Cornell University Library
QK 569.D46W86 1892
Desmids of the United States and list of
3 1924 001 799 331
31924001799331NEW AND ENLARGED EDITION.
DESMIDS
OF THE
UNITED STATES
AND
LIST OF AMERICAN P E DI AST RUMS
WITH NEARLY
FOURTEEN HUNDRED ILLUSTRATIONS
Sixty-four Colored Plates.
BY THE REV FRANCIS WOLLE,.
Member of the American Society of Microscopistx.
BETHLEHEM, PA..
MORAVIAN- PUBLICATION OFFICE.
1892.
1892.
1892.TO
Dr. 0tto Zcorbstebt,
OF THE UNIVERSITY OF LUND, SWEDEN,
THIS LITTLE WORK IS
Debicateb,
IN RECOGNITION OF HIS GREAT AND VALUABLE CONTRIBUTIONS
TO THE HISTORY OF CRYPTOGAMIC PLANTS,
BY HIS GRATEFUL FRIEND,
THE AUTHOR.PREFACE.
In the “American Journal of Science and Art,” A. I). 1847, Prof.
J. W. Bailey, of West Point, said:—“With the exception of six or
eight, I am not aware of any published account of Marine Alga.
Of our fluviatile (fresh-water) Alga, I find no published notice,
although they appear to have been studied with some care by the
indefatigable Schweinitz,” and at a little later date he adds:—“It.
appears that to Schweinitz is due the credit of being the first to collect
and to study any of our fresh-water Alga." I refer with all the
more pleasure to these remarks concerning the late Rev. L. D. von
Schweinitz, of Bethlehem, Pa., that he was a friend of my youth,
and the first to draw my attention to the study of cryptogamous
plants. It is only proper that ample credit should be given to this
the first collector of our fresh-water Alga in this the first monograph
published in the United States, on that class of Alga known as
Desmids.
Nearly forty years ago Prof. J. W. Bailey contributed to the
“American Journal of Science and Art,” two papers, one describing
a few new species of Desmids from the Catskill mountains, and the
other, “ Notes on the Alga of the United States;” following these
we have “ Microscopical Observations made in South Carolina,
Georgia, and Florida—Smithsonian Institute, A. D. 1850, 50 pp.”
These observations cover Infusoria and Alga, the latter comprising
a list of one hundred and twenty-five species, among which appear
a few newly discovered Desmids which are illustrated and described.
Horatio C. Wood, Jr., M. D., published in 1872, through the Smith-
sonian Institute, “A Contribution to the History of the Fresh-Water
Alga of North America.” In this publication Dr. Wood brought
together all the recorded observations that had been made up to that
time, in this country and in Europe, upon the Alga of the United
States. His list of Alga includes about one hundred and sixty
species of Desmids.
In a collection made by Stephen J. Olney, near Providence, R. I.,
during the years 1846-48, there were about fifty species of Desmids.
My first contribution to the literature of the fresh-water Alga
appeared in the “Torrey Botanical Bulletin of New York,” in 1877,
wherein are described thirty Desmids not heretofore found in the
vVI
DESMIDS OF THE EXITED STATES.
United States. Every succeeding year up to 1-SS3,1 have recorded in
the same journal the results of my observations upon this interesting'
class of American flora; what my success has been, may be inferred
from the fact that I have in my herbarium nearly five hundred well
authenticated species and varieties of American Desmids.
Only the great pleasure I derived from collecting, and studying
the life-history of this heretofore neglected class of plants, enabled
me to make light of, and to overcome, the -erious obstacles I met
with at the outset of my labors. There were no home correspondents
with whom to co-operate and no accessible good works to guide me
in my researches over this almost wholly unexplored field. My first
encouragement came from abroad. The late Dr. L. Rabenhorst, of
Meissen, Prussia, and the late Alexander Braun, of Berlin, sent me
many valuable communications, and to the former particularly, I
furnished many set- of mounted specimens of our Algce for his serial
of decades of Algce Exsiccate. I am particularly indebted, however,
to Dr. Otto Xordstedt, of the University of Lund, Sweden, for his
kindness in determining the identity of certain American species
discovered by me with those already known in Europe; and also in
confirming my impressions concerning the restriction of others solely
to the United .states.
My grateful acknowledgments are also due for valuable notes and
papers, to Dr. V. B. 'Wit-truck, of the Scientific Academy of Stock-
holm; X. Wille, of Christiana, Xorway; F. Hauck, Trieste; Dr. J.
Rostafinski, Cracow; G. Lagerheim, Stockholm, and others.
Meanwhile, the subject had awakened interest in various parts of
the United States, and specimens began to come in from places it
would have been impossible for me to have visited. Among those
to whom I am particularly indebted for favors of this kind, are:—Mr.
H. \V. Ravenel, Aiken, S. C'., who during the past eight or more
years, has sent me many interesting specimens, from his own State,
Georgia and Florida; Capt. J. Donnell Smith, Baltimore, Md., who,
in 1*7* and l*7h, sent me over seven hundred specimens of fresh-
water Algce gathered in Florida; in his collections the Desmids were
not numerous, but they included specimens not found elsewhere;
Mr. F. H. Hosford, assisted by Mr. C. G. Pringle, Charlotte, Vt..
whose collections were copious in northern Vermont; and Miss
Eloise Butler, Minneapolis, Minn., who was a most successful col-
lector of Desmids; I am indebted to her for all the species in the
list which are assigned to Minneapolis. My acknowledgments would
not be complete did I omit to mention the practical interest taken
in my labors by the Rev. H. D. Kitchel, and his son, Mr. H. S.
Kitchel.
In the descriptive parts, I have abbreviated the name of the dis-
coverer of each plant, the reader being referred, for additional infor-
mation, to the appended list of names alphabetically arranged with
their abbreviations, and with the title of the books con-tilted in the
compilation of this work.PREFACE.
Vll
Although this work is believed to be exhaustive of all now known
concerning the Desmid's of the United States, yet the author regards
it only as the pioneer to others much larger and therefore more
valuable, wherein will be recorded the achievements of those who
will perhaps be indebted to this work for their first introduction to so
fascinating a study as that of the fresh-water Algol of our country.
F. W.
Bethlehem, Pennsylvania,
February, 1884,
PREFACE TO SECOND EDITION, 181)2.
September, 1891, found us unable to supply the occasional demands
for a copy of Desmtds of the United States. Some of the plates
were reproduced by means of the camera; these, in connection with
other plates and some copies of letterpress remaining from the
original publication made a very limited number of complete copies,
which, however, soon proved insufficient. The demand for more
encouraged the idea of another edition of the work.
Since the original publication in 1884 quite a number of discoveries
were made. Some of these were published on eight plates, and issued
in connection with the Fresh-water Abode of the United
States. Still later discoveries fill two more plates. Putting these
together we get a volume with one-fifth more plates than the original.
To make a new’ edition the fact is evident that the demand for a
book of the kind, naturally limited, has been pretty well supplied,
and hence the risk of sale greatly increased. The author’s consider-
ation must be to curtail expenses. This he hoped to do in a satis-
factory way by furnishing a book with many additional plates, figures
all hand-colored, without an increase in price. The plan was to omit
the descriptive part of the book as far as it relates to species, believ-
ing the distinct forms of the Desmids sufficient for identification, but
upon maturer consideration and advice have concluded to make a
complete reprint, adding all known later discoveries. This will
add greatly to the size of the volume and proportionately to the
expense, but in every other regard will make the most satisfactory
work for reference.
The discoveries of species new to the United States the past few
years, have not been as numerous as might have been expected in so
great a territory as belongs to us. A few have worked with success.
W. L. Poteat, of North Carolina, published a preliminary list of Des-
mids from his State. W. N. Hastings, Rochester, New’ Hampshire,
has been doing a good work as is evidenced by the plants acknowl-
edged to his name. G. Lagerheim, of Sweden, received material
from Massachusetts containing a number of new forms. \Y. Joshua;VIII
DESMIDS OF THE UNITED STATES.
AM AA'est and AV. B. Turner, of England, in like manner, made re-
searches in American waters. F. AA\ Harvey, Orono, Maine, has
been active in researches among the Alga;. Many others might be
named who have made a beginning. Personally have done very
little collecting. The explorations so delightful in the past have
become impossible by the advance of years, failing health and con-
sequent loss of vigor of body.
In foreign countries much interest prevailed, judging by the nu-
merous papers which made their appearance the past few years.
Dr. Otto Xordstedt, of Lund, Sweden, a veteran in the field, has
added to his previous achievements his contribution to the Algae of
Brazil; his discoveries in the Arctic regions, in Greenland and Spitz-
bergen and in Bornholm; he worked up also the collections made
by Dr. S. Berggren in New Zealand and Australia. Dr. AVille, of
Stockholm, made three contributions to the Desmids of Norway, of
South America and of Nova Zembla. Dr. Schaarschmidt has taken
care of the Desmids of Hungary. AV. M. Maskell presented three
valuable papers on the Alga (Desmids) of New Zealand. Dr. Lager-
heim tells of Bengal plants ; Roy & Bisset of Japan gatherings ; AAT.
Joshua, of Burmah ; Eug. Wanning of Central Brazil; A. AAV Ben-
nett of North Cornwall and English Lake Districts; Maria Lewin of
collections in Spain; A\T. AVest, gatherings in Yorkshire; J. P. Bisset
in Lake AVindermere; John Roy in Scotland, and probably many
others not represented in my library.H AMES OF AUTHORS
Which are abbreviated in the text, together with the titles of the
works consulted in the preparation of this monograph.
A. Br.—Alexander Braun. Algarum Unieellarium genera nova et
minus cognita. Leipzig, 1855.
Arch. — W. Archer. Desmidese in Pritchard’s History of Infusoria.
London, 1861.
Notes, in the Proceedings of the Natural History Society, Dub-
lin, 1862-1863. Notes in the Journal of the Microscopical Society,
London.
Ao.—C'. A. Agardh. Species Algarum, Lund;e 1820 and Systema Al-
garum. Lund, 1824.
Bail.—J. W. Bailey. Microscopical Observations made in South Caro-
lina, Georgia and Florida. Washington, 1851.
Notes on Algfe of the United States; American Journal of
Sciences and Arts. 1846 and 1853.
Breb.—A. de Brebisson. Liste des Desmidiees observees en Basse-
Normandie. Cherbourg, 1856.
Bulnh.—O. Bulnheim. Einige Desmidieen; Beitraege zur Flora der
Desmidieen Sachsens. Dresden, 1863.
Cleve.—P. T. Cleve. Bidrag till Kannedomen om Sveriges Soetvat-
tensalger af familjen Desmidieae. Stockholm, 1864.
Cohn,—Ferdinand Cohn. Desmidiaceae Bongoenses. Halle, 1879.
Corda.—A. J. Corda. Observations sur les Euastr6es et les Cosmariees.
Carlsbad, 1835-1840.
D. By.—A. de Bary. Untersuchungen ueber die Familie der Conju-
gaten. Leipzig, 1858.
De Not.—G. de Notaris. Elementi per lo Studie delle Desmidiaeeie
Italiche. Genova, 1867.
Delp.—J. B. Delponte. Specimen Desmidicearum subalpinarum.
Augusta- Taurinorum, 1873.
Eheb.-C. G. Ehrenberg. Verbreitung und Einfluss des mikrosko-
piscben Lebens in Slid und Nord-Amerika. Berlin, 1843.
Gay.—Fr. Gay. Essaj diine monograpbie locale des Conjugacees.
Montpelier, 1884.
Klebs.—G. Klebs. Ueber die formen einigen Gattungen der Des-
midisecen Oestpreusen. Konigsburg, 1879.
Grun. — A. Grunow. Ueber die in Rabenhorst’s Decaden ausgegebenen
Suesswasser Diatomeen und Desmidiaceen von der Insel Banka.
Leipzig, 1865.
IXX
1'ESMIHS OF THE UNITED .STATES
Hass. - A. H. Hassall. A History of the British Fresh-water Algie.
London, 1S45.
Hofm. - W. J. B. Hofmeister. Ueber die Fortpflanzung der Desmidieen
und Diatomen. Leipzig Berichte u, 1857.
Kirch.—O. Kirchner. Kryptogamen flora von Sehlesien. Breslau,
1878.
Kg.—F. T. Kuetzing. Deutselilands Algen in buendigen Beschrei-
bungen. Xordhausen, 1845. Species Algarum. Leipzig, 1-849.
Lund.—P. M. Lundell. De Desmidiaceis qua? in Suecia invents® sunt,
observationes critica?. Upsal, 1871.
JlENEfiH. - J. Meneghini. Synopsis Desmidearum hucusque cogni-
tarum. Halle, 1840.
Meven. — F. J. F. Meyen. Beobaehtungen ueber einige niedere Aigen-
formen. Bonn, 1*29.
Naeg.—C. Xaegeli. Gattungen einzelliger Algen. Zurich, 1849.
Xord.—O. Nordstedt. Desmidieie Arctose. Stockholm, 1875.
18 Fain. Desmidicete Brasilia*. Stockholm, 1869.
Desmidieie ex insulus Spetsbergensibus et. Beeren Eiland.
Stockholm, 1872.
Bidrag til Ktennedomen om Sydligare Xorges Desmideer.
Lund, 1873.
Desmidieie in Italea et Tyrolia. Stockholm, 1876.
De Algis Aquaedulcis ex insulis Sandvicencibus. Lund, 1878.
De Algis nonnulis, praecipue Desmidicis inter Utricularius
Musei Lugduno-Batavi. Lund, 1.880.
Rab.—L. Rabenhorst. Flora Europaea Algarum Aquie dulcis et Sub-
marinae. Leipzig, 1.868.
Rales.—J. Ralfs. On the British Desmidieie. London, 1848.
Reinsch. — P. Reinsch. Die Algenflora des mitleren Theiles von
Franken. Kiirnberg, 1867.
De Speciebus Generibusque nonnullis novis ex Algarum et
Fungorum classe. Frankford, 1867.
Wall. — G. C. Wallich. Descriptions of Desmidiaceie from lower Ben-
gal. London, 1860.
Wille.—X. Wille. Ferskvandsalger fra Xovaja Semlja samlede af Dr.
F. Kjellman paa Xordenskioelds Expedition, 1875. Stockholm,
1S7U.
Bedrag til Kundskaben om Xorges Ferskvandsalger. Chris-
tiania, 1880.
Witte.-V. B. Wittrock. Anteckningar om Skandinaviens Desmidi-
aceer. Upsal, 1869.
Algie aquae dulcis exsiccatae praecipue sc-andinavieae, quas
adjeetis algis marinis chlorophyllaceis et phycochromaceis dis-
tribuerint V. R. Wittrock et O. Xordstedt. Faso. I.-XII. Up-
salie, 1873-1883.
Wood.—H. C. Wood. A Contribution to the History of the Fresh-
water Algie of North America. Washington, D. C., 1874.INTRODUCTION.
The following preliminary remarks may prove interesting to
those who have not heretofore paid much attention to the sub-
ject which has inspired the preparation of this volume.
The term Algce signifies Sea-weeds, and is used to designate
certain marine and fresh-water plants, which because they bear
no flowers, stamens nor pistils, and in fructification produce
spores instead of seeds, are styled cryptogamous plants. The
Algce comprise not only sea-weeds properly so-called, but like-
wise the gelatinous, or scum-like substances found floating on or
near the surface of ponds, ditch water and placid streams; only
a very small proportion of the entire class of fresh-water Algce
is confined to trunks of trees, shady recesses, or to rocks dripping
with moisture.
Owing to the life-like peculiarities exhibited in some stages of
their development and growth many of the Algce were believed
by Ehrenberg and other micoscropists of his time, to belong to
the animal kingdom, but the wholly vegetable character of the
Algce is now too well established to admit of further controversy.
Howsoever great in other respects their individual differences
may be, the Algce possess certain characteristics which are com-
mon to them all. They are cellular, flowerless and devoid of
roots; their home is in the water; the very few which affect
other localities, die when deprived of moisture. Their nutri-
ment is absorbed through their entire surface from the medium
in which they live. They are totally devoid of vascular tissue,
in fact, are merely congeries of simple cells on the arrangement
of which depends their structural differences.
Few classes of plants present greater diversities of form than
do the Algce. Some are minute enough to tax the powers of our
best microscopes, while others are a constant source of astonish-
ment because of their enormous size, stretching as some of them
xiNil
f'ESM IPS OF THE UNITED STATE-.
do. nearly two hundred feet across their marine beds, and with
stems sufficiently thick wherefrom to manufacture handles for
small tools and cutlery.
Those which consist of only a few cells, contrast very forcibly
with others which in appearauce. but in appearance only, present
the branches, stems, twigs and foliage of highly developed plants;
nor are they less opposite in what may be termed their sociality,
from the fresh-water hermits scattered more or less sparsely in
secluded places, up to those immense aggregations in mid-ocean
which resemble sub-aqueous forests, or form floating islands
miles in diameter, where multitudes of marine creatures find
permanent homes.
Equally diversified is their range of habitat; no geonomie
condition suffices to exclude the Algce: they greet the traveler
on the confines of vegetation, near the highest mountain tops,
amid snow and ice1, and are brought up by marine explorers
from great depths below the surface of the sea.
To overlook their color would be to neglect a very striking
characteristic. The predominant tint of the entire class, in-
cluding both marine and fresh water varieties, is green; then
pink grading off' into all the shades of purple, and finally olive,
from golden green and bright tawny to black : indeed there are
few if any colors, from the most gorgeous to the dullest, but are
to be found among the Algce. They are also interesting for the
many useful purposes to which they have been and are applied.
We are under no small obligation to them for aiding to keep the
atmosphere in a wholesome condition, since they absorb carbonic
acid largely and exhale immense quantities of oxygen. The
extinction of certain kinds would prove an annoying loss to our
materia medica. They nourish a large variety of fish and molusca,
and in some localities, constitute a nutritions fodder for cattle
aud pigs; moreover, of some kinds there are made sauces, soups
and blanc-mange which are highly appreciated by epicures,
while others as fertilizers, are largely used by sea-coast farmers.
Of what further benefit they may be to mankind it would be
rash to predict, but it is within the bounds of probability, that
the microscopic study of the fresh water varieties, if pursued
hereafter as ardently as during the past few years, will result in
1 In a recent publication by V. B. Wittrock, of the Scientific Academy of
Stockholm, he describes the Snow and Ice flora of the Arctic Zone. The
Snow flora comprises about 40 species and varieties of fresh-water Algcv, and
the Ice flora about 10 species. They belong to 25 genera. Ten species and
varieties are new.INTRODUCTION.
XIII
a considerable modification of our ideas concerning the genera-
tion and growth of certain life-germs.
For the behoof of the uninitiated, a few words may here not
be out of place, on
HOW" TO FIND, HOW TO COLLECT, VXD HOW TO PRESERVE
Fresh-water Algce. As a large majority of them, especially the
Desmids, are free-floating plants, it would be a waste of time to
seek them in rapid waters; they affect pools, sluggish streams
and ponds; the latter afford the most satisfactory results to the
explorer, when the pond is a mile or more in length and is fed
by one or two creeks; the indentations on the margins of such
a pond and its tributaries, usually abound in water grasses and
mosses which shelter and support the floating Algce.
The outfit need not consist of more than a nest of four or five
tin cans (tomato or fruit) one within the other for convenience of
carriage; ten or a dozen wide-mouthed vials, and a small ring-
net of fine muslin at the end of a rod about four feet in length.
Should a boat be needed it can usually be hired on the spot.
After selecting what seems to be a good locality, drag the net a
few feet among the grasses and mosses, above indicated, allow
the bulk of the water to drain through the muslin, and then
empty the residue into one of the cans; repeat this process as
often as may be desirable. Ten or fifteen minutes after the cans
have been filled, most of the surface water may be poured off,
and the remainder transferred to a glass vial, where the solid
contents will gradually sink, and the superfluous water can be
again poured off, and the vessel filled up with deposits from
other vials. In shallow places, what is known as s.vamp-moss
(Sphagnum', bladderwort (Utricidaria), water-milfoil (Jlyriophyl-
lum) or other finely cut-leaf water plants are likely to abound ;
these should be lifted in the hand and the water drained, or
squeezed from them into a tin can to be subsequently treated as
already stated. A few drops of carbolic acid in each vial, just
enough to make its presence perceptible, will preserve the con-
tents for months and even years from deterioration; the green
coloring matter (Chlorophyl) may fade, but this in the case of the
Desmids, is of little importance; nevertheless, wnen practicable,
always examine the material when fresh. When dried on paper
for the herbarium, the specimens can still, after being moistened
with water, be microscopically examined, but not with the bestXIV
DESMIDS OF THE UXITED STATES.
results, since the drying is apt to collapse, or otherwise distort
the cells.
The collector will not know the value of his find, until it has
been brought drop by drop under the lens of his microscope, and
out of the entire mass he may discover nothing to reward his
labors; this however should not discourage him, as one or two
failures are to be expected prior to meeting with an adequate
reward. His interest in the study will be greatly enhanced if
he keeps a record of it in sketches of what the microscope reveals
to him. These sketches should, of course, be very exact, and in
order that they may be so, it is necessary that the microscope
should be provided with an eye-piece micrometer with which to
measure the length and breadth of the figure to be sketched ; a
half inch per rtfei (.001") or 25 n is the most convenient, though
1 or | of an iuch may be a preferable scale for the larger forms.
It is so difficult to separate specimens from their accompanying
foreign matter, that it is seldom amateurs can mount them satis-
factorily on slides, and therefore this method of preserving
specimens is not open to recommendation.
Although in the microscopic study of the fresh water Alger
much has been done within the past few years, much more re-
mains to be accomplished. The field, instead of growing smaller,
seems to widen out with every fresh discovery ; localities thought
to have been exhausted of additional possibilities, have in sub-
sequent seasons, yielded ample returns to the patient explorer;
and if the old territory is not sufficiently attractive, there are
vast regions into which no student has yet penetrated, where,
doubtless, the harvest awaiting the reaper dwarfs all that has
been heretofore garnered.DESMIDS.
Order, ZYGOSPORE; Family, CONJUGATE.
The Desmids form a large group, nearly equal in number of
species, to that of all the other orders of fresh-water Algce. They
are microscopic plants, and are to be found floating free in pools,
ponds and sluggish streams in all parts of the world ; at least
representatives of them are to be met with in every clime, from
the frigid arctic latitudes to the torrid equatorial zone; but un-
like the higher order of plants this wide difference in temper-
ature is not in these Algce always accompanied by corresponding
structural difference; for in New Jersey, varieties have been
discovered, which previously were thought to belong exclusively
to the hottest parts of South America, and in the same State are
also found species peculiar to the region of Nova Zembla, and
Spitsbergen ; we may assume these latter to have been a northern
legacy to New Jersey upon the breaking up of what is known as
the Glacial period, but we have no plausible reason to give for
the presence in the same localities of species which are indigenous
to Brazil and the East Indies. In every country, however, there
are varieties of Desmids that have not been found elsewhere; a
remark which applies peculiarly to the United States, where
nearly one hundred species wholly distinct from any heretofore
known, have been discovered, and aie now for the first time col-
lectively described in this work.
The Desmids are all more or less gelatinous; certain genera
as Hyalotheca, Desmidium, Sphaerozosma, and some species of Cos-
marium, and of Staurastrium, have a distinct, wide, colorless en-
velope ; but the majority are provided with nothing more than
an extremely thin mucous covering, which, though hardly per-
ceptible under the microscope, becomes sufficiently evident in
the firmness with which the Desmids adhere to the paper on
which they are dried.
1516
DESMIDS OF THE UNITED STATES.
The cell, that is to say. the plant, is multiform, varying from
the simple cylindrical and fusiform, to the denticulate, c-renulate,
lobed and otherwise much indented margins of the equal parts
into which the cell is with few exceptions, beautifully and sym-
metrically divided. The division of the cell into two equal
parts is effected by a transverse constriction, usually so deep
as to leave about a third of the diameter of the constricted cell
for a connecting link between the two parts; sometimes, how-
ever, the constriction is so slight as to produce merely an obtuse
angled sinus on each side of the cell; a few have no constriction.
The wall , cytioderm i of the cells is not constituted alike for all
the genera; in some cases it appears to be of a silicious character,
judging by the appearance of the empty case, and by the firm-
ness with which it retains the contour of the cell, even years
after the Desrnid had been collected : but usually the wall is more
fragile and easily liable to collapse or rupture, unless the speci-
men is kept in a preservative fluid.
One of the characteristics of Desmids which confirmed many
of the earlier microscopists in the belief of their animal char-
acter, was their seemingly voluntary movements. These move-
ments are most apparent in the larger forms of C'losterium andfc
Cosmarium, but are more or less evident in all of them; they
consist of slow, steady oscillations, and sometimes they go for-
ward and backward, similar to the movement of diatoms, but
slower, therefore less observable. By means of this locomotive
power, they work themselves to the surface when gathered into
a vessel with dirt and other foreign matter, and collect in such
positions as are most exposed to the light. Many theories have
been advanced to account for this phenomenon, but hitherto all
have failed to establish a satisfactory explanation.
Another movement belonging to the Desmids is that of the
granules within the cells. This is always present in good living
specimens, and consists in a circulation of granules in the watery
fluid next to the cell walls; they appear to be constantly passing
to and fro between the center and the ends of the cells.
A third motion belongs to the so-called cacuoles of Clo.steriums,
Docidiums and Peniums. In the end of many of these cells is a
well-defined globular, transparent space vacuole > filled with a
number of small granules, significantly called, by the Germans,
tanzenden kdrnchen, or dancing granules, because of their sprightly
activity. A similar behavior of the granules in the bodies of
smaller Desmids, and in the cells of filamentous Alya , is often
observable, particularly in unhealthy plants. Xo satisfactoryZYGOSPORiE.
17
explanation of these movements has yet been given. To some
they appear a mystery, but, are they more mysterious than the
circulation of blood in our arteries and veins, or than that of the
so-called cyclosis in the higher plants'? Nearly, if not quite all
vegetable germinal matter, displays some spontaneous activity,
and it is more than probable that the like characteristic seen in
the Desmids, must be ascribed to the same causes whatever they
may be.
MULTIPLICATION.
Multiplication among the Desmids takes place by two pro-
cesses. The one is simply a division and growth, the other is
through what may be termed sexual intervention.
The first process is merely a modification of ordinary vegeta-
tive growth, that is to say, a peculiar cell multiplication by
division. Plate XV, figs. 5, 6, are two semi-cells of a Docidium,
which have separated by the development of short processes
(fig. 7); these, primarily very small, commence their growth
from out of the center of the base of each semi-cell. The figure
represents them somewhat advanced ; they develop rapidly, and
soon become exact counterparts of the original mother-cells, then
they separate. Thus two cells are developed from one; the same
process is repeated, the two produce four, the four eight, and
so on.
Plate XVII, figs. 12, 13, represent a Cosmarium, the one the
perfect plant, the other in process of division; the ends are the
halves of the mother-cell; the parts between, the partially de-
veloped forms of the new semi-cells. Plate XIX, fig. 27, repre-
sents a similar growth of a denticulate form ; the teeth are not
apparent until the young parts have attained nearly their full
size.
Plate XLIV, fig. 8, is a series of four Hicrasterias truncata,
which represent the stages of growth by division; a cell pro-
ducing two, and the two, four, under the rather unusual circum-
stance of adherence after division ; only a fragment of the series
is shown in the figure. Fig. 11 is a similar fragmentary series
of adhering cells which must originally have numbered no less
than sixty-four. I counted thirty-eight which could not have
occurred in a regular course of division.
There are some peculiarities attending the process of multi-
plication. The new semi cells are not always exact counterparts
of the mother semi cell. Plate XVIII, fig. 18, Cosmarium monili-
Jorme; here there is an enlargement of the new, central semi-
218
DESMIDS OF THE EXITED STATES.
cells, probably developed under more favorable circumstances
than the original cell. An impoverished condition is more fre-
quently the result. Plate XXXIV is a striking illustration of
such an instance in Micrasterias Torreyi. Fig. 1 is nearest the
typical form described by Bailey, the other seven are varieties
which occurred by division. I found them variously attached
one to the other ; one half distinct from the other half, and some
so different from the typical form that had they not been mingled
with many others they could easily have been mistaken for other
species. Did these departures from the normal type continue
indefinitely, the original form would soon be lost, but the true
type as described nearly forty years ago by Prof. Bailey is pre-
served to this day. The changes are probably due to an impov-
erished condition of the plant. This suggests the cause of the
second mode of multiplication, viz.:—that by
REGENERATION.
This process is figured to some extent on many of the plates
of our illustrations. Plate I, tigs. 7-12, show how the separated,
floating joints of a Hyalotheca are drawn together, and unite by
means of a gelatinous tube (fig. 9) into which the contents of the
cells gradually empty; the tube enlarges as represented in the
figures of the progressive stages (figs. 10, 11) to the perfected
zygospore ifig. 12). The three circular forms united, are the
divided cells or semi-cells.
Plate III, fig. 3, are two cells separated from the filament (fig.
1) drawn together and united by a gelatinous tube mutually
protruded; through this the green cellular contents (Chloropliyl)
of the one passes out into the other, thus producing the regen-
erated spore (fig. 4).
Plate II, fig. 8, is a simpler process; the contents normally
separated in each joint, flow together (fig. 9), and condense;
then enlarge (fig. 10i and finally break loose (tig. 11) to produce
the new plant, Plate III, figs. 5-9, illustrate another method
of reproduction : two cells are drawn together, when they unite
(fig. 6) and bind themselves closely until they fuse into one
body, (figs. S. 9).
Plate IX, fig. 2, is another instance, varying only in form, the
two cells in the first stage of conjugation; fig. 3, the developed
zygospore with the empty semi-cells or husks still attached. Figs.
1, 9, 10, 11, 16, are zygospores of various species of Closterium.
This condition of copulation and developed spores, zygospores, or
sporangiums as often termed, is frequent ; the next step or ger-ZYGOSPORE.
19
mination is, if not of rare occurrence, very rarely detected.
Dr. de Bary, of Germany, enjoyed a favorable opportunity; he
describes the whole process substantially thus: Two cells are
drawn together by a conjugal influence which we have no means
of detecting ; the semi cells separate (Plate XXVII, fig. 27), and
pour out their contents; those of the one cell unite with those
of the other, at first without a distinct investment, but soon the
mass acquires a membranous envelope (figs. 28. 29), forms a
matrix, or sporangium in which are reproduced new plants pos-
sessed of invigorated vitality. The envelope of the matrix or
zygospore is primarily thin and smooth, but by degrees it acquires
increased thickness, and in the Cosmariums, usually a granular,
tuberculated (fig. 2.8), or more frequently a spinous surface (fig.
29); the spines being sometimes simple but commonly forked at
their extremities. The next step so difficult to be traced is the
opeuing of the wall of the zygospore (fig. 29), setting free small
spheres of sarcode; as they issue they enlarge and acquire a
gelatinous, or thin membranous wall. The wall thickens and
the sphere enlarges (fig. 30), the contents constrict (fig. 31),
first in one direction and then transversely to the plane of the
first incision (fig. 32); these parts develop and set free two or
four new plants in size and form like the mother-cell, except in
the cytioderm or membrane; this is not granular, but smooth,
and so remains until after the multiplication by division takes
place. After the first division the new semi-cells assume the char-
acteristic granular surface ; the result of this first division is two
plants each composed of one granulated and one smooth semi-
cell. The second division will make two perfect cells and two
which retain the one smooth semi-cell; the third division pro-
duces eight cells, all of which except the original two semi-cells
will be of typical form.
Hofmeister’s view's are somewhat at variance with those of
De Bary in regard to numbers; he affirms that the contents of
the sporangiums of Cosmariums are transformed by repeated
binary subdivisions into eight or sixteen cells, which assume the
orginal form, but not full size of the parent, before they are set
free by the rupture or diffluence of the wall of the sporangium.
The sporangiums of Closterium, Staurastrum and of other genera
are supposed to germinate in the same manner as Cosmarium.
Plate XXVII, fig. 33, is a cluster of Closteriums surrounded by
a membrane, found by Ralfs ; he however questions whether this
is a germinating sporangium.
Encysted clusters of Desmids are not necessarily evidence of20
DESJIIDS OF THE EXITED STATED
germination. I have found many such cysts enclosing sometimes
only one large specimen, as Euastrum verrucosum. but more fre-
quently six. or eight smaller Desmids in one cyst: these were at
first a source of perplexity. Upon consultation with men and
books I found Huxley to say: “Encystment is very common
among all the Giliata ; and a species of Amphileptus has been seen
to swallow, or rather envelope a stalked bell-animalcule, and
then become encysted upon the stalk of its prey."
Prof. Smith writes with reference to a case of encysted dia-
iomes : “the group of 2Yavicula seen, are simply a group that were
devoured and their protoplasm digested by an Amoeba. They
constantly are ejected in this way from the body of the Amoeba
after the nutriment has been abstracted, and look like an en-
cysted mass with an envelope complete.”
This subject of multiplication by regeneration is full of interest
for the microscopist, and opens a large and unexplored field.
The frequent variations in outline of form in certain species is
calculated to mislead, and perhaps suggest notions of variation
of species, but close observation will soon dispel such notions,
and prove that they are merely temporay results of exhausted
vitality in the process of multiplication by division; they occur
most frequently in the latter part of the summer season. After
regeneration through copulation, the zygospores become winter
resting spores and lie dormant until the following spring, then
germinate and reproduce the true counterpart of the original
form of the species.DESMIDS OF THE UNITHD STATES.
Order, ZYGOSPORE;®.
Green or brown Algce, unicellular, either free cells or united
into filamentous fascia. Sexual propagation takes place by an
act of copulation followed by conjugation or zygose. Two cells
of like appearance are attracted to each other, and unite ; the
contents of the two cells flow together, commingle, and form
a primordial cell called a zygospore; this develops a double or
triple episporium, or membranous envelope.
In rare cases twin zygospores are developed.
Family, CONJUGATE.
Cells free, or united into simple series or filaments; no branches
and no terminal growth. Contents of cells (cytioplasm) chloro-
phylous green, arranged in parietal bands, axillary lamina, or
stellate nuclei.
Sub-Family or Group, DESMIDIE;®.
Composed of symmetrical cells, usually constricted in the
middle, often of beautiful, ornamental forms, single or conjoined
into filiform series, and sometimes involved in a maternal jelly.
Asexual multiplication takes place by transverse division, or
separation of the semi-cells (Plate XVII, fig. 13 ; Plate XIX,
fig. 27); and development of new parts similar to the mother
semi-cells.
Copulation takes place between two floating or free cells (Plate
XXVII, fig. 27), and produces a zygsopore with a firm middle
membrane, and usually a more delicate inner and outer coating.
The zygospore, after a longer or shorter period of rest, develops
one or more regenerated daughter cells.22	DESMIDs OF THE UNITED STATES.
Omus. GOXATOZYGOX. D. By.
Cells long, cylindrical, or truncate spindle form, without con-
striction. united into fragile, filiform straight series: at maturity
they separate and become geniculate, copulate and produce spher-
ical zygospores: these separate quickly from the empty cells.
Two species only have been recognized in this country.
G. asperum. <'Ralls) Bab. Probably identical with G. Ralfsii,
De By. Plate I. fig. 1.
Cells long, cylindrical, ten to twenty times as long as wide,
very slightly, or not at all reduced in thickness at the ends.
Cytioderm fine-granularly roughened.
Diameter 11-12 p.
Occurs frequently in ponds of New Jersey.
G.	pilosa.m. Wolle. Plate I, fig. 2.
Cells twelve to twenty times as long as wide, loosely con-
nected : cytioderm more or less densely clothed with small,
straight hairlike spines : cells cylindrical, terminal one of a
filament slightly attenuated, end rounded.
Diameter 15 p. : with spines 25 p.
Habitat the same as the preceding.
Genus, HYALOTHECA. Ebrb.
Plate I, figs. 3-11.
Cells short, cylindrical, usually with a slight obtuse constric-
tion in the middle; disciform in end view, closely united into
long filaments, which are inclosed, each in an ample, colorless
mucous sheath. Clilorophyl mass in each cell, end view, six to
ten radiate.
H.	DISSILIEXS, (Smith) Breb. Plate I. figs. 3. 4. 5.
Filaments elongated, cells slightly contracted in the middle,
usually about half as long as broad. Variable in size.
Diameter 20-36 p.
Var. hiaxs. Wolle. Plate XII. figs. 14-16.
Differs from the typical form in having the lateral margins
of the cells arched with an acute notch in the middle.
Diameter 25-50 p.
Budd’s Lake, N. J., and Florida.
Frequent in ponds and sluggish, shallow waters. The fre-
quency of this plant soon familiarizes it ; usually it is found
intermingled with other forms, but sometimes it has entireH YAI.OTH EC A.
23
control of small pools, trenches and outlets of springs. In its
younger state it is attached to the muddy bottom, or sticks or
stones ; but more commonly it is found in floating masses.
The filaments are generally fragile, but sometimes they occur
elongated and strong. When gathered in proper season, and
kept in water for a few days, the cells separate at the articu-
lations, and float in free joints, which being nearly square,
readily turn over and present the circular end view, with the
stellate arrangement of the ehlorophyl. I have had a quantity
in good condition for observing the successive stages of conju-
gation. The cells separated the same day the collection was
made; and soon thereafter copulation of cells commenced.
Plate I, figs. 7, 8, are two floating cells, one in front and the
other in transverse view ; they are drawn to each other by
some hidden conjugal influence, put forth a mucous tube and
unite as fig. 9, then each cell breaks into two ; thus four parts
are united ; sometimes all present themselves to view, but
more commonly only three are visible, as figs. 10 and 11. The
ehlorophyl concentrates to the space between the cells ; fig.
10, shows an early stage ; fig. 11. a more advanced condition ;
and fig. 12, the developed zygospore. Single matured zygo-
spores are frequently noticed in gatherings from waters where
the plant prevails.
