcauv. (= Palis.) Beauvois, A. M. F. J., Palisot de Bland. Blandow, Otto C. Blytt Blytt, Matthias N. Brid. Bridel, Samuel E. Broth. Brotherus, Dr. V. F. Bruch Bruch, Philipp Bryol. Eur. Bryologia Europaea. A publication by Bruch & Schimper. C. Miill. Mulltr. C. De Not. De Notaris Dicks. Dickson, James Dill. Dillenius, Johann J. E. G. B. Britton, Elizabeth G. Ehrh. Ehrhart, Friedrich Funck Funck, Heinrich C. Fiirnr. Fiirnrohr Grev. Greville, Robert K. Grout Grout, Dr. A. J. Gunn. Gunnerus, Johann E. Hall. Haller, Albert von Hammar Hammar, Olof Hamp. Hampe, Ernst Hedw. Hedwig, Johann Hoffm. Hoffmann, George F. Hook. Hooker, William J. Hook. & Tayl. Hooker, W. J., & Taylor, Thomas XXIV ABBREVIATIONS Hornsch. Hornschuch, Christian F. Hiiben. Hiibener, J. W. P. Huds. Hudson Jaeg. & Sauerb. Jaeger & Sauerbeck James James, Thomas P. Kaur. Kaurin Lesq. Lesquereux, Leo Leyss. Leysser, Friedrich W. von L. Linnaeus, Carolus Limpr. Limpricht Lindb. Lindberg, Sextus O. Loesk. Loeske Menz. Menzies, Archibald Michx. Michaux. Andre Milde Milde, Julius Mitt. Mitten, William Mohr Mohr, Daniel M. H. Mull. MuUer, C. Myr. Myrin, Claes G. Neck. Necker, Noel Joseph de Nichols Nichols, George E. Palis. (= Beauv.) Palisot de Beauvois, A. M. F. J, Paris Paris, E. G. Rabenh. Rabenhorst, Ludwig Ren. & Card. Renauld & Cardot Rich. Richard, Louis C. M. Roell Roell Rohl Rohl, E. von Roth Roth, Georg Schimp. Schimper, W. P. Schmid. Schmidel, Casimir C. Schreb. Schreber, Johann D. C. von Schrad. Schrader, Heinrich A. Schwaegr. Schwaegrichen, Christian F, Sibth. Sibthorp, John Sm. Smith, John Stark. Starke Stroem Stroem, Hans Sull. SuUivant, WiUiam S. ABBREVIATIONS xxv Sull. & Lesq. SuUivant & Lcsqucreux Sw. Swartz, Olaf Timm Timm, Joachim C. Turn. Turner, Dawson Vill. Villars, Dominique Wahl. Wahlcnbcrg, Gcorg VVarnst. Warnstorf, C. Web. Weber, Friedrich Web. & Mohr Weber, Friedrich, & Mohr, Daniel M. H. Weinm. Weinmann, J. A. Weis Weis, Ludwig Willd. Willdenow, Carl L. Wils. Wilson, William HOW TO KNOW THE MOSSES INTRODUCTION If it were not for the mosses, it is difficult to say how barren the woods would be or how much beauty would be lost to nature. Wherever mosses occur there is an added bit of color. The eye is attracted by the green, velvety clumps of the upright plants, the delicate texture of the prostrate ones, or by the brighter color of the slender fruit-stalks. Mosses are relatively small plants, but they often form a conspicuous part of the vegetation, owing to the extensive branching and the prolonged growth of the stems and their rapid multiplication. (See illustrations throughout the book; also parts of a moss, Plate I.) The plants are always some shade of green, often brightened by touches of red, orange, or yellow in the fruit and fruit-stalk. They consist of a stem and leaves, although either of these may be greatly re- duced. The stems are erect, prostrate or ascending, branched or unbranched, reaching several inches in length in the largest species, while others are so short that there is only a tiny tuft of leaves, and the fruit and fruit-stalk are the conspicuous parts of the plants. (See chapter on ''Habit and Manner of Growth," p. 12.) The leaves vary in size, the longest 2 HOW TO KNOW THE MOSSES measuring fully one-half inch, while many others are too small or too closely folded to be seen easily. The beginner will mistake branches for leaves at first, especially when the leaves are small and the branches numerous. (See chapter on "Leaves," p. 15.) A Httle experience in examining different kinds of mosses will best enable one to know what are branches and what are leaves. Mosses branch much as other plants do, and the leaves usually grow all around both the stem and the branches, sometimes thickly covering them and so closely overlapping that the outline of the leaf cannot be seen. The leaves are better seen when moist, as they usually spread then more than when dry. If the plants are held to the light, at least the tips of even the small leaves generally can be seen standing out around the stems and branches. The leaves are thin and flat, while the branches are usually cylindrical in general outline, especially when the leaves are small and closely folded. The appearance of most mosses changes according to the amount of moisture in the leaves. When moist, the leaves are well expanded and usually spreading; when dry, they either becomie more erect and fold against the stem, closely overlapping, or else they are twisted and curled (crisped). Unlike dried flowering plants, mosses when dried are not past reviving, but can be restored to fresh conditions by being placed in water. This is due to difference in the structure and function of parts of the plants. Plants of the higher INTRODUCTION 3 orders are dependent upon roots for absorbing most of their food and moisture and this is carried up through the stem and distributed to all parts of the plant by means of conducting cells. The leaves, as well as other parts of the plant, are entirely surrounded with a special layer of cells the outer walls of which contain a substance called ^'cutin," which renders this coating practically water- and gas-proof. This waterproof coating prevents excessive evaporation and also ab- sorption of water. Mosses, on the other hand, are not dependent upon roots for absorbing water, and the leaves and other parts of the plant are not provided with a waterproof coating. This structure not only causes mosses to dry easily, but also enables them to absorb water quickly through the entire surface of the leaves and all parts of the plant and so resume the appearance of fresh plants when dried specimens are placed in water. Mosses are widely distributed, and are found in all sorts of places except in salt water. They grow on moist and on dry ground ; on bare rocks and ledges and on those that are covered with soil; on trees; on decay- ing wood, such as old logs and stumps; on old roofs; and even in streams and ponds and in places that are sometimes submerged. They are especially abundant in cool, moist woods and luxuriant swamps where old logs are rotting, but many may be found in drier and more open places, such as old fields and meadows, and even along the roadside. HOW TO KNOW THE MOSSES The name ''moss " is commonly applied to a number of plants that do not belong to the true mosses. Only a few of these plants, especially some of the hepatics, resemble the mosses in general appearance; the others are very different in structure, growth, or color; and two belong to the flowering plants. Lichens are often called mosses by those unfamiliar with the lower forms of plant-life; but the absence of Reindeer Moss Cladonia rangijerina Red-tipped Moss Cladonia cristatella LICHENS Beard Moss Usnea barbata anything like leaves arranged around a stem, and of the bright green of foHage or grass, at once separates them from the mosses and other higher plants. A lichen is composed of an alga and a fungus living to- gether in a state of mutual benefit. Although the alga supplies a little chlorophyll, or green matter, the gen- eral color of lichens, especially when dry, is usually some shade of gray or very pale green, or, if green when moist, becoming gray when dry. Some species are orange or brown. The plant-body is called a thai- INTRODUCTION Ills, which means without a true stem and leaves, in the sense that these terms are used in connection with the higher plants. Some lichens are flat, more or less disk-shaped; some are erect and have a hollow, stem- like structure which is often branched; while others are thread-like and hang from trees. The stiff, shrubby growth called *' reindeer moss," the winter food of the reindeer; the ''red- tipped moss" with bright-red fruit-caps; and the "beard moss" which hangs like a gray beard from old trees, are all lichens. Sea mosses (Algae) belong, with the lichens and fungi, to a lower order than the land mosses. Although the true mosses grow on cliffs by the sea, they nev«r grow in salt water as the algae do. Irish moss used in cooking is an alga. The so-called "club mosses" (Lycopodiaceae) are Lycopodium luciduliim Reduced Lycopodium obscurum Reduced CLUB MOSSES 6 HOW TO KNOW THE MOSSES larger, coarser, more robust plants than the mosses and belong to a higher order. They have woody stems and stiff, evergreen leaves. "Stag's horn moss" is a popular name for some species of Lycopodium, differently used in different locahties. Long Moss (Tillandsia) Flowering Moss (Pyxidanthera) Reduced Reduced FLOWERING PLANTS The "long moss" which hangs in long tufts from branches of trees in the South, and the "flowering moss" which grows prostrate in the pine barrens of New Jersey and southward, belong to the flowering plants, and will not be confused with the mosses except in name. " Florida moss " is the long moss. The hepatics or liverworts, especially the leafy liver- worts sometimes called "scale mosses" (Jungermanni- ales) , somewhat resemble certain mosses, and one needs to know something of their appearance in order to recognize them. They are a rather dark green, and are INTRODUCTION 7 found in moist woods on rocks, trees, old logs, etc., not infrequently growing with mosses. The true liverworts {Marchantiales) do not have a true stem or leaves, but are broad and flat, and cling closely to the substratum. They are less frequently Liverwort (Marchanlia) Scale Moss i^azzania) HEPATICS confused with mosses. It is in regard to the leafy liver- worts, or ''scale mosses" (Jungermanniales) , that one particularly needs a word of warning. The scale mosses have leafy stems and are pros- trate, ascending, or erect. The leaves are usually rounded, lobed, or cleft, often curved under at the tips, and never have a midrib. There are two rows of leaves, one on each side of the stem, with a third row of modi- fied leaves underneath; so that the plants are not only flattened, but have also two distinct surfaces. This flattened appearance of the stems and the peculiar shape of the leaves are good distinguishing character- istics that separate these hepatics from the mosses. The leaves of mosses are never lobed or cleft, and are usually arranged all around the stem, so that the 8 HOW TO KNOW THE MOSSES plants do not show a distinct upper and lower surface. A midrib may or may not be present. In many species it can be seen when the plants are held to the light. In the genus Fissidens (p. 97) the leaves are in only two rows and mHomalia (p. 186) nearly in two rows, but they do not curl under at the tips as the leaves of he- patics so often do. In some other mosses the leaves appear to be in two rows, as they turn in two opposite directions and are somewhat flattened, but in these cases the shape of the leaves or the presence of the fruit helps to distinguish the plants. The mosses are more numerous than the hepatics. On account of the importance of distinguishing certain hepatics, the following table may be helpful : — Leafy Hepatics Mosses {Jungermanniales) Plants Always flattened, with Not always flattened, usually two distinct surfaces; the without a lower or back surface, lower or back surface to- ward which the leaves curl sometimes bearing what appear to be root- lets. Leaves Arranged in two oppo- Usually arranged equally site rows; rounded, lobed around stem; never lobed or cleft or cleft, often curved un- and when rounded not curved der at tips. under at tips. Midrib Absent. Present or absent. Classification and Life History The mosses, or Musci, and the liverworts, or He- paticae, are the two divisions of the Bryophytes, a Class coming between the fungi and the ferns. The mosses INTRODUCTION 9 are more numerous than the liverworts and are divided into three Orders: I. Sphagnales, or peat mosses; II. Andreaeales; III. Bryales, or true mosses. The first two Orders are described in separate chapters, as they differ in structure from the true mosses. See Sphag- nales (p. 73) and Andreaeales (p. 75). The reproduction of mosses is accomplished in two general ways, sexually and asexually. In the asexual or vegetative reproduction, that is, multiplication by other means than by the sexually formed s pores, either small organisms, known as ''gemmae," produced among the leaves or at the end of slender branches, become separated from the parent plant and develop new individuals, or parts of the plants, such as bits of the stem, branches, or leaves, become detached and grow into new plants. In the sexual reproduction, mosses, like ferns, start from a spore, not from a seed. The spore first produces a green thread-like growth called protonema, and upon this a tiny bud develops that grows into the leafy plant. The male and female flowers occur at the apex or on the side of the stems and branches, sometimes growing on the same plant and sometimes on separate plants. The sexual organs are microscopic, but the male buds are often conspicu- ous and surrounded by a rosette of bract-like leaves that are green, red, or orange. The sperms from the male flowers swim in moisture, after rains or heavy dews, to the egg-cell of the female flower. After fertili- zation takes place, the fruit or capsule develops, en- lo HOW TO KNOW THE MOSSES closing the spores. The capsule is usually borne above the plant on a stalk of varying length, called the seta. When the seta is very short or lacking, the capsule is almost hidden in the surrounding leaves. At the mouth of the capsule are special parts that serve to protect the spores until they are mature and ready to be scattered to develop new plants under favorable conditions. As special reference is made in the Keys to the char- acter of the capsule, leaves, and stems, they are de- scribed in chapters by themselves. (See "Habit and Manner of Growth," p. 12, ''Leaves," p. 15, "Cap- sules," p. 20.) Some mosses are short-lived, but many are peren- nial, and continue their growth annually at the tips of the stems and branches, or develop new plants from underground stems. There are no true roots, but the plants are attached to their substratum by radicles, or rootlets. Radicles are not only at the base of the stem, but sometimes cover the greater part of it, forming a brown or whitish, felt-like coating, called tomentum. The simple structure of mosses enables them to ab- sorb moisture easily, and where extensive growths occur, they perform an important service to plant-life by holding back much of the rainfall, allowing the water to soak into the earth gradually instead of running off the surface. They also add to the rich- ness of the soil through their decay, and assist in the disintegration of rocks. A few of the larger species are used as a packing material. Sometimes they are INTRODUCTION ' ii dyed and used for decorative purposes, especially by milliners. Mosses may be collected and grown in the house if a little care is taken to keep them moist. It is well to collect enough of the substance upon which the plants grow so as not to disturb the rootlets. A number of different kinds may be placed together in a fern globe or in an open dish. A Httle experience will show one how much sun and how much moisture are required. Too much sun will make the plants dry too quickly, and too much moisture without enough sun will make the plants mould. It is often of great interest to gather plants with very young fruit and then watch the cap- sules develop and the new shoots grow. HABIT AND MANNER OF GROWTH Mosses have certain ways of growing and of branch- ing that are important generic characteristics and these should be noticed when specimens are collected for determination. There are two chief types of growth by which all mosses fall naturally into two main divisions. In one, the acrocarpous mosses, which often form a deep, thick growth, the stem is typically erect (Plate I, Fig. i), not branched or with only a few branches, and the fruit is borne at the tip of the stem, sometimes ap- pearing lateral by the new growth of the plant. (Plate I, Figs. 2, 3.) In the second type, the pleurocarpous mosses, which often form thin, fiat, tangled mats, the stem is generally prostrate (Plate I, Fig. 4), or ascend- ing (Plate I, Fig. 5), erect in only a few cases, much branched, and the fruit is borne on the side of the stem. The plants may be scattered singly or may grow more or less crowded together. Deep mossy mats are sometimes formed when plants with erect or ascending stems grow close together and the new annual growth is added to that of the previous year. Thin flat mats occur when the plants are prostrate or creeping and the stems and branches continue to spread and inter- weave. In some