H. mucosa, (Mert) Ealfs. Plate I, fig. 13.
Filaments scarcely fragile; joints not constricted, but
having at one of the ends a minute bidentate projection, the
adjoining end of the next joint being similar. These pro-
jections are visible only in older plants.
Diameter 19-21 y.
This plant is not so frequent as the preceding, but it appears
to be widely distributed, not in masses, but frequently mingled
with other filamentous forms. Had it from ponds of Penn-
sylvania, New Jersey, Vermont, Rhode Island, South Carolina
and Florida.
It is easily distinguished from the preceding by its wider
mucous sheath, by the straight margin of the cells, by the
longer joints and by the central gathering of the ehlorophyl.
The mucous sheath, being entirely colorless, is not easily dis-
cerned, except when surrounded by turbid water.
H. undulata, Nord. Plate LXIV.
Cells about twice as long as wide, sides concave and angles
rounded, closely connected; filaments are involved in a
wide, colorless, gelatinous sheath. The constriction of the
cells, and the rounded angles make an undulate margin.
Diameter 9-12 y. without sheath.24
DESMIDS OF THE t'XITED . TATES.
Frequent in ponds of New Jersey, Pennsylvania, etc.
There are two forms very nearly allied, this H. undulata, and
Sphaerozoxma excavation (Ralfsi, both about the same thick-
ness and same length of cell, and both in a colorless gelatin-
ous envelope; the only point of separation is in the attach-
ment of the cells ; in the Hyalotheca the cells adhere by the
whole plane of the end, and in the Spaerozosma, they are
connected by two sessile glands on the margin. To my mind
this distinction is scarcely tenable.
H. dubia, Kg. Plate I, fig. 14.
Cells about as long as wide, not constricted, closely united
into short fragile filaments, without gelatinous sheath.
Diameter 13-21 p.
This form occurs now and then in waters of ponds in New
Jersey. As the name implies, it holds a somewhat dubious
position. It is without the mucous envelope characteristic of
the other species and is usually smaller. Fruiting specimens
have not been observed.
Reasoning from observations on the life history of an allied
genus, Barnbusina, I venture to suggest that the forms re-
ferred to this species are merely undeveloped conditions of
other species.
Genus, BAMBUSINA, Kg.
Plate I, figs. 15-24.
Cells or joints barrel shaped, surrounded by one or two narrow
median bands, closely united into articulate, nodose filaments.
Chlorophyl bodies and zygospores as in Hyalotheca.
B. Brebissoxii, Kg. (B. Borreri, Cleve; Didymoprium Borreri,
Rolfs'). Plate I, figs. 15-21.
Cells somewhat longer than broad, hub or barrel-shaped,
surrounded iu the middle with two narrow bands, and another
often visible between these and the ends of the cells.
Diameter 18-25 p.
Frequent in quiet waters from Maine to Florida and far
west. A pond at Pleasant Mills, New Jersey, furnished me
with good conditions of development. The lowest traceable
stage is represented by fig. 17. A gelatinous sheath enclosing
a series of green cells ; fig. IS, four cells around which the
envelope is diffusing; these unite, end to end, then widen
and produce a form as fig. 19 ; fig. 20 is somewhat more ad-
vanced, showing small notches in the sides ; fig. 21, the begin-
ning of the central inflation and the bands ; these continue
to develop until the perfect plant is produced.DESMIDIUM.
25
Yar. gracilescens, Nord.
Wittrock and Nordstedt have, in their series of Alga- exsic-
catce, No. 367, a small variety under this name. It is very
small, but the features are those of the typical plant. It was
collected in Brazil. The same small form occurs here ; have
memorandum of it from Long wood Pond, and Wood Lake
of northern New Jersey.
B. gracilescens, Nord. Plate XLVII, figs. 13, 14.
This form is described as a variety of B. Brebissonii.
Whether viewed as such or as a distinct species, it was an
interesting discovery to find it fruiting freely in a pond near
Winter Park, Florida.
Diameter of cells 14 g ; length 23 g; zygospores 15 g.
The plant conjugates not like one of the Desmiclicce, but
more like a Zygnemacea, in longer or shorter series ; often
when the zygospores are nearly matured, the cells of one side
separate and cause the other side to bend backward.
Judging by these specimens the correctness of the generic
position of Bambmina may be questioned.
B. delicatissima, Wolle. Plate I, figs. 22, 23, 24.
Cells sub-cylindrical, surrounded in the middle by two
narrow, thick bands, twice the diameter of the cylindrical
body, cells four times as long as wide.
Diameter of body, 6-8 g.; of bands, 13-17 //.
Pond, Pleasant Mills, New Jersey.
The characteristic features of this plant are the small size,
the cylindrical form of the body, the elevation of the bauds
which surround it, and the elongated proportion of the body.
Genus, DESMIDIUM, Ag.
Plate II, figs. 1-14 ; Plate III, figs. 1-4.
Filaments fragile, elongated, triangular or quadrangular, regu-
larly twisted, two chlorophyl masses in each cell barely touching
in the middle. Margin of cells incised or entire.
D. cylinder:UM, Grev. (Didymopnum GrevilUi, Kg. j Plate
III, figs. 1-4.
Cells about half as long as broad, with a thickened border
at their junction, medianly more or less deeply incised;
transverse view elliptic, with the angles somewhat drawn
out. Filaments surrounded with a mucous sheath.26
DESMIDS OF THE EXITED STATES.
Zygospore spherical, formed by the conjugation of two
cells, the cloropliyl passing through a gelatinous connecting
tube from one cell to the other (figs. 3, 4).
Specimens occur frequently in pools and ponds all over the
country, rarely unmingled with other forms. It is readily
distingushed by its large size, deep incisions of the border,
and twisted outline.
D. quadratum. Xord. Plate LX. fig. 5.
Differs from the preceding in the cells being nearly as long
as broad, and viewed from the side, quadrate. The breadth
of the cells is only about one-fifth mote than the length : the
thickness, the same as the length. Chlorophyl mass in each
cell in end view, more or less radiate.
Diameter .45 u. : length. 33-33 y. : thickness. 33-33 </.
Found this form repeatedly during the past four years, but
rarely, except in ponds, Brown’s Mills. New Jersey. It varies
in size from the Norway typical plant, in being considerably
larger ; othewise it appears to be identical.
D. loxgate.m. Wolle. Plate LX. fig. 6.
Filaments thin : cells in front view nearly twice as long as
wide: in side view nearly 21 times longer than broad: closely
united without a thickened border at their junction : end
view broadly elliptic.
Diameter, widest part, 25-28 ;t.; thickness, 16-18 /<.: length
of cell, 35-40 /<.
This interesting new species from Brown’s Mills and Egg
Harbor, New Jersey, was found late in the season (September
22, 1883); no gelatinous sheath was observable ; the filaments
were hyaline except two chlorophyl nuclei in each cell.
D. Swartzii. Ag. Plate II. figs. 1-6.
Filament triangular, with a single longitudinal, waved,
dark line, formed by the third angle, (compare figs. 6, 8,13);
joints in front view somewhat quadrangular, broader than
long, with two slightly angular crenatures on each lateral
margin, united at the whole of their end margins by a thick-
ened border: end view triangular with the chlorophyl three-
rayed. Zygospores oval.
Diameter 36 ju., more or less.
Frequent in shallow pools, trenches and the like.
The spores are formed by the flowing together of the two
masses of chlorophyl in each cell; the united body assumes aDESM1DIUM.
27
spherical form ; this enlarges, and as it increases in size,
forces the sides of the cell apart to more than twice the origi-
nal diameter (fig. 3); when mature the sides separate and the
spores are set free.
D. QUADRAXG-ULATUM, Kg. Plate II, figs. 13, 14.
Filament quadrangular, varying in breadth from its twist-
ing, having two longitudinal waved lines; joints in front
view broader than long, with two somewhat rounded crena-
tures on each lateral margin. End view quadrangular.
Diameter 50-tiO p.
This is a form which prevails in England and on the Con-
tinent, but has not yet been found in this country. I insert
it from Dr. Wood’s contribution in anticipation of yet find-
ing it.
D. Aptogonium. Breb. Plate II, figs. (1, 7. Plate LX, fig. 7.
Joints in front view, quadrangular, broader than long,
with two rounded crenatures on each lateral margin, united
at the outer portion only of each end margin by mutual pro-
jections, thus producing intervening central oval or oblong
foramina.
Diameter 25-38 p.
Not so frequent as D. Swartzii, hut it appears to be widely
scattered from Pennsylvania and New Jersey as far south as
Florida, and probably also northward and westward.
D. Baii.eyi (Aptoffonum Baileyi, Ralfs). Plate II, figs. 8-12.
Filaments triangular, twisted as the preceding, joints
united by each end of the lateral margins only, excavated
between the angles as the preceding form ; the lateral mar-
gins are straight, not bicrenate, a characteristic which sepa-
rates it from the other species.
Diameter 25 p., more or less.
Found frequently in sluggish waters, without being con-
fined to any particular State or States.
The process of fruiting is not unlike that of D. Swartzii,
the separated portions of chlorophyl (fig. 8) unite and concen-
trate (fig. 9), then enlarge (fig. 10), press out the sides to more
than twice the diameter of a sterile filament, then break
apart and set the spores free.28
DESMIDS OF THE EXITED STATES.
Genus, PHYMATODOCIS, Xord.
Cells closely united in slieathless filaments, not at all or only
slightly twisted ; cells deeply constricted in the middle, the two
semi-cells somewhat twisted, giving the margins an irregular
outline; filaments quadrangular with sides longitudinally ex-
cavated.
P. XoRDSTERTiAxmi, Wolle. Plate LX, figs. 1-4.
Cells rectangular, about as long as wide, deeply constricted
in the middle, the sinuses somewhat enlarged inwardly and
rounded at the base ; the sinuses between the cells similar,
slightly deeper; end view quadriradiate with wide and deep
sinuses between the rays, apices rounded, emarginate ; the
two semi-cells somewhat twisted, so that the end of one ray
projects more than that of the other and produces an irreg-
ular outline; membrane smooth.
Diameter 37-40 p.
This new species in ponds at Brown’s Mills and Egg Harbor,.
Xew Jersey, and at Kissimme, Florida, differs from the form
collected in Brazil, in being one-fourth smaller ; in having
the lobes or rays in end view straight, not curved to one side,
and in having the sinuses of the cells not narrow linear, but
somewhat enlarged inwardly and rounded at base.
Genus, SPHAEROZOSMA, Corda.
Plate IV, figs. 1-10.
Cells closely united side to side by a narrow isthmus or by
means of glandular processes, deeply incised on each side, thus
forming bilobed cells, and often giving a pinnatifid appearance
to the fragile filaments.
Filaments often surrounded by a colorless gelatinous en-
velope.
Brebisson separated the forms which have the cells united
without glandular processes with a new genus Spondyeosu.m.
The distinction is hardly tenable. The modes of union, like the
gelatinous sheaths, are inconstant, hence should not be made
generic or specific characteristics.
This genus differs from the preceding in the compressed, flat,
not round, triangular nor square filaments, but deeply incised
cells, and especially in the frequent presence of the minute gland-
like connecting processes.SPHAEKOZI )SMA.
29
S. pulchrusi, Bailey. Plate IV. figs. 1, 2.
Cells twice as broad as long, deeply incised on each side,
ends rounded, junction margin straight, filaments twisted,
frequently enclosed in a gelatinous envelope.
Diameter 60-S2 p.
War. planum, Wolle. Plate IV, figs. 3, I.
Similar to typical form, except in size and in the absence
of the twist in the filaments.
Diameter 30-38 /a
Var. inflatum, Wolle. Plate LX, fig. 8.
Differs from the preceding in the central inflation, pro-
ducing a short isthmus between the cells.
Diameter 38 /a
The typical form appears to be widely scattered throughout
many States: Rhode Island, Massachusetts, Pennsylvania,
New Jersey, South Carolina and Florida. The variety jilanvm
I found in a trench aside the railroad near Metuchen, N. J.
The water was green with the abundance of it. The variety
inflafuvi occurs sparsely in ponds of New Jersey.
S. filiforme, Eab. Plate IV, figs. 5, 6.-
Cells about as long as wide, constricted in the middle with
a deep, acute incision ; ends of lobes rounded, connected by
two sessile glands.
Diameter 12-18 /a
Pond waters of Pennsylvania and New Jersey.
General appearance very near iS'. pitltskrum variety, but
smaller, and length of cell equal to the diameter. Did not
observe a gelatinous sheath mentioned by Rabenhorst; Kirch-
ner admits no sheath. Fig. 6 is very near Corda’s S. lamel/i-
ferum.
S. pulchellum (Arch.) Rab. Plate XII, figs. 8, 9.
Cells in outline oblong with the middle much inflated,
sharply incised and angles rounded ; ends narrower because
not at all or very slightly inflated ; apices square ; varying
in length from one to nearly two diameters.
Diameter 9-10 /a
Pond waters, not rare. Syn. Spondylosium bambusioides,
Witt. S. pulchellum, Arch.30
DESMIDS OF THE EXITED STATES.
S. monilifokme, Lund. Plate XLVII, fig. 11.
Series of cells often long, firm, somewhat twisted 5 usually
included in a mucous envelope. Cells average one-half
longer than broad, deeply constricted, sinus obtuse out-
wardly enlarged, back more or less produced ; seen from the
vertex triangular, sides somewhat retuse ; angles rounded,
isthmus sub-elongate, membrane smooth.
Diameter about 20 p.
Not infrequent in quiet waters, Florida ; less frequent in
New Jersey, Minnesota and Pennsylvania.
S. excavatum, Ralfs. Plate IV, figs. 8, 0, 10-12.
Cells twice as long as broad, with a deep, wide sinus on
each side, connected by two small sessile glands.
Diameter 9-12 p.
Not infrequent in ponds ; sometimes it occurs with, and
sometimes without, the gelatinous sheath.
S. vertebrates: (Breb.), Ralfs. Plate IV, fig. 13.
Cells about half as long as broad, with a deep narrow con-
striction, connected in the center by a simple, rather thick
gland ; more or less remote. Semi-cells narrow, elliptic,
smooth. Filaments twisted, usually surrounded by a mucous
sheath.
Diameter 12-11 p.
Rather rare ; the best specimens found were from Splitrock
Pond, Sussex Co., New Jersey.
S. SERRATUM, Bailey. Plate IV, fig. 7. Plate XLIII, figs. 7, 8.
Cells broader than long, deeply notched, or divided into
two transverse portions with acute, spiuelike projecting ends
which give a serrated outline to the chain. Cells closely
united by two short glandular processes. Usually sur-
rounded by a wide gelatinous sheath.
Diameter 22-33 p.. including the projections.
Prof. Bailey collected this species in South Carolina, Geor-
gia, and Florida, 1848 ; it is found frequently in New Jersey,
Pennsylvania and other Northern States.
According to Wallich this species should be classed with
Onychonema, a new genus made by him to take in the forms
which have the glandular processes long.
The glandular processes connecting the cells are sometimes
long, nearly equal to the length of a semi-cell ; in this condi-
tion it approaches very near to Onychonema /acre, Nord., a
Brazil form. The specimens vary considerably, but they doSPHAEROZI )KMA.
31
not seem to admit of separation. The cells are often only
slightly inflated, sides nearly straight; the spines, in young
condition nearly obsolete, or very small and straight, and the
glandular processes sometimes short, barely discernible, and
again so long that they lap over the cells.
S. (Onychonema) Nordstedtiana, Turner. Plate XLIII, figs.
9, 10.
Cells forming filaments of fifty to sixty cells or more con-
nected by subcapitate claspers peculiar to the genus. Length
of cells 14 p. ; breadth 18 p.; breadth of sheath 30-40 p.
The rather unusual size, and that it has not been found
where other forms prevail, Mr. Turner considers evidence
of a distinct species rather than a merely young form.
S. Wallacen? Jacobsen. Plate IV. fig. 15.
A peculiar form of which I found only two short speci-
mens in pond, Brown’s Mills, X. J. They are not identical
with the form described by Jacobsen. I record the figures
of them provisionally until other specimens may be found
to verify a good species.
Diameter 10-12 p.
S. spinulosum? Delph. Plate IV, fig. 14.
Another variety of which I found only a single specimen,,
in a pond known as Chain Dam, Northampton Co., Pennsyl-
vania. In a Florida collection are numerous well developed
specimens, which agree with Delpont’s diagnosis in being
really spinous. They have the form of cell, the measure,
and the arrangement of the spines, except perhaps that
there are more frequently only two, than three spines, on
the margin of each semi-cell. A fine and distinct species.
If the granules of the figure (Plate IV, fig. 141 were drawn
out into short spines, the typical plant would be well repre-
sented. It is not the same, but near Delpont’s described
form.
Diameter 10 p.
S. rectangulare, Wolle. Plate LX, fig. 9.
Filament wide; cells twice as wide as long, deeply con-
stricted in the middle ; semi-cells somewhat tapering near
the ends, producing acute-angled sinuses between the cells,
and between the semi-cells; ends truncate concave, and
angles often cuspidate. Membrane smooth.
Diameter 50-55 p.; thickness 18-20 p.32
DESMIPS OF THE UNITED STATES.
This form was recorded with hesitation ; it was one of the
latest finds in the fall of 1883 ; but since it occurred frequently
in ponds at Brown’s Mills, Manchester and other waters,
New Jersey.
Genus, MESOTAENIUM. Naeg.
Pahnogloea, Kg. Plate III. figs. 5-15.
Cells straight, short cylindrical, or oval, ends rounded, not
constricted in the middle. C'lilorophyl lamina axillary, sometimes
divided in the middle.
Copulation takes place by two cells uniting side by side, the
contents flowing together.
Kirchner remarks that copulation in this genus is a simple
union of two cells, leaving no husks or remains of empty cells :
(compare figs. 5-9 >. This process accords with my observations,
but Wood illustrates another mode transferred in figs. 13-15, in
which the contents of the cells flow together and are surrounded
by a new membrane ; in this case the remains of the old cells
are present.
These plants occur frequently in small pools, on dripping rocks,
damp walls, wet ground and the like ; sometimes singly, but
more frequently associated in families in a gelatinous mucus.
M. Beau Nil, D. By. (Pahnogloea macrocoeea. Kg.) Plate III,
figs. 5-9.
Cells cylindrical. 2-21 times longer than wide, ends flatly
rounded. Zygospore square, angles rounded, sides usually
somewhat concave.
Diameter 16-19 p.
Found floating, in families, in gelatinous scum, mountain
pools.
M. micrococcum, Kg. Plate III, fig. 10.
Cells oval or elliptical, about twice as long as wide, ends
sometimes slightly narrowed and rounded.
Diameter 6-11 p.
Usually in gelatinous masses on old wet wood, timbers of
sluices, etc.
M. Endlicheeianum, Xaeg. Plate III, fig. 11.
Cells cylindrical, 3-1 times as long as wide, ends bluntly
rounded.
Diameter 9-11 p.
Occasionally intermingled with filamentous forms, in gela-
tinous gatherings.SPIROTAENIA.
33
M. Clepsydra, Wood. Plate III, figs. 12-15.
Living on rocks and mosses, swimming in a transparent,
sometimes light-green jelly; cells obtusely truncated,
rounded at the ends, 2-3 times longer than broad ; chlorophyl
lamina axillary, mostly indistinct, often wanting; endochrome
light green ; nucleus generally distinct; zygospores subfuscous,
either globose or of an irregular form, somewhat resembling
that of an hour-glass; external coat irregularly excavated
and sulcate.
Diameter given by the author is r-iro", this would be .00173
= 43 p. Evidently an error, the plant cannot be so large.
The author adds, “This species was found near C'helten
Hills, growing amid mosses on the rocky juttings over which
the water was dripping. It occurs as a rather firm, transpa-
rent jelly, mostly of a light greenish tint, in which the cells
are often placed quite thickly.
Genus, SPIKOTAENIA, Breb.
Plate III, figs. 16-22.
Cells straight fusiform, single or aggregated in a gelatinous
mucus; not constricted in the middle, ends round. Chlorophyl
arranged in one or more spiral lamince on the inner surface of
the wall.
S. condensata, Breb. Plate III, figs. 21, 22.
Fusiform, or cigar-shaped, ends rounded, eight to ten
times as long as broad, with a single, broad, closely wound
chlorophyl spiral band, its revolutions numerous.
Diameter 18-25 p.
Found in meadow pools, ponds, etc. Has been collected in
many States of the Union, from New York and New Jersey,
south to Florida, and westward to Minnesota.
S. obscura, Balfs. Plate III, figs. 16-19.
Fusiform, deep green, five to eight times longer than broad,
ends attenuated, apices rounded. Chlorophyl arranged in
a number of narrow spiral, parietal bands.
Diameter 8-15 p.
The locality in which this species occurred most frequently
to me, was in small pools aside streamlets on the open slope
of our mountain sides, but found it also in New Jersey.
European specimens are quoted as large as 30 //. in diameter.
I have found none so large.
334
DESMIDS OF THE UNITED STATES.
S. bryophila, (Breb.), Bab. (6’. muscicola, D. By.) Plate III.
fig. 20.
Cells cylindrical, two to four times as long as broad, ends
obtusely rounded, chlorophyl a single, broad, smoothly
defined, widely wound spiral band ; its revolutions one or
two.
Diameter S jx.
Dr. Wood reports this species, measure and form, from near
Philadelphia, growing among some mosses which were kept
constantly wet by overhanging dripping rocks. It formed
little transparent masses of almost colorless jelly, looking like-
little drops of dew.
Genm, PENIUM, Breb.
(Xetrium, Xaeg. Cylindrocystis Menegh.)
Plate Y, figs. 1-22.
Cells straight cylindrical or fusiform, not incised nor constricted
in the middle ; ends more or less obtusely rounded. Chlorophyl
lamina axillary; when seen transversely, radiately divergent,
arms often forked, and containing starch granules.
Individuals swim free, scattered, or associated in gelatinous
masses ; cell membranes smooth or finely granulate, transparent
or fuscous, or reddish, often longitudinally striate.
Multiplication takes place by division, and by zygospores de-
veloped by the copulation of two cells. Comp. Introduction.
P. Digitus, (Ehrb.), Breb. Plate Y, figs. 1, 2: Plate LXIVr
fig. 1.
Cells ovately cylindrical, or broadly elliptical, 3-5 times
longer than broad, each end subtruncately rounded, (Plate
LXIY, fig. 1). Chlorophyl lamina lobate in the periphery,
interrupted in the middle. Plate V, fig. 1, is a variety,
more elliptic than the typical form. Fig. 2 is a transverse
section.
Diameter 60-SO p.
This species appears to be widely distributed from Maine to
Florida and westward. Very variable in size and outline.
P. lamellosum, Breb. Plate Y, fig. 4.
Cells oblong or fusiform cylindrical, often with a slight
depression in the middle, more or less attenuated towards the;PENIUM.
35
obtusely rounded ends. Arrangement of chlorophyl usually
somewhat like the last, but not separated in the middle.
Diameter 55-80 p.
Not so common as the preceding.
P. oblongum, D. By. Plate V, fig. 17.
Cells oblong cylindrical, 3-4 times as long as wide, not
constricted in the middle, slightly tapei’ing towards the
ends; apices flatly rounded. Zygospore spherical, not un-
like Plate Y, fig. 7.
I find this form mostly in fresh spring water, in gelatinous
gatherings.
P. margaritaceum, Breb. Plate Y, figs. 5, 6, 11.
Cylindrical, usually 8-9 times longer than broad, rarely,
only twice as long; not at all, or scarcely constricted in the
middle; ends rounded, ornate with pearly granules arranged
in longitudinal series which often give a denticulate appear-
ance to the margin.
Diameter 24-28 p.; length ordinarily about 225 p. I have
had specimens measuring 375 p.
Prevails over a wide range. I have it from Vermont, Con-
necticut, and almost every State southward to Florida, also
from the west to Minnesota.
It varies somewhat in size, but is easily recognized by the
arrangement of the granules.
P. spirostriolatum, Barker. Plate X, fig. 17.
Large, elongated; single cells somewhat swollen in the
center and tapering slightly towards the rotundo-truncate
ends; the cell walls possessing a number of superficial, con-
spicuous, rather coarse striae, running in a spiral direction ;
these somewhat interrupted at a number of annular rib-like
projections varying in number; these projections most nu-
merous towards the ends.
Mr. Turner, of England, who reports this form from Min-
nesota remarks, “As I do not know of the publication of any
measurements or authentic figure of this species, I may pos-
sibly be in error in referring these American forms to it:
the figures therefore must speak for themselves.”
Diameter of cells 23-31 p,; length of double cell as figured
227-260 p.
Another form, Plate X, fig. 19, which may for the present
be referred to this species, I found frequent in the Tocoi36
DESMIDS OF THE UNITED STATES.
marshes, Florida. It is unlike the preceding in the absence
of the transverse sutures or rib like projections; in the
variableness of diameter and proportionate lengths. Diame-
ter of smaller forms 15-18 pi and of larger form 37 pi. The
smaller are 10-14 and the larger 7 times longer than broad.
Chlorophyl usually thrice interrupted.
P. INTERRUPTUM, Breb. Plate Y, figs. 14, 15.
Broad cylindrical, not constricted, 5-6 times as long as
wide, suddenly tapering, cuneate near the ends, apices
rounded. Chlorophyl deep green, in matured plants inter-
rupted by three transverse pale bands; cytioderm smooth.
Diameter 38-50 pi., rarely only 16-20 pi.
Habitat the same as the preceding, rather more frequent;
readily distinguished by its transverse bands and cuneate
ends.
P. closterioides, Ealfs. Plate Y, fig. 18.
Cells narrowly lanceolate, 5-6 times longer than the
greatest diameter; sensibly attenuated from the middle to
the rounded apices. Chlorophyl contents interrupted in the
center.
Diameter 30-44 pi. Ten times longer.
Ponds, New Jersey, Pennsylvania and Minnesota.
In its general appearance and in the arrangement of the
chlorophyl, this plant has a strong resemblance to a Closte-
rium, but varies in being always straight and having the
opposite margins symmetrical.
P. truncatum, Ealfs. Plate Y, figs. 9, 10, 21, 22.
Cylindrical, not constricted, 3-4 times longer than wide,
ends truncate, square. Zygospores smooth, spherical.
Diameter 11-12 pi.
Ponds, northern counties of New Jersey. The chlorophyl
is usually more or less interrupted in the middle, producing
a pale transverse band ; membrane smooth or finely punctate.
P. iiiNUTUM, Cleve. Plate V, figs. 19, 20.
Slender, cells 4-6 times longer than broad, sides straight,
ends rounded, without inflation, and without punctures.
Diameter 11-15 pi.
This small form, perhaps more properly a Calocylindrus,
(Plate XV, fig. 12), has not come under my notice. It is re-
ported by Bailey and Olney, from Florida and from Rhode
Island. The measures are taken from Rabenh. FI. Alg. The
figure in Ralfs, Br. Desmids, and referred to as belonging to
this species is certainly distinct and is a Docidium.PENIUM.
37
P. polymoephum, Perty. Plate V, fig. 12.
Sub-cylindrical, smooth, various sizes usually intermingled
in larger families; 3-1 times longer than broad, ends more
or less attenuated, apices rounded; cytioderm somewhat
longitudinally striated.
Diameter 11-15 //.
Pools, or wet earth, Charlotte, Vermont. Collected by F.
Hosford.
P. Brebissonii, (Menegh.), Ralfs. Plate V, figs, 7, 8.
Cells smooth, cylindrical with rounded ends, transverse
central band inconspicuous ; conjugating cells persistent.
Diameter 16-17 jo
Usually congregated in a mucous stratum in small pools
and on wet grounds, Princeton, New Jersey (Bailey) and other
localities in the State. The plant mentioned by Wood ap-
pears to be nearer Closterium obtusum, Breb.
P. Navicula, Breb. Plate V, fig. 16.
Small, broadly fusiform, 1-5 times longer than broad,
tapering from the center to the rounded apices. Chlorophyl
lamina entire; cytioderm smooth.
Diameter 12-17 //.
Zygospores are said to be nearly square, somewhat drawn
out between the attached remains of the copulating cells.
The plant occurs frequently in trenches and small ponds of
Pennsylvania and New Jersey ; the fruiting cells, or zygo-
spores have not come under my personal observation.
P. JENNEEI, Ralfs. Plate XXXVII, figs. 1, 2.
Smooth, cylindrical with rounded ends, zygospores orbic-
ular, situated between the conjugating cells which are
deciduous.
Diameter 11-15 fx:
I have not recognized this form. Bailey reports it from
Florida. Rabenhorst describes it as scarcely distinguishable
from P. Brebissonii; 21-5 times longer than broad ; zygospores
mostly globose, membrane somewhat fuscous, sub-granulate.
P. crassa. D. By. Plate V, fig. 3.
Cells short, ovate-cylindrical, 11-2 times as long as wide,
chlorophyl not separated, but concentrated into two or more
nuclei in each cell.
Diameter 25-29
Collected by E. S. Cheeseman, Knowlesville, New York,
in gelatinous mucus in an aquarium.38
DESMIDS OF THE UNITED STATES
P. kupestke, Kg. Plate Y, fig. 13.
Cells ovate elliptical, length about two diameters ; apices
rounded.
Diameter 20-25 jj.
Rabenhorst unites the preceding with this form. They are
very near in size, but not the same in shape ; the one is more
cylindrical and the other inclines more to an ellipse in form.
Collected in a mucous gathering on dripping rocks.
P. Ceevei, Lund. Plate LSI, fig. 27.
See Calocylindrus.
P. cruciferum, (D. By. i. IVittr. Plate X, figs. 9-11.
Cells cylindrical, nearly twice as long as wide, scarcely
constricted, ends roundly truncate: seen from vertex orbic-
ular ; chlorophyl laminae arranged in form of a cross as seen
in transverse section; cytioderm smooth.
Syn. Cosmarium cruciferum, D. By.
Marsh pools, Florida.
P. (Cyliudrocystis) tuwtdusi, F. Gay. Plate XLY, figs. 7, 8.
Cells twice as long as broad; each semi-cell a broadly
truncated cone. Cytioderm smooth.
Diameter 28 u.
Frequent in Tocoi marshes, Florida.
Genus, CLOSTERIOI, Xitsch.
Cells simple, elongated, lunately curved or crescent-shaped,
entire, in the center not constricted but frequently marked with
from 1-5 transverse striae; the cytioderm or wall, thin, moder-
ately firm, smooth or more or less distinctly striate.
The chlorophyllous cytioplasm is mostly arranged in longitu-
dinal parietal laminae, broken in the middle by a pale transverse
band; at each end there is usually a clear, circular, colorless or
straw-colored vesicle, or vacuole, which contains minute granules
in constant motion. As the specimen dries the “dancing
granules” disappear, and the vesicle vanishes. Compare Intro-
duction, page 16. Compare also Addenda.
A distinct circulation of granules may be noticed in good
living specimens.
The Closterium in normal condition is always green, but may
be found of various tints of reddish brown; these changes of
color take place as life becomes extinct. The striated formsCI.0STEI1IUM.
39
have a firm cytioderm and retain their outline when dry or
empty ; others, not striated are more flexible and collapse when
•dried. The chlorophyl escapes by a slight separation of the
semi-cells, and leaves the case colorless.
Faded specimens of the striated forms are best adapted for
examination; the striae, barely discernible in green condition,
become distinct ; the cases flatten somewhat in drying, the
breadth in center increases and the ends appear more attenu-
ated, hence some allowance should be made in describing them.
Conjugation takes place by a process which appears the same
as in other conjugatce. Two cells drawn into close proximity,
put forth small tubular prominences by which they unite, the
ehloropliyllous cytioplasm of the two cells concentrates at their
iunction, in the connecting tube; this enlarges more and more
until the whole of the contents of the two cells are commingled,
and condense into a seed-like mass. This becomes smooth,
spherical, sometimes quadrangular, and is known as the zygo-
spore. Compare Plate IX. The coupling usually takes place
from the concave sides, but not universally; have found them
united from the convex sides also.
Section 1.—Cells more or less cylindrical, slightly bent, ends scarcely, or not at
all tapering; zygospores orbicular or square
C. obtusum, Breb. Plate VII, fig. 1.
Cylindrical, lightly curved, 5-10 times longer than broad,
ends not tapering, broadly rounded, cytioderm colorless and
smooth.
Diameter 5-11 /<.
Often in gelatinous masses on planks, on the sides of flumes.
Pennsylvania.
C. juncidum, Balfs. Plate VII, figs. 2, 3.
Cells long cylindrical, somewhat curved and tapering
towards the ends; 20-30 times longer than broad, apices
obtusely rounded; vacuole small and indistinct.
Diameter 11-12 /u.
Variable in thickness and length ; occurs frequently in
ponds from Maine to Florida.
C. juncidum, forma graciluma-laeyissima, Breb. Plate VI,
fig. 21.
Very much smaller than the type-form and destitute of
striae.
Frequent, in ponds near Maitland, Florida.40
DESMIDS OF THE EXITED STATES.
C. macilextem. Breb. Plate TII, fig. 6.
Very long cylindrical* slightly curved aud reduced in
thickness near the ends, apices rounded; 20—40 times longer
than the diameter. Cytioderm smooth, colorless, or yel-
lowish. usually with 1-4 transverse striae. Zygospore spher-
ical, smooth.
Diameter 12-13 ft.
Ponds, Pennsylvania, New Jersey. Not rare.
C'. exsis. Delp. Plate VI, figs. 13, 14.
Cell elongate, about twenty times longer than broad, sub-
linear, or slightly attenuated from the middle to the apices ;
ends not curved ; cytioderm smooth.
Diameter 36 ft.
Not rare in ponds, Minnesota, Pennsylvania and New
Jersey.
C. gkactle, Breb. Plate VII, figs. 4, 5.
Long cylindrical, 20-30 times as long as broad, nearly
straight, ends somewhat curved and slightly reduced in
thickness; cytioderm smooth and colorless. Zygospores
according to Brebisson quadrangular, with rounded angles,
each of which bears a short spine.
Diameter 5-6 ft.; zygospores 28-30 ft. long; 22 ft. broad.
Not infrequently intermingled with other desmids from
ponds, New Jersey, Pennsylvania, etc.
C. laxceolatU-M, Kg. (O. tenue, Bailey). Plate IX, fig. 14.
Cells semi-lanceolate. 6-10 times longer than broad, grad-
ually tapering, ends subacute, chlorophyl fillets several;
larger granules in a single series. Empty frond colorless
and destitute of striae.
Diameter 40-50 ft.
Pools, Florida; New York, (Bailey). Hundreds of speci-
mens in a gathering made by Prof. Cragin, Kansas. Stouter
and proportionately shorter than C. acerosum.
C. DiDYMOTOcmi. Corda. Plate IX, figs. 12. 13.
Broad cylindrical, slightly curved, 6-12 times longer than
broad, slightly tapering towards the ends which are broadly
truncate, square; vacuole distinct containing many '‘danc-
ing granules;” cytioderm yellowish, finely longitudinally
striate.
Diameter 30-32 ft.CLOSTERIUM.
41
Not abundant, but turns up now and then with other forms,
in smaller ponds of Pennsylvania, New Jersey and Minnesota.
Plate V| fig. 10, represents a large form and distinct va-
riety corresponding to description by Delponte. Oytioderm
not longitudinally striate, but smooth and apices obtu.sely
rounded.
Diameter 50-60 p.
Minnesota and New Jersey.
C. decussatum, Kg. Plate VII, figs. 9, 10.
Cylindrical, curvature scarcely appreciable ; 7-12 times
longer than broad; very slightly tapering near the obtusely
rounded ends, cytioderm distinctly decussately striate.
Diameter 20-25-30 p.
Frequent in ponds, Mt. Everett, Massachusetts, August,
1882, and ponds northern part of New Jersey. Kiitzing of
Germany appears to have been the only individual who ob-
served this species. He sent a drawing to Ralfs, but he ques-
tioned the correctness of his friend’s vision ; he remarks,
“Prof. Kiitzing represents the striae as regularly crossing each
other, so as to form diamond-shaped reticulations. As this
appearance is not unusual in dried specimens, when the
flattened cell permits the striae of both surfaces to be visible
together; I will venture to suggest the possibility that Prof.
Kiitzing’s drawing may have been taken from a cell in that
condition.”
The correctness of Kiitzing’s observations is readily estab-
lished by an examination of the plants as found in Gilder
and other ponds on Mt. Everett. They are cylindrical and
may be rolled over to display the decussated striae on every
side alike.
C. angustatum, Kg. Plate VII, figs. 21, 22, 23.
Cells sublinear, 16-18 times longer than wide, very slightly
attenuated; ends obtusely rounded. Cells present 4-5 some-
what prominent longitudinal striae ; 2 or 3 transverse bands
or striae are also frequently distinct; vacuole subremote
from the apex, small. Dried specimens brownish yellow.
A variety is frequent with the striae loosely crossing each
other, decussately.
Diameter 15-25 p.
Ponds, Berkshire Mountains, Mass.42
DESMIDS OF THE UNITED STATES.
Section II.—Cells slightly bent, the back (dorsum) more or less convex, the op-
posite (ventral) side almost straight, distinctly attenuated from the middle to the
ends. Zygospore globular, smooth.
€. Lunula, Ehrb. Plate LXI, fig. 26.
Cells large, semilunar, 5-6 times longer than broad,
smooth, or very finely striate, indistinct, back high convex,
lower side straightish, ends attenuated, rounded. Cliloro-
phyl globules numerous; vacuole usually distinct and con-
tains many actively moving granules.
Diameter 80-110 pi.
Frequent in small ponds.
The figure is not a good typical form. It should not be
curved so much at the end.
Var. striatum, Wolle. $ 'j"j ->
Differing from the ordinary form by having the cytioderm
finely, but distinctly striate.
€. Cucumis, Ehrb. Plate VII, figs. 17, IS.
Cells smooth, stout, semiluuate; ends broadly rounded.
Ehrenberg’s figure represents this species about five times
longer than broad ; in form somewhat resembling C. Lunula,
not so large, and lower side more concave. Ehrenberg col-
lected it in the State of New York. The figures are from
plants found in New Jersey and Pennsylvania. They are
evidently closely allied to C. Lunula.
C. subtile, Breb. Plate VIII, fig. 2.
Cells very slender, acicular, slightly curved, narrow lan-
ceolate, apices acute, cuspidate.
Diameter 3-1 pi.
Ponds, New Jersey. Rather rare.
C. acerosum, (Schrank), Ehrb. Plate VII, figs. 7, 11.
Linear fusiform or slightly curved, 15-24 times longer
than wide, lightly tapering towards the ends; apices nar-
rowly truncate, or obtusely rounded, transparent or yel-
lowish ; cytioderm rather indistinctly, or not at all striate.
Chlorophyl globules 11-14 arranged in a simple axillary
series in each semi-cell; vacuole small with numerous cor-
puscles. Zygospore globose, or broadly elliptic.
Diameter variable, 35-62 u.
Plate X, figs. 1, 2. A specimen finely in fruit; presenting
the peculiarity of two forms of zygospores, single and twin,
oval, the longer axis at right angles with the axis of the
cells. Cell walls finely but distinctly striate.GLOSTERIUM.
43
One of our most common species, often forming gelatinous
floating masses on small ponds and pools. I have it from
many States, and probably it exists in every one.
The entire chlorophyl of this species often retracts itself
from the cell-wall and breaks up into a number of oval or
globular forms, every one of which acquires a firm envelope.
Plate IX, fig. 17, represents one of these forms.
C. pbelongtjm, i Breb. \ Delph. Plate VI, figs. 15, 16.
Cells somewhat linear, cylindrical, elongate, about thirty
times longer than broad, slightly curved, apices obtusely
rounded, sometimes slightly recurved ; cytioderm striated.
Diameter 20-21 /<.
Ponds, Pennsylvania and Minnesota.
C. subcostatum, Nord. Plate VIL- fig. 11.
Cells usually four to five times longer than broad; back
rather high arched, below nearly straight, may be either
slightly concave or convex ; apices obtusely rounded. Mem-
brane usually yellowish brown with 9-12 longitudinal costae.
Diameter 50-60 g.
C. NASUTUM, Void. Plate VII, fig. 12.
Large, fusiform, only slightly curved, about five times as
long as wide, gradually tapering from the middle to near the
ends, then suddenly contracting, making the sides parallel,
to the truncate or rounded apex. Cytioderm smooth. Speci-
mens of this species from Cypress Swamp, Florida, appear
perfectly straight and somewhat thicker and longer than the
forms hitherto noted, apical vacuole distinct. Chlorophyl
arranged in five or six fillets; centrally separated, length
seven times more than the breadth. Coll. A. C. Stokes.
Diameter 75 yu. more or less.
Ponds, Berkshire Mountains, Massachusetts.
The only counterpart to this form, hitherto found, is from
Brazil, and is represented in Witt, and Nord’s Algce Exsiccatce
No. 366.
C. tubgidum, Ehrb. Plate VII, fig. 15 ; Plate VI, figs. 3, 4.
Dorsum convex, lower margin somewhat concave, inclin-
ing upward at the rounded ends; upper margin with a de-
pression near each extremity: empty cells reddish brown,
striae numerous, fine but distinct.
Diameter 64-75 g.
Wet, marshy places, Pennyslvania,44
DESMIDS OF THE UNITED STATES.
0. attexuatum, Ehrb. Plate IX, fig. 5.
Somewhat curved, attenuated, suddenly contracted at the
end into a narrow conical point; empty frond reddish, faintly
striated.
Diameter 34-42 p.
I quote this diagnosis from Ralfs’ Br. Desmids; think we
ought to find, but am not satisfied that I had a genuine
species.
C. STEIGOSUM. Ehrb. Plate VII, figs. 13, 14; and Plate LXIV,
figs. 9, 10.
Long fusiform, at the ends somewhat bent, 19-24 times as
long as broad, slightly tapering from the middle to the thin,
finely rounded apices. Vacuole small and indistinct. Cytio-
derm colorless, smooth.
Diameter 10-16 /t.
Pond waters, Pennsylvania and Xew Jersey. Plate LXIV,
figs. 9, 10, represent a fruiting form, collected in abundance,
near Ocean Beach, July, ’83. In form near C. parvuhim, but
proportionately so much longer than the species, I take it for
a variety of C. strigosum. Diameter of cells 10 u.\ length
200 ,u.; twenty times longer than wide.
section III.—Cells more or less falcate; dorsum and ventral margins both con-
vex, arched in the same direction, ends tapering. § A. form slightly curved,
i B. forms strongly curved, sometimes almost semi-circular.
C. striolatum, Ehrb. Plate VII, figs. 8, 20.
Cells slightly bent, 8-16 times longer than broad, ends
reduced to one-fourth the largest diameter, apex obtusely
rounded. Vacuole full size, containing many active gran-
ules. Cytioderm of older forms, reddish brown, distinct
striate. Zygospore orbicular, smooth.
Diameter, 30-48 ji.
Plate VI, figs. 5-8. Distinct from forms on Plate VI.
Fig. 8 may be considered of doubtful value.
Frequent in shallow pools.
1 find three varieties, the one 6-8 times longer than broad
(Plate VI, fig. Si; another 10-15 (Plate VI, fig. 20); and the
third only 4-5 times longer than broad. They may be recog-
nized as varieties, int*mirdinm, Ralfs; elongation, Rab.; and
iuinidiim, Rab. The latter is very near Nord’s. xubcostatum.
The variety elongation is more slender and more delicately
striate than the others.CLOSTERIUM.
45
•C. costatum, Corda. Plate VII, fig. 19.
Fusiform, more or less curved, 6-8 diameters in length,
ends rounded; tapering from t he middle to about one-third
the largest diameter; vacuole large, containing many danc-
ing granules. Membrane in front view has 5, or rarely 6-8
longitudinal striae or costae. Zygospores spherical or ovate.
Diameter 63-70 p.
C. Delpontii, Klebs. (C. Crassum, Delp.) Plate VI, fig. 9.
Cells cylindrical, somewhat inflated in the middle, gradu-
ally tapering to an obtusely rounded apex ; distinctly striate
with one, two or three sutures about the middle; cell twenty
times (more or less) longer than broad.
Diameter 35-45 p.
Delponte’s name of Crassum having been previously ap-
plied to another species by Rabenhorst, Klebs changed it.
C. lineatum, Ehrb. Plate VII, fig. 16.
Long, straight and cylindrical in the center, ends greatly
attenuated and slightly incurved, apices obtusely rounded,
distinctly striate; chlorophyl globules, about twenty in each
semi-cell, placed in a single axillary series; vacuoles small,
remote from the apices.
Diameter 24-36 p.
Var. costatum. Plate 10, fig. 3.
This variety differs from the usual form in having the
striae very thick aud few in number. The figure represents
one of many fruiting specimens found by W. N. Hastings,
Rochester, N. H.
C. Braunii, Reinsch. Plate , fig. 19.
Frond large, nearly straight, linear in front view, tapering
rather suddenly near the obtusely rounded apices, a central
suture; 5 to 10 distinct longitudinal costae. Cells usually
brownish yellow about 12 times as long as wide.
C. decorum, Breb. Plate VIII, fig. 1.
Moderately arched, 12-16 diameters in length, gradually
tapering from the center to one-fourth or one-fifth of largest
diameter; ends rounded; vacuole small. Cytioderm finely
striate. Zygospores angular in European specimens.
Diameter 34^11 /r.
Frequent in marsh pools and the like localities.
Pennsylvania, New Jersey, and probably every State.
Pictou, Nova Scotia.46
DESMIDS OF THE UNITED .TATES.
Occurs occasionally in sluggish waters, Pennsylvania and
New Jersey. This form is separated from C. striolatum,
mainly by the larger number of striae ; the one has 12-15 and
the other 20-30.
C. abeolatum, Wood. Plate VIII, figs, 3, 4.
Fusiform, straiglitisli, or very slightly curved, the ventral
side often a little concave in the middle; 9-10 times longer
than broad, moderately attenuated at each end; the apices
truncately rounded; cell-membrane reddish brown, thick
and firm, distantly profoundly striate, and very minutely
but distinctly granulate or areolate; median sutures very
distinct, 4-10 in number.
Diameter 60 g.
Dr. Wood remarks: “I found this species growing in a
quiet pool of pure water, in a wild, deeply wooded ravine,
near Danville, Central Pennsylvania. It was in great abund-
ance, forming a translucent greenish jelly, one or two gills of
which might have been readily gathered.” “ This species is
very closely allied to O', turgidum, Ehrb., agreeing pretty well
with it in general outline and size. I think, however, the
peculiar markings upon the membrane are sufficient to sepa-
rate it.” “The turning up of the ends, generally so marked
in C. turgidum is mostly entirely absent in this species, rarely
C. suBDTRECTini, West. Plab , fig. 20.
Frond about fifteen times longer than broad, gently taper-
ing, the middle portion nearly straight, slightly curved near
the ends, which are truncate with rounded corners, cytio-
derm finely striate, with three distinct transverse sutures.
Diameter 26-27 g.; length 390-400 g.
C. AJIBLYONEMA, Ehrb.
A form bearing this name was accredited to the United
States by Dr. Ehrenberg. Prof. Bailey, about thirty years
since, examined the character of the plant, and pronounced
it the same as C. lineatum.
C. ACTJTUii, Breb. Plate VIII, figs. 11, 12.
Small, slightly bent, 6-12 times longer than broad, gently
tapering from the middle to the rounded ends; cytioderm
colorless and smooth. Zygospores angular.
Diameter 9-11 g.
there is some tendency to it.”
Ponds, Massachusetts. J. R. M. S., Nov., 1888.
Not rare in marsh pools, Pennsylvania and New Jersey.CLOSTERIUM.
47
C. Dian-E, Ehrb. Plate VIII, figs. 8, 9. Plate IX, fig. 4.
Plate VI, figs. 1, 2.
Crescent shape, sometimes a full semi-circle as variety
arcvatum, Breb., attenuated from the middle to the rather
sharp ends, vacuole not definitely defined; transverse striae
sometimes evident. Ends are separated by about 10 diam-
eters. Specimens Plate LV differing somewhat in size. Not
rare. Zygospores spherical, smooth.
Diameter 16-20 //.
Quiet waters, Rhode Island to Florida.
C. acuminatum, Kg. Plate VIII, figs. 18, 19.
Similar to Diarue, somewhat larger and less curved, ends,
sharper, vacuoles more distinct; membrane very finely
striate, or smooth.
Diameter 25-28 pi.
Not rare in marsh pools ; conjugated cells frequent.
Pennsylvania.
C. Jenneri, Balfs. Plate VIII, fig. 5.
Crescent shaped, small, slightly tapering, six to eight
times longer than broad, ends obtusely rounded; vacuole-
large, containing many active granules; cytioderm color-
less, smooth.
Diameter about 14 pi.
Rhode Island (Bailey); Pennsylvania, New Jersey.
C. Venus, Kg. Plate VIII, fig. 6.
Small, more or less slender, nearly semi-circular, eight to-
twelve times longer than the diameter; gradually tapering
from the middle to the sharp ends; vacuole distinct; cytio-
derm colorless and smooth ; chlorophyl homogeneous.
Diameter 8-10 pi.
South Carolina, (Ravenel); Pennsylvania, New Jersey,,
frequent.
C. parvulum, Naeg. Plate VIII, fig. 7; and Plate IX, fig. 16.
Six to eight times as long as wide; differs from C. Venus-
in being rather less arched and stouter, vacuoles not so well
defined, and chlorophyl lamina more evident.
Diameter 12 pi.48
DESMIDS OF THE UNITED STATES.
Section IV.—Cells falcate as the preceding; upper margin very convex, lower
side concave with a more or less conspicuous central inflation, ends tapering.
Zygospores spherical, smooth.
C. Ehbenbergii, Menegh. Plate VIII, fig. 16.
Large, stout, five to six times as long as the central diam-
eter ; upper margin very convex, lower side ventricosely
much inflated ; ends rounded ; cytioplasm with large gran-
ules, numerous, scattered; no striae, and no central suture
evident. Of the zygospore, Archer says, “it is smooth,
placed betweeen the slightly connected empty conjugating
fronds, the endoelirome during the process of conjugation
emerging from the opened apex of a short conical extension
from the under side of each younger segment (or shorter
one) of each pair of recently divided fronds; the conjugat-
ing fronds being produced immediately previously by the
self-division of a pair of old fronds—two sporangia (zygo-
spores ) being thus the ultimate produce of the two original
fronds.”
Diameter 75-110 r. Delp. 51-79 //.
Ponds, Pennsylvania and New Jersey; common.
Var. immane, Wolie. Plate VIII, fig. 17, similar to the typical
form except in size.
Dameter 208 //.
Not Infrequent in Budd’s Lake, and larger ponds of Kew
Jersey.
€. bobustum, Hast. Am. Mic. J., July, 1892.
Cells large, semi-lunar, a little more than four times as
long as wide; eytioderm smooth; dorsum high convex;
ventrum somewhat concave, ventricose; chlorophyl globules
large, numerous scattered ; vacuoles large, terminal distinct,
with many moving granules.
Diameter 100-120 R.
Rochester, N. H., Dec., 1890. Had very much the appear-
ance of C\ Ehreiibergii, with the ends less attenuated.
C. iuoxilifeeum, Ehrb. Plate VIII, fig. 16.
Very near C. Ehrenbergii, but somewhat smaller, six to
nine times longer than broad, ends subacute; eytioderm
light straw-colored, smooth or finely striate; large chloro-
phyllous granules in a single longitudinal series in the center
of the cell.
Diameter 46-55 M-CLOSTERIUM.
49
There appear to be two varieties of this species; one with
rather broad truncately rounded ends ; the other, smaller
with more pointed ends.
Georgia; Rhode Island; (Bailey). Pennsylvania and New
Jersey; occurs frequently.
C. Leibleinii, Kg. Plate VIII, figs. 13 and 20.
In outline bears a strong resemblance to the two preceding,
but is shorter, stotiter, upper margin more convex and ends
more acute; lower margin concave with a central inflation.
Diameter 40-60 p.
Found in ponds with the two preceding.
Yar. cuetitm. 'West. Plate XLIII, fig. 22.
Differs from the typical form by its shortened ends. Has
the appearance of a miniature C. Ehreribergii.
J. R. M. 8., Nov., 188S.
C. Balfsii, Breb. Plate VIII, fig. 10.
Stout, finely and densely striated, curved, rapidly attenu-
ated into somewhat linear beaks which are shorter than the
ventricose body ; 6-8 times longer than broad.
Diameter 42-47 /<.
Pond near Perth Amboy, New Jersey.
Color of this species changes from green to a yellow brown ;
the upper margin is convex, the lower concave but ventricose
at the center; chlorophyl vesicles rather irregularly disposed
in a single row : a transverse suture is usually evident in the
middle.
section V.—Cells more or less curved, ventral margin also somewhat in Hated,
but the end drawn out into beak or seta-like extensions. Zygospores angular.
C. ROSTRATTJM, Ehrb. Plate IX, figs. 1, 2, 3. Plate XLIII,
fig. 21.
Lanceolate-fusiform, ends thin, drawn out to nearly half
the length of the body; cytioderm light yellowish, densely
but finely striate; chlorophyllous vesicles and vacuoles
usually indistinct; the latter when seen has 12-15 actively
moving corpuscles.
Diameter 23-40 /<.
Var. bkevirostratum, West.
Differs from the usual form in its short and less attenuated
beak.50
DESMIDS OF THE UNITED STATES.
Ponds, Massachusetts. J. R. M. S., Nov., 1888.
Frequent in ponds, Pennsylvania, New Jersey, Vermont,
Connecticut, Florida.
In this vicinity, Bethlehem, Pa., copulating specimens are
of common occurrence.
C. pkonoi, Breb. Plate VI. fig. 22.
Cells very small, sublaneeolate, each end drawn out into
a setaceous beak about half as long as the body; cytioderm
finely striate.
Diameter 7-12 /.i.
Ponds, Florida.
C. Kuetzingii, Breb. Plate IX. fig. S.
Straight in the middle, smaller than the last, narrow lan-
ceolate, each extremity tapering into a long slender setaceous-
beak, which is curved at the obtuse ends, and less than the
length of the body.
Diameter in middle 17 n.
Rather rare in ponds, Pennsylvania and New Jersey.
C. setaceum, Ehrb. Plate IX. figs. 6, 7, 9, 10. 11.
Very slender. Smaller than the preceding; 20-25 times
longer than broad, upper and lower margins equally convex;
ends tapering into long seta-like beaks, colorless, somewhat
enlarged at extremities, longer than the length of the body ;
striae close, faint, central suture solitary. Zygospore cru-
ciform.
Diameter 10-11 //.
Frequent in Pennsylvania, New Jersey, Massachusetts, etc.
Solitary and conjugating. Bailey reports it from Rhode
Island, Georgia and Florida.
Genus, DOCIDIUM. Breb.
Cells straight, cylindrical or fusiform, elongated, apices
rounded, truncated or divided ; transverse view circular: con-
stricted at the middle, with or without a suture between the
semi-cells which are usually inflated at the base.
Docidium, like Closterium, has in most instances terminal va-
cuoles which contain numerous ‘‘dancing granules.” The pres-
ence or absence of these vacuoles, and the arrangement of the
chlorophyllous cytioplasm, whether parietal or axillary, have
been made points for generic separation between otherwise
similar forms. These distinctions seeming too uncertain andDOCIDIUM.
51
variable in different stages of growth, I put them all together,
and retain Docidium in preference to Pleurotaenium, as the older
name.
D. Archerii, Delp. Plate XII, fig. 2.
Cells smooth, cylindrical, about twenty times longer than
broad; scarcely attenuated from the middle to the ends ;
apices broadly rounded or truncate; base of semi-cells with
one or two undulations. Chlorophyl usually arranged in
numerous small parallel bands.
Diameter 50-60 yu.
Numerous in pond, .Luzerne C'o., Pa.
D. crenulatum, (Ehrb.), Bab. (Pleurotaenium nodulosum. D. By.
Docidium nodulosum, Ball’s.) Plate XI, fig. 1.
Cell very stout, the thickened sutures forming a projecting
rim; 8-16 times longer than broad, scarcely attenuated;
regularly inflated at intervals so as to form an undulated
margin; the basal inflation the most prominent; ends sud-
denly contracted and truncated, furnished with three or four
teeth in view, below the margin ; cytioderm coarsely punc-
tate.
Diameter 40-60 /a.
Frequent in ponds from Vermont to Florida; Minnesota.
D. CLAYATUM, (Kg. i, D. By. Plate XI, fig. 8.
More slender than the last, suture not prominent, 16-24
times longer than broad, sensibly enlarged at the ends, more
or less clavate; apices broadly rounded or truncate; cytio-
derm firm, colorless, densely and irregularly punctate.
Diameter, smaller forms 23-25 /<., larger forms 36-42 yu.
Figure S has not the proportionate length.
Pennsylvania, New Jersey, South Carolina and Georgia.
D. Trabecula, (Ehrb.), Xaeg. (Docidium Ehrenbergii, Balfs.)
Plate XI, figs. 2, 3, 4; and Plate XV, figs. 1-7.
Long cylindrical, eight to twenty times longer than broad;
tapering moderately from the center to the ends; apices
truncatelv rounded, not dentate; suture forming a sharply
defined rim, the inflation adjoining often having a smaller
one above it. Sometimes there is a contraction near the
apex fig. 2). Cytioderm smooth. Zygospore globose,
smooth, surrounded by a colorless gelatinous envelope.
Diameter 25-35 g. Length 180-450 //.
Occurs frequently, and will probably be found in every
State in the Union.52
DESMIDS OF THE UNITED STATES.
D. teuncatum. Breb. Plate XI, ligs. 6, 7.
Cells stout, six to eight times longer tliau broad, with a
single inflation at the base of the semi-cell, tapering to the
truncate, or broadly rounded, entire, ends; suture forms a
thick rim, which projects on each side.
Diameter 50-75 p.
Florida, Minnesota, Pennsylvania.
Peculiarities of this species are the large diameter and
shortness of cells in comparison with the breadth ; the at-
tenuated ends, truncate, or broadly rounded apices, solitary
inflation at the base of the semi-cells and consequent even
sides. Florida furnished the best developed forms.
D. rectum, Delp. Plate X, figs. 20, 21.
Cells cylindrical, straight, twelve or more times longer
than broad ; slightly narrower at the truncate apex than at
the base; moderately swollen at the base of the semi-cells.
Diameter 25-28 p.
The distinction which Delponte makes between this form
and I). Baculum, to which it is very closely related, is, that
it is perfectly straight, while the former is •‘straightish,”
somewhat bent, although not so represented, Plate XI. figs.
3, 4, Des. U. S. The central inflations are usually larger in
D. Baculum than in 1>. rectum.
D. Flotowfi? Eab. A variety. Plate XI, fig. 5.
Large, about eight times longer than the larger diameter;
suture distinct; solitary inflation at base of semi-cells ; sides
straight, tapering slightly in straight lines from the center
to the broad truncate apex, each angle furnished with a
prominent tooth ; cytioderm firm, coarsely verrucose.
Diameter at base of semi-cell 6S p.; at apex 50 p.
From pond on Mt. Everett, Massachusetts. A large, firm
and distinct form; not identical with the described plant, but
it is tolerably near it.
D. Baculum (Breb.), D. By. Plate XIV, figs. 3, 4.
Bather long, cylindrical, straightish margins slightly ta-
pering towards the ends, or nearly parallel; apices truncate,
rounded. Cytioderm smooth and colorless.
Diameter 14-22 p.
In general form very near I). Trabecula, but smaller and
devoid of the terminal vacuoles.
Ponds, Pennsylvania, New Jersey and Florida. Bailey
found it also in Georgia.DOCIDIUM.
53
D. Baculum, var. Floridense, Wolle. Plate XI I, fig. 5.
Differing from the typical form, having the margins wavy
from base of semi-cell to apex.
Diameter 15 -17 p.; length of cell often thirty times greater.
Frequent in pond near Maitland, Florida, March, 1885.
Probably the same as the next following.
D. Ehrenberg-ii, Balfs. Var. Floridense, Wolle.
Differs from D. Trabecula, Xaeg., described, page 2, and
from the typical form of D. Ehrenbergii, of Balfs, Delponte,
and others in its more slender cell, and in the larger number
of nmbonations. Cell twenty or more times longer than
broad; medianly distinctly constricted, without an evident
suture or projecting rim. Semi-cells tapering slightly, in
direct lines from the center to the end, with not only one or
two inflations (nmbonations) at the base, but four, five or
more, often extending in slight undulations to near the end ;
apex squarely truncate, bordered by three to five minute
tubercles.
Diameter 10-20 p.; length 300-100 p.
Cypress Swamp, Florida.
D. CORONATCM, Bab. Plate XIV, figs. 0, 10.
Cells stout, cylindrical, slightly tapering from middle to
ends; suture projecting on each side; semi-cells inflated at
the base and bordered by one or two rows of tubercles at the
apex, which produce a crenulate appearance.
A smaller form has the suture imperfectly developed.
Vacuoles, ’with active granules, are usually large and dis-
tinct.
Diameter 22-56 p.
Ponds, Pennsylvania, New Jersey, Massachusetts.
D. CORONULATUM, Grun. Plate LXIV, fig. 16.
Smooth or finely punctate, subcylindrical, slightly attenu-
ated near the ends; apices truncate, ornate with a crown of
pearly teeth. Twelve times as long as broad.
Diameter in middle 38 p. Xear the ends .33 p.
The original form of this species was found in the East
Indies ; the plant was somewhat thicker, but of about the
same proportionate length, and so near otherwise, I adopt
the name. Collected it in northern New Jersey ; found the
finest specimens in Green Pond, commonly several united ;
had as many as ten cells in a series. They are without a
suture, and apparently without vacuoles. Found the same
in Florida.54
DESMIDS OF THE UNITED STATES.
D. constrictor Bail. Plate XIV, fig. 2.
Cells ■with moderately deep constrictions, which separate
four equal, gently curving prominences on each semi cell;
end view entire. Apex furnished with a few conspicuous
teeth of which four are ordinarily in view. Plant 10-12
times longer than broad.
Diameter 40-50 /.<.
This species bears some similarity to D. nodosum in its
wavy margins, but the undulations are less prominent, and
the transverse sections are quite distinct ; in the one they are
circular, in the other undulate ; compare Plate XI, fig. 11,
sections of D. nodosum.
D. (Pleurotaenioi breve. Wood.
Robust, 4-8 times longer than broad, distinctly constricted,
but not undulate in the middle; slightly attenuated towards
the ends: apex truncate and somewhat rounded; cvtioderm
very thick, densely minutely granulate; margins either
straight or shortly undulate.
Diameter 20-24 pi.
Dr. Wood remarks, "This species was sent to me by Dr.
Billings, who obtained it near Washington, D. C'. The mar-
gins are sometimes straightish, but in other fronds there are
three or more distinct, short undulations or rounded projec-
tions in each half margin.”
The shape of the semi-cell is very near Plate X, fig. 12, but
only about half the size, not so undulate and not spinous.
D. nodosum, Bail. Plate XIV. figs. 11.12, and Plate XV, fig. 20.
Semi-cells with four prominent nodes separated by con-
strictions ; end view six crenate, formed by whorls of tuber-
cles : s-10 times longer than broad.
Diameter 45-55 pi. in center; ends about half as thick.
Frequent in ponds, Pennsylvania, Xew Jersey, Massa-
chusetts.
D. repandum, Welle. Plate XIV, fig. 1.
Smooth or punctate, about twenty times longer than broad,
margins repand or undulate from the base of the semi-cell to
near the end: only slight variation in diameter from base to
end; apices truncately rounded, and sometimes slightly di-
lated. Xo suture.
Diameter 25 /<.
Sparsely found in Pennsylvania and Xew Jersey.DOCIDIUM.
55
D. Woodii, Delp. Plate XII. fig. 4.
Cells cylindrical, six to ten times longer than broad;
apices rounded; basal inflation of semi-cell large, wide and
high; cytioderm smooth.
Diameter at ends 50 yu.; inflation 65 yu.
Pond, Ocean County, New Jersey.
D. Georgicum, Lagli. Plate X, fig. 16.
Cells large, twelve times longer than broad; moderately
constricted in the middle; suture none; semi-cells much
swollen about the middle; basal part with four larger and
smaller undulations, alternating large and small; ends
somewhat attenuated ; apices roundly truncate; membrane
hyaline, punctate, thickest at the ends—no aculei nor teeth.
Diameter of cells, basal parts 54 yu. ; middle 75 yu. ;
apices 39 yu.
Pond waters, Georgia.
D. dilatatum, (Cleve), Lund. Plate LXI, fig. 32.
Cells slender, cylindrical, 15-20 times longer than broad,
undulate-nodose ; base moderately inflated and longitudin-
ally plicate; no suture evident; semi-cells usually with
eight inflations and corresponding constrictions; apices
roundly truncate and more or less dilated.
Diameter 13-16 yu.
Brown’s Mills, and other ponds, New Jersey.
D. SINTJOSUM, Wolle. Plate XIV, figs. 6, 8 ; variety fig. 7.
Slender, undulate, smooth, cylindrical; 20-24 times longer
than broad; semi-cell with eight constrictions; ends trun-
cate, straight or slightly concave, each angle furnished with
a short, stout tooth ; basal inflation not plicate.
Diameter 12-14 yu.
Yar. breve, Wolle. (Fig. 7) only half the length, and only four
constrictions to a semi-cell.
Diameter 12-14 yu.
Very near the preceding, but armed with teeth at the apex,
not plicate, and sometimes only half the length. Pond,
Pleasant Mills, New Jersey.
D. undulatum, Bail. Plate XIV, fig. 5.
Cells small, cylindrical with undulating margins, 18-20
times longer than the diameter; moderately constricted in56
PEslIIDS of THE EXITED STATES.
the middle : inflation at base of semi-cells very slightly
larger than the undulations, apices rounded.
Diameter 10-12 «.
Bailey found this species in fresh waters of Florida ; I have
it from the same State, and from ponds at Hanimonton and
Dennisville, New Jersey.
D. hibsutum, Bail. Plate XIII. fig. 13.
“Semi-cells many times longer than broad, slightly in-
flated at base, surface hirsute, a small species resembling D.
Trabecula in form, but strongly hirsute on its outer surface.”
These, the words of Prof. Bailey: his figure has the appear-
ance of a Gonatotygon, but guided by his comparison with
I). Trabecula, I .judge my figure represents the same plant.
The cytioderm is densely hirsute throughout.
Diameter 24-30 p.
Sluggish waters, eastern Pennsylvania.
D. SPixosoi. Wolle. Plate XIII, fig. 12.
Cells large, subeylindrieal, 3-10 times longer than the
larger diameter: margins undulate with three or four more
or less prominent inflations : central constriction deep, and
suture conspicuous ; apex truncate, about two-thirds as wide
as the base of the semi-cell, cytioderm firm, clothed with
densely set spines : two or three rows around the apex firmer
and longer than the others.
Diameter 40-4S p.
Pond, Dennisville, New Jersey.
D. erenulatum, Ehrb., D. nodosum, Bail.. D. hirsutum, Bail.,
have features in common with this form. I have separated
it in view of the armor of spines with which it is clothed;
these are not hairs, nor gelatinous contractions, but decided
and firm spines.
D. verbEcosum, (Bailey >. Rails. Plate XIII, figs. 4. 5.
Cells cylindrical, tapering very slightly from the center to
the apex; margins made erenate by numerous whorls of
quadrangular prominences. Length about twelve times the
breadth.
Diameter 25-33 p.
Occurs frequently in ponds, Mt. Everett, Mass., and sparsely
in quiet waters, northern Xew Jersey. Bailey found it orig-
inally in Rhode Island and Xew York.DOCIDIUM.
57
D. minutum, Ralfs. Plate LXI, figs. 29-31. Plate XIII, fig. 9.
Slender, elongated, smooth, cylindrical, linear or slightly
tapering, ends round : 10-30 times longer than broad ; a
single inflation, more or less prominent at the base of the
semi-cell.
Diameter 7-9 pi., or more rarely 10-12 pi.
Ponds, Florida, Massachusetts and New Jersey.
This minute plant is near a form described by Delponte as
P. rectum, but it has twice the diameter. Ralfs describes his
D. minutum, which has the same diameter as ours, only five
or six times longer than wide. Our forms vary greatly in
proportionate length and breadth ; the shortest, however, is
ten times as long as bripad. They vary also much in thick-
ness and in the central inflation ; sometimes the constriction
is barely perceptible, and again marked by a strongly in-
flated border. The various forms frequently occur in groups,
and evidence specific relationship.
D. tridentuiajm, Wollc. Plate XIII, fig. 10.
Near the preceding in form and structure but average
somewhat larger, and often granulate; apices crowned with
a few prominent teeth, usually three in view.
Diameter 12-13 pi.
Pleasant Mills, Brown’s Mills, etc., New Jersey.
The inflation at the base of the semi-cells is more prominent
than is usual in D. minutum.
D. costatum, Wolle. Plate XIII, fig. 2.
Fusiform, 7-3 times longer than broad; slightly con-
stricted in middle ; inflated gradually from the base of the
semi-cell to about one-third the length, then gradually taper-
ing to the truncated, slightly dilated and dentate apex ;
margins with regular crenae, produced by twenty or more
distinct transverse costae or rib-like lines.
Diameter, widest part 25 pi., constriction 20 pi., ends
15-17 pi.
Found by H. D. Kitchel in pond, Berkshire Mountains,
Massachusetts, 1882.
The specimens which came under my observation were not
vegetative—too old ; this species needs verification.
D. verticillatum. (Triploceras verticillatum , Bail. Plate XIII,
figs. 1, 11.
Cells large subcylindrical, with numerous whorls of small,
oblong, often tooth-like prominences ; 7-16 times longer than
broad ; ends with three bidentate diverging processes.
Diameter ordinarily 38-45 pi.5 $
DESMIDS OF THE I'SITED STATES.
Tar. TUEGiDUir, (fig. 11). \Tolle. Shorter and stouter, often 60 /<■
Of frequent occurrence in pond waters. Maine to Florida.
The number of whorls varies from 12-16 in a semi-cell.
In living condition the cells are green, but more commonly
they are found of brownish red color.
Plate X. fig. IS. This illustration given as another of
many forms in which this species often occurs. The third
diverging process of the apical termination not always
evident.
W. X. Hastings. Rochester, Xew Hampshire, reports this
form frequent in the Cocheco River.
D. geacile. {Triplocerasgraeile\ Bail. Plate XIII, figs. 3. 6, 7. S.
Differs from the last in usual smaller size of cell, smaller
and more acute tooth-like prominences of the whorls.
Diameter 2o-2$ g., exceptions, up to 40 //.
Habitat the same as the former.
The whorls appear to be composed of a double series of teeth,
but frequently the second row is barely evident. Fig. 3 is of
unusual size. Fig. 7 represents a condition of dissolution ;
the contents have escaped, and the parts constituting the cell
have separated, contracted and assumed a partially inverted
position.
Genus. CALOCYLIXDRUS. D. By.
Cells straight, cylindrical, ends rounded or truncate : semi-
cells without basal inflation, or longitudinal plication: chloro-
phyl parietal or axillary.
C. Ralfsii. (Kg.). Kirch. ( Cosrnarium cylindricum. Balfs). Plate
XT. fig. 17.
Cells cylindrical, about twice as long as wide. Semi-cells
subquadrate in front view, broadest at the extremity : cytio-
derm more or less granulated.
Diameter about 24 /i.
Pools fresh water, Pennsylvania and Few Jersey.
C. De Bakyi. Arch. Plate XLT, fig. 12.
A specimen from Minnesota, the typical form, unlike the
one fig. 5. Plate XT. which is more like a form of C. Cu-
cumis: the constriction is not deep, linear, but merely a
shallow notch, hence De Bary classified it with Pleurotaenium.C A LOG V LIN D I; US.
59
C. MINUTUS. (Ralfs), Kirch. (Penium minutum, Cleve). Plate
XV, fig. 12. Plate V, figs. 19, 20.
Cylindrical, 4-6 times as long as broad, slightly constricted
in the middle, ends rounded, membrane smooth.
Diameter 11-16 ,n.
Florida, South Carolina, (Bailey), Rhode Island, (Olney).
This minute and apparently variable plant has not come to
my notice. It is classed by different authors both as a Penium,
and a Docidium.
C. Cucurbit A, (Breb.), Kirch. (Cosmarium Cucurbita, Breb.)
Plate XV, fig. 14.
Cells punctate, cylindrical, about twice as long as broad,
slightly constricted at the middle, rounded at the ends.
Diameter 22-25 yu.
Pennsylvania and New Jersey.
C. curtus, (Breb.), Kirch. (Cosmarium curtum, Breb.). Plate
XV, figs. 15, 16.
Cells somewhat fusiform cylindrical, about twice as long
as wide, slightly constricted at the middle, the ends sub-
conically rounded, cytioderm smooth.
Diameter 20-32 yu.
Pennsylvania, New Jersey, and other States.
Fig. 16 represents a small form collected several succeeding
Summers, in gelatinous masses on the muddy bottom of a
small pool; thousands were present; the other (fig. 15) is the
larger, typical form.
C. Cordanum, Breb. Plate XLIX, fig. 28.
Diameter about half the length ; gentle and slightly con-
stricted in the middle ; ends round or somewhat truncate ;
cytioderm lightly granular or punctate. End view circular.
Diameter 26-27 /r.; length 47-50 yu.; isthmus 17-19 yu.
This form is reported by W. B. Turner, as found in Nova
Scotia.
C. gonnatus, (Breb.), Kirch. (Cosmarium connatum, Breb.)
Plate XV, figs. 8, 9.
Cells short and thick, subcylindrical, about one and one-
half to two times longer than broad, ends broadly rounded ;
constriction forms a wide, shallow sinus ; cytioderm dis-
tinctly punctate.
Diameter 45-75 yU.
Pennsylvania, New Jersey, Florida, New York, Vermont,
Minnesota, etc.; probably distributed everywhere.60
PESMIDS OF THE UNITED STATES.
This is one of the largest species of the genus and most
common. The end view is nearly a perfect circle : front view
of a semi-cell constitutes about two-thirds of a circle ; a dis-
tinct border is always present, and often appears striated.
Yar. min'oe, Xord. Plate XV. fig. I1*. Plate LX. fig. 18.
This form is in all essential points like the last, except in
dimensions.
I have found almost every possible variety of size, measur-
ing in diameter from HO to 40 a. This fact furnishes a pre-
sumptive evidence that the smaller forms are merely unde-
veloped conditions; young plants evolved from sporangiums.
in accordance with Hofmeister’s theory. See Introduction,
p. 10.
C. pseudoconnatus. Xord. Plate XV. fig. 11. Plate LX. figs.
10. 11.
Similar to the two preceding in form and structure, but in
size usually smaller than the typical plant. The distinctive
feature is in the arrangement of the elilorophyl: this is not
homogeneous, hut divided in each semi-cell, in front view,
into two parts, and in end view, into four parts.
Marsh pools, Pennsylvania,
The value of the arrangement of the chlorophyl as a spe-
cific character, needs, I think, further corroborative evidence.
C. Clever tLund.Wolle. (Penium Cleni. Lund.) Plate LXL
fig. 27.
Cell subcylindrical, '21-3 times longer than broad, some-
what constricted in the middle : semi-cells cylindrie-sub-
conieal. ends distinctly attenuated and rounded at apices:
vertical view a perfect circle. Xuelei large, elliptic single
or rarely twinned. Membrane finely punctate, at apices
sn bg rauula t e p u net a t e.
Diameter 40-50 it. Length 115-118 /<.
Brown’s Mills, New Jersey.
The plant is slightly larger than Luudell’s form, but so
good a counterpart in form and structure, I take it to be the
same species ; by measurement the constriction is somewhat
deeper. The decided constriction makes the natural position
of this form, I think, a member of the present genus, not-
withstanding the observations made by Lundell in the
arrangement of the chlorophyl.