genera, rounded cushions are formed EXPLANATION OF PLATE I Acrocarpous Mosses Fig. I. Parts of a moss; stem erect, not branched; fruit at apex of stem. Fig. 2. Fruit appearing lateral by forking of stem. Fig. 3. Fruit appearing lateral by new growth of plant. Pleurocarpous Mosses Fig. 4. Stem prostrate; fruit on a short lateral branch. Fig. 5. Stem ascending; fruit on side of stem. FRUIT -- FRUIT- STALK stem; •- OR CAPSULE OR SETA : LEAVES RADICLES ^ w ^ r t Plate I. ILLUSTRATIONS OF TERMS HABIT AND MANNER OF GROWTH 13 when a number of plants grow together in separated tufts instead of spreading over any extent of surface. The stems may be not branched at all or slightly branched by forking (Plate II, Fig. i), or with numer- ous lateral branches arranged pinnately (Plate II, Fig. 2), bipinnately (Plate II, Fig. 3), tripinnately (Plate II, Fig. 4), irregularly (Plate II, Fig. 6), in clusters (Plate II, Fig. 7), or like the branches of a tree (Plate II, Fig. 5). Sometimes the primary stem is creeping and the secondary stems erect or ascending, more or less branched (Plate II, Fig. 8). In this case, care must be taken to separate the plants and not to mistake a pleurocarpous moss with prostrate stem and erect branches (Plate II, Fig. 8) for an acrocarpous moss with erect stem (Plate I, Fig. i). The pleurocarpous mosses, usually creeping or pros- trate, grow in tangled mats with interwoven stems and branches so that no great length can be easily separated, while individual plants of the acrocarpous mosses, growing erect, are easily separated. Two or more kinds of mosses are often found growing together. When plants with erect stems (acrocarpous mosses) are mixed, it is not difficult to separate them, especially if the leaves of the different species are distinctly unlike; but one prostrate species (a pleurocarpous moss) may grow on top of another of similar growth quite con- cealing it, or the stems and branches of both mosses may grow together on the surface, sometimes so inter- >v 14 HOW TO KNOW THE MOSSES woven that it is almost impossible to separate them. Such mixed material is not good to study or to keep for the herbarium. It is not unusual to collect an ap- parently good fruited specimen and upon careful exam- ination to find that the fruit of some moss quite hidden from view has pushed up through the conspicuous growth on the surface, giving a wrong idea of the cap- sule that really belongs to the moss first noticed. The color of a moss given in descriptions is that of the leaves, as the leaves so thickly cover both the stem and branches, but sometimes when the leafy part is small, the color of the fruit-stalks is more conspicuous. In a few cases when moist plants are held to the light, the stems and branches of the new growth show con- spicuously red through the leaves. (See Pohlia, p. 1 27 ; Bryum, p. 129; Hylocomium, p. 225; Hypnum, p. 229.) When this is the case it is mentioned in the descrip- tions; otherwise color is given only under ^'Plants" and repeated under *' Leaves." Sometimes the lower part of the stem is covered with reddish-brown or whitish radicles, forming a felt-like coating called tomentum, which often mats the stems together. (See Dicranum, p. 87. ) EXPLANATION OF PLATE II Branching of Acrocarpous Mosses {Lines represent stems and branches) Fig. I. Stems forked. (The usual manner of branching; for exceptions see Philonotis, p. 145, and Drummondia, p. 116.) Branching of Pleurocarpous Mosses Fig. 2. Stem pinnate. (Branches quite regularly arranged on opposite sides of stem.) Fig. 3. Stem bipinnate. (Some if not all of the pinnate branches branched again.) Fig. 4. Stem tripinnate. (Some if not all of the bipinnate branches branched again.) Fig. 5. Stem tree-like in branching. (Branches only toward the tip of the stem, like the branches of a tree.) Fig. 6. Stem irregularly branched. (Varying in many ways but not regularly pinnate, bipinnate, tripinnate, or tree-like.) Fig. 7. Stem with branches arranged in clusters. Fig. 8. Primary stem creeping, secondary stems erect oi- ascending, usually branched. Plate II. ILLUSTRATIONS OF TERMS LEAVES The leaves of mosses vary in size, shape, arrange- ment, position, and color, and it is necessary to train the eye to notice these variations in order to recognize the generic characteristics. Care must be taken not to mistake branches for leaves, when the leaves are very small and the branches are more conspicuous. Mosses branch much like other plants and the leaves are much more numerous than the branches, some- times thickly covering both the stem and the branches. When the leaves are very small and closely folded, the branches look cylindrical, but if the plants are held to the light, at least the tips of the leaves can usually be seen sticking out around the branches. Unlike the leaves of other plants, the leaves of mosses nearly always consist of only a single layer of cells, except where the midrib occurs or at the margin of the leaf when it is thickened. This simple structure makes the leaves dry readily and also absorb moisture readily, and adds a special interest to the study of mosses, as dried specimens can be easily restored to fresh conditions by being placed in water for a few minutes. This has been tried with plants that had re- mained dry for over one hundred years, and it was found that the leaves still expanded quickly. In an- i6 HOW TO KNOW THE MOSSES other instance, two different mosses were soaked and dried fifty times without injury to the plants except that the color of the leaves faded. A midrib, called a costa, may or may not be present, and it may be single, double, or forked. In some of the largest leaves it can be seen if the plants are held to the light. (See Mnium punctatum var. elatum, Plate VI, Fig. 5.) It shows like a dark line through the center of the leaf, and is usually slender, but in the Polytri- chaceae (p. 156) it is much wider, sometimes occupying the greater part of the leaf blade. The leaves never have a stalk, but grow directly on the stem and branch. Leaves on the same plant may vary in size. Those that are typical and that should be selected for study are along the middle part of the stem or branch. The leaves near the base of the stem, as well as those at the tip, are often smaller or not well developed. Plants not bearing fruit sometimes grow more luxuriantly than fruited specimens and therefore have larger leaves. When the plants are much branched (pleurocarpous mosses), the leaves on the stem are often larger than those on the branches. Many leaves are large enough to be seen easily, the longest measuring fully one-half inch; many that are smaller can be seen when the plants are held to the Hght or against something white; while still others are too small or too closely folded against the stem or branch to be seen without a lens. Leaves vary in shape from hair-like to nearly round, LEAVES 17 but they are never compound, lobed, or deeply cut. The leaves of the acrocarpous mosses, those coming under Division A in the Keys, may be divided as rela- tively long and narrow, or short and broad. Those that are relatively long and narrow may be hair-like throughout, or broader at the base and gradually nar- rowed (Plate III, Fig. i), or about the same width throughout and then end in a hair-like tip (Plate III, Fig. 2). The leaves that are relatively short and broad may be ovate (Plate III, Fig. 3), or ovate-oblong (Plate III, Fig. 4), or elliptical (Plate III, Fig. 5), or nearly round (Plate III, Fig. 6). The leaves of most of the pleurocarpous mosses, coming under Division B in the Keys, vary less in shape and are less easily seen, as they are so small or so closely folded. Although there are some similar to those described above, the shape that is most common is more or less ovate at the base ending in a straight tip (Plate III, Fig. 7), or in a curved tip (Plate III, Fig. 8). The edge of the leaf may be entire or serrate, but in only a very few mosses are the serrations seen without a lens. When the cells along the margin of the leaf differ from those of the rest of the leaf, the leaf is said to be bordered. In the large leaves of Mniuni punc- tatum var. elatum (Plate VI, Fig. 5), the thickened border can be seen like a fine, dark-green line around the leaf. Leaves are described as ''crisped" when they be- come crinkled, curled, or twisted in drying. 1 8 HOW TO KNOW THE MOSSES The arrangement and position of the leaves are important characteristics in determining mosses, and ones that can be easily studied. Leaves usually grow all around the stems and branches (Plate III, Fig. 9), but in Fissidens (p. 97), Distichium (p. 83), and in a few other genera not in- cluded in this book, they are arranged in only two rows on opposite sides of the stem and He flat like the pinnae of a fern (Plate III, Fig. 10). They are called ''erect" when they He about parallel with the stem (Plate III, Fig. 11); "wide-spreading," when they stand out nearly at right angles to the stem (Plate III, Fig. 12) ; '' erect-spreading," or '' not wide-spreading," when they are between erect and wide-spreading; and ''turned to one side" (secund), when they look as if blown in one direction (Plate III, Fig. 13). In some of the pleurocarpous mosses the leaves appear in two rows when they are evenly parted and turned in two opposite directions (Plate III, Fig. 14). There is often a difference in the position of the leaves when moist and when dry. For instance, leaves that are wide-spreading when moist may become closely folded when dry instead of becoming crisped; in other cases they are not much changed in drying. Many shades of green are found in the mosses. Some are glaucous (whitish) or bluish, some golden or yel- lowish, and some bright, olive, or dark green. There is often a variation in color, even on the same plant, as the oldest leaves turn brown or dark, while the young- EXPLANATION OF PLATE III Leaves of Acrocarpous Mosses LEAVES relatively LONG AND NARROW Fig. I. Broader than hair-like. Fig. 2. Ending in a hair-like tip. LEAVES RELATIVELY SHORT AND BROAD Fig. 3. Ovate, or egg-shaped. Fig. 4. Ovate-oblong. Fig. 5. Elliptical. Fig. 6. Nearly round. LEAVES OF MOST PLEUROCARPOUS MOSSES Fig. 7. Ovate at base, ending in a straight tip. Fig. 8. Ovate at base, ending in a curved tip. ARRANGEMENT OF LEAVES Fig. Q. Leaves on stem and branches. Fig. 10. Leaves in two opposite rows, giving the plants a flattened appearance. LEAVES ARRANGED EQUALLY AROUND STEM Fig. II. Leaves erect. (Nearly parallel to stem.) Fig. 12. Leaves wide-spreading. (More or less at right angles to stem.) Fig. 13. Leaves turned to one side. (Secund.) Fig. 14. Leaves curved and turned in opposite directions, giving a braided appearance along the stem and branches. Plate III. ILLUSTRATIONS OF TERMS LEAVES 19 est are usually very light; the leaves along the central portion of the stem give the typical color of the plant. Although the color is quite characteristic when the plants are normal, it is rather unreliable, as it is often affected by the various conditions under which the plants may grow. CAPSULES The capsule of a moss is often spoken of as the '* fruit." It is the swollen case containing the spores at the end of a slender stalk called the seta, or partly hid- den_by the surrounding leaves, and develops, like all fruit, after the flower has been fertilized. (Plate IV, Fig. I.) Great care must be taken when studying the cap- sule to be sure it is old enough to show the typical form and position. A young capsule is nearly always pale green and very slender, shrinking a good deal when dry. A capsule is mature when the spores are ripe and ready to be scattered, and it is then yellowish- or red- dish-brown, well filled out, and does not wholly lose its characteristic shape in drying. Sometimes a green capsule is sufficiently developed to show the typical form, but it must be at least filled out if not beginning to change color. When the spores have all been scat- tered, the capsule is spoken of as empty, but in many cases it retains its characteristic shape for some time. Often both old and young capsules may be found at the same time. Extremes in either case should not be used for study, as a very old capsule becomes dark and decayed or broken, or, if at first erect, it may become bent over. Most mosses mature their spores in the fall or early winter, the rest do so in the spring or summer. CAPSULES 21 The capsule is usually borne above the leafy plant on a fruit-stalk, or seta (Plate IV, Fig. i) of varying length. In some cases the capsule is partly hidden by the sur- rounding leaves when the seta is very short. If the seta comes from the apex of the stem or of a well- developed branch, the fruit is spoken of as terminal " and the moss is called "acrocarpous " ; if the seta comes from the side of the stem or is on a very short lateral branch, the fruit is spoken of as '' lateral " and the moss is called ''pleurocarpous." The color of the seta is usually yellowish or reddish. An erect capsule is upright like the seta; when not erect, it may be inclined, horizontal, or drooping. For the various shapes of capsules and their characteristic positions see Plate IV, Figs. 3-16. There are interesting parts of the capsule — the operculum and the peristome — that with the calyptra serve as a protection while the fruit is immature. (See Plate IV, Figs. 1,2.) The calyptra is like a hood covering the young cap- sule. It usually falls off before the spores are ripe, but if it remains on until the capsule fills out, it is often pushed upwards and finally covers only the beak of the operculum. In a few cases the calyptra is covered with hairs. (See Ulota, p. 119, and Polytrichum, p. 162.) It may be hood-shaped (cucullate) (Plate IV, Fig. 17) or like a beaked cap (mitrate) (Plate IV, Fig. 18). Nearly all capsules open by means of a lid, or oper- culum. It is the upper portion of the capsule that be- 22 HOW TO KNOW THE MOSSES comes detached and falls off when the spores are ripe. It may be convex (Plate IV, Fig. 19), cone-shaped (Plate IV, Fig. 20), short-beaked (Plate IV, Fig. 21), or long-beaked (Plate IV, Fig. 22). Underneath the operculum surrounding the mouth of the capsule, there is usually a tiny fringe called the peristome which may be single or double. The outer peristome is composed of filaments called "teeth" that are sensitive to moisture; they usually shade from red to orange or yellow. The inner peristome is more dehcate than the outer, and its divisions are called "segments." In wet weather the teeth are tightly closed together to prevent the spores from being washed out in masses; when dry, they separate and bend back allowing the spores to sift out. The number of teeth, and their size, shape, and character are often important points in determining species when studying mosses with a microscope. (See Plate V, Fig. 6 ; Plate VI, Fig. 2; Plate VII, Fig. 4.) EXPLANATION OF PLATE IV Capsules Fig. I. Capsule with calyptra and operculum in their natural place. Fig. 2. Calyptra and operculum removed to show peristome. SHAPES AND POSITIONS OF CAPSULES {Drawn without the operculum) ERECT CAPSULES Fig. 3. CyUndrical. Fig. 4. Angular. Fig. 5. Top-shaped. Fig. 6. Urn-shaped. Fig. 7. Elliptical. Fig. 8. Oval, or egg-shaped. Fig. 9. Pear-shaped. Fig. 10. Fig. II. Fig. 12. Fig. 13- Fig. 14. Fig. 15- Fig. 16. CAPSULES NOT ERECT Cylindrical, horizontal. Cylindrical, much curved. Cylindrical, hanging down. Globular. Pear-shaped with neck distinct. Angular, horizontal. Ovate, or egg-shaped, pointed. SHAPES OF THE CALYPTRA Fig. 17. Hood-shaped (cucullate). Fig. 18. Like a beaked cap (mitrate). SHAPES OF THE OPERCULUM Fig. 19. Convex. Fig. 20. Cone-shaped (conic). Fig. 21. Short-beaked. Fig. 22. Long-beaked. •peristome: 9= ?. 10 12 15 lb 17 OUU 18 » A ZO 21 C ) 22 Plate IV. ILLUSTRATIONS OF TERMS THE KEYS EXPLAINED The object of the Keys is to give the student a non- technical guide to the genera and in some cases the species of the mosses he is likely to notice, and to en- able him to recognize them without the aid of a lens. No preliminary knowledge of the mosses is necessary except of their habitat; that is, the natural locality of the plants, as ground, rocks, trees, etc. The numbers in the Keys refer to the genera in ''List of Genera" (p. 70). Illustrations of the descriptive terms used will be found on Plates I, II, III, IV. Two separate Keys are provided, each including all the mosses described in the book. The Leaf Key is based upon the character of the leaves with further subdivisions, and the Capsule Key is based upon the character of the capsules with further subdivisions. In some cases the leaves alone or the capsules alone are not sufficient to determine a moss, and for this reason the Leaf Key is carried out with capsules and the Cap- sule Key is carried out with leaves. Stem characteris- tics are given when helpful in dividing the mosses into groups. The length of the stem is measured from the rootlets through the leafy portion; but does not include the fruit-stalk. (See Plate I, Fig. i.) In both Keys the mosses are first divided in the usual way. Division A including the acrocarpous mosses with 24 HOW TO KNOW THE MOSSES the stems generally erect and not much branched, and the fruit at the apex of the stem ; Division B including the pleurocarpous mosses with the stems generally prostrate and much branched and the fruit on the side of the stem. As is to be expected with any key based on general characteristics, certain exceptions may be found and certain difficulties encountered. The chief of these are as follows : Mosses coming under Division A may not be strictly erect and may be more or less branched, but the fruit is terminal, although it may appear lateral by the time it is mature on account of the new growth of the stem, which is not so dark a green as the older part. The fruit of Fissidens (p. 97) may be terminal or lat- eral, but the stems are erect and little branched. The stems of the Grimmiaceae (p. iii) and the Orthotricha- ceae (p. 116) may be more or less prostrate with erect branches, but the fruit is borne at the tip of the stem or branch. There are a few erect mosses that come under Division B, but the fruit is always lateral and the stems are usually much branched. If a moss has more than one habitat it is placed in the Keys under more than one head; for instance, under "Plants growing on the ground" and ''Plants growing on rocks," etc. Leaves of moist plants are described. In Division A, when the leaves are so small that the relative shape cannot be estimated, the mosses are classed under ''Shape of leaves when moist not easily seen." If the THE KEYS EXPLAINED 25 leaves are large enough to show the entire outline when the plants are held to the light, the mosses are placed under the next corresponding head, ''Shape of leaves when moist easily seen." In Division B the mosses are divided a little differently, as the leaves vary less in shape and in many cases the entire outline is not so necessary in determining the genera. When the leaves are large enough to show whether they are straight or curved, the mosses are placed under ''Leaves when moist easily seen " ; when the leaves are too small or too closely folded to show this characteristic, the mosses are placed under "Leaves when moist not easily seen." In both the Leaf Key and the Capsule Key the posi- tion and the shape of the capsule that are given are always those of the fully developed fruit. In order to recognize when the capsule is mature see chapter on "Capsules " (p. 20). f HOW TO USE THE KEYS Suppose we have collected in late spring or eariy summer a moss growing on dry soil, abundantly fruit- ing and conspicuous for the dark-red fruit-stalks and capsules. After soaking a piece of the specimen in water for a few minutes, keeping the re- maining part dry, and separating some of the moistened individual plants, we find they look like these. Let us use the Leaf Key first. We find that there are two main divi- sions, A and B. Under Division A we read, ''Fruit at the apex of the stem or of a well- developed branch, sometimes appearing lateral by the new growth of the plant. Stems generally erect, and often not branched; or, if slightly branched by forking, usually with not more than two or three branches." Under Division B we read, ''Fruit on the side of the stem or on a very short lateral branch. Stems prostrate or ascending, rarely erect, usually much branched (with more than two or three branches.)" We examine our plants and find that the stems are erect with only one or two branches. The fruit on one of the plants is terminal and on the other two it appears lateral, but as the growth above the point where the fruit-stalk is attached to the stem is HOW TO USE THE KEYS 27 lighter green than that below, we decide that it must be the new growth of the plant and that the fruit was at first at the tip of the stem. We place our plant under Division A because the erect stems only a Httle branched, even without the fruit, bring it there. We found the moss growing on the ground. Under ''Plants growing on the ground" we find: "I. Shape of leaves when moist not easily seen" and "II. Shape of leaves when moist easily seen." The note states that the leaves must be seen well enough to estimate their rela- tive shape. By holding our moist specimens to the light or laying them on something white, we note that most of the leaves though small are easily seen to be long and narrow. Our plant comes, then, under "II. Shape of leaves when moist easily seen. a. Leaves long and narrow." The next headings are, "Stems one-half inch long or less" and "Stems more than one-half inch long." The stems of our plant are not more than one- half inch long, so we place it under the first of these heads. The next divisions are, "Leaves hair-like throughout" and "Leaves broader, sometimes ending in a hair-like tip." The leaves of our plant look hair-like throughout, so we read further under this head, " Cap- sule erect" and "Capsule not erect." The capsules of our plant are not erect, so we follow the second heading to the right and come to the genus numbers i, 2, 4, 6, 7, 8, 26, 36. Turning to the "List of Genera" (p. 70), we are referred to the page where each genus is de- scribed and illustrated. Turning to number i. Trema- 28 HOW TO KNOW THE MOSSES todon, we see that two of the conspicuous character- istics in italics are ''seta greenish-yellow" and ''cap- sule with a long neck." As the seta of the plant we are studying is not yellow and the illustration of the capsule does not look like the capsule of our plant, we pass to the next genus number and turn to the descrip- tion. 2. Ditrichum, we read, has one species with hair- like leaves, and a capsule that is sometimes incHned, but the seta is again yellow and the leaves in the illus- tration are much longer than those on our plant, so we pass to the next description — 4-. Ceratodon. Here the description and illustration correspond perfectly to our specimen. However, to make sure, we glance at the illustrations of the remaining numbers. 6. Dicranella has leaves turned to one side, unHke the leaves of our plant. 7. Oncophorus has leaves crisped when dry, while the leaves of our dry specimen fold straight against the stem. 8. Dicranum has leaves usually turned to one side. The illustration of the capsule of the two remaining genera, 26. Leptohryum and 36. Webera, are so different from the capsule of the moss we are studying that we feel reasonably sure that the plant under consideration is number 4. Ceratodon. Although in every instance it is safer to study fruited specimens, about fifty per cent of the common genera can be identified without the aid of the capsule if sufficient care is taken. An illustration to show what can be done with a sterile moss is here given. HOW TO USE THE KEYS 29 The moss used in the foregoing illustration will serve as an example. Going back to the beginning of the Key, we find that the capsule did not come under consider- ation until we had placed our specimen under *'IL a.," and further, under ''Stems one-half inch long or less," ''Leaves hair-like throughout." Now, suppose we have no capsule to aid us and we cannot tell whether the plant belongs under "Capsule erect" or "Capsule not erect." We must look up all the genera coming under both these heads, which are 1,2, 3, 4, 6, 7, 8, 11, 15, 26, 36, 38, and compare with our moss the illustra- tions and descriptions, especially the characteristics in italics, but omit all reference to seta and capsule, i. Trematodon we throw out because the illustration shows the leaves much longer than those of our plant, and it grows on damp soil, whereas we found our plant on dry soil. 2. Ditrichum in one case has leaves too small to be seen easily and in the other species they are again too long. 3. Saelania occurs especially in lime- stone regions, and the leaves are bluish-green, while those of our moss are a rather dark green. 4. Ccratodon corresponds in both illustration and description to our specimen, but to make sure that we are not mistaken we look through the rest of the genera. 6. Dicranella we discard because the leaves turn to one side. 7. Oncophoriis we discard because the leaves are too long and become crisped in drying, while those of our plant fold straight against the stem when dry. 8. Dicranum has leaves turned to one side. 1 1 . Wcisia has leaves too 30 HOW TO KNOW THE MOSSES long and the plants are too short. 15. Barhula is not common and the leaves are crisped when dry. 26. Leptohryum has leaves too long. 36. Wehera has stems too short with longer leaves. 38. Georgia looks more like our plant but in reading the descriptions we find that it usually grows on decaying wood and less fre- quently on the ground; and besides, scattered among the plants are stems with larger leaves arranged in a cup-like cluster at the tip. We find nothing of this kind in our specimen, so this genus will be discarded, leaving only 4. Ceratodon that agrees with our plant in every way. The following is an example of how to use the Cap- sule Key. We will use the same moss that we used for the Leaf Key. We have already decided that the plant belongs in Division A, under "Plants growing on the ground.'^ The next divisions are, "I. Capsule erect,'' and "n. Capsule not erect." Our capsule is not erect. Under this head we find the various shapes of capsules given. Turning to the "Illustrations of Terms" (Plate IV) , we decide that our capsule is cylindrical. Under *' Capsule cylindrical" we come to "Leaves long and narrow" and "Leaves short and broad." In using the Leaf Key we found that the leaves of our plant were long and narrow, hair-like through- out. Following this heading to the right we find the genus numbers i, 2, 4, 6, 7, 8. Looking through the illustrations and descriptions we find again that HOW TO USE THE KEYS 31 4. Ceratodon is the only one that corresponds to our specimen. It will readily be seen that when one arrives at the same genus number in the Capsule Key as in the Leal Key the determination is verified. HELPFUL SUGGESTIONS If in doubt what true mosses are, see Introduction p. I, or use the Prehminary Key, p. 39. When collecting mosses for determination it is neces- sary to notice habitat, that is, the natural locahty of the plants. They are found on the ground, on rocks, on trees, on decaying wood, or in ponds and streams. In spite of the fact that earth-covered rocks and rotting logs in deep, moist woods offer practically the same soil conditions as the ground, the mosses are divided according to actual situation, for simplicity of arrange- ment in the Keys. For instance, if a moss is found on a rock that is covered with soil, it is placed under ^'Plants growing on rocks"; or if a moss is found on a piece of an old log broken off and lying on the ground, it is placed under '' Plants growing on decaying wood." Notice the way the plants are growing; whether the single plants are growing apart from each other, or crowded together, with the stems erect, forming tufts, rounded cushions, or deep mats by prolonging their growth at the tips, or whether the stems are prostrate and inter- woven, forming thin mats by continuing their growth horizontally. See chapter on "Habit and Manner of Growth," p. 12. Care must be taken to gather whole plants and not merely a part of the stems. To be sure the mosses are HELPFUL SUGGESTIONS 33 well developed, select the hest-looking growth for study, the largest and greenest plants, and when possible those that are hearing fruit. The fruit or capsule of a moss is the swollen spore-case at the end of a slender stem called the fruit-stalk or seta. The capsule is usually borne above the leafy plant, but sometimes it is partly hidden in the surrounding leaves. Gather generously, at least what would be equal to two square inches, so as to allow for breaking the plants when separating them, to get the average characteristics of several plants, and to have some plants moist and others dry while studying them. Fold each specimen in a paper wrapper by itself and on the outside write habitat ''on ground" or "on rock," etc., and place and date of collecting for possible future reference. If the plants are placed in a tin box tightly covered, they will keep their fresh condition for several days and it will save moistening them for study, but care must be taken to remember the habitat of each specimen. When no fruit is found, the genus can still be deter- mined in many cases by studying the character of the growth and the leaves, and carefully reading the de- scriptions of all the mosses that come under both *' Capsule erect" and "Capsule not erect." There are some mosses that cannot be definitely named without the aid of the capsule. When this is the case, it will be mentioned in the descriptions of the genera. When in doubt where to place a sterile moss that is somewhat branched, try it under both Division A and Division B. 34 HOW TO KNOW THE MOSSES Carefully separate a few single plants in order to see the length of the stems, the average character of the leaves, and the manner of branching. It is not always easy to do this without breaking the stems, especially if one has no tweezers for the work. Fingers at best are clumsy instruments in handling the smallest mosses; possibly a wire hairpin would be of some as- sistance. Sometimes two or more kinds of mosses will be found growing together. If the leaves or the general characters are plainly different, the student will readily notice that he has collected more than one species. But it sometimes happens that an apparently good fruited specimen is one sterile moss growing on top of another moss that is fruited, and that the fruit-stalks are really attached to the moss growing underneath, although they have pushed up through the conspicuous growth on the surface. To avoid making a mistake in such a case, always follow the fruit-stalk down to the stem on which it is growing and carefully pull out as long a piece of the stem as possible, and compare it with the rest of the specimen. When stems with numerous branches are closely interwoven, no very great length can be separated and one must get the average characteristics from several small pieces. Examine moist plants. If mosses are collected in a dry condition, they must be moistened for study, as other- wise leaves that can be easily seen when the plants are moist may be so closely folded against the stera when dry that they will not be noticed. For instance, HELPFUL SUGGESTIONS 35 the leaves of Pogonatum hrevicaide (p. i6i) are long and narrow, easily seen when moist, though few in num?jer, but when dry they fold against the stem and one is liable to overlook them and misplace the moss under *' Leaves when moist not easily seen." Mosses may remain dry for an indefinite period and then can be restored to fresh conditions by being placed in water. Quickest results can be obtained by using hot water. This process of reviving dried mosses may be repeated as often as required, without injury to the plants. When the leaves have fully expanded, remove the plants from the water and absorb the extra moisture with soft linen. The leaves of a few species dry so quickly that it may be necessary to replace the plants in water two or three times while studying them. If plants are allowed to remain in water for a number of days, the leaves and capsules lose their natural color and turn dark. To dry mosses, separate the individual plants and place them in sunKght or merely expose them to dry air. In case they do not dry readily, a Httle artificial heat may be used by taking the plants in a pair of tweezers or between the ends of a wire hairpin, or by placing them on a piece of paper and holding tliem near a light or over some source of heat; but if too much artificial heat is used, making the leaves dry too quickly, they do not come into the characteristic dried condition. Pressure should not be used for naturally dried plants. 