O. Tiiwaitesii, Ralfs. Plate XV. fig. 19. Plate LXI. fig. 28.
Cells two or three times longer than broad, fusiform in
front view; circular in end view: constriction a shallowCOSMARIUM.
fil
sinus; ends high-rounded, cytioderm not at all, or very in-
distinctly punctate ; elilorophyl scattered.
Diameter about 30 ft.
Florida, (Bailey); frequent in pond, Spring Lake, Mon-
mouth County, New Jersey.
C. diplospgra, Lund. Plate XY, fig. IS.
Cell large, twice as long as broad, subcylindrical, moder-
ately constricted in the middle, very slightly but distinctly
enlarged from the center towards the ends ; apices broadly
rounded; end view circular; cytioderm colorless and
smooth. Cytioplasm has usually a tint of reddish brown.
Diameter 25-30 ft.- length 53-58 ft.
Frequent in ponds, Berkshire Mountains, Massachusetts.
C. costatus, Wolle. Plate XY, fig. 13.
Cell ovaliform, nearly twice as long as wide ; moderately
constricted in the middle. Front view a constricted oval,
end view circular ; cytioderm longitudinally costate ; costae
5-7, distinct, converging at the apices. Color of older plants
reddish brown.
Diameter 50 ft.; length 90 ft.
Pond, Mount Everett, Massachusetts, 1882.
According to some authors this plant might be classed with
Docirliiim, but having no inflation at the base of the semi-
cells, and no plication in the ceil walls, I give it a place here.
Genus, COSMAKIUM, Corda.
Cells oblong, cylindrical, elliptical or orbicular with margins
smooth, dentate or crenate; always more or less deeply con-
stricted in the middle ; ends rounded or truncate and entire, not
emarginate, lobed or sinuate ; end view oblong or oval, some-
times with a swelling in the middle of the longer sides ; chloro-
phyllous cytioplasm parietal, or more or less concentrated in the
center of the semi-cells, or divided into two masses ; (cytioderm
(cell-walls), smooth, punctate, warty, or very rarely, spinous.
Zygospore spherical, tuberculated or spinous, seldom smooth or
angular.
The plants of this genus are recognized by their short form
and entire end. They are usually about 1) times as long as
wide ; sometimes shorter and sometimes longer, rarely over
two diameters in length. Ends always entire, not emarginate
or incised.62
DESMIDS OF THE UNITED STATES.
They may be conveniently divided as follows :
1.	Chlorophvl parietal—distributed on the inside of the walls
of the cells.
2.	Chlorophvl more or less concentrated into one or two
masses, (nuclei,) in each semi-cell.
I End view round, oval or elliptic without central
inflation.
1.	Cytioderm (cell-wall) smooth, or punctate.
2.	Cytioderm verrueose.
3.	Cytioderm spinous.
jj End view round, oval or elliptic, with a central in-
flation on each side.
4.	Cytioderm smooth or punctate.
5.	Cytioderm verrueose or spinous.
C. ovale, Ealfs. Plate XVI, figs. 8, 9.
Large, oval or elliptical, nearly twice as long as broad,
ends rounded; central constriction deep linear; isthmus
about one-third of the diameter of the cell; semi-cells with
straight base, angles rounded and sides convex, gradually
converging. Cytioderm granularly rough, with one or two
rows of larger pearly granules near the margin, producing
a dentate appearance.
Diameter about 100 p. (range from 62 to 112 p.).
Ponds, Pennsylvania, New Jersey, New York, South Caro-
lina, Rhode Island, Minnesota, etc.
C. De Baeyi, Archer. (Pleurotaenium cosmarioid.es, De By.)
Plate XVIII, fig. 5. Probably the same as Calocylindrus
Be Baryi. Plate XLV, fig. 12.
Cells oblong, twice as long as broad, with flatly rounded
ends; constriction narrow, straight, linear. Cytioderm
smooth or finely punctate ; chlorophyl parietal.
Diameter 50-54 p.; length 104-110 p.
Ponds, Berkshire Mountains, Massachusetts.
C. Cucumis, Corda. Plate XVIII, figs. 6, 7, 8, 9.
Cells oval, one and one-half to one and three-fourths times
longer than broad, ends broadly rounded; constriction linear;
cytioderm smooth ; chlorophyl covering the inside of the
walls of the cells.
Diameter 46-56 p. Thickness 36-40 p. Isthmus about
one-third of the diameter of thte cell.
Frequent from Maine to Florida.
Besides the measures given, forms are found of much
smaller dimensions. Figs. 7, 8, fl represent such ; every pos-
sible size, from the largest to the smallest, and down to aCOSMARIUM.
65
diameter of 15 /*. are not rare. These I consider undeveloped,
or young conditions of the plant evolved from zygospores.
Compare Introduction, p. 19.
C. constrictum, Delp. Plate LXI, figs. 1-4.
Cells smooth, about one-half longer than broad; deeply
constricted; sinus acute-angled; semi-cells near a three-
fourth circle, with inferior angles rounded; end view oval;
lateral view of cell an oblong with ends rounded and middle
constricted. Somewhat in character with C. Cucumis, but
proportionately shorter.
Diameter 30-38 p.
Frequent in small ponds, New Jersey, Pennsylvania, etc.
C. Scenedesmus, Delp. Plate LXI, figs. 7, S, 9.
Cells smooth, not as long as broad, depressed, constriction
deep, sinus narrow linear; semi-cells subsemicircular, base
nearly straight, ends a depressed arch, angles rounded; end
view elliptic; side view circular.
Diameter 32-38 p.
Reminds strongly of D. Phaseohts, but has no reniform
base, and no central inflation. Sinus of fig. 7 too much am-
pliated.
Occurs frequently.
C. quadratum, Ealfs. Plate XXI, figs. 8, 9, 10.
Smooth, deeply constricted at the middle; semi-cells in
front view quadrate, with a slight protuberance on each side
above the base, giving the sides a refuse appearance, angles
rounded; elilorophyl in larger forms usually divided into
two masses.
Diameter, smaller form 20-23 /.i.; larger form 40 yu.
Ponds, Pennsylvania, rather rare. Minnesota.
The apices of the two forms differ ; the smaller ones are
more or less retuse, and the larger ones convex. The length
of each is twice the diameter.
C. anceps, Lund. Plate XXI, fig. 11.
Small, full twice as long as broad, hexagonal-oblong; sinus
narrow linear; side view oblong with sides slightly emar-
ginate; apices rounded; semi cells quadrate, rather longer
than broad, tapering moderately from base to end ; end view
sub circular. Membrane smooth; isthmus half the diameter
of the cell.
Diameter 17-1S yU.; iength 4-7-10 yu.64
DESMIPS OF THE EXITED STATES.
The only plant I have found to harmonize with this de-
scription, was collected by J. D. Smith in Florida. It agrees
very well except in length, being nearly equal to three
diameters.
paetulum. Breb. Plate XSI, figs. 12. 13.
Cells small, ovate elliptical, slightly constricted, apices
truncate, two to nearly three times as long as wide ; margins
entire, or sometimes lightly erenulate; semi-cells short
conical, broadly truncate or sometimes with apex refuse:
eytioderm smooth or finely punctate.
Diameter 18-22 u.
Florida, collected by J. D. Smith.
C. Americaxcm, Lagh. Plate XLIX. figs. 15, 16.
Cells small, sinus rather obtuse and widening outwardly :
semi-cells sub-circular, the center with seven larger granules
isix peripheral and one central) and twelve, more or less
distinct, around these: vertical view elliptic; lateral view
sub-circular. Membrane smooth excepting the central
granules.
Diameter of cell 22 ft. ; length 40 ft. ■ thickness IS //.;
diameter isthmus 6 ft.
Pond near Tewksbury, Massachusetts.
C. granatum, Breb. Plate LXI, fig. 13. Plate XVIII, figs.
14, 15.
Cells one and one-half times as long as broad ; constriction
narrow linear; semi-cells trapezoidal, with straight bases,
rounded angles, sides gradually converging ; apex truncate :
variable in size.
Diameter 2(>-32 //.; isthmus about one-third the diameter.
Frequent in quiet waters. Pennsylvania, New Jersey. Mas-
sachusetts, Florida and Minnesota.
Plate LXI. fig. 13, is the typical form; the others, Plate
XVIII, figs. 14,15, are varieties, near Wille’s variety elongatum.
C. Wollea.xu.m, Lagh., var. graxuliferoi. Lagh. Plate
XLIX. figs. 1. 2. Syn. C pseudogranatum. Voile. Des.
LL S., p. 15s.
Cell rather large, one-fourth longer than wide; sinus
somewhat ampliated inwardly and outwardly: semi-cells
sub-semi-circular, base subreniform. dorsum narrowly
rounded, angles rounded, margins finely crenulate-dentate;COSMARIUM.
65
in vertical view oval; in lateral view broadly oval. Mem-
brane distinctly punctate.
Diameter 54 g.; length 66 g.
Tewksbury, Massachusetts.
The author of the present name for a Cosmarium, G. von
Lagerheim, of Stockholm, Sweden, finds that we have du-
plicated the name pseudogranatum, previously used by Nord-
stedt, hence re-names the form as above. The new variety
granuliferum reminds one of C. cymatopleurum, Nord., G. de
Notarisii, (Witt.), Nord., and C. capense, Nord., but it is
distinct.
€. moniliforme, Ealfs. Plate XVIII, figs. 16, 17, IS, 19.
Cells twice as long as wide ; semi-cells spherical, united by
a narrow isthmus; four semi-cells often in series ; cell mem-
brane smooth.
Diameter 16-24 g.
Frequent in ponds, Pennsylvania, New Jersey, Massachu-
setts, Florida, etc. Fig. 18 represents a peculiarity noticed
now and then, that in multiplying by division, (Introduction
p. 17), the new daughter semi-cells are larger than those of
the mother cell; if this is not always the case such are fre-
quently found.
C. globosum, Bulnh. Plate LX, figs. 14-17.
Cells small, light greeu, bicocciform, scarcely compressed,
nearly one-third longer than wide, very slightly constricted,
sinus acute; semi-cells circular, exclusive of the confluent
bases, entire, cytioderm smooth or finely punctate.
Diameter 20-24 g.; length 25-33 g.
Not infrequent in ponds intermingled with other forms.
Plate XV, fig. 20, represents a variety which stands between
this species and moniliforme.
Diameter about 20 ,u.
Pennsylvania, New Jersey, Massachusetts.
C. perforatum, Lund. Plate XLVIII, fig. 32.
Somewhat circular, slightly longer than broad, moderately
constricted in the middle, sinus acute angled, enlarged out-
wardly, rarely linear; semi-cells sub-semi-circular, back
high convex, with the middle slightly flattened or rarely
slightly retuse; end view broadly elliptical; lateral view
circular with base broadly truncate. Membrane distinctly
but sparsely punctate, often with larger granules arranged
566
DESMIDS OF THE EXITED STATES.
in triangular form on basal part. Isthmus fully half of the
diameter of the cell.
Diameter 57-63 p.; length 60-6S p.
Ponds, Minnesota.
C. bioculato:. Breb. Plate XVIII, figs. 21, 22.
Cells small, somewhat longer than broad; constriction
deep, producing a gaping notch ou each side. Semi-cell
compressed, oval, with convex base, short convex sides and
rather fiat apex. Cytioderm smooth or finely punctate.
Zygospore globose, without spines.
Diameter 15-16 p.; length about 17 p.
Rhode Island, Massachusetts, Pennsylvania, New Jersey, etc.
C. ehombusoides, Wolle. Plate XLIX, figs. 6, 7.
Cells nearly as long as wide ; semi-cells in form of a rhom-
bus, sides all equal, straight or slightly convex ; nearly half
as long as broad; sinus between, deep and wide; isthmus
one-fourth of diameter; end'view rhombuslike; membrane
finely punctate.
Diameter 55-65 p.; length 50 p.
From collections made by Mrs. Hanson and Miss Haggin
in pools near Lake Tahoe, California, August, 1886.
C. LOBATVLUM, TColle. Plate XLVIII. figs. 33, 31.
Small, one-third longer than broad, end of semi-cell
broadly truncate; sides convex with a slight contraction
near the apex ; side view circular with end truncate. Mem-
brane finely and closely punctate, or granular.
Diameter 25 p.; length 33 p.
Ponds, Minnesota.
C. Quimbyii, Wood.
Cells small, subelliptical, profoundly constricted in the
middle, joined by translucent bands into families ; semi-cells
seen from the front elliptical, and nearly twice as long as
broad; from the vertex elliptical, from the side roundish.
Chlorophyl masses single in each cell. Cytioderm thin,
smooth.
Diameter 18 p.; length 25 p.
“This plant was found in a spring near Camden, N. J.f
upon whose bottom it formed a gelatinous translucent, green-
ish mass. The cells are joined by bands into families, in
which the little parent cell is generally very distinct, it, orCOSMARIUM.
67
rather the two cells into which it first divides, remaining in
the center of the group.” Wood, p. 35.
I would suggest this to be very near, or identical with C.
tinctum, Ralfs.
C. tinctum, Ealfs. (Sphaerozosma tinctum, Eab.) Plate XIX,
fig. 31.
Cells small, somewhat longer than broad ; isthmus broad,
constriction outwardly enlarged; semi-cells oval; chlorophyl
a single mass; cytioderm smooth, often tinted with yellow,
brown or red.
Diameter 10-15 /x.
Of the sporangium, Ralfs writes, 11 It is large in proportion
to the cells, and quadrate with an empty segment of the
fronds permanently attached at each corner. Sometimes the
fronds couple in a crossed position, when the sporangium
appears variously twisted or distorted.”
I find single specimens of this plant occasionally, but have
not had a satisfactory group of them, or fruiting specimens.
C. TUMiDUM, Lund. Plate XVIII, fig. 23 ; Plate XXT, fig. 20.
Cells somewhat longer than broad, constriction narrow
linear. Semi-cells suboval, rather flat base, apex broad con-
vex, with one chlorophyllons mass. Cytioderm punctate
and more or less grauularly rough in the central part, margin
smooth. Plate XXI, fig. 20, appears to be a variety of
this form, coarsely granular.
Diameter 20-33 jx.
Pennsylvania, New Jersey, etc.
In front view this species bears some resemblance to C.
Phciseolus, Breb., but differs in being proportionately longer,
and in not having the base of the semi-cells reniform, and in
not having an entirely smooth membrane. Some specimens
are very distinctly punctate, others not so evidently except
away from the margins. Kirchner makes two varieties:
a. genuimtm, cytioderm distinctly granular in the middle; b.
subtile, cytioderm finely punctate over the whole cell.
C. inflatum, Wolle. Plate XLVIII, figs. 18, 19.
Cells one-half longer than broad; semi cells gradually en-
larged from a narrow base to a broadly dilated end; end
view broadly elliptic; lateral view circular, with somewhat
flattened sides; membrane finely punctate or smooth.
Diameter 25-28 fx.; length about 40 fx.
Ponds, Minnesota.68
DESMIDS OF THE UNITED STATES.
C. SEJUNCTUM. Wolle. Plate LXI. figs. 18-20.
Membrane smooth, slightly longer than broad; semi-cells
semicircular with angles rounded, separated by a vide,
nearly linear sinus; isthmus connecting the semi-cells is
narrow, less than one-fourth the breadth of cells.
Dameter 20-25 yu.; length 25-30 yu.
Pond, near Malaga, New Jersey, and Minneapolis, Min-
nesota.
Usually two forms of this plant are recognized, the one
longer than the other; the longer slightly retuse, which is the
typical form; the other not retuse, and not so long.
Sometimes found in considerable numbers in gelatinous
gatherings on dripping rocks and in small pools. The va-
riety Septextbioxale, found near Amherst, Mass., not so
frequent.
C. vaeiolatum. Lund. Plate XIX, figs. 3, 4.
Small elliptical, twice as long as wide, constriction deep,
narrow, linear; semi-cells, base straight, sides rising at right,
angles, then curving gradually and producing an almost
circular apex, sometimes slightly retuse : end view broadly
elliptical; side viewobovate. Cytioderm more or less punc-
tate ; isthmus one-third of the whole diameter. Chlorophyl
nucleus single.
Diameter 15-17 /<.
Ponds, southern New Jersey, Hammonton, etc.
C. CIECULAEE, Eeinsch. Plate XLVIII, fig. 37.
Cells nearly circular: present form slightly shorter than
broad; sinuses narrow linear; lateral view ovoid, end view
elliptic; isthmus one-third of diameter of cell; membrane
finely punctate.
Diameter 75-85 yu.; length 70-75 yu.
Frequent in marsh pools, Tocoi, Florida. This form is con-
siderably larger than the one described by Reinsch, and not
quite equal in length and breadth, but otherwise very near it,
and certainly nearer than the plant described by Lundell
under the same name.
C. eoxTBACTUM, Kirch. Plate XIX, fig. 1. Plate LXI, fig. 24.
Cells one and one-half times as long as wide; sinus pro-
duced by the constriction, deep and narrow, widening out-
wardly from the base. Semi-cells oval, with convex baseCOSMARIUM.
69
and convex apex, containing each one chlorophyl nucleus ;
cytioderm distinctly punctate.
Diameter 24 p.
Denmark, and other ponds, New Jersey.
C. sexangulare, Lund. Plate XIX, figs. S, 9. Plate LX,
fig. 13.
One-fifth part longer than wide; constriction deep; sinus
linear within and widening outwardly. Semi-cells more
or less hexagonal-elliptic; ends truncate, sides obtusely
rounded ; end view elliptical; side view circular. Cytio-
derm finely punctate.
Diameter 25-42 p.
Occurs frequently in ponds, Pennsylvania, New Jersey.
The hexagonal feature of the semi-cells is not always as dis-
tinct as described ; in the figures 8 and 9 it was inadvertently
omitted altogether, nevertheless, they represent a common
form of the species.
C. depressum, (Xaeg. ’, Lund., not Bailey. Plate LXT, figs. 10,
11, 12.
Cells usually slightly shorter than wide; constriction deep;
sinus widening outwardly; semi-cells compressed oval; the
long sides flattened, the others rounded; one chlorophyl
mass in each. Membrane finely punctate.
Diameter 20-25 p.
Frequent in pond, Spring Lake, N. J. They are smaller in
size than the European form ; otherwise identical.
Bailey in his contribution, describes another plant under
the same name. Naegeli’s description has claim of priority,
hence must stand. In order to avoid further confusion, I
change the name of the former, and in honor of the author
call it C. Baileyi.
C. Baileyi, Wolle. (0. depressum, Bailey.) Plate XIX, figs.
17,18.
“Elliptical, binate, division in the plane of the longest
axis. Segments entire, nearly twice as long as broad,
rounded above, very much flattened at base;” cytioderm
punctate.
Diameter 36-48 p.
Florida, (Bailey); and ponds, Mount Everett, Mass.
“This species resembles C. bioculatum, Breb., but the seg-
ments are much closer together, and are angular, not rounded
at the basal extremities.” Compare Note under C. depression.70
desmids of the united states.
C. OBsor.ETUM. Beiuseh. Plate LX. fig. 12.
Cells elliptic, about one-fourth more in breadth than
length. Deeply constricted : sinus rounded at the base, then
gradually narrowed towards the lateral angles of the semi-
cells. which come close together; semi-cells in end view
elliptical; side view circular. Isthmus about one-third the
diameter of the cell. Membrane punctate or smooth ; chlo-
rophyl concentrations or nuclei, two.
Diameter 110 /<■; length 80 ft-
I adopt Reinsch’s name for this plant. In general form it
is the same; the two distinct nuclei also correspond, but in
size it is much larger and the angles of the semi-cells are not
at all or but slightly contracted. I collected it in a sluggish
streamlet, Ocean Grove, X. J. It is near C. Bciileyi, but
differs in the form of the sinus, and in having two nuclei in
each semi-cell; it is also twice the size.
C. Begnesi, Eeiusch. Plate XLIII, fig. 4.
Bare and of doubtful value. Has the appearance of a cell
of Sphaerozosma.
C. sinuosum, Lund. Plate XIX, fig. 2. _
Twice as long as wide, rectangular, constriction not deep,
sinuses narrow linear, not widened outwardly: semi-cells
quadrangular, equilateral, sides and apices somewhat refuse;
end view subcircular; lateral view elliptic-oblong; mem-
brane smooth; isthmus one-third of the diameter of cell;
nucleus single.
Diameter 16-18 ft.
Pond, Berkshire Mountains, Mass.
C. Meneghinii, Breb. Plate XIX, fig. 7.
Cells 1-11 times as long as wide; constriction forms a
narrow linear sinus; semi-cells subquadrate, base straight,
apex flat, truncate or slightly concave: sides straight or
concave, corners rounded, diagonally truncate or slightly
refuse; single chlorophyl mass in each semi-cell. Very
variable. Kirchner makes three varieties:
a.	genuinum, with sides and ends and upper angles retuse.
Diameter 20-22 ft.
b.	angirfomm, Bab., sides and ends straight, upper and
lower angles diagonally truncate.
Diameter 18 ft.C( iSMARIUM.
71
c.	continuum, Bab., more elongated, semi-eells nearly
quadrilateral, all angles truncate, or rounded.
Diameter 9-26 /.<.
Found frequently ; probably has a wide range north, south,
and west.
d.	simplicismnum, Wille. Plate XLIII, figs. 11-13.
A variety of forma octangularis, Wille.
Pond near Amherst, Massachusetts.
C. octogonum, Delp. Yar. constrictum, Lagh. Plate XLTX,
figs. 34, 35.
Cells in front view oblong-tetragonal deeply constricted :
semi-cells trapezoidal: in vertical view elliptic with middle
somewhat inflated; isthmus one-third of diameter of cell.
Membrane smooth. Yar. constrictum is more deeply con-
stricted, sinus wider and semi-cell in vertical view not
inflated.
Tewksbury, Massachusetts. From these specimens the
significance of the name is not evident. Instead of three
crenulations or angles on each side of the semi-cell, Delponte
describes “sometimes four,’’ or eight to the semi-cell. Has
some resemblance to C. Braunii, Eeinsch, but is not so regular.
C. polygonum, Xaeg. Plate XIX, fig. 30.
Small, polygonal, about as long as wide, entire, sinus very
narrow; semi-cells hexagonal-oblong, angles subacute or
obtuse; apices straight or rounded; cytioderm smooth or
punctate.
Diameter 15-20 g.
Ponds, New Jersey and Massachusetts. Not frequent.
C. lunatum, Wolle. Plate XIX, fig. 16.
Cells nearly as long as wide, circular, constriction deep
and forms a wide rounded or oval sinus; semi-cells lunately
curved, back circularly arched, base concave; angles of the
two semi-cells, more or less acute, approximate closely.
Cytioderm punctate ; isthmus usually less than one-third of
the diameter. End view elliptical; side view circular.
Diameter 25-28 /j.
Brown’s Mills, N. J.
C. aculeatum, Wolle. Plate XIX, fig. 15.
Medium size, suborbicular, length slightly less than the
diameter: constriction deep, forming, by the incurving of
the angles of the semi-cells, two elliptical sinuses; cytioderm72
DESMIDS OF THE UNITED STATES.
primarily more or less densely aculeated; later the aculei
drop off and leave short granule-like stumps; end view
elliptical.
Diameter 33 /n; length 30 M-; breadth of constriction 10 /<.
Pond, Minneapolis, Minn. Collected by Miss E. Butlerr
1882 and 1883.
C. Sholandicum, Lund. Plate XIX, figs. 35, 36.
Cells somewhat longer than wide; isthmus narrow, con-
striction deep, sinus narrow linear; semi-cells semicircular
with straight base and arched back sometimes subtruncate,
angles (inferior) obtuse, mounted with a papilla ; end view
elliptical; lateral view circular. Membrane distinctly punc-
tate. C'hloropliyl masses two in each semi-cell.
Diameter, 31-48 jx.
Various localities, Pennsylvania and New Jersey.
Usually the cells are about one-eighth longer than broad ;
they vary considerably in size. At Pleasant Mills, New Jersey,
there is a variety which is somewhat depressed, measuring
one-eighth less in length than breadth. The distinguishing
feature of this species is the papilla at each angle.
C. exiguum, Archer. Plate XIX, figs. 13, 14.
Cells very small, smooth, oblong, 11-2 times as long as
broad; medial constriction slight; semi-cells subquadrate,
containing one chlorophyl nucleus; ends obtusely rounded.
Diameter 12-15 /<.
Florida, collected by J. I). Smith, 1878.
C. notabile, Breb. Plate XIX, fig. 11.
Cells small, about twice as long as broad, margins entire
or moderately undulate-crenate; ends truncate; semi-cell
more or less pyramidal, base somewhat reniform, end broadly
truncate; angles rounded, cytioderm smooth or finely
granulate.
Diameter 22-28 /u
Ponds of eastern Pennsylvania.
C. UNDULATU3I, Corda. Plate XIX, fig. 20.
Cells 11 times as long as wide, ends broadly rounded,
margins undulate; deeply constricted, sinus gradually en-
larged outwardly ; semi-cells semi-orbicular; sides and back
broadly rounded, margins undulate crenate, usually with
nine crenae to a semi-cell; cytioderm smooth. Zygospores-
spherical, armed with long spines bi- or tri-fid at apices.
Diameter 40-44 //.DESMIDS OF THE UNITED STATES.
72a
C. Braunii, forma major, Reinsch. Plate XLVITI, figs. 28, 29.
Cells small, one and one-half times longer than broad, sinus
narrow linear; sides with two emarginations ; ends truncate,
membrane smooth ; lateral view oval; vertical view elliptic.
Diameter 25-28 /.<.; length 36-40 />■
Ponds, Stillwater, Minnesota.
C. (Euastrum,) Sendtnerianum, Reinsch. Plate XL VIII, figs.
30, 31.
Cells nearly twice as long as wide; sinus narrow linear;
semi-cells nearly as long as wide, ends rounded, lateral
margins each with four or five crenulations; lateral view of
whole cell elliptic with more or less of a constriction in the
middle; end view oval.
Diameter 25 //.; length 44 /i.
C. NITIDULUM, De Not. Plate XXI, figs. 16, 17, 18; and Plate
LXIII, figs. 9, 10.
Cells small, smooth, of nearly equal length and breadth;
constriction deep, sinuses narrow linear; basal angles of
semi-cells obtusely rounded, sides rounded, ends roundly
truncate; viewed from the vertex elliptic; from the side,
subovate.
Diameter 22-30 n.; length 25-35 ft.
Not infrequent in pond waters. The figs. 16, 17, should
have the ends moderately flattened.
C. pseudonitidulum, Nord. Plate XXI, fig. 19.
Varies from the preceding in its somewhat larger size and
more quadrangular form. The basal angles of the semi-cells
besides being rounded, protrude slightly.
Diameter 38 /r.
Found this form only in Northampton County, Pennsyl-
vania.
C. laeve, Rab. Plate XVIII, fig.‘10. Var. Septentrionale,
Wille. Plate XLIII, fig. 14.
Cells one and one-third to one and two-thirds longer than
broad, constriction deep; sinus narrow linear; semi-cells
with high-rounded ends, usually somewhat retuse. Cytio-
derm finely granular.
Diameter 14-16 /-<.COSMARIUM.
73
Yar. crenulatum, Wolle. Plate XIX, figs. 10, 19, is usually
smaller in size and numbering ten to fourteen crenae to a
semi cell. This variety is near C. crenatum, but is separated
by the rounded ends. The typical form is from South Caro-
lina and Rhode Island, (Bailey); the variety from ponds,
eastern Pennsylvania and New Jersey.
C. crenatum, Ralfs. Plate LX, figs. 31, 32.
Cells oblong, usually nearly twice as long as wide, deeply
constricted in the middle; semi-cells crenulate at the mar-
gins, flattened at the ends ; generally have twelve or fourteen
crenae; cytioderm punctate. Zygospore globose, studded
with protuberances which terminate with a divided apes.
Diameter 30-38 /j.
Rhode Island, New Jersey, Pennsylvania, and other States.
Not frequent, but occurs every now and then.
C. Naegelianum, Breb. (O. crenatum, Naeg.) Plate LXI, fig. 21.
Small, somewhat longer than broad, sinus narrow linear;
semi-cells, with sides sinuate-crenate, converging from the
broad flat base to the broadly truncate, entire or imperfectly
quadricrenate ends; cytioderm finely granulate or smooth.
Diameter 20 p., or a little more or less.
Not rare. Bears some resemblance to C. crenatum in front
view, but is smaller and proportionably much shorter; the
crenae of the sides are usually less in number, and those of
the ends imperfectly developed.
C. venustum, Rab. Plate XIX, fig. 31.
Length of cell equal to about 1 \ diameters; constriction
deep; sinus narrow linear; semi-cells have a flat base, rounded
lower angles, sides somewhat convergent; each with two
notches of equal size; ends truncate, and slightly retuse.
One clilorophyl mass in each semi-cell; membrane smooth.
Diameter 24-30 /a.
Occasional in ponds, Pennsylvania and New Jersey.
C. Reinschii, Arch. (Dublin Microscopical Club.) Plate XIX,
fig. 12.
Somewhat longer than broad, deeply constricted, sinus
narrow linear; ends truncate; sides convex, erose, dentate
or notched. Membrane smooth ; end view elliptic, without
a central inflation.
Diameter 30-35 /(.
Not frequent, but is found in Lake Hopatcong, N. J., and
in ponds, eastern Pennsylvania.74
PESMIDS OF THE UNITED . TATES.
C. ITolmiexse, Lund. Plate XIX, fig. 23.
Cells twice as long as wide, elliptic-rectangular, moder-
ately constricted, sinus narrow linear; semi-cell subquadrate,
sides straight or subeonvex, slightly converging until near
the somewhat dilated apices; ends obsoletely crenulate;
dorsum truncate-undulate, angles rounded. Viewed from
the vertex elliptic with the poles obtuse-angled; side view
rectangular-elliptic; membrane smooth. Chlorophyl homo-
geneous or in a single mass.
Diameter 33 //.; length 03 /<•
Collected by F. H. Hosford, Mt. Mansfield, Vt., 1881.
Differs slightly from Lundell’s figure in the crenulations,
and in being less restricted near the ends.
Var. integrum, Lund. Plate XIX, figs. 24, 25.
Differs from the typical form in having no crenulations
nor plications near the apices, and no undulations on the
ends.
Diameter 32-36 jj.
Mountain spring, Rockdale, Pa.
C. Ansatum, Kg. Plate XIX, fig. 22.
Cells twice as long as broad; constriction wide but not
deep; semi-cells have a flat base, rounded lower angles, sides
converging, concave; ends truncately rounded; membrane
punctate; end view oval.
Diameter 28-31 ju.
Ponds, Pennsylvania, rather rare.
Scarcely separable from a variety (fig. 2S) of C. Holmiense,
except by the punctate membrane and the usually wider
sinus; the latter is not correctly represented in fig. 22, should
be two or three times wider and not quite so deep.
C. pyramidatum, Breb. Plate XVII, figs. 16, 17.
Cells scarcely twice as long as broad, suboval; constric-
tion deep, linear; semi-cells pyramidal, rounded at basal
angles, sides convex, gradually converging to the somewhat-
truncate ends; punctate; end view broadly elliptic.
Diameter 50-85 )x.
A common species found probably in every State of the
Union.
"Var. stenonotum, Xord. Plate XVII, figs. IS, 19.
This subspecies is separated from the typical form by the
shape of the sides of the semi-cells, which are somewhatCOSMAHJUiM.
75
retuse near the apices; for perfect identity the ends ought
not to be retuse; my specimens are slightly concave.
Size about the same as the typical plant.
Found this variety in collections made by Miss E. Butler,
Minneapolis, Minnesota, and by A. D. Balen, Plainfield,
New Jersey.
C. pseudopyramidatum, Lund. Plate XVIII, figs. 11, 12.
In habitat, in form and proportions like the true plant,
but only about half the size. It corresponds with G. pyra-
midatum, variety minus, Eeinsch; Eab. Alg. Exsic. Xo. 1902.
Besides these, Ealfs has a Forma major, which I have in-
cluded in my general grouping (fig. 17).
C. Ealfsit, Breb. Plate XVIII, fig. 1.
Orbicular or suborbicular, deeply constricted, sinus narrow
linear; semi-cells nearly semicircular; inferior angles ob-
tuse, dorsum high convex; cytioderm smooth or finely
punctate.
Diameter 60-100 p.; length 70-120 p.
Pennsylvania, New Jersey, not frequent, but turns up every
now and then, sometimes in considerable numbers.
In size, form, and arrangement of chlorophyl, this species
is often a good representative of C. Candianum, Delp.
C. pachydermum, Lund. Plate XVIII, figs. 2, 3.
Cells 11-11 times longer than broad; sinus narrow linear;
semi-cells with straight base, rounded angles; sides rise
nearly at right angles and then converge, forming a high
arch; they contain two chlorophyl masses; viewed from
the vertex, oval; isthmus wide, cytioderm firm, distinctly
punctate.
Diameter 75-100 p.
Had specimens from Budd’s Lake, New Jersey ; from Ne-
braska Notch, Vermont, collected by C. G. Pringle ; and from
Mt. Everett, Massachusetts.
This species is separated from C. Ralf&ii, by its usually
greater proportionate length, firmer cytioderm, and wider
isthmus.
C. galeritum, Nord. Plate XIX, figs. 46, 47, 48.
Cells slightly longer than wide, with narrow isthmus,
deep constriction and narrow, slightly gaping sinus; semi-
cells triangular with straight, or somewhat reniform base,
rounded lower angles, convergent, straight, or slightly con-76
DESMIDS OF THE UNITED STATES.
vex sides; ends more or less truncate; membrane smooth;
end view oval; side view circular.
Diameter 40-55 p.
Springs and ponds, Pennsylvania and New Jersey.
Fig. 47 represents a small form found in a pond on Mt.
Everett, Mass., measures only 29 /.. diameter. The smaller
size, straight sides, and more broadly truncate ends may
prove it to be a different species. I note it provisionally a
variety of the typical plant.
C. sphalerostichum, Nord. Plate XLYIII, figs. 26, 27.
Cells small, somewhat longer than broad, sinus narrow
linear; semi-cells subreniform-trapezoid, base straight; in-
ferior angles nearly right; ends in middle truncate and
nude, granulate, granules often in two or three vertical
series, often scattered, inconstant as name implies. In ver-
tical view elliptic, margins granulate; in lateral view cir-
cular, granulate. Zygospore globose or subglobose, smooth.
Diameter 13-14 p.; length 16-20 p.
New Jersey and Pennsylvania. Resembles C. orthosticum,
Lund., but is somewhat smaller, ends truncate and granules
not so regularly arranged.
C. polymazum, Xord. Plate XIX, figs. 38-40.
Cells about as long as wide, deeply constricted; sinus
narrow linear, widening somewhat outwardly; semi-cells
subelliptic, margins with about sixteen crenae, and within
the margins a concentric series of granules to correspond;
area smooth with six papillae arranged in the form of a tri-
angle, three in the first row nearest the margin, then two,
then one; seen from the vertex, elliptical, truncate at ends,
with a papilla at each angle and from these two longitudinal
series of granules; three papillae on each side (omitted in
the figure); lateral view circular, with end truncate, and two
rows of granules extending from the angles of the truncate
end of one semi-cell to those of the other; the margins of
the sides ornate with three papillae.
Nordstedt made this form, found by him in Norway, a
variety of Lundell’s C. monomazum, which has not occurred
here ; the other C.polymazum, is frequent in Denmark Pond,
N. J.
C. ocu life rum, Lagh. Plate X. figs. 7, S.
Cells small, deeply constricted, sinus inwardly and out-
wardly more or less dilated; semi-cells semicircular-trian-COSMARIUM.
77
gular, ends retuse, sides slightly convex or straight, inferior
angles obtuse; above the middle a single large granule and
below it a series of six small granules arranged in a semi-
circle, ends tending towards the retuse apex ; viewed from
apex oval, from sides subcircular. Membrane smooth.
Diameter of cell 24 /r.; length 32 u.
Poud, Tewksbury, Mass.
C. Donnellii, Wolle. Plate XIX, figs. 41, 42.
Cells nearly as long as wide, suborbicular; sinus narrow,
gaping ; semi-cells somewhat flattened, semicircular with
angles rounded; margin formed of about eighteen large
pearl-like granules; area smooth with a series of three larger
granules, or papillae in the center. End view oval, three
papillae on each side.
Diameter 37-45 yu.
Found in collections made by J. Donnell Smith in Florida,
1879.
C. taxichondrum, Lund. Plate XIX, figs. 32-34.
Cells suborbicular, slightly longer than broad ; sinus deep,
narrow, linear, barely widened at the mouth; semi-cells
semicircular, margin of base nearly straight, membrane
thickened at the angles; face ornate with a single large
granule at the isthmus, and two somewhat arched rows near
the dorsal margin, one with three and the other with five
or six granules; seen from the vertex, elliptic with five or
six granules on each side; cytioderm punctate; isthmus
one-fourth of the diameter of the cell. Chlorophyl nuclei
two.
Diameter 40-50 >i.
Occurs frequently in ponds, northern New Jersey, Penn-
sylvania and Massachusetts.
Xar. bidentueum, Lagh. Plate XLIX, figs. 17,18. Distinguish-
ing feature; in vertical view elliptic, somewhat contracted at
ends, the angles bidentate.
C. pseudotaxichondrum, Nord. Plate XLIX, figs. 22, 23.
Scarcely as long as broad, deeply constricted, sinus con-
siderably widened outwardly; semi-cells semicircular with
the middle more or less truncate or depressed; the angles
somewhat thickened and often terminating in a tooth-like
point; above the basal line is an arched transverse series of
four granules; end view elliptical with four granules on each78
DESMIDS OF THE EXITED STATES.
side; lateral view circular, with two inconspicuous granules
on opposite sides ; membrane punctate. Isthmus about one-
third of the diameter.