36 HOW TO KNOW THE MOSSES To see the shape of the leaves or the color of the stem, hold the plants to the Hght or in strong light, or against something white. The leaves that are best developed are usually along the middle part of the stem. If the leaves conceal the stem too much, strip them off by drawing the stem from the tip toward the base through the firmly pressed tips of thumb and finger. Red stems usually show through the leaves. Do not mistake branches for leaves. As the leaves of mosses are so much smaller than those of other plants and the branches are often more conspicuous than the leaves, care must be taken to avoid this mistake. When the plants are held to the light, in most cases the leaves, or at least the leaf -tips, can be seen stick- ing out around the stem and the branches. If the leaves are too small to be seen, the cylindrical appear- ance of the branches and their arrangement on the stem should be sufficient to distinguish them from leaves. (See Plates II, III.) // in doubt about the length of the stem or the shape of the leaves, try the moss under each head. The length of the longest stems is given and the characteristics of the largest leaves. To see these, examine several indi- vidual plants. When estimating the length of the stem, do not include the fruit-stalk. The length that is given is measured from the rootlets only through the leafy portion and does not include the seta. (See ''Illustrations of Terms," Plate I, Fig. i.) / HELPFUL SUGGESTIONS 37 When considering the shape and position of the cap- sule, do not include the operculum. (See "Illustrations of Terms," Plate IV.) The operculum is the hd that covers the mouth of the capsule. It drops off natu- rally when the spores are mature, and sometimes be- fore this takes place, it is loose enough to be easily removed with tweezers or fingers. Do not he alarmed at a long list of genus nujnhers. A glance at the illustration of each genus will show whether it is necessary to read the entire description. Always carefully read it if there is any doubt about the illustration being like the moss in question. Every point in the Keys and in the descriptions is important. Follow the Keys carefully and study the descriptions thoroughly. A specimen must correspond in every point to its description. Care must be taken to gather normal plants. The beginner at times will not do this. Puzzling variations may be found in mosses as in other plants and also in animals. But one ought not to think that every doubtful case is one of these abnormal growths, for it may be due to some imperfect use of the Keys or descriptions caused by overlooking some detail. When a moss has no definite character and the fruit is lacking, one may be in doubt where to place it even after careful comparison with the illustrations and descriptions. In this case, one must sometimes wait until fruited plants are found, or possibly a compound microscope and technical books are necessary. A troublesome specimen can usually be 38 HOW TO KNOW THE MOSSES placed in its family if not in the exact genus. It is well when possible to verify one's determinations by comparing the specimens with authentic material, which can generally be found in Museums of Natural History. KEY TO DISTINGUISH MOSSES FROM COMMON HEPATICS AND LICHENS Note. When one is in doubt what arc mosses, the following Key should be used before trying the Leaf Key or Capsule Key, as hepatics and lichens are sometimes collected for mosses. (See illustrations of lichens and hepatics, pp. 4, 7; also illustrations of mosses throughout the book.) Plants growing flat without stem or leaves ^ Plants usually dark green .... Hepatics (Marchantiales) , p. 7. Plants usually some shade of gray, or if green when moist, becoming gray when dry, sometimes brown or orange .... Lichens, p. 4. Plants erect, ascending, prostrate, or hanging from trees; with a true stem or, in lichens, apparently having a stem Stems without leaves ; ^ usually some shade of gray, or if green when moist, becoming gray when dry .... Lichens, p. 4. ^ The plant-body of some hepatics belonging to the Marchantidcs is like a broad, flat leaf, sometimes elongated, often with a midrib, and usually branched by forking. A very young plant may resemble two or three leaves, but no distinct stem will be found and the apparent leaves will not be ar- ranged in two opposite rows or around a stem, as in the leafy hepatics {Junger' mannialcs) or the mosses coming under the next head. 2 The short branches of certain lichens may be mistaken for leaves. The leaves of the hepatics and mosses coming under the next head are flat and thin, while the branches of lichens are round. When in doubt what are leaves, the color of the plants is usually a safe guide. Lichens when ilry are more gray than green and are very stitT and brittle. Hepatics and mosses are more a foliage-green and do not dry gray or become as still and brittle. 40 HOW TO KNOW THE MOSSES Stems with leaves always some shade of green, never gray. Leaves arranged in two opposite rows, rounded, lobed, or cleft, often curved under at tips, usually dark green; midrib absent; under or back side of stem toward which leaves curl sometimes bearing what appear to be rootlets .... Hepatics {Jungermanniales or Scale Mosses), p. 6. Leaves usually arranged equally around stem (in only two rows in Fissidens, p. 97), sometimes flattened on two opposite sides of stem, never lobed or cleft and when rounded not curved under at tips, varying from light to dark green; midrib present or absent, rarely seen without a lens. Plants usually growing in bogs or very wet places; stems erect, much branched (branches at tip of stem forming a thick head) ; leaves usually light, green or tinged with red .... Sphagnum or Peat Moss, p. 73. Plants growing on rocks in mountainous regions; stems erect, short and inconspicuous; leaves very dark, almost black .... Andre aea, p. 75. Plants growing in all sorts of places, on wet or dry ground, rocks, trees, decaying wood, and in streams or ponds. Stems generally erect, and often not branched; or if slightly branched by forking, usually with not more than two or three branches; fruit at apex of stem or of well developed branch, sometimes appearing lateral by new growth of plant .... Acrocarpous Mosses, p. 77. Stems prostrate or ascending, rarely erect, usually much branched (with more than two or three branches) ; fruit on side of stem or on a very short lateral branch .... Pleuro- CARPOus Mosses, p. 172. LEAF KEY TO GENERA A. Fruit at the apex of the stem or of a well-developed branch, sometimes appearing lateral by the new growth of the plant. Stems generally erect, and often not branched; or, if slightly branched by forking, usually with not more than two or three branches.^ Acrocar- pous Mosses, p. 77. B. Fruit on the side of the stem or on a very short lateral branch. Stems prostrate or ascending, rarely erect, usually much branched (with more than two or three branches).^ Pleiirocarpous Mosses, p. 172. Note. In many cases the genus can be determined without the aid of the capsule. When in doubt where to place a sterile moss that is somewhat branched, try it under both Division A and Division B. A {Fissidens, p. 97, with fruit both terminal and lateral may be found here) Plants growing on the ground I. SHAPE OF LEAVES WHEN MOIST NOT EASILY SEEN (Leaves too small or too closely folded to show if they are relatively long and narrow or short and broad) Stems one-half inch long or less. Capsule erect . . . . 2, 15, 16, 38, 40. Capsule not erect .... 25, 28, 34, 37. ^ For arrangement of branches sec " Illustrations of Terms," Plate II. 42 HOW TO KNOW THE MOSSES Stems more than one-half inch long. Capsule erect .... 38, 40. Capsule not erect .... 34. II. SHAPE OF LEAVES WHEN MOIST EASILY SEEN (Leaves must be seen well enough to estimate their relative shape) a. Leaves long and narrow (more than four times longer than broadest part) Stems one-half inch long or less. Leaves hair-like throughout. Capsule erect .... 2, 3, 6, 8, 11, 15, 36, 38. Capsule not erect .... i, 2, 4, 6, 7, 8, 26, :i^6. Leaves broader, sometimes ending in a hair-like tip. Capsule erect .... 8, 13, 39, 40, 41. Capsule not erect .... 8, 9, 27, 29, 39, 41. Stems more than one-half inch long. Leaves hair-like throughout. Capsule erect .... 3, 6, 38. Capsule not erect .... 4, 6, 7, 8, 26, 32, 33, 34. Leaves broader, sometimes ending in a hair-like tip. Capsule erect .... 8, 13, 39, 40, 41. Capsule not erect 8, 9, 27, 28, 30, 31, 35, 39, 41. h. Leaves short and broad (less than four times longer than broadest part) Stems one-half inch long or less. Capsule erect .... 10, 16, 18, 24. Capsule not erect .... 10, 25, 28, 30. Stems more than one-half inch long.^ Capsule erect .... 10, 18. Capsule not erect .... 10, 28, 29, 30, 31. ^ If No. 63 has been mistaken for an acrocarpous moss, it will apparently belong here. LEAF KEY 43 Plants growing on rocks, bricks, mortar, etc. I. SHAPE OF LEAVES WHEN MOIST NOT EASILY SEEN (Leave? too small or too closely folded to show if they are relatively long and narrow or short and broad) Stems one-half inch long or Icss.^ Capsule erect .... 2, 22, 23. Capsule not erect .... 25, 28, 34. Stems more than one-half inch long.^ Capsule erect .... 21, 22, 23. Capsule not erect .... 28, 34. IT. SHAPE OF LEAVES WHEN MOIST EASILY SEEN (Leaves must be seen well enough to estimate their relative shape) a. Leaves long and narrow (more than four times longer than broadest part) Stems one-half inch long or less. Leaves hair-like throughout.^ Capsule erect .... 3, 6, 8, 12, 14. Capsule not erect .... 4, 6, 7, 8, 26, 34. Leaves broader, sometimes ending in a hair-like tip. Capsule partly concealed by leaves .... 19. Capsule not concealed. Capsule erect .... 8, 22, 23, 41. Capsule not erect .... 8, 9, 27, 28, 30, 41. Stems more than one-half inch long. Leaves hair-like throughout.^ Capsule erect .... 3, 5, 6, 8, 12, 14. Capsule not erect .... 4, 6, 7, 8, 26, 32, S3, 34- ^ See AnJrcaca, p. 75. 44 HOW TO KNOW THE MOSSES Leaves broader, sometimes ending in a hair-like tip. Capsule partly concealed by leaves .... 19. Capsule not concealed. Capsule erect .... 8, 13, 22, 23, 41. Capsule not erect .... 8, 9, 27, 28, 30, 41. b. Leaves short and broad (less than four times longer than broadest part) Stems one-half inch long or less. Capsule erect .... 10, 15, 18, 21. Capsule not erect .... 10, 25, 28. Stems more than one-half inch long. Capsule erect .... 10, 17, 18, 20. Capsule not erect .... 28, 29, 30. Plants growing on roots or trunks of trees I. SHAPE OF LEAVES WHEN MOIST NOT EASILY SEEN (Leaves too small or too closely folded to show if they are relatively long and narrow or short and broad) Stems one-half inch long or less; capsule erect .... 22 Stems more than one-half inch long; capsule erect .... 21, 22. II. SHAPE OF LEAVES WHEN MOIST EASILY SEEN (Leaves must be seen well enough to estimate their relative shape) a. Leaves long and narrow (more than four times longer than broadest part) Stems one-half inch long or less; capsule erect .... 8, 13, 22, 23. Stems more than one-half inch long; capsule erect .... 8, 22, 23. LEAF KEY 45 b. Leaves short and broad (less than four times longer than broadest part) Stems one-half inch long or less. Capsule erect .... 10, 17. Capsule not erect .... 10, 30. Stems more than one-half inch long. Capsule erect .... 10, 21. Capsule not erect . . . . 10, 30, 31. Plants growing on decaying wood, as old logs, stumps, etc. I. SHAPE OF LEAVES WHEN MOIST NOT EASILY SEEN (Leaves too small or too closely folded to show if they are relatively long and narrow or short and broad) Stems one-half inch long or less. Capsule erect .... 38. Capsule not erect .... 28. Stems more than one-half inch long. Capsule erect .... 38. Capsule not erect .... 28. II. SHAPE OF LEAVES WHEN MOIST EASILY SEEN (Leaves must be seen well enough to estimate their relative shape) a. Leaves long and narrow (more than four times longer than broadest part) Stems one-half inch long or less. Leaves hair-like throughout. Capsule erect .... 6, 8, 38. Capsule not erect .... 4, 6, 7, 26. Leaves broader, sometimes ending in a hair-like tip. Capsule erect .... 8, 38, 40, 41. Capsule not erect .... 8, 27, 28, 41. 46 HOW TO KNOW THE MOSSES Stems more than one-half inch long. Leaves hair-like throughout. Capsule erect .... 6, 8, 38. Capsule not erect .... 4, 6, 7, 8, 26. Leaves broader, sometimes ending in a hair-like tip. Capsule erect .... 8, 38, 41. Capsule not erect .... 8, 27, 28, 41. b. Leaves short and broad (less than four times longer than broadest part) Stems one-half inch long or less; capsule not erect .... 28, 30. Stems more than one-half inch long; capsule not erect. . . . 28, 29, 30. B Fruit on the side of the stem or on a very short lateral branch. Stems prostrate or ascending, rarely erect, usu- ally much branched (with more than two or three branches).-^ Pleurocarpous mosses. Note. In many cases the genus can be determined without the aid of the capsule. When in doubt where to place a sterile moss that is somewhat branched, try it under both Division A and Division B. Plants growing on the ground I. LEAVES WHEN MOIST NOT EASILY SEEN (Leaves too small or too closely folded to show if they are straight or curved) Stems pinnately branched; capsule not erect .... 57, 58, 71- Stems bipinnately or tripinnately branched; capsule not erect .... 57, 68. 1 For arrangement of branches see "Illustrations of Terms," Plate II. LEAF KEY 47 Stems irregularly branched.^ Capsule erect 50, 53, 75. Capsule not erect .... 59, 71, 79. II. LEAVES WHEN MOIST EASILY SEEN (It is necessary only to see if the leaves are straight or curved, the entire outline need not show) Stems pinnately branched. Leaves straight; capsule not erect .... 57,58,64,66,67, 68, 69, 71, 74. Leaves curved; capsule not erect .... 62, 66, 70, 71. Stems bipinnately or tripinnately branched ; leaves straight ; capsule not erect .... 68. Stems tree-like in branching; leaves straight; capsule erect 45- Stems irregularly branched. Leaves apparently on two opposite sides of the stem.^ Leaves straight; capsule not erect .... 72, 73, 75, 80. Leaves curved; capsule not erect .... 71. Leaves turned to one side,^ more or less curved. Capsule erect .... 44. Capsule not erect .... 44, 62, 71. Leaves arranged equally around stem, straight. Leaves wide-spreading ; capsule not erect .... 59, 61, 63, 64, 67, 73, 75, 78. Leaves not wide-spreading.^ Capsule erect .... 44, 50. 75. Capsule not erect . . . . 44, 58, 61, 71, 74, 75, 76, 79. ^ If No. 34 has been mistaken for a plcurocarpous moss, it will apparently belong here. 2 If No. 31 has been mistaken for a plcurocarpous moss, it will apparently belong here. 48 HOW TO KNOW THE MOSSES Plants growing on rocks, sticks, etc. in or at the edge of streams, ponds, or water-holes I. LEAVES WHEN MOIST NOT EASILY SEEN (Leaves too small or too closely folded to show if they are straight or curved) Stems less than three inches long; irregularly branched; capsule not erect .... 79. II. LEAVES WHEN MOIST EASILY SEEN (It is necessary only to see if the leaves are straight or curved, the entire outline need not show) Stems less than three inches long. Stems tree-like in branching; leaves straight; capsule erect .... 45. Stems irregularly branched. Leaves straight, erect or spreading.'- Capsule erect .... 44. Capsule not erect .... 44, 59, 61, 65, 75, 77, 79. Leaves more or less curved and turned to one side. Capsule erect .... 44. Capsule not erect .... 44, 65. Stems more than three inches long, irregularly branched. Leaves straight, erect or spreading.^ Capsule erect .... 43, 44. Capsule not erect .... 44, 59, 65. Leaves more or less curved, sometimes turned to one side. Capsule erect .... 44. Capsule not erect .... 44, 62, 65. 1 If No. 19 has been mistaken for a pleurocarpous moss, it will apparently belong here. LEAF KEY 49 Plants growing on rocks not in streams, ponds, or water-holes I. LEAVES WHEN MOIST NOT EASILY SEEN (Leaves too small or too closely folded to show if they are straight or curved) Stems pinnately branched; capsule not erect .... 57, 71. Stems bipinnately or tripinnately branched; capsule not erect .... 57, 68. Stems irregularly branched.^ ^ ^ Capsule erect 50, 53, 54, 55, 56. Capsule not erect .... 59, 60, 71, 75, 79. II. LEAVES WHEN MOIST EASILY SEEN (It is necessary only to sec if the leaves are straight or curved, the entire outline need not show) Stems pinnately branched. Leaves straight; capsule not erect .... 57, 66, 67, 68, 69, 71. Leaves curved; capsule not erect .... 62, 66, 70, 71. Stems bipinnately or tripinnately branched ; leaves straight ; capsule not erect .... 68. Stems somewhat tree-like in branching; leaves straight; capsule not erect .... 49. Stems irregularly branched.^ ^ ^ Leaves apparently on two opposite sides of stem. Leaves straight. Capsule erect .... 48, 55. Capsule not erect .... 72, 73. Leaves curved; capsule not erect .... 71. * If No. 34 has been mistaken for a pleurocarpous moss, it will apparently belong here. 2 If No. 19 has been mistaken for a pleurocarpous moss, it will apparently belong here. ■'' If No. 21 has been mistaken for a pleurocarpous moss, it will apparently belong here. 50 HOW TO KNOW THE MOSSES Leaves turned to one side, curved; ^ capsule not erect 62, 7I0 Leaves arranged equally around stem, straight. Leaves wide-spreading. Capsule almost concealed by leaves .... 42. Capsule not concealed. Capsule erect .... 54, 56. Capsule not erect .... 59, 61, 67, 73, 75, 78. Leaves not wide-spreading.^ 2 3 Capsule erect .... 46, 50, 51, 75. Capsule not erect .... 61, 71, 75, 76, 79. Plants growing on roots or trunks of trees I. LEAVES WHEN MOIST NOT EASILY SEEN (Leaves too small or too closely folded to show if they are straight or curved) Stems irregularly or rarely pinnately branched.^ Capsules erect .... 50, 51, 52, 53, 55, 56. Capsule not erect .... 59, 60, 68, 71, 75. Stems bipinnately or tripinnately branched; capsule not erect .... 68. II. LEAVES WHEN MOIST EASILY SEEN (It is necessary only to see if the leaves are straight or curved, the entire outline need not show) Stems pinnately branched; capsule not erect .... 68, 69, 70. Stems bipinnately or tripinnately branched; capsule not erect .... 68. ^ If No. 34 has been mistaken for a pleurocarpous moss, it will apparently belong here. 2 If No. 19 has been mistaken for a pleurocarpous moss, it will apparently belong here. ' If No. 21 has been mistaken for a pleurocarpous moss, it will apparently belong here. LEAF KEY 51 Stems irregularly or rarely pinnalcly branched. Leaves apparently on two opposite sides of stem.^ Leaves straight. Capsule partly concealed by leaves .... 47. Capsule not concealed. Capsule erect .... 48, 55. Cai)sule not erect .... 80. Leaves curved; capsule not erect .... 71. Leaves turned to one side, curved; capsule erect .... 52. Leaves arranged equally around stem, straight.- Capsule erect 46, 50, 51, 52, 56, 75. Capsule not erect .... 75, 78. Plants growing on decaying wood, as old logs, stumps, etc. I. LEAVES WHEN MOIST NOT EASILY SEEN (Leaves too small or too closely folded to show if they are straight or curved) Stems pinnately branched. Capsule erect .... 51, 52. Capsule not erect .... 71. Stems bipinnately or tripinnately branched; capsule not erect .... 57, 68. Stems irregularly branched. Capsule erect .... 50, 51, 52, 53, 56. Capsule not erect . . . . 59, 71, 75. ^ If No. 31 has been mistaken for a plcurocarpous moss, it will apparently belonj; here. ' If No. 21 has been mistaken for a plcurocarpous moss, it will apparently belong here. 52 HOW TO KNOW THE MOSSES II. LEAVES WHEN MOIST EASILY SEEN (It is necessary only to see if the leaves are straight or curved, the entire outhne need not show) Stems pinnately branched. Leaves straight. Capsule erect .... 51, 52. Capsule not erect .... 67, 68, 69, 71. Leaves curved. Capsule erect .... 52. Capsule not erect . . . . 62, 70, 71. Stems bipinnately or tripinnately branched; leaves straight; capsule not erect .... 68. Stems irregularly branched. Leaves apparently on two opposite sides of stem. Leaves straight; capsule not erect .... 72, 73, 75, 80. Leaves curved; capsule not erect .... 71. Leaves turned to one side, curved. Capsule erect .... 52. Capsule not erect .... 62. Leaves arranged equally around stem, straight. Leaves wide-spreading. Capsule erect .... 51, 52. Capsule not erect .... 67, 73, 75, 78. Leaves not wide-spreading. Capsule erect .... 50, 75. Capsule not erect 7ij 75- Scale Inches Millimeters 10 15 20 25 30 35 40 45 60 55 60 65 70 75 CAPSULE KEY TO GENERA A. Fruit at the apex of the stem or of a well developed branch, sometimes appearing lateral by the new growth of the plant. Stems generally erect, and often not branched; or if slightly branched by forking, usually with not more than two or three branches.^ Acrocar- pous Mosses, p. 77. B. Fruit on the side of the stem or on a very short lateral branch. Stems prostrate or ascending, rarely erect, usually much branched (with more than two or three branches^) Pleurocarpous Mosses, p. 172. Note. When in doubt where to place a moss that is somewhat branched, try it under both Division A and Division B. A {Fissidens, p. 97, with fruit both terminal and lateral may be found here) Plants growing on the ground I. CAPSULE ERECT a. Capsule cylindrical Shape of leaves when moist not easily seen. (Leaves too small or too closely folded to show if they are rela- tively long and narrow or short and broad) .... 2, 15, s^, 40. ^ For arrangement of branches sec "Illustrations of Terms," Plate II. 54 HOW TO KNOW THE MOSSES Shape of leaves when moist easily seen. (Leaves must be seen well enough to estimate their relative shape.) Leaves long and narrow (more than four times longer than broadest part). Leaves hair-like throughout .... 2, 3, 6, 8, ii, 15, 38. Leaves broader, sometimes ending in a hair-like tip 8, 13, 39, 40, 41. Leaves short and broad (less than four times longer than broadest part) .... 10, 18. b. Capsule angular (four- to six-sided) Leaves long and narrow (more than four times longer than broadest part) .... 41. c. Capsule top-shaped or urn-shaped Shape of leaves when moist not easily seen. (Leaves too small or too closely folded to show if they are rela- tively long and narrow or short and broad) .... 16. Shape of leaves when moist easily seen. (Leaves must be seen well enough to estimate their relative shape.) Leaves short and broad (less than four times longer than broadest part) .... 16, 24. d. Capsule egg-shaped, pointed Leaves long and narrow (more than four times longer than broadest part) .... 36. II. CAPSULE NOT ERECT a. Capsule cylindrical Leaves long and narrow (more than four times longer than broadest part). Leaves hair-like throughout .... i, 2, 4, 6, 7, 8. CAPSULE KEY 55 Leaves broader, sometimes ending in a hair-like tip 8, 9,30,31,35,39,41. Leaves short and broad ^ (less than four times longer than broadest part) .... 10, 29, 30, 31. b. Capsule angular (four- to six-sided) Leaves long and narrow (more than four times longer than broadest part) .... 41. c. Capsule pear-shaped Shape of leaves when moist not easily seen. (Leaves too small or too closely folded to show if they are rela- tively long and narrow or short and broad .... 25, 28. Shape of leaves when moist easily seen. (Leaves must be seen well enough to estimate their relative shape.) Leaves long and narrow (more than four times longer than broadest part) .... 26, 27, 28. Leaves short and broad (less than four times longer than broadest part) .... 25, 28. d. Capsule globular Shape of leaves when moist not easily seen. (Leaves too small or too closely folded to show if they are rela- tively long and narrow or short and broad) .... 34. Shape of leaves when moist easily seen. (Leaves must be seen well enough to estimate their relative shape.) Leaves long and narrow (more than four times longer than broadest part) .... 32, 33. Leaves short and broad (less than four times longer than broadest part) .... 34. 1 If No. 63 has been mistaken for an acrocarpous moss, it will apparently belong here. 56 HOW TO KNOW THE MOSSES e. Capsule egg-shaped, pointed Leaves absent .... 37. Leaves long and narrow (more than four times longer than broadest part) .... 36. Plants growing on rocks, bricks, mortar, etc. I. CAPSULE ERECT a. Capsule cylindrical Shape of leaves when moist not easily seen. (Leaves too small or too closely folded to show if they are rela- tively long and narrow or short and broad) .... 2, 22, 23. Shape of leaves when moist easily seen. (Leaves must be seen well enough to estimate their relative shape.) Leaves long and narrow (more than four times longer than broadest part). Leaves hair-like throughout .... 3, 5, 6, 8, 14. Leaves broader, sometimes ending in a hair-like tip 8, 13, 22, 23,41. Leaves short and broad (less than four times longer than broadest part) .... 10, 15, 17, 18. h. Capsule angular {Jour- to six-sided) Leaves long and narrow (more than four times longer than broadest part) . . . .41. c. Capsule elliptical, oval, or pear-shaped Shape of leaves when moist not easily seen,^ (Leaves too small or too closely folded to show if they are rela- tively long and narrow or short and broad.) 1 See Andreaea, p. 75- CAPSULE KEY 57 Capsule partly concealed by leaves .... 19. Capsule not concealed by leaves .... 21. Shape of leaves when moist easily seen. (Leaves must be seen well enough to estimate their relative shape.) Leaves long and narrow ^ (more than four times longer than broadest part) .... 12, iq, 23. Leaves short and broad (less than four times longer than broadest part) .... 20, 21. II. CAPSULE NOT ERECT a. Capsule cylindrical Leaves long and narrow (more than four times longer than broadest part). Leaves hair-like throughout .... 4, 6, 7, 8. Leaves broader, sometimes ending in a hair-like tip 8, 9, 30, 41. Leaves short and broad (less than four times longer than broadest part) .... 10, 29, 30. h. Capsule angular {jour- to six-sided) Leaves long and narrow (more than four times longer than broadest part) . . . .41. c. Capsule pear-shaped Shape of leaves when moist not easily seen. (Leaves too small or too closely folded to show if they are rela- tively long and narrow or short and broad.) . . . 25, 28. Shape of leaves when moist easily seen. (Leaves must be seen well enough to estimate their relative shape.) * See Andreaea, p. 75. 58 HOW TO KNOW THE MOSSES Leaves long and narrow (more than four times longer than broadest part). Leaves hair-like throughout .... 26. Leaves broader, sometimes ending in a hair-like tip .... 27, 28. Leaves short and broad (less than four times longer than broadest part) .... 25, 28. d. Capsule globular Shape of leaves when moist not easily seen. (Leaves too small or too closely folded to show if they are rela- tively long and narrow or short and broad) .... 34. Shape of leaves when moist easily seen. (Leaves must be seen well enough to estimate their relative shape.) Leaves long and narrow (more than four times longer than broadest part) .... 32, 33. Leaves short and broad (less than four times longer than broadest part) .... 34. Plants growing on roots or trunks of trees I. CAPSULE ERECT a. Capsule cylindrical Leaves long and narrow (more than four times longer than broadest part) .... 8, 13, 22, 23. Leaves short and broad (less than four times longer than broadest part) .... 10, 17. b. Capsule elliptical, oval, or pear-shaped Shape of leaves when moist not easily seen. (Leaves too small or too closely folded to show if they are relatively long and narrow or short and broad) .... 21, 22. CAPSULE KEY 59 Shape of leaves when moist easily seen. (Leaves must be seen well enough to estimate their relative shape.) Leaves long and narrow (more than four times longer than broadest part) .... 22, 23. Leaves short and broad (less than four times longer than broadest part) .... 21. II. CAPSULE NOT ERECT Capsule cylindrical Leaves short and broad (less than four times longer than broadest part) .... 10, 30, 31. Plants growing on decaying wood, as old logs, stumps, etc. I. CAPSULE ERECT a. Capsule cylindrical Shape of leaves when moist not easily seen. (Leaves too small or too closely folded to show if they are rela- tively long and narrow or short and broad) .... 38. Shape of leaves when moist easily seen. (Leaves must be seen wtU enough to estimate their relative shape.) Leaves long and narrow (more than four times longer than broadest part). Leaves hair-like throughout .... 6, 8, ^S. Leaves broader, sometimes ending in a hair-like tip ....8,38,41. b. Capsule angular {four- to six-sided) Leaves long and narrow (more than four times longer than broadest part) .... 41. 60 HOW TO KNOW THE MOSSES II. CAPSULE NOT ERECT a. Capsule cylindrical Leaves long and narrow (more than four times longer than broadest part). Leaves hair-like throughout .... 4, 6, 7, 8. Leaves broader, sometimes ending in a hair-like tip .... 8, 41. Leaves short and broad (less than four times longer than broadest part) .... 29, 30. h. Capsule angular {four- to-six-sided) Leaves long and narrow (more than four times longer than broadest part) .... 41. c. Capsule pear-shaped Shape of leaves when moist not easily seen. (Leaves too small or too closely folded to show if they are rela- tively long and narrow or short and broad) .... 28. Shape of leaves when moist easily seen. (Leaves must be seen well enough to estimate their relative shape.) Leaves long and narrow (more than four times longer than broadest part). Leaves hair-like throughout .... 26. Leaves broader, sometimes ending in a hair-like tip 27, 28. Leaves short and broad (less than four times longer than broadest part) .... 28. CAPSULE KEY 6l Fruit on the side of the stem or on a very short lateral branch. Stems prostrate or ascending, rarely erect, usually much branched (with more than two or three branches).^ Pleurocarpous Mosses, p. 172. Note. When in doubt where to place a moss that is somewhat branched, try it under both Division A and Division B. Plants growing on the ground I. CAPSULE ERECT Leaves when moist not easily seen (too small or too closely folded to show^ if they are straight or curved); stems irregularly branched .... 50, 53, 75. Leaves when moist easily seen. (It is necessary only to see if the leaves are straight or curved, the entire outline need not show.) Leaves more or less curved; stems irregularly branched .... 44. Leaves straight. Stems irregularly branched .... 44, 50, 75. Stems tree-like in branching .... 45. II. CAPSULE NOT ERECT a. Capsule long-cylindrical (at least four times longer than broad) Leaves when moist not easily seen (too small or too closely folded to show if they are straight or curved). Stems pinnatcly branched .... 57, 5S, 71. > For arrangement of branches sec "lUustrations of Terms," Plate II. 62 HOW TO KNOW THE MOSSES Stems bipinnately or tripinnately branched .... 57. Steins irregularly branched .... 59, 71. Leaves when moist easily seen. (It is necessary only to see if the leaves are straight or curved, the entire out- line need not show.) Stems pinnately branched. Leaves straight 57, 58, 64, 71, 74. Leaves curved .... 62, 70, 71. Stems irregularly branched. Leaves apparently on two opposite sides of the stem.^ Leaves straight .... 72, 73, 80. Leaves curved .... 71. Leaves turned to one side, curved .... 44, 62, 71. Leaves arranged equally around stem, straight. Leaves wide-spreading .... 59, 61, 64, 73, 78. Leaves not wide-spreading . . . . 44, 58, 61, 71, 76. b. Capsule short-cylindrical (less than four times longer than broad) Leaves when moist not easily seen (too small or too closely folded to show if they are straight or curved). Stems pinnately or irregularly branched ... 71, 79. Stems bipinnately or tripinnately branched .... 68. Leaves when moist easily seen. (It is necessary only to see if the leaves are straight or curved, the entire outline need not show.) Stems pinnately branched. Leaves straight .... 66, 67, 68, 69, 71. Leaves curved .... 62, 66, 71. Stems bipinnately or tripinnately branched; leaves straight .... 68. * If No. 31 has been mistaken for a pleurocarpous moss, it will apparently belong here. CAPSULE KEY 63 Stems irregularly branched. Leaves straight^ .... 63, 67, 75. Leaves curved .... 62. Plants growing on rocks, sticks, etc., in or at the edge of streams, ponds, or water-holes I. CAPSULE ERECT Leaves when moist easily seen. (It is necessary only to see if the leaves are straight or curved, the entire outline need not show.) Leaves straight, erect or spreading." Capsule partly concealed by leaves; stems long, floating, irregularly branched .... 43. Capsule not concealed. Stems tree-Hke in branching .... 45. Stems irregularly branched .... 44. Leaves more or less curved and turned to one side 44. II. CAPSULE NOT ERECT a. Capsule long-cylindrical (at least four times longer than broad) Leaves when moist easily seen (it is necessary only to see if the leaves are straight or curved, the entire out- line need not show) ; stems irregularly branched. Leaves straight, spreading .... 44, 59, 61. Leaves more or less curved and turned to one side .... 44, 62. * If No. 34 has been mistaken for a plcurocarpous moss, it will apparently bclont; here. * If No. 19 has been mistaken for a pleurocarpous moss, it will apparently belong here. 64 HOW TO KNOW THE MOSSES b. Capsule shorUcylindrical (less than four times longer than broad) Leaves when moist not easily seen (too small or too closely folded to show if they are straight or curved); stems irregularly branched .... 