Diameter 30 g.
Brown’s Mills, Mew Jersey, is the only locality which has
hitherto furnished this form. The original, found in Brazil,
differs somewhat in the “sinu lineari, extrorsum vi.v ampliato,n
Our form has the sinus decidedly enlarged towards the
mouth.
G. von Lagerheim appears to give too much prominence
to simple differentiations—mere vagaries of the same species.
They may be briefly noted.
1.	C. taxichondrum, var. bidentulnm, as above.
2.	G. pseudotaxichondrum, cells more depressed.
3.	C. pseudotaxiclxonifmi, var. trichondmm, semi-cells ornate
with a single row of three granules.
4.	C. pseudotaxichondrum, var. quadridentulum; in front view,
the inferior angles bidenticulate.
5.	C. pileigerum. Merely a depauperated form of the above.
Pond, Tewksbury, Massachusetts.
C. AXISOCHONDKTJM, Ford. Plate XIX, figs. 43-45.
Cells subquadrate, length and breadth nearly equal; sinus,
narrow linear; semi-cells subsemicircular, dorsum broadly
truncate; in center two horizontal rows of large granules of
three each, and two intermediate granules below and above;
smaller granules, more scattered on each side; viewed from
the vertex, elliptic, with three larger granules on each side
and a number of smaller ones within the margin ; the middle
bare; lateral view obovate, circular. Isthmus one-third the
diameter of cell.
Diameter 30-38 //.
Denmark Pond and other ponds of northern Mew Jersey.
The original of this species was collected on the Sandwich
Islands and described by Dr. Nordstedt.
C. quinakium. Lund. Plate XLIX, figs. 10, 11.
Cells subhexagonal, about one-fourth longer than broad ;
constriction deep linear; semi-cells subtrapezoid, narrowed
toward the subtruncate apex, sides somewhat convex, infe-
rior angles obtuse, margins obsolete granulate-dentate;
within the margin a series of prominent granules, in center
five obtuse granules arranged in two transverse series;COSMARIUM.
79
membrane punctate; in vertical view elliptic granulate
around the margin ; in lateral view circular.
Diameter 33-35 p.; length 39-42 /;.
Tewksbury, Massachusetts.
C. kitchelii, Wolle. Plate XXI, figs. 1-3.
Cells suborbicular, about one-fourth longer than broad,
deeply constricted ; sinus narrow linear; semi-cells semicir-
cular, margins crenulate, with about IS crenae; within, two
concentric rows of granules corresponding with the crenae ;
area smooth excepting two, rarely three, transverse rows of
three larger granules each, in the middle; viewed from the
vertex, ovate-elliptic with three larger granules on each side,
and four series of smaller granules extending from end to
end ; lateral view circular with two granules on each side,
and four central series.
Diameter 40 p.
Collected by Rev. H. D. Kitchell in a pond near Ham-
monton, New Jersey. This species is readily recognized by
the large marginal granules, end and side view, and by the
four parallel central series of smaller granules. It bears
some resemblance to C. polymazum, but differs in the central
granules and in the double row of marginal smaller granules.
C. trachypleukum, Lund. Plate XIX, figs. 26-29.
Cells about one-fourtli longer than the diameter; isthmus
narrow; sinus narrow, enlarged outwardly; semi-cells sub-
reniform; ends truncate, nude in center; the margins of the
sides armed with five or six conical spines; the area close to
the margin, is set with numerous conical spines arranged in
short concentric series ; the middle is ornate with seven
granules, six in a circle and one in the center ; between
these granules punctate; viewed from the vertex, elliptic
with three prominent granules on each side ; within the
margin, and near it, is a series of conical granules; lateral
view circular. Chlorophyllous nuclei, two.
Diameter 33-40 p.
Frequent in ponds, eastern Pennsylvania and New Jersey.
C. triplicattjm, Wolle. Plate XXII, figs. 3-6.
Cells about one-fourth longer than broad, subrectangular ;
angles obtuse ; sinus between the semi-cells linear; margins
irregularly granulate crenate ; membrane rough with larger
and smaller granules : the larger ones arranged in series of
three; three on the margin of each of the three superior80
DESMIDS OF THE UNITED STATES.
rounded angles, three within the margins, and three near
margin between the angles (sometimes the granules appear
to border the whole semi cell); on the margin of the sides
near the inferior angles two larger granules, and within the
margins a few scattered smaller ones; end view quadran-
gular-oval, with two series, usually of six larger granules,
on each of the longer sides, one of the series on the margin,
and the other within. Zygospores .spherical, with long
spines, fig. 6.
Diameter of cell 40 p.; length about 50 p.
Ponds, Pennsylvania and New Jersey.
The nearest approach to this species is C. Ungerianum,
Naeg. It is separated by its smaller size, the details of out-
line and the arrangement of the larger granules.
C. Xordstedtii, Delp. Plate XLVIII, figs. 23-25.
Cells somewhat longer than broad, constriction deep;
semi-cell rectangular oblong about twice as wide as long,
granulate around the margins, center usually nude.
I adopt this name for a form widely distributed, but va-
riable ; sometimes it resembles C. triplicatum in size and
shape, but differs in the number and arrangement of the
granules, which are not in series of threes, but in continuous
eccentric rows. Sometimes they cover the upper half of the
semi-cell, then again only one or two rows occur within, but
close to the margin; the center and basal half are usually
nude. The sides are not so straight as figured by Delponte,
but the front and end views are always more or less rec-
tangular-oblong.
Eeinsch has named a very different form C'. Nordstedtii; it
is nearly, if not entirely, identical with C. cyclicum, Lund.
C. Seelyanum, Wolle. Plate XXI, figs. 33-35.
Cells small, quadrangular, deeply constricted ; sinus nar-
row linear; semi-cells twice as wide as long, with a small
rounded notch in the middle of the sides, the superior angles
somewhat produced laterally; dorsum slightly produced in
the middle and crenated; membrane at the superior, and at
the inferior angles and near the margin of the ends, each
with three or four granules; in the center a circular cluster
of larger granules.
Diameter 25-30 p.
Frequent in pond at Elmira, N. Y., 1882.
§ Membrane granular without a central inflation.COSMARIUM.
81
€. mrcROSPHiNCTUM, Xord. rar. paryitla, Wille. Plate XLIX,
figs. 20, 21.
Cells small, elliptic, oue-half longer than wide, moderately
constricted, sinus narrow linear; semi-cell subelliptic, apex
in vertical view broadly elliptic, granulate within the margin,
center nude ; in lateral view suborbicular. end truncate.
Diameter of cell 25 /x.; length 33 n.
Tewksbury, Massachusetts.
€. margaritiferum, Menegh. Plate XVI. figs. 1-3.
Cells about one and one-half times longer than broad, sinus
narrow, usually more or less enlarged outwardly: semi-cells
semiorbicular, somewhat reniform or oval, with rounded in-
ferior angles, convex sides and broadly rounded, not truncate
end. Cytioderm rough with pearly granules; end view
elliptic; zygospores orbicular.
Diameter 25-50 yu.
This species varies in size and form. The rough membrane
distinguishes it from crrnatum and C. umhdritum; its
rounded ends from C. Botrytis, its smaller size and less posi-
tive kidney form from C. rrnifonne. It appears to be as
widely distributed as the most common of this genus.
€. punctulatum, Breb. Plate XVI, fig. 4.
This form is very similar to C. marguvitifermi, but it is
smaller, the pearly granules less conspicuous, and the ends
more flattened. The membrane is sometimes not granular,
but punctate. It is found in the same localities, and appears
very nearly related.
Diameter of cells 20-30 y.
€. polymorphum, Xord. Plate XLIX, figs. 31-33.
Suborbicular, deeply constricted, sinus narrow linear;
semi-cells semicircular, base straight, ends truncate; two
granules above the base, three about the middle of the area ;
punctate between the two series ; granulate near the margin;
in vertical view broadly elliptic, granulate within the mar-
gin, center nude; in lateral view suborbicular, end truncate.
Diameter of cell 25 /c; length 33 /<.
C. Botrytis, Menegh. Plate XVI, figs. 5-7.
Cells one, and nearly two times as long as broad ; sinus
narrow linear; semi-cells with nearly straight base, some-
times inclining to reniform; sides converging from the in-
682
DESMIDS OF THE EXITED STATES.
ferior rounded angles to the flat, truncate end ; cytioderm
evenly covered with large pearly granules. Zygospores-
orbicular, spinous with long, thin spines, the ends much
divided.
Diameter 35-62 /a
A very common plant, and very variable in the size, and
in the proportions of length and breadth.
Var. TUMIDUM, Wolle. Plate XX, figs. 3-5.
In outline, front view, very near C. Botrytis, yet entirely
unlike it in side and end views, which show a central infla-
tion. Found it in only one locality in a meadow pool, near
Bethlehem, Pa. Further observation may prove it a dis-
tinct species.
C. Brebissonii, Menegh. Plate XYI, figs. 10, 11.
Cells somewhat longer than broad; semi-cells semiorbicu-
lar, rough with conic spines or granules; end view elliptic
or oval.
Diameter 15-65 /<.
Cells generally larger than C. mcirgaritifcrum ; semi-cells
more oval, but separable only by the armor of conical granules.
Xot so frequent as the preceding, but appears to be widely
distributed.
C. conspersuji, Balfs. Plate XVII, figs. 1, 2.
Cells somewhat longer than broad, quadrilateral, angles
obtusely rounded ; constriction deep, produces a linear notch
on each side; granules pearly, large, depressed, giving a
crenulate appearance to the margin.
Diameter 50-73 //.
A beautiful and conspicuous species, frequently found in
large numbers; it is easily distinguished by its large size and
quadrangular form.
C. C'ONSPERStnr. var. retusum, Wolle. Plate XLVI, fig. 5.
(Comp. Des. U. S., p. 75.)
Unlike the true form in the depressed or retuse ends;
sides also incline inwardly from the base of the semi-cell to
the end.
Diameter averages the same as the type-forms.
Ponds, Minnesota.
C. tetrophthATAic.M, (Kg.). Breb. Plate XYI, fig. 13.
Cells one-third to one-half longer than broad; semi-cells
semiorbicular somewhat elevated, rough with pearly granulesCOSMARIUM.
83
which give a crenate appearance to the margin ; chlorophyl
masses two, often very conspicuous.
Diameter 60-78 /<.
Rather common. The semi-cells are usually near in form
to two-thirds of a circle. The transverse view is broadly
elliptic. The four chlorophyl nuclei, which are frequently
very prominent, two in each semi-cell, probably suggested the
name, four-eyed.
0. Paedalis, Cohn. Plate XLIX, figs. 3-5.
Cells suborbicular or subquadrate, equal or slightly longer
than broad, constriction narrow linear or often somewhat
dilated inwardly, and more or less ampliated outwardly ;
semi-cells transversely oblong, subreniform; base and vertex
truncate or concave, angles inferior and superior rounded ;
lateral view suborbicular; vertical view oblong, sides
straight; membrane verrucose, verrucae (papillae) obtuse,
regularly arranged in diagonal rows.
Diameter 54-57 y.; length 75-SO	; thickness 39 p.;
isthmus 18-20
Lagerheim reports this African plant from Tewksbury,
Mass. It has not come under my notice. Looks like a close
relation to some form of C. conspersum. The figures repre-
sent a front, a lateral and a transverse view, copied from
Cohn’s figures.
C. intermedium, Delp. Plate XVI, fig. 12.
Cells very near the preceding (C. tetrophthalmum), some-
what smaller, semi-cells more absolutely semiorbicular, not
so elevated.
Diameter 45-50 /(.
Habitat same as the preceding.
C. dentatum, Wolle. Plate XVI, fig. 15.
Cells about one-half longer than wide; constriction deep,
forms gaping sinuses ; cytioderm rather closely set with small
pearly granules; the margins of the rounded sides of the
semi-cells dentate with large and distant conical projections,
or teeth ; ten to twelve on each side. The ends broadly
rounded are devoid of projecting teeth. End view of cell
oval; lateral view elliptic with a constriction in the middle.
Diameter 90-100 //.; length 145-160 //.
This plant has hitherto been found only in Pennsylvania,
New Jersey, Florida and Massachusetts.
It is separated from C. ovale, its nearest kin, by the shape
of the semi-cells, which are not triangular, or conical, but
broadly oval, and by the nudity of the apices.84
DESMIDS OF THE EXITED STATES.
C. latltji, Breb. Plate XVI, fig. 14.
Large, slightly longer than broad: constriction deep,
sinuses narrow, somewhat enlarged within ; semi-cells broad
reniform, sides rounded, and back (dorsum) broad, rather
flatly rounded, margins dentate-crenulate; cytioderm cov-
ered with pearly granules which are disposed in curved,
concentric series.
Diameter about 60 p.
Bears a resemblance to C. margwitiferum, but it is some-
what larger ; and according to Brebisson, more flatly rounded
in the middle, and base more reniform. Find it rather rarely
intermingled with other forms, and sometimes question the
characters for a good species.
C. RENiFOKME. (Balfs), Arch. Plate XVII, figs. 10, 11.
A diagnosis of this species would not differ from the last,
C. latum, except in the size of pearly granules, which are
nearly twice as large, ( well shown in the empty cell fig. 11)
and in the more decided reniform figure of the semi-cells.
The only habitat hitherto found for this form is a pond in
Florida ; collected by J. Donnell Smith, of Baltimore, Md.,
1879.
0. oohthodes, Xord. Plate XVII, figs. 3, 4.
Cells one and one-half times longer than broad, somewhat
elliptic-oblong, deeply constricted, sinuses narrow linear;
semi-cells semicircular or subtriangular, sides convex ; apices
truncately rounded, or frequently slightly retuse in center;
margins densely crenated ; viewed from the vertex, elliptic,
from the side, obovate. Membrane densely verrucose, ver-
rucae large, depressed, arranged in subregular or concentric
series.
Diameter 52-70 p.
Hitherto have found this variety only in eastern Pennsyl-
vania. The original of the species was found in northern
Sweden, and described by O. Nordstedt; it bears the resem-
blance to C. Botrytis, and C. tetrophthalmian, but differs in
the form of the verrueae which are short cylindrical truncate;
in tetrophthalmum the verrueae are triangular hemispherical
obtuse, and in C. Botrytis triangular with subacute apices.
C. Portianum, Archer. Plate XVII, figs. 12-14.
Cells about one-third longer than broad, deeply constricted;
semi-cells oval, remote, separated by a wide sinus); isthmus
about one-fourth the diameter of the cell, membrane granular.
Diameter 25-33 p.COSMARIUM.
85
Frequent in ponds, Pennsylvania, New Jersey, Massachu-
setts, Minnesota and Connecticut.
C. orbiculatum, Ealfs. Elate XVII, figs. 20, 21.
Twice as long as wide ; semi-cells spherical, connected by
a narrow isthmus ; cytioderm covered with large granules.
Zygospore, according to Ealfs, orbicular, studded with large
verrucae.	>
Diameter 20-33 p.
Met with it frequently in ponds of New Jersey and Penn-
sylvania.
0. EXCAVATUM, Nord. Yar. duplo major, Lund. Plate LXIY,
figs. 14, 15.
Cells nearly twice as long as wide, constriction wide and
deep; end view orbicular; semi-cells subspherical with trun-
cate base ; verrucae of membrane, producing a crenulate
margin.
Diameter 21-25 //.
Not rare in ponds, Pennsylvania, New Jersey, etc.
Wille, of Norway, describes a form “elliptic",” most nearly
allied to ours in front view, but elliptical in end view. Nord.’s
and Lund.’s described forms are orbicular in end view.
Yar. teigonum, Lagh. Plate XLIX, figs. 24. 25.
Cells in vertical view triangular, sides straight, or some-
what convex, angles rounded.
Diameter of cells IS length 20 /<.; thickness 18 /;.
Tewksbury, Massachusetts.
C. suborbiculare, Wood. Plate XXYII, fig. 24.
Cells small, a very little longer than broad, with the margin
irregularly crenate, or crenate-undulate; semi-cells from the
side orbicular, from the vertex elliptical; sinus very narrow,
but within somewhat excavated; cytioderm thick, sparsely
coarsely granulated; granules subdistant, in each cell ar-
ranged in one or two curved marginal series and in a central
group of two or three short rows.
Diameter 30 yu.; length 33 yu.
Saco Lake, New Hampshire, (Lewis).
C. amoenum, Breb. Plate XVII, figs. 5, 6, 7.
Cells twice as long as broad, sides parallel, ends rounded ;
constriction deep, linear; semi-cells rough with large, obtuse,
papilla-like pearly granules; side view much compressed,
about thrice as long as broad; semi-cells contain two chlo-
ropliyl nuclei.86
DESMIDS OF THE UNITED STATE.'.
Var. TUMIDUM. \Yolle. has the sides, front view, not parallel,
but swollen or rounded.
Diameter 20-25 u.
Rhode Island (Olney), Florida (Bailey).
Frequent in Pennsylvania, New Jersey, Massachusetts.
C. ORTHOSTICUM, Lund. Plate XXI. figs. I. 5.
Cells slightly more in length than the diameter, deeply
constricted, sinus narrow linear ; semi-cells subelliptic, sides
rounded, base and dorsum nearly straight, coarsely verru-
cose; verrucae in 6-S vertical series; from the vertex elliptic;
verrucose on or near the margins, area punctate; from the
side, circular. Chlorophyl nucleus single.
Diameter 20-30 ft.
Ponds, northern New Jersey and Mount Everett, Mass.
C. elegantissimum, Lund. Plate XYII, figs. 8, 9.
Cells two to two and oue-lialf times longer than broad,
perfectly cylindrical, ends arched: slightly constricted;
viewed from the vertex, circular; margins verrucose-crenate;
membrane with emargiuate verrucae disposed in twenty-two
longitudinal series, of which about nine are visible in front
view; these are arranged transversely also, in eight or nine
series on each semi-cell; the same contains two clilorophyl-
lous nuclei.
Diameter 29-33 ft.
I found this plant in collections made in Florida ; it differs
somewhat in size from Lundell’s Swedish form, being more
variable in length, varying from two to three diameters ; the
number of longitudinal series, if actual series, is greater than
specified ; the transverse series agree.
C. notabile, Breb. Plate XIX, fig. 11.
Length of cell nearly equal to two diameters, margins
somewhat undulate-crenate. ends broadly truncate; semi-
cells, base somewhat reniform, sides con verging from the
base to the broadly truncate end ; angles rounded : cytioderm
smooth or finely granulate.
Diameter 25-30 ft.
Met with rather rarely in shallow pools and on dripping
rocks.
C. Hajimeri, Eeinsch. Plate XXL figs. 27, 36-38.
Small, smooth: semi cells in form of a truncate cone, the
end either straight or slightly retuse, the sides rounded
below and slightly concave above; the truncate ends aboutCOSMARIL'M.
87
one-half the diameter of the cell; end view usually a regular
ellipse; lateral view of cell oblong with central constriction.
Diameter 20-24 /(.
Frequent in ponds. Reinscli describes several forms; a
larger and a smaller size, one with straight ends, another
emarginate ; end view usually elliptic. Among our varieties
I find one with inflated center ; of eleven drawings made in
my sketch book nine are without central inflations, and two
with them, the latter even more inflated than the variety
retusiforme, found in Norway, and described by Wille.
C. Nymannianum, Grun.
Cells somewhat hexagonal, finely punctate; semi-cells
slightly broader than long; base rather flat, sides converging
from the base to the broadly truncate end, lower part promi-
nently rounded, sinuate near the end; apex often refuse.
Diameter 36-3S /<.; length 50 /./., more or less.
In front view, this is a common form, barely sepai-able from
the following — C. sublobaturn; in lateral, and in end view
however, they ought to be distinct by the absence or the
presence of a central inflation. All the specimens examined
personally evidenced more or less of an inflation, or at least
a tendency to it; have not been convinced of having a genu-
ine C. Nymcmnianum. I set them down to C. sublobatum.
Semi-cells with central inflation; cytioderm smooth or punc-
tate.
G. Turpinii, Breb. Plate XX. figs. 24, 25.
Cells of equal length and breadth; constriction deep, forms
a narrow linear or acute-augled sinus, outwardly ampliated ;
semi-cells triangular, lower angles rounded, apex truncately
rounded; sides somewhat concave; central inflation granu-
late, and sometimes emarginate ; cytioderm finely granulate
or punctate.
Diameter 55-70 j-t.
Not rare ; frequently in large numbers in ponds, New Jer-
sey, Pennsylvania and other States.
C. sublobatum, Archer. Plate XXI, figs. 21, 22.
Cells somewhat oblong, about one-half longer than broad,
sinus linear; semi cells swollen at the base, gradually nar-
rowed toward the truncate ends; inferior and superior angles
rounded; apex broadly truncate, sides sinuate; with central
inflation.
Diameter 38-44 y.
Ponds, Pennsylvania, New Jersey; not abundant, but
probably widely distributed.88
DES.MIDS OF THE UNITED STATES.
C. BETUSOi, Perty. Plate XXI, figs. 25. 26.
Small, of nearly equal length and breadth, entire; sinus
deep, linear: semi-cells with subreniform base, sides sinuate
and converging to a truncate end; angles rounded; end
view centrally protruding.
Diameter 22-30 p.
Pennsylvania and New Jersey.
C. maegaeitum, Wolle. Plate XXII. figs. 25. 26, 27.
Suborbicular, from one to one and one-third times as long
as wide; sinus narrow linear; semi-cells somewhat semi-
circular, margins undulate crenate. or emarginate ; two or
three surface swellings near the base which cause prismatic
reflections from the smooth pearl-like membrane.
Diameter 22-25 p.
Found the first of this form in Splitrock pond, Xew Jersey,
but occasionally since in other localities of the same State,
and in Pennsylvania.
C. tithophoku.u, Xord. Plate XXII. figs. 28. 29, 30.
Cells about as long as wide, circular, deeply constricted ;
sinus an acute angle considerably ampliated (angle about
20°); semi-cells from the base cuneate-semicircular; end
view elliptical with a prominent central elevation: laterally
seen, obovate-c-ircular with a mamilliform prominence on
each side.
Diameter 28 p.; length 30 p.
Collected this form from ponds on Mount Everett, Mass. It
corresponds so nearly with a plant found on the island of
Java, described by Dr. Xordstedt, I adopt the name as his
choice.
C. homalodeemum. Xord. Plate XX. fig's. 19, 20.
Slightly longer than broad, deeply constricted; sinus
narrow linear with the mouth considerably ampliated ; semi-
cells trapezoid with a subreniform base : sides refuse: ends
truncate, and often refuse; superior angles obtuse, inferior
broadly rounded: seen from the vertex, elliptic-oblong with
the middle somewhat inflated; lateral view ovate. Ends
about half as wide as the breadth of the cell. Cytioderm
finely, often indistinctly, punctate.
Diameter 40 p.
Ponds, Mount Everett, Mass.
The typical plant was found in the Arctic region, on the
island of Spitzbergen. It is described by Dr. Xordstedt as
measuring 48—51 u. in diameter, about one-fifth larger than
our plant; hitherto found only in one locality, ltsl and 1882.C'OSJIARIUM.
89
C. cruoiatum, Breb. Plate XXI, figs. 23, 24.
Length and breadth nearly the same, ends broadly trun-
cate; deeply constricted; sinus narrow, enlarged outwardly;
semi-cells trapezoid-reniform, inferior angles obtuse; sides
incline towards the truncate end ; margins somewhat crenate.
Two nuclei in each semi-cell; membrane finely granulate or
punctate.
Diameter 22-24 pi.
Swamp and marsh pools ; rather rare.
C. Phaseolus, Breb. Plate XXI, figs. 28-32.
Cells about as long as wide, smooth; constriction deep,
forming a linear, excavated, notch on each side; semi-cells
reniform; end view elliptic with a slight projection in the
middle of each side.
A common species to be found, probably in every State of
the Union.
C. birejie, Xord. Plate XXII, figs. 23, 24.
Small, about as long as wide, deeply constricted, sinus
wide at the mouth ; semi-cells elliptic, base and back some-
what truncate; in the center a large verruca; viewed from
the end, elliptic, with a prominent cylindrical verruca in the
center of each side; lateral view, obovate furnished with a
similar verruca. Membrane smooth.
Breadth 13 pi.; length 14 pi.
Denmark Pond and Budd’s Lake, N. .1.
0. Scrliephackeanum, Grun. Plate XXL figs. 14, 15.
Very small, subquadrate, as broad as long, smooth, entire,
deeply constricted; semi-cells depressed, ends broadly
truncate, or plane-convex ; sides convex, often projecting at
an obtuse angle; center more or less inflated.
Breadth 12 pi.; if not equal, slightly less in length.
Occurs occasionally in large numbers, but more frequently
it is found singly in ponds of Pennsylvania, New Jersey,
Massachusetts, Minnesota.
jj Cells with a central inflation, membrane granular.
C. ornatum, Ralfs. Plate XXI, figs. 39-45; Plate LX, figs.
22-24.
Cells of nearly equal length and breadth, constriction
deep, narrow; semi-cells with a somewhat reniform base,
angles broadly rounded, end truncate; sides inflated below,
and contracted and concave near the end, thus producing a90
PESMIDS OF THE UNITED STATES.
truncate projection which in end view forms a rounded lobe;
membrane rough with pearly granules which give a dentate
appearance to the margin.
Diameter 33-45 p.
Not uncommon ; probably no form is more generally dis-
tributed throughout the earth. It is variable in size, in the
arrangement of the central granules and in the projection.
Tar. protractum. Plate LX, fig. 22 ; Plate XX, fig. 29.
The figure (Plate LX) represents a form collected July,
1883, by my friend, Dr. Kitchel, in Lake Minnetonka, Minn.
He found it freely intermingled with the typical form (fig.
23). It is in all its parts, except the more protracted ends,
so like the true form, I consider it merely a variety of C.
ornatum. Plate XX, fig. 29, is a good representation of C.
protraction, Xaeg., but the specimens, found in large num-
bers, clearly show their connection with C. ornatum. Com-
pare note under C. protractum.
C. Laoexse. Xord. Plate XLIX, figs. 26, 27.
Semi-cell in vertical view, in the middle much swollen
and the ends inflated, granules large; center smooth. It
is an exaggerated development of C. ornatum and hence a
variety of it.
Tewksbury, Massachusetts, and not infrequently in New
Jersey ponds.
C. Sportella, Breb. Plate LX, figs. 28-30.
Very nearly as long as broad, deeply constricted; semi-
cells subreniform, sides somewhat dilated and rounded, end
broadly truncate, margins erose-spinous or denticulate;
eytioderm granular.
Diameter 33-36 /(.
Harvey Lake, Luzerne County, Pa. Bears some resem-
blance to C. ornatum, but ends do not protrude ; granules are
more spinous than rounded, producing the erose appearance
of the margins. Found many specimens in this one locality,
but did not recognize the form elsewhere.
C. protractum. (Xaeg.), Archer. Plate XX, figs. 27-28.
But slightly longer than wide, constriction deep, sinuses
narrow linear, often ampliated from the acute angles; semi-
cells with tumid base, twice as broad as long, angles rounded,
sides deeply sinuate below the truncate end. Viewed from
the vertex, elliptic with a central inflation; membrane
granular.
Diameter 70-80 /<.COSMAEIUM.
91
The plants recognized by different authors as of the present
species, by their protracted ends of the cells, are very variable
in size and detail of form. Plate XX, figs. 27, 28 represents
the true form ; from pools in marshy grounds, Pennsylvania.
Fig. 29 is another form, less than half the size, found in num-
bers in a pond near Branchville, Sussex County, N. J. Plate
LX, fig. 22, is a third variety from Minnetonka Lake, Minn.,
intermediate in size, but so closely related to C. ornatum in
size, form, and arrangement of granules, I call it a variety of
that species. The other (fig. 29) is evidently of the same
connection, hence I transfer it from the position given it by
Naegeli to companionship with the latter.
C. commiserate, Breb. Plate XXI, figs. 49-51.
Semi-cells short reniform, three times broader than long,
rough with pearly granules; end view with a constriction
between the central inflation and the extremities.
Diameter 34-38 jj. ; length 25-30 //.
Sparsely found in ponds in Pennsylvania, New Jersey, New
Hampshire, and probably most of the States.
C. subcrenatum, Hantzsch. Plate XXI, figs. 6, 7; Plate XXII,
fig. 20.
Cells with apices or ends more or less distinctly quadri-
crenate, sides with (4-) 6 crenae; within the margins three
or four series of granules; the swelling near the basal line
has usually five short series of granules; viewed from the
vertex, elliptic, apices truncate-retuse, sometimes rounded ;
on the swollen middle are often seen five prominent granules;
lateral view, ovate, with basal swellings and truncate ends.
Diameter 20-26 ju.; length 23-36 ju.
Ponds, and sluggish streamlets, Pennsylvania, New Jersey,
Massachusetts, Minnesota.
C. erotuberans, Lund. Var. granulatum, Wolle. Plate
LXII, figs. 13, 14, 15.
Cells about one-fifth longer that broad; constriction deep,
narrow linear; semi-cells nearly twice as wide as long, base
straight, sides somewhat diverging from the basal line;
superior angles nearly right, inferior angles obtuse ; near the
middle of the cell is a small granulated tumor; seen from
the vertex elliptic with a central swelling on each side;
lateral view nearly spherical; membrane granular.
Diameter 25-28 /<.
From a small pond near Minneapolis, Minn. This desmid
is evidently not-the same as found in Sweden and described92
DESMIDS OF THE EXITED STATES.
by Lundell, but it possesses the principal feature, the “protu-
berans” derived from the excess of the diameter of the end
of the semi-cell over the measure of the base. It differs in
the less prominent central inflation, and in having the mem-
brane granular, not punctate. Kirchner describes a new
species, C. pseucloprotuberans, which has no central inflation,
no granules nor puncta.
C. Quasillus, Lund. Plate XX, figs. 13, 14, 15.
Somewhat longer than broad, constriction deep, sinus
linear. Semi-cells trapezoid, narrowed from the broad,
straight base to the truncate end; sides, below, granulate
dentate, above undulate; end slightly undulate; angles, in-
ferior and superior, obtusely rounded; cytioderm coarsely
granulate, the verrucae in subconcentric lines; end view
shows a basal, granulated protuberance.
Diameter 60-70 g.; length 66-75 /<.
I found this form first in the vicinity of Bethlehem, Pa., in
the year 1S77, and then described it in the “ Bulletin Torrey
Bot. Club,” of New York, Yol. VI, p. 186, as a new species,
C. irregulare, in reference to the irregular size of the crenae
of the sides. Later researches revealed Lundell’s earlier de-
scription.
Since 1877, have found the same plant in various localities
in Pennsylvania, Massachusetts and Xew Jersey.
C. Eveeettex'se, Wolle. Plate XX, figs. 10, 11, 12.
Cells as long as wide; constriction deep ; sinus linear, often
much ampliated; semi-cells with ends broadly rounded, or
truncate, sides convex; membrane rough with large verrucae
arranged in concentric series; apex usually nude, surrounded
by short, acute, conical teeth ; end, and transverse view
show a decided central inflation.
Length and breadth, 50-52 /(.
Ponds, Jit. Everett, Mass.
C. Eloiseanum, \Yolle. Plate XXII, figs. 1, 2.
Cells large, one-tliird longer than broad; constriction
forming a deep, linear, outwardly widening sinus on each
side; semi-cells semicircular, margins set with long pointed
teeth or aculei; center inflated and granularly rough, inter-
mediate area smooth or punctate; end view oval with a
granular tumor on each side, and two somewhat converging
series of teeth or aculei extending from end to end.
Diameter 75 /<.; length 100 g.COSMARIUM.
93
A species originally found in Minnesota, by Miss Eloise
Butler, now turns up also in New Jersey, Splitroek Pond, and
more recently Mr. W. N. Hastings has been collecting fine
specimens near Rochester, New Hampshire. The specimen
represented, Plate XXII, is an old form and caused too many
teeth to be illustrated. A single series on the periphery of a
semi-cell does not exceed 23-25.
0. Broomei, Tliwaites. Plate XX, fig. 6-9.
Usually as long as broad, sometimes slightly longer,
obtuse-quadrangular; sinus narrow linear; semi-cell oblong-
quadrangular, twice as broad as long, angles, inferior and
superior, obtusely rounded, base plane, end broadly truncate
and often slightly retuse, or moderately convex; end and
side views evidence a distinct central inflation; cytioderm
rough with pearly granules arranged in suberect lines.
Diameter 30-45 /.<.
Appears to be entitled to the term “ common.”
C. Pseudobroomei, Wolle. Plate LXII, fig. 36, 37.
This new species is in all its details of structure like the
preceding, but entirely devoid of a central inflation.
Diameter 30-45 y.
Wood Lake, northern New Jersey, furnished scores of
specimens of this species the past Summer, 1883.
C. biretum, Breb. Plate XX, figs. 1. 2.
Subquadrangular or polygonal; a deep constriction forms
a narrow linear sinus ; semi-cells obtuse-quadrangular, with
subreniform base, and end broad, subplane-convex, dilated;
cytioderm rough with pearl-like granules arranged in con-
centric series; end view shows a prominent central swelling.
Diameter 55-60 yu.
Rather rare, singly among other Algce, but occasionally in
quantities. Had a cluster of Ocdogonhim from a sluggish
stream near Closter, N. J., literally covered with specimens
of this species.
Yar. Feoridense, Wolle. Plate XLVI, fig. 6.
Differs from the typical form in its somewhat larger size,
but principally in the retuse ends.
Diameter 70 y.
Frequent along the shores of lake at Kissimme, Florida.
C. caeeatum, Ralfs. Plate XXI, figs. 46, 47, 48.
Suborbicular, deeply constricted, sinus narrow linear;
semi-cells subsemicircular, diameter equal to twice the91
DES-MIDS OF THE UNITED STATES.
length ; margins scolloped or broadly crenate, with four cre-
natures at the end, one on each side at the base, and one
intermediate between it and the end; the lateral, basal ones
are the largest; membrane sulcated between the crenatures;
rough with pearly granules; end view oval, somewhat in-
flated at the middle.
Diameter 40 /<., more or less.
A distinct species which turns up frequently in smaller
numbers.
C. quadrifariuji, Lund. Plate XX, figs. 16, 17, 18.
About one-fourth longer than broad, deeply constricted,
sinus narrow linear; semi-cells, semicircular: inferior angles
nearly right; margin composed of 17 emarginate-truncate
verrucae; within the margin a similar series ; basal tumor
orbicular, furnished with 12-17 larger granules; viewed
from the vertex, elliptic, with a granulated tumor on the
middle of each side, and four series of granules extending
from end to end ; lateral view has a granulated swelling on
each side and four granules on the end terminating four
series. Two ehlorophyllous nuclei in each semi-cell.
Diameter 33-36 //.; length 40-44 /<.
Frequent in ponds, Alt. Everett, Mass.
C. Kjellmanii, Wille. Plate LX. figs. 19, 20, 21.
Xearly equal iu length and breadth, deeply constricted in
the middle, sinus linear with mouth considerably ampliated;
semi-cells cordiform, sides nearly straight, or low convex;
apex truncate with four or six light crenulations; the sides
each with six indentations; granules arranged in radiating
lines, none in the center, but a basal tumor has five vertical
series of granules; observed from the vertex the semi-cells
are narrow elliptic, with a tumor on each side.
Diameter 20-25 yu.
Wood Lake, Sussex County, New Jersey.
C. stjbcruciforme, Lagh. Plate XLIX, figs. 12-14.
Small, somewhat circular, the constriction introrsely and
extrorsely ampliated ; semi-cells reniform, the end rounded,
not crenulate; angles rounded verrucose with margins den-
ticulate; a central inflation granulate; in vertical view
subcruciform, angles granulate; in lateral view ovate-cir-
cular. Membrane punctate.
Diameter of cell 32 /J. ; length 36 //.; thickness 25 u.COSMARIUM.
95
Reminds one of C'. ornatum, Focke, and also of C. subreni-
forme, Nord.
Tewksbury, Massachusetts.
C. Blyttii, AVille. Plate XXII. figs. 31,* 32, 33.
Small, somewhat longer than broad; semi-cells subreni-
form, apex truncate with four crenulations; sides erose-
crenate (crenae three); semi cells within the margin, granu-
late, granules arranged in two series of about fourteen and
nine; in center a small prominence. Lateral view circular
with a papilla on each side; end view elliptic, with a promi-
nence or papilla on each side.
Diameter 14-15 /(.; length 17-18 //.
Waters of Sussex County, N. J. ; Longwood Pond ; Wood
Lake.
C. speciosum, Lund. Plate XXII, figs. 7, 8, 9; 14, 15.
Cells about one and one half times longer than wide;
elliptic-oblong, constriction forms a narrow linear sinus ;
semi-cells with sides slightly convex, but moderately converg-
ing to the subtruncate end; inferior angles nearly square,
base plane; margins crenate, crenae eighteen ; within the
margins granulate; granules arranged in regularly radiating,
and concentric series ; at the base seven to eight vertical
series of smaller granules; viewed from the vertex elliptic
with a central inflation, ends crenulate; lateral view sub-
ovate : thickness of cells about one-half of the diameter of
the cell; isthmus equal to about one-tliird of the measure of
the breadth.
Diameter 33-50 /<.; length 50-75 /<.
The plants recognized as the C. speciosum of Lundell, are
usually larger than the Swedish forms, but they have the
same outline, truncate end, swollen centers, arrangement of
granules and crenulate margins.
C. supraspeciosum, Wolle. Plate LXI, figs. 5, 6.
Large, broadly oval, about one-third longer than broad,
ends truncate ; deeply constricted ; isthmus rather less than
a third part of the breadth of the cell; sinus narrow linear;
margins crenulate with thirty or more crenae to each semi-
cell ; usually about sixteen on each side and five or six on
the truncate end; ornate with large undivided granules
arranged in concentric and at the same time, radiating
series, extending from the margin nearly half way to the96
DESMIDS OF THE UNITED STATES.
center : central area nude except five or six vertical series of
smaller granules : end view shows a prominent central infla-
tion ; lateral view broadly ovate, sinuate towards the ends.