79. Leaves when moist easily seen (it is necessary only to see if the leaves are straight or curved, the entire out- line need not show); stems irregularly branched. Leaves straight, erect or spreading .... 65, 75, 77, 79- Leaves more or less curved and turned to one side .... 65. Plants growing on rocks not in streams, ponds, or water-holes I. CAPSULE ERECT Leaves when moist not easily seen (too small or too closely folded to show if they are straight or curved) ; stems irregularly branched ^ . . . . 50, 53, 54, 55, 56. Leaves when moist easily seen. (It is necessary only to see if the leaves are straight or curved, the entire outline need not show.) Capsule partly concealed by leaves ; - stems irregularly branched; leaves straight .... 42. Capsule not concealed. Stems irregularly branched. Leaves apparently on two opposite sides of stem, straight 48, 55. ^ If No. 21 has been mistaken for a pleurocarpous moss, it will apparently belong here. * If No. 19 has been mistaken for a pleurocarpous moss, it will apparently belong here. CAPSULE KEY 65 Leaves arranged equally around stem, straight. Leaves wide-spreading .... 54, 56. Leaves not wide-spreading ^ .... 46, 50, 51, 75. II. CAPSULE NOT ERECT a. Capsule long-cylindrical (at least four times longer than broad) Leaves when moist not easily seen (too small or too closely folded to show if they are straight or curved) Stems pinnately branched .... 57, 71. Stems bipinnately or tripinnately branched ...» 57. Stems irregularly branched .... 59, 60, 71. Leaves when moist easily seen. (It is necessary only to see if the leaves are straight or curved, the entire outline need not show.) Stems pinnately branched. Leaves straight .... 57, 71. Leaves curved .... 62, 70, 71. Stems somewhat tree-like in branching; leaves straight .... 49. Stems irregularly branched. Leaves apparently on two opposite sides of stem. Leaves straight .... 72, 73. Leaves curved .... 71. Leaves turned to one side, curved .... 62, 71. Leaves arranged equally around stem, straight. Leaves wide-spreading .... 59, 61, 7.3. Leaves not wide-spreading .... 61, 71, 76. * If No. 21 has been mistaken for a pleurocarpous moss it will apparently belong here. 66 HOW TO KNOW THE MOSSES b. Capsule short-cylindrical (less than four times longer than broad) Leaves when moist not easily seen (too small or too closely folded to show if they are straight or curved). Stems bipinnately or tripinnately branched .... 68. Stems irregularly branched^ .... 75, 79. Leaves when moist easily seen. (It is necessary only to see if the leaves are straight or curved, the entire outline need not show.) , Stems pinnately branched. Leaves straight .... 66, 67, 68, 69. Leaves curved .... 62, 66. Stems bipinnately or tripinnately branched; leaves straight .... 68. Stems irregularly branched. Leaves turned to one side, curved .... 62. Leaves arranged equally around stem, straight. Leaves wide-spreading . . . . 67, 75, 78. Leaves not wide-spreading ^ . . . . 75, 79. Plants growing on roots or trunks of trees I. CAPSULE ERECT Leaves when moist not easily seen (too small or too closely folded to show if they are straight or curved) ; stems irregularly or pinnately branched ^ 50, 51. 52, 53, 55, 56. Leaves when moist easily seen (it is necessary only to see if the leaves are straight or curved, the entire outline need not show) ; stems irregularly or pinnately branched. ^ If No. 34 has been mistaken for a pleurocarpous moss, it will apparently belong here. 2 If No. 21 has been mistaken for a pleurocarpous moss, it will apparently belong here. CAPSULE KEY 67 Leaves apparently on two opposite sides of stem, straight. Capsule partly concealed by leaves .... 47. Capsule not concealed .... 48, 55. Leaves slightly turned to one side, straight or curved .... 52. Leaves arranged equally around stem, straight ^ 46, 50^ 51, 52, 56. II. CAPSULE NOT ERECT a. Capsule long-cylindrical (at least four times longer than broad) Leaves when moist not easily seen (too small or too closely folded to show if they are straight or curved). Stems pinnately branched .... 71. Stems irregularly branched .... 59, 60, 71. Leaves when moist easily seen. (It is necessary only to see if the leaves are straight or curved, the entire outHne need not show.) Stems pinnately branched; leaves curved .... 70, 71. Stems irregularly branched; ^ leaves curved .... 71. b. Capsule short-cylindrical (less than four times longer than broad) Leaves when moist not easily seen (too small or too closely folded to show if they are straight or curved). Stems pinnately or irregularly branched .... 68, 71, 75- Stems bipinnately or tripinnately branched .... 68. Leaves when moist easily seen. (It is necessary only to * If No. 21 has been mistaken for a plcurocarpous moss, it will apparently belong here. 2 If No. 31 has been mistaken for a plcurocarpous moss, it will apparently belong here. 68 HOW TO KNOW THE MOSSES see if the leaves are straight or curved, the entire outHne need not show.) Stems pinnately or irregularly branched. Leaves apparently on two opposite sides of stem. Leaves straight .... 75, 80, Leaves curved .... 71. Leaves arranged equally around stem, straight .... 68, 69, 75, 78. Stems bipinnately or tripinnately branched; leaves straight .... 68. Plants growing on decaying wood, as old logs, stumps, etc. I. CAPSULE ERECT Leaves when moist not easily seen (too small or too closely folded to show if they are straight or curved); stems irregularly or pinnately branched ^ 50. 51, 52, 53, 56. Leaves when moist easily seen (it is necessary only to see if the leaves are straight or curved, the entire outhne need not show); stems irregularly or pin- nately branched. Leaves straight . . . . 50, 51, 52. Leaves curved .... 52. II. CAPSULE NOT ERECT a. Capsule long-cylindrical (at least four times longer than broad) Leaves when moist not easily seen (too small or too closely folded to show if they are straight or curved). Stems pinnately branched .... 71. Stems bipinnately or tripinnately branched .... 57. Stems irregularly branched . . . . 59, 71, 75. CAPSULE KEY 69 Leaves when moist easily seen. (It is necessary only to see if the leaves are straight or curved, the entire outline need not show.) Stems pinnately branched, leaves curved .... 62, 70, 71. Stems irregularly branched. Leaves apparently on two opposite sides of stem. Leaves straight .... 72, 73, 80. Leaves curved .... 71. Leaves turned to one side, curved .... 62. Leaves arranged equally around stem, straight. Leaves wide-spreading .... 73. Leaves not wide-spreading .... 71. b. Capsule short-cylindrical (less than four times longer than broad) Leaves when moist not easily seen (too small or too closely folded to show if they are straight or curved). Stems pinnately branched .... 68, 71. Stems bipinnatcly or tripinnately branched .... 68. Stems irregularly branched .... 71, 75. Leaves when moist easily seen. (It is necessary only to see if the leaves are straight or curved, the entire outUne need not show.) Stems pinnately branched. Leaves straight .... 67, 68, 69, 71. Leaves curved .... 62, 71. Stems bipinnately or tripinnately branched; leaves straight .... 68. Stems irregularly branched. Leaves straight .... 67, 75, 78. Leaves curved .... 62. LIST OF GENERA Note. The genera are numbered in the order selected for the book. PAGE 1. Trematodon 77 2. Ditrichum 78 3. Saelania 80 4. Ceratodon 81 5. Distichium 83 6. Dicranella 84 7. Oncophorus 86 8. Dicranum 87 9. Leucobryum 95 10. Fissidens 97 11. Weisia 100 12. Hymenostylium loi 13. Tortella 102 14. Didymodon 104 15. Barbula 105 16. Pottia 106 17. Tortula 107 18. Encalypta 108 19. Grimmia iii 20. Rhacomitrium 113 21. Drummondia 116 22. Orthotrichum 117 23. Ulota 119 24. Physcomitrium 122 25. Funaria 123 26. Leptobryum 126 LIST OF GENERA 71 27. Pohlia 127 28. Bryum 129 29. Rhodobryum 131 30. Mnium 134 31. Aulacomnium 139 32. Plagiopus 143 ^S. Bartramia 144 34. Philonotis 145 35. Timmia 148 36. Webera 1^0 37. Buxbaumia 152 38. Georgia 154 39. Catharinaea 1^6 40. Pogonatum 160 41. Polytrichum 162 42. Hedwigia 172 43. Fontinalis 17^ 44. Dichelyma 177 45. Climacium 179 46. Leucodon 182 47. Neckera 185 48. Homalia 186 49. Thamnium 187 50. Entodon 189 51. Platygyrium 191 52. Pylaisia 192 53. Thelia 195 54. Myurella 196 55. Anomodon 198 56. Leskea 201 57. Thuidium 202 58. Helodium 205 59. Amblystcgium 208 60. Homomallium 210 72 HOW TO KNOW THE MOSSES 6i. Hygroamblystegium 211 62. Drepanocladus 213 63. Calliergon ^ 216 64. Acrocladium 217 65. Hygroh>^num 218 66. Ctenidium 221 67. Rhytidiadelphus 223 68. Hylocomium 225 69. Hypnum 22g 70. Ptilium 230 71. Stereodon 231 72. Isopterygium 238 73. Plagiothecium 240 74. Camptothecium 243 75. Brachythecium 244 76. Cirriphyllum 250 77. Oxyrhynchium 251 78. Eurhynchium 252 79. Bryhnia 254 80. Rhynchostegium 256 CLASS BRYOPHYTES Sub-Class Musci ORDER I. SPHAGNALES (Peat Mosses) Family SPHAGNACEAE A FAMILY containing but a single genus. SPHAGNUM (Dill.) Ehrh. (Sphag-num) A genus containing a great many species found in bogs and swampy woods, along the margins of ponds, sometimes submerged, on moist banks by streams, and more rarely in drier situations. An old Greek name for some plant. Plants crowded together, sometimes form- ing dense, extensive growths; varying in color from pale to bright green, and in some species from pink to deep red; fruit not common. Stc?ns usually erect, continuing growth at the tips, sometimes reaching several feet in length, but, as a rule, the older portions be- coming so decayed and fragile, that only a cymbmum few inches of the plants can be gathered ; 7nuch branched; branches arranged in clusters along the stem, shorter and more crowded at the tips forming a conspicuous head. 74 HOW TO KNOW THE MOSSES Seta absent, but represented by an outgrowth called a pseudopodium. Leaves sharp-pointed or spoon-shaped, closely folded and overlapping, or spreading; especially adapted for holding water. Capsule oval; brown; on a pale stalk; wrapped in leaves until mature; without a peristome; mature in summer. Operculum convex. Range, cosmopolitan in suitable habitats, more abundant in the cooler bogs of North America and Europe. In economic value, the Sphagnums are the most im- portant of the Bryophytes. The peat of commerce is obtained from the firm, compressed mass of the older portions of the plants that is formed at the bottom of bogs. This mass is cut into bricks and, when dried, is used for fuel, especially in Scotland and Ireland. Sphagnum is also valuable as a packing material. In certain localities it is used as a filling for mattresses and pillows, and, as a non-conducting substance, it is wrapped around steam-pipes or packed in the walls of houses. When moist, it is used by gardeners and flor- ists for packing vegetables and plants, as the peculiar structure of the leaves enables them to absorb and hold moisture like a sponge. It has been discovered in Germany, England, and Scotland that, owing to its absorbing qualities. Sphag- num can be successfully used for surgical dressings as a substitute for prepared cotton wool. ORDER II. ANDREAEALES Family ANDREAEACEAE A FAMILY containing only one genus. ANDREAEA Ehrh. (An-dre-ae-a) A genus containing many species, growing on rock, but not on limestone, usually in mountainous regions; three species occurring in our range; not common. Named after Andrea, an apothecary of Hanover, Germany. Plants small and fine, growing in dense or lax tufts on rocks; reddish-brown to almost black. Stems erect, slender, short, usually about ^^^ inches long; con- spicuous. Capsule inclined, cylindrical, with a long neck, giving the appearance of a very long slender fruit; reddish-brown; mature in summer. Operculufn long-beaked. Range, Canada and the northern United States; Europe. The long slender fruit of Trematodon and the shining, yellow fruit-stalks first attract the eye and are the im- portant characteristics for determination. The moss is not conspicuous when not fruited. Two other mosses with short stems and hair-like leaves are Ditrichum pallidum (p. 80), and Leptobryum (p. 126), but the capsules are very different, and as none of these plants are likely to be collected except when fruited, there is no danger of confusing them. 2. DITRICHUM Timm (Di-tri-chum) A cosmopolitan genus of many species, three of which are common. Name derived from the Greek for ** two," and '^ hair," referring to the divided teeth of the peristome. Plants crowded together, growing on the ground, rarely on rocks; bright or yellowish-green; fruiting abundantly; not conspicuous unless in fruit ; common. Stems erect, short, usually less than }^ inch long. DICRANACEAE 79 a. Leaves too small to show outline; closely folded when dry; a rather bright green. Seta usually less than i inch long; reddish-brown. Capsule erect, cylindrical, slender; reddish-brown; mature in autumn. Operculum short-beaked. D. tortile. D. vaginans. b. Leaves easily seen, long, hair-like, spreading; yellowish- green. Seta usually i-i/4 inches long; yellowish. Capsule erect or slightly inclined, long, cylindrical; yellowish ; mature in June. Operculum short-beaked. D. pallidum. Ditrichum tortile (Schrad.) Lindb. and Ditrichum vaginans (Sull.) Hamp. are both found in the eastern half of North America and in Europe, the former also in Asia and Africa. They resemble each other too closely for the beginner to identify them easily. They grow on moist banks, often along roadsides, very rarely on rocks. The stem^s and capsules are very slender, and the leaves are so small and so closely folded, es- ^'[['^llil^ pecially when dry, that one is hardly con- capsuie scious that there are any leaves at all, as ^"^^'■^^^• the plants look as though they consisted of tiny green stems with the fruit and fruit-stalks. No other small mosses with small erect capsules are commonly found on moist soil. Barbula (p. 105) has erect cap- sules, but usually grows on drier soil, is less com- 8o HOW TO KNOW THE MOSSES mon, and the leaves are crisped when dry, so that the steins do not look smooth and slender. Georgia pellucida (p. 154) also has small erect capsules and slen- der stems, but its favorite habitat is decaying wood; it less frequently grows on the ground, and mixed with the fruited plants are usually sterile stems with larger leaves arranged at the tip of the stem in a cup-like cluster containing gemmae, or brood bodies capable of reproducing the plants. b Ditrichum pallidum (Schrad.) Hamp. can be recog- nized by the long yellow seta and slender capsule, erect, or slightly inclined, sometimes becoming hori- zontal when old, and by the long hair-like leaves. It usually is found on bare ground in woods. For comparison with other mosses having hair-like leaves see Trematodon (p. 77), Dicranella (p. 84), Weisia (p. 100), and Leptohryum (p. 126). Ditrichum -^^^^^> Ontario to the Gulf of Mexico, west to pallidum, Kansas; Europe; Asia; Africa. 3. SAELANIA Lindb. (Sae-lan-i-a) A genus containing but one species found on earth and in crevices of rocks, especially limestone, in moun- tainous or hilly regions; rare. Named after Saelan, a Scandinavian moss student. t DICRANACEAE 8i Plants thickly crowded together; glaucous or light bluish- green above, brown below; fruit occasional. Stems usually less than i inch long, erect, slender, slightly branched. Leaves long, hair-like, erect; some at least showing the characteristic glaucous or light bluish-green color. Seta about % inch long; yellowish or pale reddish. Capsule erect, cylindrical; reddish; mature in early autumn. ^ , . Saelania Operculum cone-shaped, not easily seen. giaucescens Range, Greenland and Labrador to the Mid- dle Atlantic States, west to British Columbia and Colo- rado; Europe; Asia; New Zealand. Saelania giaucescens (Hedw.) Broth. (5. caesia Lindb.) is to be expected only in elevated regions, especially in limestone country. It is at once distin- guished by the glaucous bluish-green of the upper leaves. No other moss has this peculiar color. The plants first impress one as being coated with some foreign matter, and a hand-lens shows the back of the leaves covered with a white substance. 4. CERATODON Brid. (Ce-rat-o-don) A genus of many species widely distributed. Name derived from the Greek for " horn " and '' tooth," referring to the teeth of the peristome. Ceratodon purpiireus (L.) Brid. is found all over the world, growing on barren soil, burnt-over places, rocks, 82 HOW TO KNOW THE MOSSES old roofs, and even on the sand at the seashore. It is very common and fruits abundantly. Plants crowded together; fruiting abundantly; most con- spicuous when in fruit ; a rather dark green. Stems erect, usually about y?, inch high; often slightly branched by forking at tip of old growth. Leaves short, hair-like, spreading when moist ; somewhat folded when dry; a rather dark green. Seta about i inch long; becoming dark red when fruit is mature. Capsule cylindrical, inclined; dark red like seta and grooved when mature, turning brown when very old; sometimes appearing lateral by new growth of stem; mature in spring. Operculum cone-shaped. Range, a cosmopolitan species. Ceratodon purpilreus is one of our commonest mosses and one of the first to attract the eye in early spring. In March, when the snow disappears, the slender young fruit-stalks have already reached nearly their full height and are beginning to turn from green to red; although the capsules are still so spear-like that one can hardly tell where the seta ends and the capsule begins. By late May or early June both have become the characteristic dark red that suggested the name purpureus. Often the new growth starts at the tip of the stem, sometimes forking before the fruit is mature, causing the seta to look as if it came from the side of DICRANACEAE 83 the stem; but when this occurs, the new leaves are lighter green than the old ones and one readily sees what has taken place. The distinguishing characteristics of Ceratodon are the dark-red capsule and seta combined with the short erect stems and short hair-like leaves. When the plants are not fruited they are not conspicuous, unless the growth is quite extensive, and are not easily recog- nized. One can bear in mind that Ceratodon grows in dry, barren places and that the leaves are short, hair- like, and wide-spreading when moist. Sterile plants of Pohlia nutans (p. 127) often grow quite extensively, and this moss is also a very common one; but it is found in damper places, having leaves wider, larger, and more erect than in Ceratodon and the stems gen- erally red, especially in the young plants. 5. DISTICHIUM Bryol. Eur. (Di-stich-i-um) A small genus. Name derived from the Greek for a *' double row," referring to the leaves arranged in two rows. Distichium capillaceum (Sw.) Bryol. Eur. (Swartzia montana Lindb.) is found in mountainous regions, growing on rocks and ledges, especially limestone; not common; fruit occasional. Plants thickly crowded together; glossy; bright or dark green above, reddish-brown below. Stems very slender, usually 1-4 inches long; branched. 84 HOW TO KNOW THE MOSSES Leaves long, hair-like, spreading when moist; more erect when dry; arranged in ofily two rows ; bright or dark green. Seta about i inch long; reddish. Capsule erect, cyhndrical, slender; reddish- brown; mature in summer. Operculum cone-shaped, not conspicuous. Range, Europe, North America, Tasmania, New Zealand. This species is usually found on rocks in Dishchum ^YiQ mountains, especially in limestone re- capillaceum ' ^ -^ Portion of gions. The distinguishing characters are the \lig^d ^^' ^^^^ slender stems and the long hair -like leaves. The plants are soft and silky in appear- ance. The leaves are in two opposite rows, but this is not always clearly seen, especially if the leaves are crowded. Sometimes they are separated enough to show this arrangement and also the white sheathing bases which make the stems appear white and shining. 6. DICRANELLA Schimp. (Di-cra-nel-la) A genus of over one hundred species, only two of which are at all common in our range. The name means a " little " Dicranum; Dicranum is from the Greek, referring to the shape of the teeth of the peristome. Plants growing close together on damp soil and upturned roots, rarely on earth-covered rocks ; common ; freely fruiting. Stems erect, slender, usually less than i inch high. Leaves long, narrow, hair-like, usually turned to one side; not much changed when dry; bright to dark green. DICRANACEAE 85 Seta less than i inch long; yellowish in the two common species, reddish in the others. Capsule cylindrical, symmclrical and erect, or unsymvietri^ cat and slighlly inclined; reddish-brown; ma- ture in autumn. Operculum long-beaked. Range, Newfoundland to Florida, west to the ^ -. Pacific; Europe; Asia. J IT Dicranellaheteromalla (Dill.,L.) Schimp. Dicrandia , , . , 7 7 • 7 7 . heteromalla has the unsymmetrical capsule, slightly in- clined, and when dry and empty it suddenly capsule en- 1 , 1 , larged. curves in just below the mouth. Var. orthocarpa (Hedw.) E. G. B. has the capsule erect and symmetrical, not curved in below the mouth. These two small mosses are typical little Dicranums. Their long hair-like leaves, usually turned to one side, and the long-beaked operculum are very characteristic. Dicranum jlagcllare (p. 89) somew^hat resembles Di- cranella, is next to these in size, and has erect capsules; but it commonly growls on decaying logs, and the stems are longer, thicker, and matted together with radicles; the leaves are coarser, usually crisped when dry; and if the tiny branchlets (flagella) can be seen sticking up above the upper leaves, one may be sure that the moss is Dicranum jlagcllare and not Dicra- nella. Ditrichum pallidum (p. 80) has hair-like leaves, yellow seta, and erect capsule; but leaves, seta, and capsule are all longer than in Dicranella. See also Weisia (p. 100). 86 HOW TO KNOW THE MOSSES 7. ONCOPHORUS Brid. (On-c6-pho-rus) A genus of several species widely distributed, one of which occurs in certain parts of our range. Name derived from the Greek for " something puffed out/' referring to the swelling at the base of the capsule. Oncophorus Wahlenbergii Brid. {Cynodontium vi- rens var. Wahlenbergii S chimp.) grows on the ground, on rocks, and on decaying logs, in moun- ^ tainous and hilly woods ; not common ; fruit occasional. Plants growing close together forming small bright- green tufts, dark below. Stems erect, up to i/^ inches long; some- Oncophorus times forked. a en ergtt Leaves long, hair-like; spreading when moist ; XrgeV"' loosely curled when dry, giving the plants a woolly appearance; bright green. Seta %- 1 inch high; yellowish or pale reddish. Capsule cylindrical, much curved and inclined; orange- yellow in spring, with a tiny red swollen spot at the base and the peristome showing like a red band around the mouth; when past maturity, darker and about the same color throughout; mature in spring. Operculum long-beaked. Range, Canada and the northern United States; Europe; Asia. One needs to collect Oncophorus in the spring to see the leaves and capsules in their best color. By fall, the DICRANACEAE 87 fruit has become dark and broken, while the new cap- sules are merely slender spears. The plants have a characteristic curly appearance when dry, due to the long leaves slightly curling. Two other mosses with similar growth, leaves, and habitat, are Dicranum fus- cescens (p. 93) and Bartramia pomiformis (p. 144). The leaves of these two species become somewhat crisped in drying, but they are not so distinctly curled as in OncopJiorus, and in the Dicranum they are more or less turned to one side. The lower part of the stems of both Dicranum and Bartramia is usually covered with a felted mass of brown radicles, called tomentum, which is not found on the stems of OncopJiorus. The fruit of Bartramia, if present, distinguishes the genus at once, as it is round instead of cylindrical ; but the fruit of Dicranum is similar to that of OncopJiorus in general appearance, although usually not so curved. With a hand-lens the small projection at the base of the capsule can be seen, which suggested the name of the genus. 8. DICRANUM Hedw. (Di-cra-num) A large cosmopolitan genus comprising several of our common mosses. Name derived from the Greek for a '' two-pronged fork," referring to the teeth of the peristome. Plants varying in size, often robust, growing close to- gether, forming mats or tufts, on damp soil, rocks, decaying 88 HOW TO KNOW THE MOSSES logs, and rarely on living trees; bright to dark green; fruit of most species common. Stems erect or ascending, usually ^^-3 inches long; branched by forking, or unbranched; often covered with brown or whitish radicles forming a felt-like coating called tomentum. Leaves long and narrow, often curved and turned to one side (secund), more rarely equally spreading; in some species crisped when dry; bright to dark green. Seta }i-2 inches long; sometimes two or more setae to- gether ; often appearing to come from the side of the stem on account of the new growth of the plant; usually reddish; yellowish when not solitary. Capsule cylindrical, erect and symmetrical, or inclined and curved; yellowish or reddish; mature in summer or autumn. Operculum long-beaked. Peristome red, easily seen in some of the larger species, appearing like a red band at the mouth of the capsule. For comparison with Catharinaea and Polytrichunij which also have long narrow leaves, see p. 171. The different species are divided as follows : — • a. Capsule erect D. fulvum. D. longijolium. D. flagellare. D. viride. D. montanum. b. Capsule not erect . . .D. scoparium. D. Drummondii. D. fuscescens. D. majus. D. undulatum. EXPLANATION OF PLATE V DiCRANUM Fig. I. D.fidvmn. Fig. 2. D. flagdlare. Fig. 2a. Branch of D. flagdlare showing flagella, enlarged. Fig. 3- D. fuscescens. Fig. 4. D. scoparinm. Fig. S- D. mididatum. Fig. sa. , Leaf of D. iindidatiim, enlarged. Fig. 6. Peristome of Dicranum, enlarged. I'LAiK V. DICRANUM DICRANACEAE 89 a. Capsule erect Dicranum fulvum Hook. (Plate V, Fig. i) is a com- mon species growing only on rocks. The plants are medium in size, dark green above, dark brown below. The lower part of the stems is often covered with radi- cles. The leaves are more or less turned to one side; somew^hat crisped when dry; usually rather dark green. The fruit matures in autumn. Range, Nova Scotia to Wisconsin, south to North Caro- lina and Missouri; Europe. When this species is not fruited it somewhat resem- bles certain forms of D. scoparium (p. 91), which also grows on rocks. Typical plants of D. scoparium are taller and the leaves are more turned to one side, not changing much when dry. When the plants are fruited, they are easily distinguished by the position of the capsule. See also D. fuscescens (p. 93). Dicranum flagellare Hedw. (Plate V, Fig. 2) is tisu- ally found on old logs and stumps in moist woods. It is a common species, generally fruiting freely, maturing in summer. Range, Nova Scotia to North Carolina; Mexico; Europe; Asia. A small species with stems about i inch long, the lower part covered with felt-like tomentum, or radicles. The leaves are somewhat curved and turned to one side; usually crisped when dry; bright or yellowish- 90 HOW TO KNOW THE MOSSES green. Fine branchlets, called flagella (Plate V, Fig. 2a), are often present and should be looked for at the tips of the stems. They are erect, rather stiff in appear- ance, sometimes numerous, and about the same size and color as the leaves, although they themselves are covered with very minute leaves. Care must be taken not to mistake very young capsules or new leaves for the flagella. The leaves are usually slightly curved and more hair-like at the tips and the young capsule is covered with the yellowish calyptra. D.flagellare when fruited most closely resembles Dicranella heteromalla var. orthocarpa (p. 85), as both have erect capsules. See under that species for comparison. Sterile plants, unless the flagella can be seen, may be mistaken for D. fuscescens (p. 93), and both occur on decaying wood, but D. flagellare is more frequent and has a wider range, as D. fuscescens is found chiefly at a higher altitude. It is safest always to name species only from fruited specimens. There are three other Dicranums with erect capsules that occur on living trees, but they are rare; Dicranum montanum Hedw., Dicranum longifolium (Ehrh.) Hedw., and Dicranum viride (Sull. & Lesq.) Lindb. The fruit is very rare. Dicranum montanum is a very small species with stems usually not more than }^ inch long, found on trees and decaying logs. The leaves are shorter and more hair- DICRANACEAE 91 like than other species and become much crisped when dry. They are yellowish to dark green. Range, Newfoundland to Manitoba, south to West Vir- ginia; Europe; Asia. Dicranum longifolium occurs on rocks and trees in mountainous or hilly woods. The stems are usually 1-2 inches long and the leaves about }4 mc//, often longer; curved and turned to one side; not much changed when dry; light green, and glossy. Range, Nova Scotia to North Carolina, west to British Columbia and Colorado; Greenland; Europe; Asia. Dicranum viride is found on decaying logs as well as on living trees. It is a small species, usually not more than I inch high. The leaves are yellowish to dark green, spreading when moist, a Kttle crisped when dry and the tips are usually broken of, which is the dis- tinguishing characteristic, but not always easily seen without a lens. Range, Newfoundland to the Rocky Mountains, south to Pennsylvania and Ohio. b. Capside not erect I. Seta solitary Dicranum scoparium (L.) Hedw. (Plate V, Fig. 4) is by far the most common species and is very variable. It grows on soil, rocks, or decaying wood in dry or 92 HOW TO KNOW THE MOSSES moist woods. The fruit is frequent and matures in August or September. Range, Canada and the United States; Europe; Asia. Often large clumps of this species occur not bearing fruit; then again the plants will be well fruited. The stems are sometimes very long, up to 4 inches, as they continue growth at the tips, dying down below. The older parts are thickly covered with brown radicles. The leaves are often more than % inch long, usually slightly curved and turned to one side, but sometimes shorter and equally spreading, little changed when dry; yellowish-green. It is the Dicranum most fre- quently collected, but varies so in size and general ap- pearance that puzzling forms are often found. The usual large size of the plants, the long leaves more or less turned to one side, not much changed when dry, are typi- cal characteristics. There are two other Dicranums, D. Bergeri Bland. {D. Schraderi Web. & Mohr), and D. Bonjeani De Not., that grow in sub-alpine bogs and marshes and closely resemble certain forms of D. scoparium, but they are not so common and are too difficult for the beginner to identify as species, although the generic characters are easily recognized in leaves and capsule. The leaves are shorter with broader tips and are more erect than the typical leaves of D. scoparium. See D. fulvum (p. 89) and D. fuscescens (the follow- ing species). DICRANACEAE 93 Dicranum fuscescens Turn. (Plate V, Fig. 3) is found on rocks and decaying wood in mountainous regions. The plants are usually well fruited, and ma- ture in the autumn. The stems are about i ^ inches long, often branched, brown below, and matted to- gether with radicles. The leaves are more or less curved and turned to one side, crisped when dry, es- pecially in the upper part. Range, Labrador to South Carolina, Alaska to California; Europe; Asia. D. fuscescens may be distinguished from D. scopa- rium by its smaller size, and narroiver, somewhat shorter, leaves, more crisped when dry. It is also much less fre- quent. If sterile plants are found on rocks they may be confused with D. fulvum (p. 89), but the stems of D. fuscescens are lighter hrown below and thickly covered with radicles, and the leaves are more curled when dry. 2. Setae clustered Dicranum undulatum Ehrh. (Plate V, Fig. 5) is easily recognized by the wavy leaves and clustered setae^ 2-5 on one plant. It grows on moist soil and earth- covered rocks in hilly woods. Fruit mature in summer. Range, Canada and the northern United States; Eu- rope; Asia. The stems of D. undulatum are stout, often 3-4 inches long, sometimes prostrate in the lower part, and 94 HOW TO KNOW THE MOSSES thickly covered with brown or whitish radicles. The wavy leaves (Plate V, Fig. 5a) are very long, glossy, and bright yellow-green; wide-spreading or slightly turned to one side, the uppermost erect; not much altered when dry. Catharinaea undulata (p. 157) also has wavy leaves, but they become very crisped when dry, and the stems are not covered with radicles. Dicranum Drummondii C. Mlill. has clustered setae and is found in locahties with D. undulatum, but less frequently. It may be easily distinguished from the latter by the leaves, which are never wavy and become crisped when dry. Range, northern United States, south to New Jersey and Colorado. There is one other Dicranum with clustered setae, but it is very rarely found. Dicranum majus Smith. This species occurs in the mountains and again along the coast in the northern part of our range. The stems are long as in the two preceding species and the leaves are very long, usually regularly turned to one side; light to dark green, and glossy; not wavy, and not crisped when dry. The stems are only slightly covered with radicles in the lower part. Range, Greenland to Maine; Alaska; Europe; Asia. Family LEUCOBRYACEAE A SMALL family occurring chiefly in the tropics with the exception of the following genus which is almost cosmopolitan. 