Diameter 65-70 /<.: length 90-95 //.
Occurs frequently in ponds, northern New Jersey and in
Pennsylvania.
C. Pectinoides, VTolle. Plate XXII. figs. 12. 13.
Suborbicular, somewhat longer than broad, constriction
deep, sinus narrow linear within and widening outwardly;
semi-cells semiorbicular with the angles rounded, undulate
on the margins with twenty or more crenulations; rough
with geminate rows of pearly granules symmetrically ar-
ranged in radiating and concentric lines. On green cells
the united twinned granules appear oblong and the crenu-
lations dentate ; at the base of the semi-cells the inflation is
marked with six, more or less distinct, vertical series of
smaller granules ; end and side view evidence a distinct basal
protuberance.
Diameter 45 /u. ■ length 60 //.; somewhat variable in size.
A resemblance to forms of many seaside shells suggested
the name. Not abundant, but is found frequently in smaller
ponds of Pennsylvania and New Jersey.
This form is near C. pulcherrimum, Nord., but differs in the
gaping sinus, the rounded inferior angles of the semi-cells,
the number of crenulations, and larger size.
C. Pseudopectixoides, Wolle. Plate XXII, figs. 16, 17. IS.
Differs from the typical plant in its smaller size, less num-
ber of crenulations, and absence of the series of granules on
the basal inflation ; instead the granules are scattered.
Diameter 30-35 /<.
Have this form from Florida, from the White Mountains,
N. H., and the Lehigh Valley, Pa.
C. nasutum, Xord. Plate XXII, fig. 19.
Nearly one-fourth longer than broad, constriction forms a
narrow linear sinus; semi-cells semicircular, margins ineised-
crenate, crenae eight, smooth or granulate ; cytioderm rough
with eight radiating series of granules; end view oval with
an inflation on each side.
Diameter 30-36 p.
Rare, differs from the typical, Arctic form in being smoother,
not so strongly marked with coarse granules.COSMARIUM.
97
C. pycnochondrum, Nord. Plate XXII, figs. 10, 11.
About one-fifth longer than the diameter; subliexagonal,
constriction deep, sinus narrow linear; ends truncate quadri-
crenate; angles inferior and superior obtusely rounded;
sides moderately convex with about six crenae each; at base
nine to twelve vertical, or somewhat diverging series of
granules; membranes ornate with additional granules ar-
ranged in lines, at the same time radiating and concentric ;
the former courses are double, and often triple near the
margin; central area within the concentric rows, is nude.
Seen from the vertex, or from the side, a basal inflation is
evident; thickness of the cells, equal to about half the
length; isthmus measures about half as much as the breadth.
Diameter 50 /■>.; length 79 /<.
The only locality from which I had this form is Nebraska
Notch, Vt., from collections made by C. G. Pringle. It differs
from the typical, Arctic (Spitzbergen) form in its greater pro-
portionate length.
C. PULCHERRI1UUM, Nord. Plate LX, figs. 25-27.
Cells oblong, ends rounded, about one-third part longer
than broad, margins crenulate, constriction deep, sinus nar
row linear, not ampliated towards the mouth ; semi-cells
subsemicircular, inferior angles square, basal center inflated
and furnished with about five vertical series of granules;
lateral view broadly ovate, end rounded, and base of each
side more or less inflated; membrane granulate near the
margins, granules arranged in about four to five concentric
series ; area nude between these and the vertical series.
Diameter 33 /<.; length 40 r.
This desmid is proportionately shorter than the typical
forms described by Dr. Nordstedt. The one from Brazil and
the other from the island of Spitzbergen, which measures one
and one-third to nearly twice as long as wide. My specimens
are from Minnesota, and from several localities of eastern
Pennsylvania.
C. radiosum, Wolle. Plate XXII, figs. 21, 22.
Cells orbiculate, about one-eighth longer than broad; semi-
cells semicircular, separated by a deep narrow linear sinus ;
ends round or slightly depressed, clothed with semiorbicular
granules arranged in about thirty-five radiating lines; basal
inflation has about eight vertical, or somewhat diverging98
DES.VIDS OF THE UNITED STATES.
series of granules; lateral view subreetangular oblong ; end
view elliptic with central inflation.
Diameter 50 t-i.: length 56-5S //.
Sluggish waters, Northampton Co., Pa.
Genus. TETMEMORUS, Ralfs.
Cells cylindrical or fusiform, slightly constricted in the middle,
narrowly incised at each end, but otherwise entire. Cytioderm
mostly punctate or granulate.
The cells are elongated as in Penium, from which, however,
this genus may be distinguished by the incised ends and by the
central constriction.
T. Bkebissonii. «Menegh.), Ralfs. Plate XXIII. figs. 1-2: Plate
LXI, fig. 36.
Cells in front view cylindrical, not attenuated at the trun-
cately rounded ends; in lateral view fusiform, attenuated
from the middle to the rounded ends: cytioderm striately
punctate. Cells four to sis times longer than broad.
Diameter 18-20 p.
Frequent in ponds everywhere.
Var. TURGIDUS, Ralfs. Plate XXIII, figs. 4. 5.
This variety is larger, the constriction greater, and the
semi-cells somewhat inflated. It approaches in form T.
granujatus. but is more constricted at the middle, its punctae
are arranged in longitudinal lines, and front and side views
are unlike.
Diameter 40-48 p.
T. granulates, Ralfs. Plate LXI, figs. 33. 34.
Cells five to sis times longer than broad, both in front aud
lateral views, fusiform, and ending in colorless projecting
lip-like process ; slightly constricted in the middle. Chloro-
phyl usually with a longitudinal series of large granules.
Membrane irregularly punctate.
Diameter 3S-50 n.
Frequent in ponds, and readily recognized by its figure,,
both in front and lateral views, fusiform.
T. laevis. (Kg. . Ralfs. Plate LXI, fig. 35;- Plate XXIII, fig. 3.
In front view somewhat tapering with truncate ends
lateral view fusiform ; punctae none, or very indistinct;
four to sis times longer than broad.
Diameter 20-22 /\XANTHIDIUM.
99
Not so frequent aB the preceding, but not confined to any
particular localities.
T. minutus, D. By. Plate XXIII, figs. 7, 8, 9.
Smaller than the preceding, only three times longer than
broad, membrane smooth.
Diameter 18-20 /<.
Had this species from Florida, New Jersey and Pennsyl-
vania.
T. gigantetts, Wood. Plate XXIII, fig. 6; Plate XII, fig. 1.
Very large, oblong, three times longer than broad, with
the ends not'usually attenuate but broadly rounded; suture
profound, linear; cytioderm irregularly granulately punc-
tate ; somewhat plicate at the base of the semi-cells; cells
often contracted near the end.
Diameter 75 /a. more or less.
Ponds, Pennsylvania and New Jersey.
Genus, XANTHIDIUM. Ehrb.
Cells single or geminately concatenate, inflated, profoundly
constricted; semi cells compressed, entire, spinous, protruding
in the center as a rounded, truncate, or denticulate tubercle.
Cytioderm firm, the spines with which it is armed, simple or
bi-tri-furcately divided at the ends. Zygospores globose, smooth
or spinous.
X. armatum, (Breb.;, Ralfs. Plate XXIY, figs. 1-4.
Semi-cells largest at the base, about as long as broad, armed
with numerous, short, stout spines terminated by two, three
or more diverging points.
Diameter 62-140 /a
Very variable in size. Fig. 1 is a finely developed form
from Mt. Everett, Mass. The other two are more usual
varieties found in all the States with which I had any com-
munication.
This is the only species with spines divided at the apex.
Wood has two more, as X. nrctiscon and X. coronation, but
these must be separated from this genus, and placed with
Staurastrum.
The following have subulate spines:
X. ACULEATUM, (Ehrb.), Breb. Plate XXVI, figs. 10, 11, 12.
Spines subulate, more or less scattered ; central projection
truncate, obscurely dentate.
Diameter 62-70 /.i.100
DES.MIDS OF THE UNITED STATES.
Prof. Bailey reports this species from South Carolina,
Georgia and Florida.
X. Columbian cm. Wolle. Plate XLY, figs. 10, 11.
Cells about one-third longer than wide ; divided by a deep
constriction forming much ampliated. acute-angled sinuses;
semi-cells oblong hexagonal, superior and lateral angles each
produced into a firm aculeus ; within the margins, four, often
indistinct, aculei; end view more or less regular hexagonal,
each angle somewhat produced and surmounted by a firm
aculeus; within the margin are four aculei, the ends of which
often extend over the margin ; cytioderm smooth.
Diameter 60 p.; length So p., without aculei.
Pond, Ocean County, New Jersey.
X. BISEN A El um, Ehrb. Plate XXVI. figs. 7, S, 9.
Cells in front, view broader than long; constriction deep,
sinus acute angled; spinous; spines subulate, marginal, gem-
inate; central projection somewhat truncated and margined
with pearly granules.
Diameter 65-73 p.
West Point, N. Y. iBailey.)
Ralfs suggests that this is the same as his X. Brebissonii.
The number of spines appears to be variable. Bailey and
Ehrenberg’s figures have six pairs of spines. Brebisson’s,
eight; whilst some British specimens have ten to each semi-
cel).
X. ckistatum, (Breb.), Ealfs. Plate XXIV, figs. 5-8.
Semi-cells with a solitary spine on each side at the base,
the other spines geminate, in four pairs. Central protuber-
ance, short conical.
Diameter 40-55 p.
Pennsylvania, New Jersey, South Carolina, Georgia, etc.
X. asteptum. Xord. Plate XXIV, figs. 9. 10, 11.
About one-fourth longer than wide ; semi-cells octangular-
oval, or truncate-triangular, with two diverging, somewhat
curved, subulate spines on each side, and two geminate spines
at each of the two superior angles. Cytioderm smooth or
punctate.
Diameter 40-48 p. without the spines.
Rather rare ; quiet waters, Pennsylvania and New Jersey.XANTIIIDIUM.
101
X. easciculatum, (Ehrb.), Ralfs. Plate XXV, figs. 4, 5.
Semi-cells with four, rarely six pairs of long, subulate,
marginal, spreading spines ; central projection, minute coni-
cal, not beaded.
Diameter 55-65 //. without the spines.
Var. hexagontim, Wolle. Plate XXVI, fig. 5.
Large angular, with four pairs of short subulate spines.
Var. minus, Wolle. Smaller in size, and spines short.
Plate XXV, figs. 6, 7, front and lateral view of a semi-cell
which appears to develop a sporangium without copulation.
T found but one specimen of the kind, and record it as a
peculiar abnormal act.
Var. subalpinum, Wolle. Plate XLV, fig. 9.
Prof. Delponte, in his Desmijdiacearum Subalpinabum,
p. 168, describes this species differently from that described
above, the variation being mainly in the wider separation
of the lateral spines. To distinguish the two I make the
above variety.
Not rare in ponds, New Jersey and Minnesota.
X. antilopjeum, (Breb.). Kg. Plate XXVI, figs. 1, 2.
Differs from the preceding in smaller size than the typical
X fasciculatum, and in the reverse curvature of the lateral
spines.
Diameter 45-50 p.
Var. polymazum, Nord. Plate XXVI, figs. 3, 4.
LTnlike the true form in the series of bead-like granules
over the central protuberance.
Var. triquetrum, Lund. Plate XXV, figs. 1, 2, 3.
Instead of an oval, end view, this is triangular, similar to
■ a form discovered by the author < Lund.) in Sweden, and to
another from Brazil, described by Dr. Xordstedt.
The only locality for this variety, hitherto found, is a trench
near Quakertown, Bucks County, Pa. The other forms may
be called common.
Var. Minneapoliense, Wolle. Plate LXIII, fig. 16.
A new form from Minneapolis, Minn., possessing the pe-
culiarity of a fifth pair of aculei immediately over the central
protuberance and bead-like series of granules.
Var. truncatum, Hast. Plate XLII, figs. 3-5.
Front, lateral and end views. Same as X. Tijlerianum,102
DESMIDS OF THE UNITED STATES.
West. The former was published a year earlier than West’s
name, hence stands by right of precedence.
This variety differs in having the spines at the superior
angles deflected horizontally and continuous with the margin
of the truncate or slightly convex ends of cell.
Ponds and streams, ^Rochester, New Hampshire, and Am-
herst, Mass.
Yar. Canadense, Joshua. Plate XLIII, figs. 2, 3.
Front and end views. Cytioderm minutely punctate, pos-
sessing no protuberance or granulation, resembling the var.
Minnmpoliense in the possession of a fifth pair of spines, the
extra pair in the center of each semi-cell.
Pic-tou, Nova Scotia.
Diameter of cells (S. acul.) 45-50 u. of all the varieties.
X. RECTOCORNTTTUM, Wolle. Plate XXV, figs. 10, 11.
Cells as long as wide; constriction linear, sinus sometimes
slightly excavated, and sometimes gaping; semi-cells semi-
circular, finely punctate or smooth ; two rows of beads above
the central protuberance, the one with 6-10, and the other
under it with half the number; another series of beads on
the base forming a ring around the isthmus; ends broadly
rounded, nude; basal angles with two pairs of aculei, or sub-
ulate spines; the one horizontal, the other vertical; trans-
verse view somewhat in the form of an hourglass, truncate,
crenate at the ends with two vertical aculei in the center.
Diameter without spines, 55-60 p.
Frequent in ponds, Mount Everett, Mass.
This species differs from A', antiiopceum in having the ends
of the cells bare, the upper pairs of spines not incurved nor
divergent, but erect, straight, attached to the sides, and
springing from the basal angle. It is also quite unlike that
species in the three series of beads, and in its transverse view.
X. tetracentrotum, Wolle. Plate XXY, figs. S, 9.
About as long as broad, smooth, constriction deep, sinus 1
enlarged outwardly; semi-cells subreniform or subhexagonal,
base somewhat convex, ends broadly rounded ; basal angles
on each side armed with a pair of subulate spines; central
protuberance low, over it sometimes a series of bead-like
granules.
Diameter 33-37 /<., without spines; 60 /u. with spines.
Pond, Sussex Co., N. J.
The form and character of this species is very near C. anti-
iopceum, but it is smaller and bears only two pairs of aculei,
not four or six.ARTHRODESMUS.
103
Genus, ARTHRODESMUS, Ehrb.
Cells simple, compressed, deeply constricted in the middle ;
semi cells broader than long, with a single spine or mucro on
each side, bat otherwise smooth and entire.
A. convergens, (Ehrb.), Ralfs. Plate XXVI, figs. 19, 20, 21.
Semi-cells elliptic, each having its spines curved towards
those of the other semi-cell.
Diameter 38-40 p.
Several varieties are acknowledged to this species, one with
shorter and almost straight spines, another with broadly fusi-
form cells. Plate XXVI, figs. 22, 23,1 place with the varieties.
This species is common.
A. fragilis, Wolle. Plate XXVI, figs. 16, 17, 18.
Semi-cells broad, oblong-oval; aculei straight and parallel,
i. e., the aculeus of one semi-cell is parallel with that of the
other; deciduous. Chlorophyllous nuclei, two.
Diameter 33-38 p.; length somewhat less.
Central New Jersey, pond at Hammonton, and other waters.
A. Rauii, Wolle. Plate XXVI, figs. 13, 14, 15.
Cells slightly longer than broad, aculeated or verrucose ;
aculei short and stout, deciduous, leaving, after falling off,
large verrucae ; usually six on the margin of each end, and
two curved series of about six each on the membrane within
margin; semi-cell broadly elliptic, with a single outwardly
curved aculeus at each end.
Diameter of cell without aculei 38 p.; with aculei 63 p.
This species was collected with swamp moss (Sphagnum),
by E. A. Rau, in a pond near Newfield, N. J. It bears some
resemblance to A. divergens, Rab., but it is not subtillissime
verrucolosus; also to A. qucidridens, Wood, but it is twice the
size of that plant, and not quadridens.
A. ovalis, Wolle. Plate XXVII, figs. 13, 14.
Cells small, smooth, often about one-fourth longer than
wide ; semi-cells oval, armed at each end with a straight or
diverging aculeus.
Diameter 20 p., without aculei.
Ponds, Mt. Everett, Mass.
The smaller size, the straight, erect or slightly diverging
spines, I consider sufficient to separate this form from A.
convergens.104
DESMIDS OF THE UNITED STATES.
A. subulatus, Kg. Plate XXVII, tigs. 11, 12.
Semi-cells elliptic, larger than the preceding, with long,
subulate, erect or somewhat diverging spines.
Diameter 30-35 g.
Ponds, New Jersey ; rather rare. I have somewhat modi-
fied the original diagnosis, by putting diverging for converg-
ing, and thus claim for this plant a distinct position.
A. orbicularis, Wolle. Plate XXVII, figs. 15, 16.
Very small, smooth, orbicular; semi-cells united by a nar-
row isthmus; aculei of the two semi-cells nearly parallel.
Diameter, without aculei, 12 g.
Ponds, Mt. Everett, Mass.
A. quadridens, Wood. Plate XXVII, figs. 17, IS.
Broadly oval or suborbicular, a little longer than broad,
with the margin crenately undulate; semi-cells somewhat
reniform, at each end armed with a subulate, moderately
robust, acute, recurved, large spine; cvtioderm with a few
smallish tubercles arranged in three or four rows; semi-cells
from the vertex acutely elliptical, with the margin crenate
and the surface sparsely warty.
Diameter 19 g.; length 30 //.
Saco Lake, N. H., (Lewis) Wood.
A. ixcus, (Ehrb.), Hass. Plate XXVII, figs. 1-10.
Cells minute, smooth, as long as, or longer than broad,
constriction a deep notch or sinus; semi-cells with inner or
lateral margins turgid; outer, truncate; spines diverging,
subulate, acute; sporangium orbicular, spinous; spines
subulate.
Diameter very variable 10-36 g.
Turned up frequently in every State in which explorations
have been made.
A. octocornis, Ehrb. Plate XXVII, figs. 19-23.
Smooth, about as long as wide; the sinus produced by a
deep constriction, a wide notch. Semi-cells much com-
pressed, trapezoid, each angle terminating by one or two
subulate, acute spines; the intervals between the spines con-
cave. Some specimens without reference to size, have two
spines at each angle.
Diameter 16-25 g.
Not abundant, but scattered from Maine to Florida.ARTHRODESMUS.
105
A. incrassatus, Lagh. Plate X, fig. 6.
A large form, deeply constricted, sinus largely ampliated
outwardly; semi-cells subellipsoid, sides convex, ends highly
arched, superior angles surmounted each with a nearly
straight aculeus; in middle two series of granules arched,
nearly parallel with the ends; in vertical view rhomboid-
elliptic; in lateral view somewhat circular; membrane in
middle thickened and yellowish.
Diameter of cells 40 p. ; length 50 //., without aculei.
Tewksbury, Massachusetts.
Var. cycladatus, Lagh.
Somewhat smaller, eight granules in the middle of semi-
cell, one central and the others in circle around it.
This variety is near my Xanthidium tetracentrotum.
Tewksbury, Massachusetts.
A. notochondr'us, Lagh. Plate X, figs. 4, 5.
In size and constriction like A. incrassatus; semi-cells sub-
semicircular; sides convex, ends straight, with margins mod-
erately granulate; angles armed with a long divergent spine;
semi-cells in vertical view elliptic, with three longitudinal
series of granules ; in lateral view subcircular. Membrane
smooth, in middle somewhat thickened and yellowish.
Diameter of cells, without spines, 30 /<.; length 32 /u.
Tewksbury, Massachusetts.
A. triangularis, Lagh. Plate X, figs. 14, 15.
Sinus between the semi-cells wide, obtuse; semi-cells tri-
angular, connected by a cylindrical isthmus, ends somewhat
retuse in middle; angles subacute bearing a long straight
spine, either parallel or slightly converging; semi-cells in
vertical view lanceolate-oval; in lateral view subcircular.
Membrane hyaline, in middle not thickened.
Diameter, without spines, 25 /<.; length 30 jx.
Georgia.
A. pachyceros, Lagh. Plate X, figs. 12, 13.
Cells small, constriction an acute-angled sinus; semi-cells
suboval, sides convex, end arched, angles obtuse, each bear-
ing a firm spine, straight or slightly bent, diverging; semi-
cells in vertical view oval; in lateral view subcircular.
Membrane smooth.
Diameter, without spines, 18 /c
Properly a Cuban plant. Not sure that it was found within
our borders.ion
DESMIDS OF THE UNITED STATES.
Genus, EUASTKUM, Ehrb.
Cells obloug or elliptic, deeply constricted into two semi-cells
which are emarginate and usually incised at their ends; sides
symmetrically sinuate or lobed; provided with circular inflated
protuberances (rarely absent); viewed from the vertex, elliptic.
Zygospores spherical, tuberculose or spinous.
E. CEASSU5I. (Breb.), Kg. Plate XXVIII, figs. 1, 2, 3.
Cells about twice as long as broad, smooth; semi-cells three-
lobed ; basal lobes very broad, with a wide shallow marginal
sinus; terminal lobe cuneate. partly included in a notch
formed by the lateral lobes; incision in terminal lobe linear
or acute angled.
Diameter 6S-S2 /.(.
A large, and not rare plant in shallow spring, and pond
waters.
Yar. sckobiculatum. Lund. Plate XXIX, figs. 4, 5.
In outline very nearly the same as the type form, but
differs in having in the middle of the semi-cell four scrobi-
culae. Lundell represents only two; our form has four;
besides these excavations the plant has four papilla-like
prominences towards the ends of the semi-cells, which I do
not find alluded to; they may give claim for a distinct species.
Pond, Malaga, New .Terse}-.
E. oknatum, Wood. Plate XXVIII, fig. 4.
A species which is very close to E. crassum; perhaps not
separable from it. The author, Wood, says “it differs in
the proportionate length, being only twice instead of three
times as long as broad; in the size being only three-fourths
as large; and especially in the peculiar lateral splitting, as
it were, of the basal lobes.”
In our observations, very few specimens of E. crassum ever
exceed two diameters in length ; they vary greatly in size,
and the “lateral splitting,” a delusive appearance, is common
to all of them when the cells are empty.
Saco Lake, New Hampshire (Wood).
E. oblongum, (Grev.), Ralfs. Plate XXVIII, figs. 5, 6, 7.
Cells smooth, oblong, semi-cells somewhat five lobed;
lobes nearly equal, cuneate: lateral lobes, or the basal only,
with a broad, shallow, marginal concavity: all their angles
rounded; terminal lobe partly included between the lateralEU A ST RUM.
107
lobes, usually with a linear notch; sometimes this is obsolete
or very indistinct.
Diameter 68-75 )x.
This species is very variable, and if the end lobe, fig. 5,
were constant with the apex so broadly sinuately excised, it
should be separated ; it is often incised with an acute-angled
notch. The two forms, fig. 5, and fig. 6, are two distinct
varieties.
Rhode Island, New Jersey, Pennsylvania, Minnesota, and
other States.
E. multilobatum, Wood. Plate LXIV, fig. 11.
About twice as long as wide, profoundly constricted; sinus
moderately large; from the lateral view somewhat enlarged
and doubly biumbonate in the middle; semi-cells from the
front trilobate, the lobes separated by very wide sinuses; the
basal lobe broadly emarginate, the central lobe obtuse, the
end lobe broadly and shallowly sinuately emarginate; semi-
cells from the vertex five lobed ; cytioderm smooth.
Diameter 62 g.; length 120 /(.
Saco Lake, New Hampshire.
This form, described by Wood, has not yet come across my
path.
E. pinnatum, Ralfs. Plate XXXII, figs. 14, 15, 16.
Semi-cells five lobed; end lobe exserted, dilated, upper
margin of all the lobes nearly horizontal. The basal lobes
emarginate, and the intermediate ones smaller and entire.
Membrane punctate; terminal lobe with a linear notch.
Diameter 60-70 g.
Meadow and mountain pools, Pennsylvania.
E. humerosum, Ralfs. Plate XXXII, figs. 12, 13.
Semi-cells with terminal lobe dilated, emarginate, neck
sometimes partly included between the elongated lobes
which resemble processes ; basal lobes large, rounded, emar-
ginate. Cells smooth, two or three times longer than wide;
notch of the end lobe indistinct, or short linear.
Diameter about 75 g.
Sluggish waters, Pennsylvania.
If this form is not identical with Ralfs’ figure, it is very
near it. The plant bears some evidence of relationship also
with E. crassum and with E. oblongum, and may possibly be
merely a variety of these.108
DESMIDS OF THE UNITED STATES.
E. cuneatum. Jenner. Plate XXIX, figs. 12, 13.
Semi-cells cuneate. not lobed; terminal notch linear.
Diameter of cell 24-28 /a.: length about 75 p.
Not rare ; seems of rather doubtful value as a species.
E. jiagnificum. IVolle. Plate XXIX, figs. 6-S.
The largest of our Ernstra; about twice as long as broad ;
semi-cell five lobed, the terminal lobe exserted: dilated, end
somewhat convex, connected by a short neck; basal and
intermediate lobes entire, with a deep obtuse notch between;
upper margin of the basal lobes nearly horizontal and par-
allel with the base of the semi-cell; no prominent tumors,
but one large central undulate inflation shown in lateral
view (fig. 7). End view (fig. S) shows the terminal and in-
termediate lobes notched at each side.
Diameter 100 p.; length about 190 p.
Ponds, near Malaga and Manchester, New Jersey.
Var. ckassioides, Hastings.
A form which may be described as intermediate between
E. magnificum and E. crassum. In end view and size it is
nearly like the first, but the intermediate lobe is, in this view,
rounded, not ‘ ‘ notched.' ’ In lateral view this lobe is notched
and the central inflation is seen to be most prominent near
the base of the semi-cell. In front view it has the outlines
of E. crassum.
Collected near Rochester, N. H.
E. TCollei, Lagh. Plate XXXIII, figs. 1-5.
G. von Lagerheim, of Stockholm, Sweden, has seen fit to
change the name of our E. intermedium. Cleve, for the reason
that he finds that it does not correspond with the Swedish
plant so named by Cleve. It has much of the form, but is
much larger, having more than twice the diameter and twice
the length. Cleve states the diameter of the plant described
by him at 44 ju. ■ and length 77-80 p. Diameter of our form
is 112-120 g.; length 160-170 /<.; moreover the end of the
semi-cell of the Swedish plant is two-lobed. ours is/owr-lobed.
An apology for the error in choosing the name is unneces-
sary. Will only remark, a full description of Cleve’s plant
was not convenient at the proper time.
Var. quadhigibbekum, Lagh. Plate XLIX. fig. 29.
Semi-cells with four horizontal inflations; in vertical view
elliptic, apices acuminate, sides quadriundulate.
Tewksbury, Massachusetts.EUASTRUM.
109
Yar. cuspidatum, Wolle. Plate XXXIII, figs. 3, 4. 5.
This variety differs in being more depressed, squatty, in
having the lateral lobes cuspidate, end lobe not so wide, and
greater thickness to the body of the cell. End view fig. 5)
shows a more angular figure with end lobe cruciform; cytio-
derm punctate.
The typical form I found in various places in New Jersey ;
the variety only in a Sphagnum bed in a pond near Newfield,
New Jersey.
The original plant was found in Sweden ; our true form
agrees well in size and figure with it.
E. ansatum, Ehrb. , Ralfs. E. Ralfsii, Eab.) Plate XXVIII,
figs, b, 9, 10; and Plate XXXIII, figs. 11, 12.
Semi cells inflated at the base, and tapering upwards to
the notched but not dilated extremity ; end view cruciform.
Cytioderm punctate. There appear to be two distinct va-
rieties of this species, perhaps distinct plants; the one twice
the size of the other.
Diameter normally 25-36 g. Yar. major, diameter 62-74 g.
Frequent in ponds and quiet tvaters, widely distributed.
The various sizes may represent different stages of develop-
ment.
E. didelta. (Tnrp. ', Ralfs. Plate XXXIIl, figs. 9, 10.
Cells rather more than twice as long as broad ; semi-cells
pyramidal, inflated at the base and again at the middle; end
scarcely dilated, more or less rounded, notch linear; trans-
verse view shows four shallow lobes on each side and one
on each end. Cytioderm punctate.
Diameter 50-62 g.; length 100-125 g.
There is a smaller form which measures about one-fourth
less. Specimens often very close to the following, E. amput-
laoeum. Transverse view nearly the same.
Frequent everywhere, north, south and west.
E. pectinatum, Breb. Plate XII, figs. 10-12.
Semi-cells three lobed, terminal lobe dilated, usually en-
tire; lateral lobes broad, making the basal portion of the
semi-cell somewhat quadrilateral, horizontal, at each side
emarginate; lateral view cuneate, with two swellings near
the base and one at the apex; transverse view oval with
three lobules on each side and one or imperfectly two at each
end.
Diameter 40-50 g.; length about 75 g.110
DESMIDS OF THE EXITED STATES.
Minnesota. A number of varieties of this species have
been described by specialists in different countries. The
present is not Ralfs’ type-form, but a variety. It is common
in England, but hitherto not found here.
E. VENTKicosujr, Lund. Plate XXXI, figs. 1-3.
Large, twice as long as wide, outline subelliptic, deeply
constricted, sinus narrow linear; semi-cell trilobed, base
much dilated, polar lobe short somewhat dilated, incision
narrow linear, sides sinuate, two-lobed, superior lobe obtuse
tending upward, entire, not bifid in lateral view; basal
tumors three, intermediate two, and two in end lobe; in
vertical view elliptic, four undulations on each side; in
lateral view narrowed towards the ends, sides undulate,
apes subtruncate and dilated; shows the superior lateral
lobule entire.
Diameter 60-69 /x.; length 105 /x.
Found this plant frequent in pond, Orange County, near
Maitland, Florida. Zygospores not infrequent as fig. 1.
E. ampullaceuji, Ealfs. Plate XXXII, figs. 8-11.
Semi-cells less in length than breadth, base inflated, not
emarginate, but having on each side, near the middle, a
small tubercle, or prominence; end lobe exserted and di-
lated, its notch linear, or somewhat gaping. Membrane
minutely punctate. Transverse view, four inflations on each
side and one at each end.
Diameter 62-75
Not as common as the preceding, but not rare.
E. purtjm, Wolle. Plate XXIX. figs. 9-11.
Small, short; semi-cells three-lobed, broader than long;
basal lobe much inflated, terminal lobe short, dilated and
notched; in lateral view the base and end are more or less
inflated.
Diameter 35-45 >u.; length 55-70 /x.
The smaller form from Florida, the larger from New Jersey.
E. affine, Ealfs. Plate XXVIII, figs. 11. 12.
About twice as long as wide ; semi-cells three lobed ; basal
lobes somewhat emarginate; intermediate between them and
the end lobe on each side is a prominence, the upper margin
of which is nearly horizontal; end lobe exserted, dilated,EUASTRUM.
Ill
its notch linear. Cytioderm minutely punctate; transverse
vieV very near the two preceding.
Diameter 45-50 //.
Pennsylvania and New Jersey, to Georgia.
E. urnaforme, Wolle. Plate LXIII, figs. 11, 12.
Cells about one-third longer than broad; semi-cells urn-
shaped, three lobed ; terminal lobe dilated, centrally sinuate;
lateral lobes horizontal with sides converging, sinuate, basal
portion protruding, emarginate, upper part broadly rounded,
a rounded sinus between them and the end lobe; protuber-
ances, one at each angle of the terminal lobe; one at each
of the basal angles, two intermediate, and one between the
end and the lateral lobes.
Diameter 50 /.t.; length 55-60 /c
Wood Lake, Passaic County, N. J.
This form is nearest L. pectination, Breb., but differs in
most essential points.
E. VERRUCOSUM, (Ehrb.), Ealfs. Plate XXX, figs. 1, 5.
Cells somewhat longer than broad; rough with conical
granules; terminal lobe cuneate, no incision, but a broad,
shallow sinus; lateral lobes cuneate with ends more or less
concave; semi-cells with one large central inflation, and a
smaller one on each side; two on the end lobe.
Diameter about 75 p., for larger typical form.
Var. simplex, Joshua. Jour. Bot., Feb., 1885. Plate XLII,
figs. 12, 13.
Of stout habit, terminal lobe very short and with shallow
incision; central inflation either none or very small; no
other. It is nearest to the Cosmarium in Eeinsch’s contribu-
tion. Plate XVI, fig. 9, the verrucae are perhaps some-
what larger than in the typical plant.
Diameter 65 p.; length 85 p.
Canada.
The following varieties deserve a separate note:
Var. Crux Africanum, Wolle. Plate XXX, fig. 2.
The more angular, and more distended lobes, give this
form a stronger resemblance to an African Micrasterias, de-
scribed by Cohn, and suggests the name.
Pond, eastern Pennsylvania.
Var. alatum, Wolle. Plate XXX, fig. 4. Very near Corda’s
Cosmarium alatum.
Marsh pools near Minneapolis, Minn., and Bucks Co., Pa.11-2
DESMIDS OF THE UNITED STATES.
Yar. REDUCTUM. Xord. Plate XXX. fig. 3.
This specimen does not agree as well as many others found
in the same locality and group. I therefore add a transla-
tion of the author's diagnosis from his De Algis—Musei
Lugduno-Batavi :
“Sinus between the semi-cells linear; sides and angles
close; end lobe scarcely dilated, apex refuse, middle lobe
small: end view rectangular: tumor in the middle of the
semi-cell obovate elliptic, others very small.”
E. circulare, i Hass.), Ealfs. Plate XXXII. figs. 1, 2.
Semi-cells three-lobed. mostly with three basal tubercles;
pnd notched, scarcely dilated.
Ealfs makes three varieties: a. semi-cells inflated at the
base and attenuated upwards; 6. semi-cells emarginate at
the sides, the basal portion with five tubercles ; c. emarginate
at the sides; tubercles smaller, more numerous and scattered.
Diameter 36 p., more or less.
Rhode Island, Pennsylvania, Xew Jersey; common.
E. GEMAiATOr. Breb. Plate XXXII, figs. 3, 4.
About one-half longer than broad ; semi-cells three lobed,
lateral lobes horizontal, deeply emarginate; the protuber-
ances minutely granulate: terminal lobe dilated, broadly
emarginate; transverse view broadly elliptic, with three
granulate inflations on each side < not four, as incorrectly
drawn) and one at each end; end view shows the terminal
lobe, cruciform.
Diameter 38 p.
Found from Rhode Island to Minnesota, and southward.
E. Everettense. TColle. Plate XXXII. figs. 5, 6, 7.
Cells about twice as long as broad; semi-cells three lobed,
basal lobes wide, emarginate: end lobe dilated, notch linear;
two larger inflations near the middle, and several smaller
ones on each side, and on end lobe. Transverse views
broadly elliptic, with two protuberances on each side; side
view shows one inflation on each side.
Diameter 50-55 p.
Collected in ponds, Mount Everett, Mass.
This form bears some resemblance to E. affine, but it is
clearly separable by the broad basal lobe, by the absence of
the intermediate prominences, and by the arrangement of the
protuberances which produce distinct forms in transverse and
lateral views.EUASTRUM.
113
E. insigne, Hass. Plate XXXI, figs. 39-13.
Semi-cells longer than broad, inflated at the base, sides
entire, and tapering into a long slender neck ; end lobe di-
lated with linear notch; end view quadrangular, with angles
slightly protruding, and a swelling on each of the shorter
sides; end lobe cruciform as shown on the middle of fig. 43.
Diameter 30-35 p.
Rhode Island, Massachusetts, Pennsylvania, New Jersey
and Florida.
E. mammillostjm, Wolle. Plate XXX, figs. 14, 15.
Cells in length twice the diameter ; semi-cells three lobed ;
basal lobes wide and nearly half as high as the semi-cell,
drawn out in the center into a narrow column one-third to
one-fourth the diameter of the body; dilated at the end,
sinuate, four-parted; base with six mammiform protuber-
ances; membrane punctate; end view oval with three di-
verging mammiform prominences at each end.
Diameter of center of cell 68 p.; length 118 p.
Ponds, Mount Everett, Mass., and Sussex County, N. J.
E. Hastingsii, Wolle. Plate XLII, figs. 16, 17.
Cells small, a little more than one and one-half times as
long as broad; semi-cells three lobed, lateral lobe horizontal,
deeply emarginate; terminal lobe a stout column rather
more than one-third diameter of the body and about the
same height, dilated at the end, apex ornamented by a row
of tubercles, giving it a crenulate appearance; lateral view
similar except that the basal lobes are one-third or one-
fourth narrower; transverse view broadly elliptic, with
three inflations on each side and one on each end ; end view
shows terminal lobe a crenulate circle of about a dozen
tubercles.
Diameter 35-40 p.
Coll., W. N. Hastings, Cocheco River, New Hampshire.
E. ATTENUATUM, Wolle. Plate XXX, fig. 17.
Small, twice as long as wide; semi-cells three lobed, basal
lobes broad, emarginate; terminal lobe a column with nearly
parallel sides, apex truncate.
Diameter 35 fi.
Rather rare, but I found a considerable number in swamp
pools, Bucks County, Pa., and near Ocean Beach, N. J.
8114
DESMIDS OF THE UNITED STATES.
E. Donnellii, Wolle. Plate XXX, fig. 6.
Broadly orate, somewhat longer than broad, profoundly
constricted in the middle, sinus linear; semi-cells trilobed;
basal lobes orbicularly tumid; terminal lobes semiorbicular ;
margin of each side armed with seven or eight short, stout,
conical teeth. Semi-cells with one larger central and four
smaller inflations; three of them in a series on basal partr
and two on the end lobe. Cytioderm punctate.
Diameter 38 /*.; length 54 yu.
Florida. Coll., J. Donnell Smith.
E. formosum, Wolle. Plate XXX, fig. 16.
Xearly twice as long as broad, oval in outline; semi-cell
with six marginal lobes, apices trifid, or tridentate; central
tooth erect and the other two divergent; the sections of the
two basal lobules more rudimentary than the others. Cytio-
derm smooth.
Diameter 40 /t.; length 62 ,u.
This plant bears some likeness to E. Nordstedtianum, but
is separated from it by the less prominent teeth, and especially
by the vertical position of the end lobules and the wide sinus
between them.
E. divaricatum, Lund. Plate XXX, figs. 18, 19.
Cells one- fourth longer than broad, constriction deep, sinus
linear ; semi-cells subtriangular, gradually narrowing from a
broad base to a truncate apex; sides undulate; polar lobe
short, not dilated, linearly notched ; angles of the terminal
lobe, and of the basal lobe, armed each with a short aculeus ;
vertical view elliptic, middle of each side granulate dentate,
ends also dentate.
Diameter 32-36 yu.; length 40—45 yu.
Occasional in ponds, Pennsylvania and Xew Jersey.
E. POKORXYANUSI, Grun. Plate XXXI, figs. 33, 34, 35.
Semi-cells trilobed; basal lobes, margins crenate or emar-
ginate; terminal lobe erect, subcuneate, truncate, incised;
membrane smooth.
Diameter 17-20 p.; length equal to two diameters.
Rather common, often intermingled with the following two-
forms which are so nearly allied, that it is almost impossible
to separate them.EUASTRUM.
115
E. erosum, Lund.
Very near the preceding; in front view barely separable.
End lobe usually rather wider, and not so deeply incised;
notch obtuse-angled. End and lateral views somewhat quad-
rangular with ends imperfectly tricrenate.
E. INSULARE, Witt.
This form the author gives as a variety of E. binale. I
prefer it separated because the basal lobes are emarginate,
corresponding with the preceding two. It is distinguished
by a greater breadth of the terminal lobe and the absence
of an incision or notch; sometimes slightly sinuate. Size
rather less.
E. inerme, Lund. Plate XXXIII, figs. 6-8; Plate XXXI, figs.
30, 36.
Subelliptic; semi-cells subtriangular, apes somewhat pro-
tracted, truncate, deeply incised, not dilated or dentate;
sides biundulate, the basal crenae most prominent, obtuse,
and angle obliquely truncate; tumors three, inconspicuous
and sometimes wanting; end view subelliptic, sides bigib-
bous; side view ovate. Membrane finely punctate.
Diameter 32-38 ju.	•
Rather common.
E. crassicolle, Lur.d. Plate XXXI, figs. 37, 38.
About twice as long as wide ; sinus narrow linear; semi-
cells slightly attenuated, three lobed ; lateral lobes, lightly
sinuate-bilobulate; polar lobe broad, barely dilated, apex
emarginate; end view hexagonal, poles truncate, middle
inflated.
Diameter 14 pt.; length 28 /<.
New Jersey —not frequent.
E. cuspidatum, Wolle. Plate XXXI, fig. 32.
Diameter slightly less than length; semi-cells distinctly
three lobed, basal lobes extending laterally their own width;
end lobe subrectangular, twice the width of the other lobes,
obtusely sinuate in the center; ends of the rounded basal
lobes and of the two sections of the end lobe, surmounted
each with three firm, diverging aculei.
Diameter without aculei 25 pi.; with them 33 pi.
Pond, Absecom, N. J. Coll., H. D. Kitchel, 1882.116
DESMJD.S OF THE UNITED STATES.
E. pixgue, Elf. Plate XXXI, figs. 1, 2, 3.
Somewhat longer than broad; semi-cells three lobed, each
lobe globularly rounded : the polar lobe with a small notch;
side view oval with ends slightly truncate-crenate; end
and side views show a slight central inflation of semi-cells.
Isthmus about one-fourth the diameter of the cell.
Diameter 35-45 //.
Ponds, Atlantic and Passaic Counties, X. J. Our plants
are often without the terminal notch, but otherwise so near
the form described by Elfving, I adopt the name he has given.
E. XoRDSTEDTiANU.il, Wolle. Plate XXX, figs. 7-13; and Plate
LXIII, figs. 13-15.
Cells quadrangular-oblong, not quite twice as long as
broad; semi cells obscurely three lobed; basal lobes broad,
each divided in the middle by a rounded notch into two
lobules with tridentate or spinous ends; end lobe short, more
or less emarginate, the two sides of the apex usually some-
what reflexed, with a subacute or rounded notch between ;
lateral margins furnished with two or three horizontal spines.
End, transverse and side views 1 Plate LXIII, figs. 13, 14.
15 rectangular, with broad, square, and more or less sinuate
sides and ends; angles dentate.
Diameter 45-50 jst; length 70-75 /<.
Frequent in pond near Minneapolis, Minn,; rarer in Xew
Jersey and Pennsylvania.
E. El.egans. Kg. Plate XXXI, figs. 10-16; 25, 26.
Oblong, one and one-lialf to two times as long as wide;
central constriction narrow linear; semi-cells with sides
somewhat converging, with a constriction near the truncate,
angular end, and another, often very slight, between this
and the base; ends divided by a linear or acute angled notch;
side view oblong elliptic, apices acute-conic; end view oval
with central inflation.
Diameter 18-38 it. Common.
E. ROSTRATE.M, Pali's. Plate XXXI. figs. 8, 9.
Varies from the preceding in the protuberant, emarginate,
or angular ends having a prominent, horizontal spine on
each angle.
E. spixosum. Ealfs. Plate XXXI. figs. 4-7, 17.
Xearly allied to the two preceding, but separated by the
more decided lateral notch in the basal lobes forming twoEUASTKUM.
117
distinct lobules, each furnished with, usually, two horizontal
or diverging spines. Somewhat larger.
Diameter 35-40 g.
E. integrum, Wolle. Plate XXXI, figs, l.s-22.
Another form nearly allied to the above three species or
varieties; separated by the absence of the lower constriction
of the semi-cell. Size variable, diameter 10 30 u.
The preceding four forms are closely related, and may be
accounted mere varieties. They are frequent. Having for
comparison, scores of sketches made of plants from as many
localities in different States from Vermont to Florida and
westward to Minnesota, this division suggested itself as the
most feasible and natural. I retain the old names, but with
somewhat modified diagnosis.
The same is described as E. simpler, Lies. U. 8., p. 106.
Since the publication of the diagnosis, F. Gay, of Montpellier,
France, is found to have anticipated the adoption of the
same name for another EuaMrumform. Hence we substitute
E. integrum for E. simplex.
E. bin ale, (Turpin;, Ealfs. Plate XXXI, figs. 23, 24.
Cells minute, about one-half longer than broad, oblong-
oval; semi-cells with their basal portions entire; slightly
contracted beneath the ends; apex dilated, its central notch
acute, broad, gaping. Transverse view with two lateral in-
flations; ends truncate, angles rounded.
Diameter 15-25 g.
Plants of this species have features in common with E.
integrum, but may be readily recognized by the proportionately
shorter form and the pouting separation of the end.
E. compactum, Wolle. Plate XXXI, figs. 28, 29.
Very small, suborbicular, little longer than broad; semi-
cell broad, transversely oval; apex a slight protuberance
with a linear incision ; two small prominences, one on each
side of the apical projection.
Diameter 20-22 g.; length 28 g.
Pond, Pennsylvania.
E. obtusum, Wolle. Plate XXXI, fig. 31.
Minute, twice as long as wide; semi-cells obovate, base
flattened, sides somewhat diverging, end broadly rounded
with linear incision in the center.
Diameter 14 //.; length 25 g.
Ponds, Pennsylvania.118
DESMIDS OF THE UNITED STATES.
E. abruptum, Xord. Plate LXIII, figs. 21. 22.
Cells one and one-lialf times as long as broad ; constriction
deep, narrow linear; semi-cells trilobed, lateral lobes some-
what protruding above the base, near the middle; ends
truncately rounded and usually dentate or granulate ; end
lobe incised bifid, with exterior angles furnished with short
spines; transverse view rectangular with large central infla-
tion, end margin more or less undulate granulate, or some-
times retuse.
Diameter 28-30 /<.; length 40 p.
Passaic County (Wood Lake), X. .1.
This species does not strictly conform to the description of
the author, but it has so much in common that with his con-
sent, I adopt the name he chose for his Brazilian plant.
Genus, MICRASTERIAS, Ag.
Cells simple, lenticular, deeply constricted in the center;
viewed from the front, orbicular, or broadly elliptical; from the
vertex fusiform with acute ends. Semi-cells three to five lobed;
lateral lobes entire or incisely-lobulate; end or polar lobe entire
or sinuate or emarginate, and sometimes with angles produced
and_ bifid.
In but few species have the zygospores been detected; they
are large, globular and furnished with stout spines, which are at
first simple, then become branched at the ends.
Section I.—Cell circular; segmeuts flve-lobed; lobes approximate, the end lobe
narrower.
M. Torreyi, ( Bailey), Ralfs. Plate XXXIV, figs. 1-8.
Circular; lateral lobes deeply incised, making two or three
subdivisions to each ; all more or less tapering, and acute or
bidentate at the extremities. End lobe narrow, not exserted,
dilated at apex, concave, angles taper into acute points or
spines.
Diameter 250-300 p.
Frequent in ponds of New Jersey, Mt. Everett, Mass., and
few localities in Pennsylvania.
Often variable in the number and form of the subdivisions.
Plate XXXIV represents eight varieties, the result of multi-
plication by dividing. Compare Introduction, page 18.
M. Pseudotorrey'i, Wolle. Plate XXXVI, fig. l.
Large, circular, five-lobed; basal and intermediate lobes
bisected, sections more or less couical, ends deeply furcate;MICRASTERIAS.
119
polar lobe broadly cuneate, end truncate-sinuate, angles
cuspidate.
Diameter of cell 180 ju.
Mt. Everett, Mass.
Separated from M. Torreyi, by its smaller size, the less num-
ber of lobules and their greater similarity of form.
M. radiosa, (Ag.), Ralfs. Plate XXXY, figs. 1, 2, 3; Plate
XLIII, fig. 1.
Cells orbicular, smooth ; semi-cells rather indistinctly five
lobed; lobes dichotomously divided; ultimate subdivisions,
inflated, attenuated, furcate at the ends. End lobe narrow
cuneate, emarginate, and its angles dentate.
Diameter 150-200 p.
A beautiful species and not rare, easily recognized by its
many and deep incisions ; it is variable in size and number of
subdivisions ; the latter range from twenty to forty in a semi-
cell.
Yar. PUNCTATA, West., J. R. M. S., Nov., 1888. Plate XLIII,
fig. 1.
This differs from the usual forms of M. radiosa in having a
distinctly punctate cytioderm with the division of the lobes
more like those of M. papillifera, especially the ultimate ones.
Pond, Massachusetts.
M. Swainei, Hast. Plate XLII, fig. 1.
A form very near M. radiosa, differing mainly in the usually
more or less elongated lower lobe of the basal division of the
semi-cell, which is a constant feature; frequent in large
gatherings made by Wm. N. Hastings near Rochester, New
Hampshire.
Diameter variable, 190-250 p.
M. speciosa, Wolle. Plate XLV, figs. 1, 2.
Small, somewhat longer than broad, five lobed ; lateral
lobes unequal, the basal pair usually with only half as many
divisions as the intermediate ones; each basal lobe consist-
ing of one, and the intermediate of two lobulets, the angles
of each section drawn out into two spine-like points; ter-
minal lobe rather narrow, linear, the end exserted and much
dilated, usually with three prominent mucros at each angle;
center an obtuse angled notch, standing free with a rather
wide gap between it and the adjoining lobes; a series of
small spines often observed on the margins of the lobes.120
DESMIDS OF THE UNITED STATES.
Diameter 95 q.; length 110 of specimens from Florida;
diameter 125-150 /u.; length 155-165 /<., of Xew Jersey
specimens.
This species appears to be related to M. racliosa, var. orncita,
Xord., but is smaller; the lobes are not so deeply, nor so often
intersected, and the polar lobe is more exserted and more
dilated at the end.
II. papillifera, Breb. Plate XXXV III, tigs. S, 9.
Orbicular, with marginal gland-like teeth ; semi-cells fire
lobed; lateral lobes dichotomously incised ; incisions narrow
linear, the principal sinuses bordered by a row of minute
granules. The end lobe about as wide as the others, and
emarginate, its angles dentate. Endochrome is usually yel-
lowish or brownish green.
Diameter 95-112 /n
Is found sparsely in shallow pools, but in a wide range of
many States.
II. rotata, (Grev. 1, Balfs. Plate XXXVIII. figs. 1, 2, 3.
Orbicular, smooth; semi-cells five lobed; lobes dichoto-
mously incised with ultimate subdivisions variously biden-
tate in different plants. End lobe somewhat exserted. The
basal lobes have each four subdivisions, and the intermediate
lobes each eight.
Diameter 200-250 yu.
II. denticulata. (Breb.', Balfs. Plate XXXVIII, figs. 4-8.
Xear the preceding, but separated by the usually obtuse
apices of the subdivision, often more oval form of cells, and
equal number of subdivisions in the basal and intermediate
lobes; polar lobe not exserted. Size about the same, but
many smaller varieties. Common.
II. verrucosa, Bov. Plate XLVII, fig. 10.
In outline this species agrees with smaller forms of M.
denticulata, Balfs, but differs from these and other described
forms by the remarkable row of crenulated, circular or oval
basal inflations, crossing from side to side, larger towards
the center, gradually growing smaller towards the margins.
The original type was found in Scotland. The first from
this country is from a pond near Minneapolis, Minnesota, in
collections made by Miss E. Butler.MICRASTElilAS.
121
M. fimbriata, Ralfs. Plate XL, figs. 1-8. Zygospores from
Rochester, X. H.
Large circular; semi-cells five lobed; dichotomously in-
cised ; end lobe cnneate with a broad, shallow notch, or con-
cave end, and two or three mucros, or spines, at each augle.
The ultimate subdivisions are rounded and slightly emar-
ginate, each furnished with two spines usually divergently
curved.
Diameter about 125-250 p. Frequent.
Fruiting specimens, not heretofore observed, were received
from Rochester, New Hampshire, collected by \V. N. Hastings.
The zygospores are orbicular, spinulose; spines rather slender,
elongate, scattered, mostly furcate at the ends, and some-
times notched below the middle; punctate ends, with tips
recurved.
This species is found in various forms, as illustrated by the
figures, and may be noted as
Forma,—genuina, (figs. 1, 2). The typical plant.
Forma,—NUDA, Wo lie, 'fig. 4 . A form which occurs frequently
with almost all the subdivisions nude, devoid of spines.
Forma,—Elephantina, Wolle, (fig. 3). Of gigantic size, di-
ameter 400 fi,
Mount Everett, Mass.
Forma,—apiculata, Menegh., (fig. 2). With series of minute
spines bordering the sinuses.
Forma,—simplex, Wolle, (fig. S'. Small, oval, subdivisions
with simply one small uiucro.
This may prove a distinct species ; the two specimens I had
from Florida were too imperfect from drying for satisfactory
identification.
M. braohyptera, Lund. Plate XXXYI, figs. 6, 7.
About one-third longer than broad, elliptic, deeply con-
stricted in the middle; sinus an acute angle somewhat
ampliated; semi-cells five lobed ; polar lobes longer than the
intermediate lobes and separated from them by a wide sinus;
neck moderately distending to the dilated apex ; ( neck taper-
ing towards the apex, Lund.), depressed center forms a
wide, shallow notch. Intermediate and basal lobes short
and nearly equal in breadth; twice bisected; apices oi
lobules furnished each with two rather long, somewhat
curved spines; angles and margins of the end lobe, and122
DES.MIDS OF THE UNITED STATES.
margins of the other lobes also, provided with a few scat-
tered spines. The figures of two semi-cells show consider-
able variation in the arrangement of the spines and divisions
of lateral lobes.
Diameter 140-150 p., without spines; length 200-210 p.
Collected near Minneapolis, Minn., by Miss E. Butler.
Section II.—Cells subelliptic; semi-cells three or five lobed; lobes radiate, the
•end lobe somewhat exserted, divided and arms divergent.
M. furcata, (Ag.), Ealfs. Plate XXXIX, figs. 5, 6.
Cells five lobed; lobes bifid, their divisions linear, diver-
gent, and forked at the apex. The end lobe exserted, its
divisions divergent, producing a wide, shallow sinus.
Diameter 150-180 p.; Common.
Var. simplex, Wolle. Plate XLVII. figs. 6, 7.
Cells equal in length and breadth, two lobed, terminal
lobe exserted, its divisions spreading and producing a wide,
shallow sinus; lateral lobes usually simple, but sometimes
divided into two narrow, linear diverging sections, furcate
at apices. Length and breadth 140-150 p.
A singularly variable species. Of the thirty-one fresh speci-
mens examined during a stay at Winter Park, Florida, by
Rev. H. D. Kitchel and myself, twenty were found of normal
form as upper half of fig. 6, 7, no arms divided; five had all
the lateral arms divided, like the lower half of figure; one
had two arms divided and two single, like figure; two had
only one arm divided, and three had each two arms divided.
As two-thirds of the forms examined had all the arms single,
this is considered the type; the others, one-third, variable,
are varieties.
M. pseudofurcata, Wolle. Plate XXXIX, fig. 4.
Five lobed, simple, not bifid ; sometimes the lateral lobes
appear more like one bifid lobe on each side; in either case
only half as many lateral arms as characterize the preceding
species, M. furcata.
Diameter 150-160 p.
Not as frequent as the true form, but it has a habitat in
many localities in the Middle States.
Var. minor, Wolle. Plate XLI, fig. 11.
Small, not one-half the diameter of thq typical form, but
so nearly like it in outline, I note it as a variety. Had but
two or three specimens, from Minneapolis, Minn.MICRASTERIAS.
123
M. Crux-Melitensis, Ehrb. Plate XXXIX, fig. 3.
Semi cells indistinctly five lobed ; lobes bifid, subdivisions
short, and furcate at the apices.
Plate XLV, figs. 4, 5, two semi-cells differing somewhat
from the figures on Plate XXXIX, from Minnesota.
Diameter 100-125 /u.
Not so frequent as M. furcata, to which it often bears a
close resemblance; it is similarly divided, but the incisions
are not so deep, the subdivisions not so elongated, rather
stouter and less divergent; end lobe less exserted.
M. DICHOTOMA, Wolle. Plate LXIII, fig. 2.
Somewhat longer than broad, smooth or finely punctate;
semi-cells three lobed; lateral lobes twice bifid; the ultimate
lobules (four resulting from one) deeply furcate or clawed at
the ends; the polar or end lobe exserted on a cylindrical
neck with two diverging arms clawed at the ends.
Diameter with arms 115-200 p.; length the same to one-
fourth greater. Length of body 115 /u.- breadth of neck
15-17 ju.
Hitherto found this species in three localities only : ponds,
Malaga, and Bamber, N. J., and Harvey Lake, Luzerne
County, Pa.
M. ringens, Bailey. Plate XXXIX, figs. 1, 2.
Oblong, semi-cells three lobed, with a series of granules
inside of most of the margins; basal lobes divided by a deep
notch into two spreading arms, obtuse or slightly dentate at
the apices; terminal lobe exserted, emargiuate, extremities
obtuse.
Diameter 125-150 m-
Obtained this species from Florida only, collected by J. D.
Smith.
Var. serulata, Wolle. Plate XLVII, fig. 15.
In size and form the same as the original type from Florida.
Bailey describes it as “granular near the margins,” but not
so serrated. This new variety has the margins distinctly ser-
rated, besides having the granules or mucros near the
margins.
Diameter 115-130 /a ; length 125-145 /<.
Found in large numbers in White Bear Lake, Minnesota,
by Miss E. Butler.124
DESMIDS OF THE UNITED STATES.
Section III.—End lobe produced into four, more or less diverging, rigid, processes.
M. Americana, (Elirb. \ Eg. Plate XXXVI, fig. 2 and Vars. 3-5.
Semi-cells three lobetl; lateral lobes broad, cuneate. their
margins concave, incised-serrate; end lobe broad cuneate and
exserted, bipartite at the angles ; the subdivisions straight,
narrow, minutely dentate at the extremities, end concave.
Diameter 100-115 p.; length about one-third greater.
The wide distribution of this species entitles it to the name
it bears.
There are several varieties, the one—
Yar. recta, Voile, (fig. 3).
Is distinct in the margin of the polar lobe, which is not con-
cave and bisected, but straight with two small prominences.
Found it in a few localities in Pennsylvania and New
Jersey.
Var. Hermaxniana, Keinsch, (fig. 5.)
Distinct in the angular intersections and regularly serrate
margins.
Collected in Florida. It is not an exact counterpart of the
plant described by Reinsch, but very near it.
Var. spixosa, Turner. Plate XLIX, fig. 30.
A form not strictly from the United States, but near it,
may be introduced. Mr. Turner describes it thus : A small
compressed form. About one-eighth less in length and
breadth than the type. Central portion of segments smooth ;
lobes ornamented with short stout spines; the end lobe bear-
ing near its extremity a species of annular rugoso spinous
coronet.
Diameter 112 //.; length 136 .
Pictou, Nova Scotia.
M. Mahabuleshwarensis, Hobson. Plate XLI, fig. 10.
This form stands in close relation with the preceding
species and varieties; it is separated by having the lateral
lobes only once bisected, not twice. The margins are finely
serrated.
Diameter 125 yu., more or less.
Ponds, New Jersej , and eastern part of Pennsylvania.
51. apiculata, Menegh. Plate XLV, fig. 3.
Large orbicular or oblong, with the surface more or less
densely covered with mucros; semi-cells five lobed; lateral
lobes equal in size, not close, bisected; lobulets bifid, eachMICRASTERIAS.
125
section emarginate, mucronate at each angle; polar lobe
prominent, widely dilated, center notched, margins mu-
cronate.
Diameter 175-200 g.
Ponds, Pennsylvania, New Jersey and Minnesota; rather
rare.
M. mamillata, Turner. Plate XLYI, fig. 2.
Semi-cells papilionaceous, five lobed ; end lobe broad ; its
ends and those of the other lobes divided into palmate
shapes, with the points broadly rounded; surface adorned
with mamilliform processes radiately arranged; provided
with a process at isthmus, the purpose of which is appa-
rently (?) to strengthen the segmental union. Only one
specimen (semi-cell) seen. Seemingly related to M. apiculata.
Diameter 198 g.
Inasmuch as this semi-cell was found in collections made
in a swampy part of Harvey Lake, Pennsylvania, in which
M. apiculata occurs freely, the author would emphasize the
last remark.
M. alata, Wall. Plate XLVI, fig. 1.
In anticipation of the possible discovery of this interest-
ing and unique form in Southern Florida, I quote it from
G. von Lagerheim’s Bidrag till Americas Desmidie-flora. It is
an Indian plant, but is now also found in Cuba. The figure
is drawn direct from an India specimen in my herbarium.
M. Nordstedtiana, Wolle. Plate LXII1, figs. 3-5.
Cells of equal length and breadth, smooth; semi-cells three
lobed; the lateral lobes divided into two subcylindrical seg-
ments with a wide notch between; ends obtuse, furnished
with three or four small spines. Polar lobe exserted on a
long neck having a short conical prominence about the
middle of each side ; the ends diverge in two pair composed
of one longer and one shorter, nearly horizontal, arms; the
two are nearly parallel.
Diameter 150 g.
Longwood Pond, Passaic County, N. J., and Harvey Lake,
Luzerne County, Pa.
This species has a number of distinct features; the four
arms of the end lobe ; the protuberances of the neck ; the
lateral lobes have something in common with M. r in gens, but
they are smooth or finely punctate, not granulate ; there is
something also to remind one of M. pseuclofurcata, but the
arms are not furcate at the ends.128
DESMIDS OF THE UNITED STATES.
Section IV.—Cells circular; semi-cells obscurely five lobed, the end lobe the
broadest.
M. decemdentata, Naeg. Plate XXXVII, figs. 5, 6.
Suborbicular, granulate-punctate; semi-cells distinctly
three lobed, or obscurely five lobed; lateral lobes divided
by a small obtuse angled sinus into two lobelets, having
straight, truncate margins, angles slightly produced and
mucronate; polar lobe broadly truncate, separated from the
adjoining lobe by a narrow linear sinus; apex broadly con-
vex, sometimes sinuate, lateral angles slightly produced and
mucronate.
Diameter 83-100 pi.
Frequent in Florida ; have not found it farther north. It
differs from all forms described under this name, particularly
in size. The author, Naegeli, gives the diameter 40 u. Del-
ponte quotes subalpine forms at 50; and Zundell, the Sweden
plant also at 50 //., which is only half the size of our plant, but
omitting the measure, the description proves them identical.
M. crenata, (Breb.), Ralfs. Plate XXXVII, figs. 7, 8.
Cells orbicular; semi-cells with five shallow lobes; end
lobe very broad, cuneate. end convex, or slightly sinuate on
the margin; lateral lobelets nearly entire.
Diameter 75-85 pi.
This species is met with only occasionally, Pennsylvania,
New Jersey, Florida.
M. truncata, (Corda), Ralfs. Plate XLIV, figs. 6-9.
Orbicular; semi-cells five lobed; lateral lobes shallow;
end lobe very broad, truncate, angles bidentate; lateral ones
incised-dentate.
Diameter 50-100 pi.
One of the most common species of this genus. Variable
in size and the structure of the margins ; sometimes the lobe-
lets are obscurely toothed ; again very distinctly notched, and
another form is frequent with the angles drawn out into long
spiue-like points, fig. 7. The truncate ends are usually more
or less rounded; fig. 8 is a peculiar form with the ends perfectly
flat, and not detached from one another after multiplication
by division.
M. conferta, Lund. (M. granulata, Wood). Plate LXIV, fig. 12.
Broad elliptic, central sinus deep, narrow linear; semi-
cells five lobed, lobes and lobules always close; polar lobe
subcuneate, more or less widened from the base to the end,
sides concave and apex convex but roundly einarginate inMICRASTERIAS.
127
the middle, angles furnished with two or three small papillae;:
lateral lobes nearly equal, bisected, and again divided, each
lobule with apex furnished with two papilla-like points.
Yar. hamata, Wolle. Plate XLIV, figs. 3, 4.
In this variety, the polar lobe is not conferta, compact,
close against the adjoining lobes, as in the true form, but
widely separated in the whole length; the open space is pro-
duced by the contraction of the lobe below the apex, thus
giving it a hamate form.
Diameter 80-100 ju., length slightly more.
Ponds, Mount Everett, Mass.
The only locality from which I received the typical form is
Aiken, S. C., the same from which Wood had it. This species
was first known in Sweden, and described by Cleve, as M.
crenata. Lundell separated it from that species and named
it M. conferta; it was so recorded with figure, in his L)e Des-
midiaceis, quae in Suecia inventce sunt, published 1871, ante-
dating Wood’s contribution by at least one year; having a
priority claim, Lundell’s name is preferred. The membrane
is distinctly and largely punctate, not granulate, except when
in old condition.
M. triangularis, Wolle. Plate XLIY, figs. 1, 2.
Cells large, orbicular or oblong; semi-cells five lobed.
Polar lobe triangular, apex and sides nearly straight and
nearly equal, the angles mucronate. The lateral lobes similar,
twice bisected, apices of the lobelets emarginate or furcate.
Diameter 170-200 /u.
I found plants recognized as belonging to this new species
in three distinct localities: ponds, Broad Mountain, Pa.,
Ocean Beach and Bamber, N. J., and Florida. They vary
somewhat in outline and details of intersections, but all have
the same broad more or less triangular terminal lobe with
mucronate angles. Fig. 1 is the typical Pennsylvania form ;
fig. 2 the Florida type. The New Jersey plant had stouter
terminal lobes, and the ultimate intersections of the lateral
lobes were intermediate between the two.
Section V.—Cells oblong.	,
M. Jenneri, Balfs. Plate XXXYII, figs. 1, 2.
Cells oblong, minutely granulated; semi-cells five parted,
lobes closely approximate, cuneate lateral ones obscurely
bipartite ; the subdivisions emarginate.
Diameter 100-150 //.128
DESMIDS OF THE UNITED STATES.
This species differs from all others of this genus in the form
of the cell, often twice as long as broad. Fig. 2 is very near
a form which Reinsch denominated M. angulosum. It is pro-
portionately shorter than the typical form of Ralfs, but other-
wise so near, it scarcely admits of separation.
Section VI.—Lobes horizontal, attenuated, bidentate.
M. laticeps, Xord., 1S69.	(M. disputata, Wood, 1872.) Plate
XLI, figs. 4. 5.
Quadrangular, about as long as broad, subpinnatisected,
sinuses acute; terminal lobe nearly as long as the basal lobe;
both the lobes strongly attenuated; the polar lobe into an
acute point and the other into an acutely bidentate apex;
ends rounded or emarginate.
Diameter 160-212 n.
This species made its first appearance from Brazil and was
described by Nordstedt in 1S69 in a scientific journal of
Sweden. Wood gave the same plant a new name a few years
later. The former has a claim of priority, hence should
stand. The plant varies considerably in size, and in the form
of the terminal lobes ; some are more rounded than others.
It has been found in a large number of States.
M. osoitans, Ealfs. Plate XXXVII, figs. 3, 4.
Cells of nearly equal length and breadth: the end lobe
separated from the adjoining lobe by a rounded or acute-
angled sinus; lobe horizontal, conical, their extremities
usually bidentate. One form has the ends of the terminal
lobe acute. The end lobes are much shorter and narrower
than the others. Transverse view fusiform; membrane
punctate.
Diameter 150-160 n.
Bailey reports this species from Florida and Rhode Island,
but makes the measures much less. I have specimens from
Florida, Massachusetts and New Jersey. They were of the
given measures.
M. pinnatifida. Kg. . Ball's. Plate XLI. figs. 7. 8. 9.
Ends straight ; semi-cells deeply constricted, lobes hori-
zontal. more or less fusiform with apices bidentate.
Diameter varies from 83-110 /i.
Somewhat like the preceding, but very much smaller, and
lobes not so swollen.
Much more frequent than M. oscitnm.
Some are found with the basal lobe wide (fig. 9); these I
have named,MICBASTERIAS.
1-29
Var. INFLAT A, fig. 9.
M. Kitchelii, Wolle. Plate XLI, figs. 1, 2; Plate XLII, fig. 2.
Cells about as long as wide, sinus separating the semi-cells
an acute angle, ampliated; basal lobes subconically pro-
duced, obliquely and broadly truncate with two angles
drawn out into somewhat diverging processes, furcate at the
ends; a rounded sinus between; polar lobe separated from
the basal lobe by an ample, rounded, or oval sinus, sides
produced and furcate as the others; apex slightly convex.
Diameter 125 yu. in center; ends 75 yu.; length 125 yu.
First specimens were collected by H. S. Kitchel. in a pond,
Mt. Everett, Mass. It has occurred since in many places in
central and southern portions of New Jersey and Florida.
The general outline of this species has some resemblance to
M. adscendens, Nord., found on the Sandwich Islands, but it
is larger, the polar lobe is more exserted, and hence the sinuses
between it and the basal lobes are much wider and deeper,
broadly rounded, not “amplo-acutanyuloand the angles are
not “bidentcdebut are simply bifurcate.
It has a closer resemblance to M. depauperata, Nord., a
form found in Brazil, but it is a decidedly larger plant.
M. akcuata, Bailey. Plate XLIV, fig. 5.
Quadrangular; semi-cells three lobed; the basal lobes long
and arcuate, subtended by the transverse projections from
the ends of the slightly notched terminal lobes.
Diameter 90-110 ,u.
Collected in Florida and described by Bailey. I have found
it repeatedly in New Jersey, Pennsylvania and Massachusetts.
M. expansa, Bailey. Plate XLI, fig. 12.
Semi-cells three lobed; basal lobes subconical, lower mar-
ginal line regularly convex; terminal lobe more slender,
notched in center, spreading with an upward tendency to
an acute, often mucronate point. Usually smaller than the
preceding.
Diameter about 75 yu.
Thi^ form is near M. arcuata, but somewhat smaller, stouter,
with more regularly arched basal lobes; apices more acute,
often mucronate.
Habitat the same as the preceding.
M. qua drat a. Bailey.
Described by the author as ‘‘ Large quadrangular, three
lobed, basal lobes elongated, slightly curved, bidentate; ter-
9130
DBSMIDS OF THE UNITED STATES.
rninal lobes with two slender transverse bidentate projec-
tions.”
Diameter 110-120 m-
Found good specimens in collections made in lakes, Winter
Park, Florida. Besides the typical form also a variety which
has the ends of the basal lobes deeply bisected, to nearly half
the length.
M. Baileyi, Ralfs. Plate XLI, fig. 6.
Cells small, granulate; semi-cells three lobed; basal lobes
bipartite, apices obtuse, or finely dentate; terminal lobe
much exserted, notched, spreading arms obtuse or bidentate
at apices.
Diameter 75 /-i.
New York, Rhode Island, South Carolina, Florida (Bailey).
Ponds, New Jersey, Pennsylvania. Rather rare.
M. foliacea, Bailey. Plate XLIY, figs. 10, 11.
Cells subquadrate, smooth; semi-cells three lobed; lateral
lobes deeply bipartite, and again incised, their margins con-
cave, incised-serrate; end lobe rhomboidal, exserted, angles
entire, apex divided by a wide, rounded sinus, near the
basal margin of which are two or more tooth-like spines.
Diameter of cell SO-95 /.i.
Bailey reports this species from Worden’s Pond, Rhode
Island. I found it quite abundant in Gilder Pond, Mt.
Everett, Mass. A singular feature was the union of many cells
forming long lilaments. In the process of multiplication by
division i vide Introduction, p. 27), the terminal lobes lap one
over the other and thus maintain a hold. The chains of cells
collected were evidently mere fragments, or parts broken from
longer filaments ; they contained from 10 to 38 cells.
The details of the terminal lobe vary somewhat from the
form described by Bailey. This species has been found also-
in Florida and in Brazil, S. A.
M. mukicata, Bailey. Plate XXXV, figs. 1 7.
“Semi-cells divided by deep indentations into three trans-
verse portions; the basal with three sublinear processes on.
each side, the others with two on each side.”
The divisions, in front view, do not diverge, but spread
laterally, in such a manner that the one nearest the eye more
or less conceals its companions.
Diameter 100-125 /<■; length 150-200 /i.
Catskill Mountains, (Bailey); many localities in Pennsyl-
vania, New Jersey, Massachusetts. Not abundant, but widely-
distributed.STAU HAST HUM.
131
M. Rabeniiorstii, Kirch. Plate LXIII, fig. 6; Plate XLY, fig. 6.
Cells as long as broad, small, three lobed; terminal cell
not much wider than the lateral lobes, widened from the
base to the end, apex concave, angles terminating with two
short teeth; lateral lobes divided by a wide, almost right-
angled sinus, each half somewhat narrowed towards the
end; apex indented, a small tooth at each angle. Mem-
brane smooth.
Thus reads a free translation of Kirchner’s diagnosis.
The figure does not represent the type; merely a small form
of it.
Diameter 62-85 ye
Collected in ponds in the vicinity of Minneapolis, Minn.
Genus, STAURASTRUM, Meyen.
Cells in front view similar to Cosmarium, end view, three to six
or more, angular; angles obtuse, acute, or drawn out into elon-
gated liorn-like processes. Chlorophyl more or less concentrated
into a central mass, margins radiating towards the margins of the
semi-cells. Zygospores provided with spines.
This genus contains a large number of species; as all are fig-
ured, a complete analysis does not appear important, but for a
general guide they may be. divided into four larger sections, in
the order observed in the following list:
Section I.—Membrane of cells smooth, or rarely punctate or indistinctly gran-
ular.
Section II.—Membrane verrucose, or rough with pearly granules.
Section III.—Membrane hairy, spinulose or aculeated.
Section IV.—Membrane with angles extended into arms, or horn-like processes.
SECTION I.
St. muticum, Breb. Plate L, figs. 11-15.
Cells in front view orbicular, smooth, deeply constricted,
often involved in a mucous envelope; semi-cells elliptic; end
view triangular, or rarely quadrangular; angles rouuded,
sides slightly concave.
Diameter 33-38 yu. Frequent.
Yar. minus ( figs. 14, 15) does not differ from the typical form
except in size; measures only about one-half.132
DESMIDS OF THE UNITED STATES.
Var. ELLIPTICUM. Fig. 13. This form is more elliptic in front
view than the others. Plate XLIX. figs. 41, 42. A form
differing from that of Plate L, and more strictly elliptical,
semi-cells in front view slightly contracted near the ends.
Diameter 33-35 jx.
Pond, St. Anthony Park, Minneapolis, Minnesota.
St. orbiculare, (Ehrb.), Ealfs. Plate L, figs. 9, 10.
Orbicular, constriction narrow linear; semi-cells not ellip-
tic, but semiorbicular: end view triangular, angles rounded,
sides somewhat concave ; smooth.
Diameter 30-45 fx.
Plate XLIX, figs. 36-38 not so distinctly orbicular, some-
times approaching the form of a Turk's cap, sometimes the
sides are more concave than figured and the sinuses between
the semi-cells are not always so closely linear. It is a common
species, and often involved in a mucous envelope.
St. angulatum, West., J. E. M. S., Xov., 1888. Plate XLIII,
figs. 5, 6.
Semi-cells smooth, rhomboid, with a faint indication of an
obscure mucro; end view triangular, with concave sides.
Length 76-78 p.; breadth 60 p.; sinus 17-18 jx.
Pond near Amherst, Mass. Seen sparingly.
St. vesiculatum, Wolle. Plate XII, figs. 6, 7.
Small, smooth, about one-half longer than broad, constric-
tion deep, sinuses acute angled, much ampliated; semi-cells
subpyramidal, not as long as broad; base wide, inferior
angles round, sides convex and inclining to a rounded apex;
end view triangular, angles rather broadly rounded, sides
slightly convex or straight.
Diameter 31 p.; length 45 p.
Differs from St. cordatum, F. Gay; in front view, sinuses
are not narrow linear, but much ampliated, thereby giving
the cell a more elevated appearance. Green’s Lake, Xew
Jersey.