9. LEUCOBRYUM Hamp. (Leu-co-bry-um) A genus containing several species, mostly tropical. The name is derived from two Greek words meaning *' white moss," referring to the typical color of the leaves. Leucobryum glaucum (L.) Schimp., sometimes called '' white moss," is found on the ground and on rocks in the woods. It is very com- mon in most regions, but rarely fruits. Plants growing in cushions of vary- ing size; glaucous or whitish- green above when dry; sometimes darker green when moist; grayish-brown beneath. Stems erect, usually 1-3 inches long, thick, but easily broken; branched by forking. Leaves long, narrow, tubular from the incurved margins, erect or spreading; glaucous or whitish- green, darker when moist in the early spring, but becoming very pale w^hen dry. Leucobryum glaucum Leaf enlarged. 96 HOW TO KNOW THE MOSSES Seta usually i inch long or less, dark brown. Capsule cylindrical, curved, inclined; dark brown; mature in autumn. Operculum long-beaked. Range, Newfoundland to the Rocky Mountains; south to Florida and Louisiana; Europe; Asia; Africa. The pale-green cushions of Leucohryum are familiar to nearly every one who frequents the woods. Some- times only the surface of the cushions protrudes above the ground, and sometimes the stems seem quite, if not wholly, unattached, and the rounded tufts are lying on the top of the ground. On account of its characteristic color, Leucohryum will not be confused with any other moss except Sphagnum (p. 73). The two plants re- semble each other in color and erect growth, but the manner of branching and the leaves are very different. The branches of Sphagnum are very numerous, ar- ranged in a close head at the tip of the stem, but long, clustered, and drooping below; the leaves vary some- what in size, and are erect and closely folded or some- times spreading. The stiff, erect leaves of Leucohryum might be mistaken for the short branches that form the heads of Sphagnum, but by separating a few of the plants and comparing the illustrations no mistake will be made. Family FISSIDENTACEAE The plants of this family belong, with only a few exceptions, to the following genus. 10. FISSIDENS Hedw. (Fiss-i-dens) A genus of wide distribution, containing many species. Name derived from the Latin for *' split," and a '' tooth," referring to the teeth of the peristome. Fissidens is found in damp places, growing on the ground in moist woods or on shaded earth in green- houses, on wet rocks often along streams, and more rarely at the base of trees or on decaying wood. A few species occur fairly frequently in our range, but rarely fruit, and are not easily sepa- S] rated. Plants growing close together, sometimes forming thin mats; bright to dark green. Stems erect or ascending, usually less than I inch long, sometimes taller; not branched Leaf enlarged. or with a few branches. Leaves relatively short and broad, arranged in only two rows on opposite sides of stem; lying flat when moist, but becom- ing crisped when dry; most of the upper half double; bright to dark green. Seta terminal or lateral, ]i'i inch long; reddish. Capsule cylindrical, erect or inclined; reddish-brown; maturing from summer to winter. 98 HOW TO KNOW THE MOSSES Operculum conical or short-beaked, not easily seen. Range, throughout North America; Europe; Asia; Africa. The leaves of Fissldens differ from those of other mosses in having a double part that clasps the stem. In the larger plants it can usually be seen with the un- aided eye when the plants are held to the light. It is the lower part of the upper side of the leaf and will look thicker and darker than the rest of the leaf. The conspicuous characteristic of Fissidens is the flattened appearance of the plants, due to the leaves ar- ranged in only two rows, one on either side of the stem. Only one other moss described in this book has this arrangement of leaves, Distichium (p. ^2)) 5 but there are several that have a flattened appearance, and the leaves must be examined closely to notice that they are really in more than two rows; sometimes they dis- tinctly show that there is more than one layer. See Mnium (p. 138) and Aulacomnium heterostichum (p. 140). Among the pleurocarpous mosses the flattened appearance is more common, but the manner of growth and the branching is very different from that of Fissi- dens. See especially Neckera (p. 185) and Homalia (p. 186). Fissidens more closely resembles some of the leafy hepatics than any of the mosses. Both the hepatics and Fissidens grow on rocks and moist banks, espe- cially along streams, and it is often necessary to gather the plants and carefully examine them to tell them apart. The leaves of Fissidens lie flat when moist, are FISSIDENTACEAE 99 pointed, and when held to the light the midrib can usually be seen even if the double portion does not clearly show; while the leaves of hepatics are rounded or lobed, usually curled under at the tips, and there is no midrib. See Introduction (p. 6). The stems of leafy hepatics are usually much branched and often interweave, forming tangled mats, while the stems of Fissidcns are not much branched and can be easily separated. Family POTTIACEAE A VERY large family, occurring chiefly in the tem- perate zones. Our common genera are found on the ground and on rocks. II. WEISIA Hedw. (Weis-i-a) A genus containing many species. Named after Weis, a botanist of Gottingen, Germany. The only species of this genus found in our range is Weisia viridula (L.) Hedw. It grows on bare earth along roadsides, on banks, or in fields, sometimes on soil newly turned over in woods, but it is rarely collected. The fruit is abundant. Plants crowded together; yellow-green; thickly covered with fruit. Stems erect, very short, less than % inch long, usually about % inch. Natural Leaves long, narrow, hair-like, spreading when size and en- moist; somewhat crisped when dry; yellow- larged. green. Seta % inch long or less, greenish-yellow. Capsule short cylindrical, oval or elliptical, erect; reddish- brown; mature in spring. Operculum long-beaked, not easily seen. Range, Canada; United States; Europe; Asia; Africa; New Zealand; Tasmania. POTTIACEAE loi The stems of Weisia are so short that it is not likely to be collected except when in fruit. The small size of the plants, long hair-like leaves, short seta, and short capsule, all help to distinguish Weisia from other mosses. It is nearest in size to Pottia (p. io6), but the leaves of Pottia are much broader and the capsule is top-shaped. Ditrichum pallidum (p. 80) has short stems, hair-like leaves, and yellow seta, but the seta is much longer and the capsule is larger. In Dicranella (p. 84) the hair-like leaves are turned to one side. Tortella caespitosa (p. 103) is another short-stemmed moss, but the leaves are much broader, more crisped when dry, and the capsule is longer. 12. HYMENOSTYLIUM Brid. (Hy-men-o-sty-li-um) A genus of wide distribution, containing several species occurring chiefly in limestone re- gions. Name derived from the Greek, referring to the structure of the capsule. Hymenostylium curvirostre (Ehrh.) Lindb. (Gymnostomiim curvirostre Hedw.) is found in our range. EynunostyUum curvirostre Plants thickly crowded together, growing on Capsule en- moist rocks, usually limestone, in mountainous or hilly regions, and along the coast; hrigJit green above, brownish below; not common; fruit sometimes abundant. Stems erect, very slender, ^-4 inches long; branched. 102 HOW TO KNOW THE MOSSES Leaves hair-like, hut short; erect or somewhat spreading when moist; only shghtly twisted and more erect when dry; usually bright green in the new growth, brown below. Seta not more than }4 inch long; yellowish or light reddish- brown. Capsule erect, symmetrical, oval, very small; reddish- brown; mature in summer. Operculum with a long oblique beak, not easily seen with- out a lens. Range, Labrador to Alaska, south to California and South Carolina; Europe; Asia; Africa. Hymenostylium curvirostre occurs chiefly 07i wet cliffs in limestone regions. The plants often form a deep, dense growth, conspicuously green for about one-quarter of an inch, and then brown below. The fruit is some- times abundant. If the capsule is examined under a lens it will be seen that there is no peristome. See Didymodon (p. 104). 13. TORTELLA (C. Mull.) Limpr. (Tor-tel-la) A cosmopolitan genus containing many species. Name derived from the Greek for '* twisted," referring to the twisted teeth of the peristome. The two species occurring in our range are found on earth, rocks, and roots of trees; not common; fruit occasional. Plants crowded together; green or yellowish-green. Leaves long and narrow; much crisped when dry; green or yellowish-green. POTTIACEAE 103 Seta more than % inch long; orange-brown. Capsule long-cylindrical, erect; orange-brown; mature in June. Operculum long-beaked. Stems erect, more than >^ inch long. T. tortuosa. Stems erect, less than ^ inch long. T. caespitosa. Tortella tortuosa Tortclla caespitosa Leaf and peristome enlarged. Leaf enlarged. Tortella tortuosa (L.) Limpr. \s found on rocks in mountainous or hilly regions. Range, Greenland; Canada; northern United States; Europe; Asia; Africa. The stems of this species are usually i or 2 inches long, robust, yellowish-green above, brown below, and covered with brown radicles. Tortella caespitosa (Schwaegr.) Limpr. (Barbula caespitosa Schwaegr.) is a much smaller species than T, tortuosa. It grows on earth and roots of trees in the woods. Range, Ontario and New England to the Gulf States, west to British Columbia; Mexico; South America; Europe; Asia; Africa. I04 HOW TO KNOW THE MOSSES The two species described above are not among our common mosses. The long slender leaves, becoming much curled and crisped when dry, and the long, slender^ erect capsule are distinguishing characteristics. If the plants are found in fruit, the student will be well repaid to examine the peristome with a lens. The long teeth are shaded from orange-red to yellow, and are spirally twisted. The peristome of Barhula (p. 105) and Tortula (p. 107) is similar to that of Tortella. 14. DIDYMODON Hedw. (Di-dym-o-don) A genus of many species occurring in limestone re- gions. Name derived from the Greek for '' twin " and " tooth," referring to the divided teeth of the peristome. Didymodon rubellus (Hoffm.) Bryol. Eur. is found on wet ledges and rocks, usually limestone, in mountainous or hilly regions; not com- mon; fruit sometimes abundant. Plants growing close together; bright or dark green above, rusty -red below. Didymodon Stems usually less than i inch long; branched. rubellus Leaves hair-like; wide-spreading when moist; Leaf and somewhat crisped when dry; bright or dark lar^ed^^ ^"" g^^^n above, rusty-red on lower part of stem. Seta about ^ inch long; reddish. Capsule erect, cylindrical; reddish-brown ; mature in summer. Operculum long-beaked. Range, Alaska, Canada, and the northern United States; Europe; Asia; Africa. POTTIACEAE 105 Didymodon is to be expected on the hills and moun- tains of limestone regions. The conspicuous charac- teristic is the rusty-red color of the lower leaves, which distinguishes this species from other mosses of the same locality. 15. BARBULA Hedw. (Bar-bu-la) A large genus widely distributed. But two species are described here and they are not common. Name derived from the Latin for ''beard," referring to the peristome. Barbula unguiculata (Huds.) Hedw. is found on the ground and on stones; sometimes on stone walls. Barbula convoluta Hedw. grows on the ground in rather dry places. Plants growing close together; yellow-green; Barbula fruit often abundant. unguiculata Stems erect, short, usually less than }^ inch laJgeT" long. Leaves^ if large enough to be seen, short and hair-like; much crisped when dry. Seta about >^ inch long; reddish-brown in B. unguiculata; yellowish in B. convoluta, becoming reddish with age. Capstde long-cylindrical , erect. Peristome twisted as in Tortclla (p. 102), and Tartula (p. 107). Operculum long-beaked. Range, Canada and the northern and western United States; Europe; Asia; Africa. io6 HOW TO KNOW THE MOSSES The beginner will not be likely to collect the Bar- hulas^ unless fruited, as even moist plants are so small and inconspicuous; and when dry, they look very much dried-up on account of the tightly curled leaves. When not fruited, the short stems and the leaves crisped when dry are the only distinguishing characteristics. Barhula is common south and west of our range. See Ditrichum (p. 78), Georgia (p. 154), and Encalypta (p. 108). 16. POTTIA Ehrh. (P6tt-i-a) A large genus widely distributed. But one species occurs in our range. Named after Pott, a professor of botany in Brunswick, Germany. Pottia truncatula (L.) Lindb. grows on the ground in moist places; not common; fruit usually abundant. Plants growing close together; dull green. Stems erect, very short, about }i inch long. Leaves short and broad; usually easily seen when moist; slightly crisped when dry; dull green. Seta short, % to y% inch long; yellow-brown. Leaf and Capsule top-shaped, erect; reddish-brown; ma- capsule en- ture in autumn. larked Operculum short-beaked, not easily seen. Range, Quebec and New England to Pennsylvania; Nevada; Europe; Asia; Africa. Pottia is not very common, but is easily recognized by the top-shaped capsules. The only other moss with a POTTIACEAE 107 similar capsule is Physcomitrium, which is a little larger and more common than Pottia. It also has short stems and leaves similar in shape, but lighter colored; the seta is longer and the capsule is larger, lighter colored, and more urn-shaped; that is, with the outline more curved. See illustration of Physcomitrium (p. 122). Weisia (p. 100) resembles Pottia in size, but the leaves are hair-like and the capsule is cylindrical and more slender than that of Pottia. 17. TORTULA Hedw. (Tor-tu-la) A large genus widely distributed. But two species are described here, and they are very rare. Name derived from the Latin for " twisted," referring to the peristome. Plants growing close together on rocks and on trees in dense cushions or patches; light or dark green; fruit some- times abundant in T. muralis. Stems erect, short, about /4 inch long, or less. Leaves broad and short in T. papulosa; longer in T. muralis, with the midrib extending beyond the leaf in a hair-like tip, not easily seen without a lens; only slightly crisped when dry; light or dark green. Seta in T. muralis about H inch long; yellowish to reddish. Capsule in T. muralis long-cylindrical, erect; yellowish or reddish; mature in spring. Peristome twisted as in Tortclla (p. 102) and Barhula (p. 105). Seen with a lens. Operculum long-beaked. io8 HOW TO KNOW THE MOSSES Tortula muralis (L.) Hedw. is a rare species in the eastern United States, growing on walls and sunny rocks. The leaves of this species are four or five times longer than the broadest part, slightly crisped when dry; dull or brighter green; hoary from white, hair-like tips. The seta is orange when young, growing darker with age; the fruit, sometimes abundant, is mature in larged!" the Spring. Compare Encalypta (p. no). Range, throughout North America, a cosmopoHtan. Tortula papulosa Wils. is also a very rare species. // grows on the hark of trees, less frequently on rocks. The fruit has not been reported from America. The leaves are dark or olive-green, short and broad, Tortida ^nd fold against the stem when dry, much like papulosa ^j^Qgg oi Orthotrichum (p. 117). Orthotrichum occurs much more frequently, the stems are usually longer, the leaves longer and more gradually pointed, and the fruit can usually be found. Range, throughout the northern Atlantic States; South America; Europe; Australia; New Zealand; Tasmania. 18. ENCALYPTA Schreb. (En-ca-lyp-ta) A cosmopolitan genus containing many species, two of which, rarely collected, are described below. Name from the Greek, meaning " to cover with a veil," refer- ring to the large calyptra. ft. POTTIACEAE 109 Plants growin