Sr. bacillare, Breb. Plate XLVIII, figs. 5, 6.
Cells small, deeply constricted, sinus a wide, acute angle ;
semi-cell narrow lanceolate, base convex, ends inflated,
head-like, in vertical view 3-4-5 angled; angles radiately
produced with ends enlarged and rounded.
Diameter 25-30 p.
Pond, Minnesota.STAURASTRUM.
133
St. tumidum, Breb. Plate L, figs. 1, 2.
Large, somewhat longer than broad, deeply constricted,
with a distinct colorless gelatinous covering; semi-cells ellip-
tic or suborbicular; end view bluntly triangular, sides some-
what convex, slightly constricted near the angles, producing
a nipple-like projection. Margins app>ear striated.
Diameter 112 p.
The only habitats hitherto discovered, are marsh pools,
Bucks County, Pa., and Lee Pond, Mass.
St. grande, Bulnh. Plate L, figs. 3, 4.
Large, length and breadth the same, sinuses acute, much
enlarged outwardly; semi-cells elliptic, angles obtuse; end
view triangular, rarely quadrangular, sides slightly retuse,
angles obtuse; membrane finely punctate.
Diameter 75-83 pi.
Marsh pools, Minneapolis, Minn.
The specimens were some time in a weak solution of car-
bolic acid before being examined, and in consequence the
arrangement of the ehlorophyl was destroyed ; omitting this
consideration they agree well with measures and forms de-
manded by the diagnosis of the author.
St. magnum, Woile. Plate L, figs. 7, 8.
Cells nearly one-third longer than broad; sinuses sub-
rectangular; semi-cells broad elliptic with a short, stout,
erect mucro at each end ; end view triangular, sides straight
or slightly concave, angles mucronate.
Diameter 82 p..; length 100 p.
This species, like St. tumidum, is usually surrounded by a
wide, colorless, gelatinous sheath. I have this species from
Florida, collected by J. D. Smith.
It is separated from the preceding by its intermediate size,
proportionately greater length and the mucronate angles.
St. majusculum, Woile. Plate L, figs. 5, 6.
Somewhat larger than St. magnum; in end view, sides not
concave, but convex, mucronate; macros not erect, but ob
lique; in front view they are curved inwardly.
Diameter 100-105 g.; length 108-112 pt.
Two localities were productive of this form, Mt. Everett,
Mass., and Longwood Pond, Passaic Co., N. J.
Found no gelatinous sheath around any of the many speci-
mens examined.134
DESMIDS OF THE UNITED STATES.
St. dejectum, Breb. Plate LI. figs. 7-11 and 17-21.
Semi-cells smooth elliptic, or extrorsely lunate with sides
convex and ends nearly straight, concave, or convex; each
angle furnished with a longer or shorter aculeus, or awn:
these are sometimes horizontal, sometimes they converge, but
more frequently they diverge, directed obliquely upward.
End view triangular, or occasionally, four lobed.
Figs. 17-21 represent the more usual forms.
Tar. sieckonatum. Ralfs. Fig. 8, front view and two end views.
Tar. coxyerg-exs. Wolle. Figs. 7, 9. 10. 11, are unusual forms
collected near Minneapolis, Minn.; aculei are stout and often
stand nearly at right angles with the sides; they are also of
unusual size.
Diameter of the various forms 25-38 fx. without the awns.
A common species.
St. uegacaxthuu. Lund. Plate LXII, figs. 10, 11, 12.
Cells about as long as wide (without aculei) profoundly
constricted; sinus acute-angled, or subrectangular; semi-
cells triangular fusiform ; sides somewhat convex, ends sub-
truncate or lightly convex, angles each terminating in a
strong and long aculeus: viewed from apex triangular, or
rarely four lobed ; sides refuse; angles produced into a long
and firm aculeus; membrane finely punctate.
Diameter 50-57 yu.; length about 50 //.; aculei 15-18 //.
Pennsylvania, New Jersey; rather rare.
St. breyispixa. Breb. Plate LI, figs. 1, 2; and Plate LX IT,
figs. 2, 3.
Semi-cells smooth, turgid-elliptic, minutely mucronate;
end view triangular with sides usually so sinuate as to pro-
duce a three lobed appearance; each lobe terminated by a
short rnucro.
Diameter 45-48 )i. Smaller forms occur also.
The cells of this 9pecies vary in size and somewhat in form
from elliptic to subreniform, turgid.
Neither very rare nor common.
Tar. IXER1IE. Wille. Plate LI, figs. 3, 4; Plate XLVI, figs. 9.10.
Somewhat larger than the true form, but otherwise reminds
one of it, notwithstanding the absence of the mucros. TheSTAURASTliUM.
135
author of the name adds, “semi-cells in vertical view trian-
gular, sides lightly retuse, angles unarmed.”
Diameter 60 pi.
Northampton County, Pennsylvania; Florida.
St. Dickiei, Ealfs. Plate LI, figs. 5, 6, 20, 21.
Semi-cell smooth, subelliptic, turgid ; spines short, curved
towards those of the other semi-cell; end view triangular,
sides sinuate, angles mucronate.
Diameter 36-44 pi.
Cells are about as long as broad ; semi-cells elliptic, but
having the outer margin more convex than the inner one ;
the mucros or spines, short, curved, and directed inwardly.
It occurs not infrequently in Pennsylvania, New Jersey,
Massachusetts, and probably in every State.
St. aristiferum, Ealfs. Plate LI, figs. 15, 16.
Semi-cells smooth, triangular, constricted near the anghs,
producing a mammillate appearance. Each angle furnished
with a long awn ; end view with three, or rarely four awned
lobes.
Diameter 15-20 pi. without the awns or spines, and with
them fully twice the size.
Rather rare, but it has been found in many States, from
Rhode Island, New Jersey, to Georgia.
St. Lewisii, Wood. Plate LI, figs. 26, 27.
Smooth, with very ample sinus, obtuse-angled, which is
armed with a small spine; semi-cells from the front broadly
triangular; from the vertex, triangular, with the angles
somewhat tumid and rounded ; angles furnished with a very
large, acute, robust spine.
Diameter with the spines, 62 pi.
This species was first found by Lewis, in Saco Lake, N. H.,
and since only in one locality, the past Summer, 1883, by Bliss
Eloise Butler, of Minneapolis, Minn.
St. cuspidatum, Breb. Plate LI, figs. 23-25.
Semi-cells smooth, fusiform, connected by a long narrow
band; aculei parallel or converging; end view triangular,
or rarely quadrangular, with inflated aculeated lobes.
Diameter 25 pi.; length 30 pi.
Quiet waters, Pennsylvania and New Jersey, but not
frequent.136
DKSMIDS OF THE UNITED STATES.
St. trihedrale, Wolle. Plate LI, figs. 12, 13, 11.
Small punctate-granulate; semi-cells, in front view and in
end view triangular, angles rounded, sides concave, sinus
narrow linear.
Diameter 30 )-i.
Ponds, Mount Everett, Mass.
This species, in front view, has the appearance of a Cosma-
riurn near retusum, Perty, and angustatum, Nord., but the side
and end views are distinct. The semi-cells are three sided,
pyramidal forms unlike those of a Cosmarium.
St. trifidum, Nord. Plate LI, figs. 28, 29.
Cells about as broad as long, deeply constricted; semi-cells
short cuneate, with ends dilated, and lightly retuse; superior
angles obtuse, trisected; viewed from vertex triangular,
angles truncate, trifid ; sides somewhat concave; membrane
finely punctate.
Diameter 30-50 g. Variable in size.
Not frequent, but met with in localities widely separated,
Pennsylvania, New Jersey, and other States.
St. Avicula, Breb. Plate LI, figs. 30, 31, 32.
Semi-cells twice as broad as long, with a forked spine on
each side; each angle in end view terminated by a simple or
forked spine; cytioderm smooth.
Diameter 25-30 /<., without the spines.
Rather common species; appears to be found frequently in
every State in which explorations are made.
St. commutatum, Kg. Plate LI, figs. 33, 34.
Smooth or punctate-granulate; semi-cells diverging, ob-
verse semilunar; base broadly rounded, ends straight or
somewhat concave ; apices bifid ; end view triangular, angles
produced and apices bicuspidate; sides moderately retuse.
Diameter 35-38 g., omitting the spines.
Ponds, Lehigh Valley, Pennsylvania.
This form may not be strictly the plant described by the
author, Kiitzing ; it is near it, and appears to stand between it
and A. Bulnheirnicmum, Rab. Have seen very few of them,
hence record the name merely provisionally.
St. hr ac hi at lai, Ralfs. Plate LI, figs. 37, 38, 39; and Plate
LXIII, figs. 29, 30, 31.
Cells smooth; semi-cells with three diverging processes,
or according to other authors, 2-4-5 radiate, which are deeply
bifid or trifid at the apex; end view with three or four rays.STAURA STRUM.
137
Diameter 33-55 p. Not frequent.
The figures on Plate LXIII, represent a form noted as va-
riety Notarisii, Rab. Collected in ponds Bamber and Brown's
Mills, N. J.
St. panic ulosum, Wolle. Plate LII, figs. 39, 40.
Cells hexangular, as long as broad, membrane punctate;
punctules in radiating lines; semi-cells truncated triangles,
angles rounded; inferior angles furnished with two short,
straight aculei; end view triangular with one small aculeus
visible on each rounded angle; sides moderately convex.
. Diameter 40-50 p.
Marsh pools, near Bethlehem, Pa.
St. Bieneanum, Bab. Var. ellipticum, Wille. Plate LIU, figs.
1, 2.
Semi-cells elliptic; end view triangular with angles
rounded, sides more or less deeply concave; membrane
finely punctate, distinctly observable when the cell is empty;
punctules regularly arranged in transverse lines.
Diameter 33-38 p.
Not numerous, but hitherto found specimens in Minnesota,
Massachusetts, New Jersey, Pennsylvania and Florida.
St. inconspicuum, Nord. Plate LXIV, figs. 4, 5.
Small, about equal in length and breadth; very indis-
tinctly or not at all constricted in the middle; semi-cells
subquadrangular, ends usually slightly retuse; superior
angles produced obliquely into a geniculate arm with a
truncate end ; end view four radiate, sides concave. Mem-
brane smooth or finely punctate.
Diameter 14-16 p.
Occasional in ponds, New Jersey.
St. pseudopachyrhynchum, Wolle, Plate LXII, figs. 32-35.
Small, smooth or imperfectly punctate, slightly longer
than broad, deeply constricted; sinus wide, base rounded;
semi-cells subcuneate; from a narrow base somewhat undu-
lately widened to the broad, subtruncate end; angles rather
broadly rounded, with a slight constriction near the apex.
End view tri- or quadrangular; sides sinuate. Isthmus
about one-fourth the diameter of cell.
Diameter 20-24 p.; length 22-25 p.138
DFSMIDS OF THE UNITED STATES.
Pond, Spring Lake, N. J.
I found this new species only in one pond, but numerous ;
it bears the appearance of a relation to a Brazil plant de-
scribed by Xordstedt as St. Clepsydra, and also to a Spitz-
bergen species by the same author, St. pachyrhynehum. The
name applies well to the new form, although only two-thirds
the size and proportionately longer ; the sides also of end
view, are not “slightly concave,” but deeply sinuate.
SECTION II.
CYTIODEBM GRANULAR OK VERBTJCOSE.
.St. margaritaoeum, Ehrb. Plate LII, figs. 31-33.
Semi cells in front view subelliptic, rough with pearly
granules; outer margin convex, produced at each side into
a more or less attenuate, short process, having the granules
in transverse lines; blunt and entire at the apex. End view
circular, bordered by from 1-6, rarely 7, short, narrow, ob-
tuse, granulate marginal rays.
Diameter 30-35 yu.-
Found in all States explored, from Rhode Island to Florida.
St. striolatum, Xaeg. Plate LXII, figs. 27, 2S.
Small, as broad as long, sinus acute angled; semi-cells ob-
verse reniform; angles rounded, end concave, transverse
striate, five or six strife distinct on each lobe; end view tri-
angular, angles rounded and sides concave ; each lobe trans-
versely striate. The strife are series of smaller or larger
granules.
Diameter 22-35 p.
Not frequent, but found occasionally in distantly separated
localities, New Jersey, Pennsylvania, South Carolina, and
other States.
.St. tricorne, Breb. Plate LII, figs. 36, 37, 38.
Cells rough, with puncta-like granules; semi-cells taper-
ing on each side into a short, blunt, mostly entire, process;
end view with three or four blunt angles.
Diameter 22-28 p.
Not in so many localities, but often numerously clustered
together; Pennsylvania, New Jersey.
St. crenatum, Bailey. Plate LII, figs. 5, 6.
Semi-cells cuneate; outer margins crenate; end view with
three truncate and crenate angles; sides concave.
This species was reported by Bailey to Ralfs as found in
Rhode Island. Probably not seen since in this country.8TAURASTHUM.
1-S9
St. pseudocrenatum, Lund. (St. maamense, Arch.) Plate
XLYIII, figs. 9, 10.
Cells nearly one-fourth part longer than broad, suboval
ends somewhat truncate, deeply constricted, sinus narrow-
linear; semi-cells subsemicircular, base straight, sides sub
crenate, crenaeroughlytruncate-emarginate; endsobsoletelv
erose-dentate, inferior angles subtruncate; in vertical view
triangular, sides retuse, angles broadly subtruncate, dentate
with three granules.
Diameter 30-35 p.; length 38-12 p.
Found this species frequent in ponds, Minnesota and Cali-
fornia. This form is nearest to St. crenatum, Bailey, (in Bal fs’
Br. Des., p. 215,) but differs in having a much narrower sinus
between the semi-cells, and the semi-cells are not cuneate
flabelliform.
St. erasum, Breb., var. espinulosa, Lund. Plate XLYIII,
figs. 16, 17.
Of medium size, as long as broad, coarsely granulate, sinus
acute-angled, outwardly ampliated; semi-cells somewhat
elliptic, back nearly straight, angles rounded, more or less
dentate, with large granules; in vertical view triangular,
angles broadly rounded, sides concave.
Diameter 34-38 p.
Green’s Lake, New Jersey.
St. luteoluh, Lagh. Plate XLIX, figs. 22, 23.
Cells rather small, nearly circular, deeply constricted,
sinus narrow linear; base of semi-cell straight, back arched,
inferior angles obtusely rounded granulate-crenate. Mem-
brane thick, punctate, yellowish.
Diameter 32 p.; length 33 p.; thickness 32 p.
Tewksbury, Massachusetts.
St. Cosmarioides, Eeinsch. Plate XLVI. figs. 7, 8.
Cells large, composed in front view of two orbicular semi-
cells attached, forming an isthmus of one-third the diameter
of the cell; margins of sides finely dentate; in vertical view
triangular, angles rounded, sides slightly convex.
Prof. Reinsch describes this form as found in Pennsylvania.
To my knowledge it has not occurred since.
St. polymorphum, Breb. Plate LIII, figs. 9, 10, 24, 25.
Semi-cells in front view broadly elliptic, with sides taper-
ing into short, stout processes, ends tipped with three or
four small spines; membrane rough with minute, sometimes140
DESMIDS OF THE UNITED STATES.
acute granules; end view triangular, angles truncate, or
drawn out into short, stout processes, ends tipped with
small spines. Zygospores orbicular, armed with elongated
spines forked at the ends.
Diameter 25-30 yu.
Frequent in ponds and small pools.
St. crenulatusi, Xaeg., (Delp.). Plate LIII, figs. 26-29.
In front view hardly separable from the preceding; end
view with four, five or six angles, each produced into a short,
stout, somewhat tapering ray; ends tipped with short spines,
which are sometimes merely rudimentary.
Diameter 30-38 p.
Frequent in ponds, ditches and the like.
Some authors unite these forms with the preceding species;
others hold them as distinct for the reason that the rays often
have transverse series of large granules, which give a crenulate
appearance to the margins. Our artist failed to bring out this
feature as distinctly as it should be.
St. muricatuji, Breb. Plate LIII, figs. 3-6.
Suborbicular, deeply constricted, sinus narrow linear, or
slightly enlarged outwardly; rough with somewhat conical
granules; semi-cells subsemiorbicular, angles obtusely
rounded, or truncate; end view triangular, sides convex,
angles rounded or truncate spinous.
Diameter 40-45 yu.
Pools and ditches in many distantly separated localities,
but not very numerous.
St. asperum, Breb. Plate LIII, figs. 7, 8.
In comparison with the preceding (St. muricatum), gran-
ules are emarginate, or divided; semi-cells broadly elliptic;
sinus much wider, and sides in end view straight; otherwise
very near it.
Habitat and size the same.
St. rugttlosuh, Breb. Plate LII, figs. 41, 42.
Semi-cells elliptic, denticulate at their sides; end view
triangular, with angles broadly rounded and sides slightly
concave or straight.
Diameter about 38 yu.
Very nearly related to the preceding ; I quote the diagnosis
of the author. Bailey reports it from New York and Rhode
Island ; I add it from Pennsylvania and New Jersey. Not a
rare form.STAURASTRUM.
141
St. punctu latum, Breb. Plate LII, figs. 43-45.
Cytioderm punctate-granulate, semi-cells elliptic, straight,
ends broadly rounded ; end view triangular, angles not pro-
duced, broadly rounded, sides lightly retuse.
Diameter 30-35 ft.
Frequent in marsh pools, ditches, on dripping rocks and the
like.
St. pygmieum, Breb. Plate LIII, figs. 14-21.
Small, sinus wide, subrectangular; semi-cells cuneiform or
broadly elliptic, often alternately attached, angles more or
less obtuse, and sometimes spinous; membrane granularly
rough.
Diameter 16-25 yu.
Variable in size and form. They may be separated into
three divisions.
Porma,—genuina, Breb., figs. 14, 15.
Porma,—truncata, Wolle, figs. 16-19.
Forma,—rhomboides, Wolle, figs. 20, 21.
Found in nearly all standing or quiet waters, sometimes in
large numbers.
St. megalonotum, Ford., var. obtusum, Hast. Plate XLII,
figs. 6, 7.
Small, about one-fourth longer than broad; cytioderm
granulate; isthmus about one-half width of cell; sinuses
acute angled, opening outwardly; semi-cells truncately coni-
cal, base convex, sides concave, the truncate end with six
conical processes, only four of which are usually visible in
side view, basal angles obtuse (differing in this respect from
Arctic varieties); transverse view triangular, the angles
rounded, the sides slightly concave.
Diameter 45 /(.
Ponds and brooks, Rochester, New Hampshire.
St. Minneapoliense, Wolle. Plate XLVIII, figs. 11-13.
Small verrucose; semi-cells in front view subcuneate with
the two opposite superior angles drawn out into a short arm
with margins serrate, and apices finely toothed; arms di-
verging from the arms of the connected semi-cell; in vertical
view arms straight, body much elevated on each side; in
lateral view arms straight, short; body puffed out high on
each side, crenate on the apices.142
DESMIDS OF THE UNITED STATES.
Diameter in front view, including arms, 50-58 fi.; thick -
ness of body 20-25 //.
The front presentation, not unlike other forms, but the
vertical and lateral views are quite distinct in the usual in-
flation of the body.
The name indicates the habitat.
St. alternans, Breb. Plate LII, figs. 26-2S.
Semi-cells granulate, elliptic or oblong, two or three times
as long as wide, and from their twisted position, unequal in
front view; end view with three obtuse and rounded angles,
forming short rays, alternating with those of the other semi-
cell.
Diameter 20-2S //. Frequent.
St. dilatatum, Ehrb. Plate LXIII, figs. 32, 33.
Small, granulate; semi-cells fusiform, equal; end view
with three, four or five short, broad, truncate rays, granules
arranged in transverse lines.
Diameter 40 r. Frequent.
Distinguished from the preceding, mainly, by the semi-cells
not being twisted.
St. silatatum, Nord. Plate LTII, figs. 22, 23.
Cells in front view fully twice as wide as long, deeply con-
stricted ; sinus with rounded base, outwardly enlarged;
semi-cells sublanceolate, ends straight, lightly undulate;
end view five lobed, margins smooth.
Diameter 30 /c; length 13-16 p.
Ponds, Florida.
St. cyrtocerum, Breb. Plate LIII, figs. 30, 31.
Cells rough with minute granules; semi-cells, front view,
subcuneate, top broadly convex, superior angles produced
into short, stout, curved processes; end view triangular;
each angle produced into a curved horn-like process with
end toothed or divided; grauules arranged in transverse
lines. Semi-cells often so twisted as to make one-half appear
longer than the other half.
Diameter 35-40 m-
Var. major, Wolle. Plate LIY, figs. 1, 2.
Xot unlike the typical form except in size; often attains
to a diameter 120 /<.STAURASTRUM.
143
Yar. pentacladum, Wolle. Plate LIII, figs. 32-35.
Separated from the other forms by the number of arms ;
they vary greatly in size, always symmetrically arranged
with five curved arms.
Diameter 44-85 f*.
Have one or the other form from every State hitherto
explored.
St. paradoxum, Meyen. Plate LIII, figs. 36, 37.
Cells rough with minute granules; front view with elon-
gated diverging processes which are bifid or trifid at the
apices; end view triangular or quadrangular.
Diameter 40-60 /t.
Ponds, New York, Pennsylvania, New Jersey, Massachu-
setts.
The figures represent an extraordinary form ; usually the
apices of the processes are more minutely trifid.
Yar. Osceolense, Wolle. Plate XL VII, figs. 8, 9.
This variety differs from the typical form in its larger size,
quadrangular body and in the large trifid, hooked, apices of
the arms.
Diameter of spread of arms 60-70 /.i.
Lake Osceola, Winter Park, Florida.
St. Arachne, Balfs. Plate LIII, figs. 38-42.
Semi-cfells minutely granular, suborbicular, with elongated,
slender, often incurved processes; end view with three to-
five linear rays; apices obtuse.
Diameter 40-50 p.
Habitat same as that of the preceding. Distinguished
from it by its more slender arms and obtuse apices.
St. comptum, Wolle. Plate LITI, figs. 43-46.
Small, granulate; semi-cells subfusiform, ends convex;
arms more or less converging, separated by an elongated,
cylindrical, somewhat swollen isthmus, ribbed in the center;
vertical view six radiate; rays straight, tricuspidate at the
ends.
Diameter 30-40 p.; length 40-50 /a
Not rare in ponds, New Jersey.
St. elongatum, Barker. (St. terebrans, Nord.) Plate LVII,
figs. 11, 12.
Elongate; semi-cells subtriangular; base globosely inflated,
produced into a cylindrical column inflated at the end, and.144
DESMIDS OF THE EXITED STATES.
drawn out into three arms somewhat reflexed at the ends;
margins denticulate-undulate above, and spinous below;
apices with three or four small spines. Inflated base with
three transverse series of small papillae; end view triangular,
sides concave, denticulate.
Diameter 4.3-45 //.; length 60-75 /u.
Ponds, Pennsylvania.
Yar. tetragoxum, Wolle. Plate LXII, fig. 31.
Separated from the typical form in having in end view
four rays instead of three; in having the rays horizontal,
not reflexed, and terminating with three or four strong-
teeth ; the ends of the cells are rough with spine-like gran-
ules ; the base of the semi cells inflated, corrugated and
denticulate.
Diameter 38 ft.; length 5S yu.
Pond, Brown’s Mill, X. J.
St. scabrum, Breb. Plate LII. figs. 29, 30.
Semi-cells elliptic, scabrous; end view triangular, fringed
with minute emarginate spines ; sides straight, angles obtuse.
Diameter 25-28 /<.
Occasional in ponds, trenches and ditches, Pennsylvania
and New Jersey.
St. fasciculoides, Wolle. Plate LIII, figs. 54, 55.
Small, somewhat longer than broad, granular, sheaf-form,
slightly constricted and notched in the middle, furnished
with a small protuberance on each side the notch < front
view ), apex 2-4 cuspidate. Ends convex, angles drawn out,
each into a horizontal, short, stout, tapering process, apex
dentate. End view triangular, sides slightly, convex, angles
dentate with two or three acute, conical teeth.
Diameter 27-30 /<.; length 38 yu.
Wet rocks, Lehigh Valley, Pennsylvania.
St. pusillfm, Wolle. Plate LIII, figs. 47-50.
Very small, oblong, rectilinear, constriction indistinct;
angles produced into diverging horn-like processes; end view
ciuadrangular, angles drawn out into four diverging pro-
cesses, ends obtuse; membrane granular.
Diameter 8 /v; length 14 yu., without the processes ; about
twice the measure with them. Larger form has with pro-
cesses a diameter of 25 /c
Not rare in ponds, Pennsylvania, New Jersey.STAURA STRUM.
145
St. Franconium, Reinsch. (St. divaricatum, Wolle.) Plate
LYII, fig. 22.
This species is separated from the preceding (St. pus-ilium)
by its somewhat larger size and by having in end view, five
processes with bifid apices, not obtuse. The typical plant
is described by the author, “membrana glabra, (aut cornua
verruculosa).” Our forms are always granular.
Diameter about 30 p. with processes.
This, and the preceding, not common, but they appear in
many widely separated localities in New Jersey and Penn-
sylvania.
St. Haaboeliense, Wille. Plate LIII, figs. 51-53.
Small, about one-third more in breadth than length ; con-
striction in the middle forms a wide sinus; semi-cells in
front view subelliptic, ends bicuspidate, margins dentate;
in vertical view triangular or rarely quadrangular, sides
sinuate. Membrane granulate.
Diameter 24 p.; length 18 p.
Found this form several times in ponds, New Jersey ; it
differs slightly from St. tricorne except in the apices, which
are not obtuse but bicuspidate.
St. botropiiilum, Wolle. Plate LIII, figs. 11-13.
Somewhat longer than broad, distinctly granular; granules
arranged in concentric series; semi-cells, front view, sub-
triangular, with ends broadly truncate, sides moderately
convex or nearly straight, converging, basal angles rounded;
end view triangular, angles rounded, sides slightly convex
or straight; lateral view, subelliptic.
Diameter 36-38 p.
Collected in marsh ditches near Bethlehem, Pa. In front
view it has the appearance of a Cosmarium, like some form of
Botrytis, but in side and end views it is a Staurastrum.
St. Pringlei, Wolle. Plate LXI, figs. 25.
Cytioderm granular; of equal length and breadth; con-
striction not deep, sinus wide; semi cells subtriangular,
sides rounded, end concave with a central inflation, angles
acute. End view triangular, sides concave, angles acute.
Membrane rough with fine granules. Surrounded by a thick
gelatinous sheath.
Diameter 28-33 p.
Found by C. G. Pringle, Nebraska Notch, Vt.
10146
DESMIDS OF THE UNITED STATES.
St. Donnellii, Wolle. Plate LXIII, fig. 20.
Small, twice as long as wide, oblong-quadrate; cytioderm
punctate and sulcate; semi-cells quadrangular with basal
angles rounded, sides crenulate; superior angles (four) pro-
duced into short, obtuse, diverging processes; end view
quadrangular.
Diameter 15 p.
Collected by J. Donnell Smith in Florida.
This species is nearest St. jJusillum, but unlike it in the pro-
portionately longer cell, the almost smooth and sulcate mem-
brane, and the crenulate sides.
St. incisum, Wolle. Plate LII, figs. 12-14.
Cytioderm granulate, margins serrately toothed; semi-cells
in front view cuneate, base broad, sides diverging to a con-
vex top; the upper portion on each side produced into short,
obtuse, tapering processes; end view, five or six radiate;
rays with broad base, somewhat tapering to the obtuse
apices; sides serrately toothed; the rays separated at their
broad base by an acute-angled, or linear incision.
Diameter 36-40 /<.
Principally from Splitrock and other ponds of New Jersey.
St. pulchrum and St. distentum have a leading feature of this
species—the incision, or notch between the bases of the rays,
but they are separated by the smooth membrane and differ-
ently formed notch.
St. Meriani, Reinsch. Plate LVII, figs. 17-19.
('ells in front view subreetangular, roughly granulate,
slightly constricted in the middle; semi-cells somewhat en-
larged in the upper portion; sometimes slightly constricted
near the end ; apex rounded; end view usually pentagonal,
but varies, more rarely, from four to six angular.
Diameter 16-24 p.; length about one-half more.
Have found this species in various ponds of New Jersey
and Pennsylvania.
St. Heleneanum, Wolle. Plate LY, figs. 6, 7.
Small, finely granular; granules arranged in transverse
rows; semi-cells, front view, narrow, elliptic, ends slightly
emarginate; angles somewhat produced, and apices furcate;
vertical view triradiate, with large central inflation, rays
short, stout, tumid at base and furcate at apices; basal in-
flation furnished on each side with a small bicuspidate
prominence.
Diameter 30-36 p.STAURASTRUM.
147
Frequent in Splitrock Pond, New Jersey.
There is a trace of similarity between this desmid and St.
vestitwn, Balfs, but, while the latter has two or more slender
forked spines in the middle of each side, mine has stouter
forked prominences on the inflated base of each ray; the
sides, moreover, are not concave, but undulate convex; size
of plant much smaller.
St. Cerastes, Lund. Plate LIV, figs. 6, 7.
Rather broader than long; semi-cells in front view, ends
lunate, drawn out in the middle of the concave side into a
subconical column ; the lateral horns are robust, short, in-
curved, apices obtuse ; the exterior margin coarsely granu -
late and often very rough with large emarginate, bifid,
verrucae; the interior margin nude; end view quadrangular,
angles produced into stout, straight horns, apices tridentate;
margins and areas variously roughened, with larger and
smaller granules and often dentate with large conical, or
emarginate-bifid verrucae.
Diameter 60-70 p.
Not abundant, nevertheless a cosmopolite.
The figures represent a smoother specimen.
St. gracile, Ealfs. Plate LIV, figs. 16, 17.
Semi-cells rough, elongated on each side into a slender
process which is terminated by minute spines; end view
triradiate.
Diameter 40-50 p.; length about one-third this measure.
Ponds, pools, ditches from Vermont to Florida, and west-
ward as far as explorations have been made.
St. Ophiura, Lund. Plate LIV, figs. 10, 11.
Large, slightly constricted in the middle; semi-cells some-
what obovate, end convex and ornate with bifid papillae ;
-superior angles produced laterally with elongated, thin,
almost colorless, straight, or lightly incurved rays, with
margins more or less denticulate, and apices dentate.
Viewed from the vertex seven (rarely six or eight) rayed ;
rays attenuated, long, apices tridentate, margins serrate-
dentate; center ornate with a crown composed of seven
(rarely six or eight) four-parted papillae.
Diameter 140-150 p.; length 65-80 p.
More abundant in the waters of New Jersey than of Penn-
sylvania ; found specimens also in ponds, Massachusetts.148
DES.MIDS OF THE UNITED STATES.
Var. tetracerum, Wolle. Plate LV, figs. 1, 2.
Yar. pextacerum, Wolle. Plate LY, fig. 3.
The one foar-armed, and the other five-armed ; the crown
papillae correspond in number with the arms; in other
details they are not unlike the typical form; the serrate-
dentate margins vary greatly in different specimens.
These varieties I collected only in Denmark Pond, Passaic
County, N. J., where they occurred frequently.
St. jiacrocerum, Wolle. Plate LIV, figs. 3, 4, 5.
Yery large, granularly rough; semi-cells, front view, sub-
cuneate, truncate base and rounded top; upper angles later-
ally produced into long, slightly tapering, straight or lightly
incurved arms, margins serrate, ends bifid : end view six
radiate. Separated from the preceding partly by the less
number of arms, the less, central elevation (front view) and.
the absence of the crown of papillae.
Diameter 150-180 pi.
Not rare in New Jersey waters.
St. odontatum, Wolle. Plate LIV, figs. 8, 9.
Of equal length and breadth; semi-cells in front view sub-
quadrangular, end convex, upper angles drawn out laterally
into straight or lightly incurved arms, as long as the breadth
of the body of the cell; margins serrate, apices furcate; the
lightly rounded inferior angles, each armed with a strong,,
short, aculeus. End view quadrangular, four rayed.
Diameter 62-75 pi-; length 45 pi.
Splitrock Pond, Passaic County, N. J.
St. Rotula, Nord. Plate LY, figs. 13, 14.
Large, punctate, profoundly constricted ; semi-cells sub-
hexagonal, top truncate and furnished with a few teeth;
angles produced laterally into long, straight rays, margins
with three (or four?) tooth-like prominences; end view cir-
cular with seven to nine straight rays, margins tri-dentate-
crenate, apices trifid; at the base of each ray a large granule,,
area between, punctate.
Diameter 88-125 pi. Florida specimens 50-62 pi.
Denmark, Splitrock, and other ponds, Passaic County, N. J.;:
Florida. Very rare in Pennsylvania.
St. coronulatuh, Wolle. Plate LV, figs, ll, 12.
Twice as wide as long; semi-cells obovate; sides produced
into somewhat tapering, incurved arms, margins dentate;STAURA STRUM.
149
ends convex, bearing six oblong teeth arranged in crown-
form; viewed from the vertex, six radiate, margins delicately
serrate-dentate, apices tridentate.
Diameter 75-S5 p.
Denmark Pond, Passaic- County, and pond near Malaga,
New Jersey.
This species has the crown teeth of St. Rotula, but not the
size, number of arms, nor the serration.
Tar. Floridense, Wolle. Plate LIT, figs. 12, 13, 11.
This form has points in common with the present species,
with St. Ophiura, with St. peutadadum; but the form recog-
nized under the latter name is very slender and usually
smaller: St. Ophiura has seven arms, long, and coarsely den-
tate-serrate. Size, relative length of arms and breadth of
body, and the marginal serration and crown papillae or teeth,
make it appear most nearly allied to the present species.
Diameter 75-85 p.; exceptions 50 p.
Frequent in pond water, Florida.
St. pentac-ladum, Wolle. Plate LIT, fig. 15; Plate LV, figs.
15. 16.
Of the same general type as the preceding. It has five
rays, end view, but these are more slender, the body is
smaller and the apices are more spreading.
Diameter 10-70 p.
Gilder Pond, Mt. Everett, Mass., and in waters scattered
throughout New Jersey and Pennsylvania.
.St. leptooladum, North Plate LT, figs. 4, 5.
Semi-cells subtriangular, end broadly rounded, furnished
with small rudimentary teeth; within the margin a small
tumor; margins serrate-crenate; base truncate, superior
angles produced laterally, each into a long, thin, incurved,
granularly rough arm with a bi-tri-furcate apex ; in vertical
view, fusiform with an obtuse angled inflation in the middle.
Diameter 80-100 p.; length about 25 p.
The original, typical plant from Brazil, is described by the.
author, and figured by him with the arms strongly incurved
and body longer than our form. The plants identified as of
this species, have the arms nearly horizontal, and often
strongly recurved.
They occur frequently in ponds of New Jersey, Massachu-
setts, Minnesota, Pennsylvania, Florida and doubtless in
many other States.150
DESMIDS OF THE UNITED STATES.
St. grallatorium, Nord. Plate LY. fig. 19.
Semi-cells subquadrangular, top somewhat produced with
one, or two, small aculei at each angle; inferior angles
rounded; sides produced, each into a long, thin, colorless
ray, margins crenate-dentate, apex bi-tri-furcate; vertical
view oval, produced on opposite sides into a long thin arm.
Diameter 100-125 q.
Yar. UNGULATUM, Wolle. Plate LY, figs. 17, 18.
Besides having the apices of the rays tipped with a single
claw-like spine, they are usually shorter and stouter, varying
as the figures.
This variety is from Florida ; the typical forms from Den-
mark Pond, Passaic Co., .New Jersey.
St. fusiforme, Wolle. Plate LV, figs. 20, 21.
Semi-cells in front view, narrow fusiform, lateral angles
drawn out into long, colorless arms, margins crenate-dentate,
apices bifurcate; back or end broadly rounded or straight,
crenate; end view fusiform.
Diameter 125-138 ft.; length 38 /<.
This species appears to be related to the preceding two, but
varies from both in form of cell; from St. leptocladum, in the
longer, stouter, and straighter arms, and from St. grallatorium,
in the absence of the produced back and the aculei.
Denmark Pond, New Jersey.
St. iotantoi, Wolle. Plate LXII, figs. 5-7.
Very minute; semi-cells quadrangular, angles drawn out
into thin, diverging, granular rays, each about as long as the
diameter of the body; apices obtuse; end view triradiate.
Diameter, including the rays, 15-20 p.
The rays are so minute, they appear like a single series of
fine granules.
Found this very small species quite numerous at Ocean
Beach and at Malaga, N. J.
St. ankyroides, Wolle. Plate LXII, fig. 4 and variety fig. 3.
About as long as wide, grannlarly rough; semi-cells cylin-
drical with enlargement towards the convex end; sides pro-
duced laterally into narrow, elongate, slightly tapering, in-
curved arms, margins granulate-crenate, apices bifurcate ;
end view quadrangular, four-rayed.
Diameter 82 p.; length 75 ju.
The only water which hitherto furnished this new species
is a pond near Malaga, New Jersey.STAUEASTRUjM.
151
Var. hexacerum, Wolle. Plate LXII, fig. 3.
Somewhat stouter than the typical form and furnished
with six arms.
Ponds, northern counties of New Jersey.
In the possession of six arms it bears some resemblance to
St. coronulatum, but with nearly twice the length, and in the
absence of the circle of large granules on the convex end,
which suggested the name, it appears more nearly related to
St. ankyroides.
St. nanum, Wolle. Plate LY, figs. 8, 9, 10.
Very small, smooth, or granulate-punctate; semi-cells sub-
cuneate, sides somewhat rounded, ends broadly convex ;
superior angles produced laterally into straight slightly di-
verging arms, nearly as long as the diameter of the cell, ends
forked ; viewed from the end tri-radiate, sometimes twisted
so that the arms of the lower half cell alternate with those
of the upper half.
Diameter 20-25 g.
Frequent in ponds, Mt. Everett, Mass.
This minute species is nearest St. gracile, Ralfs, but differs
in its smaller size, more forked apices, and smoother mem-
brane.
St. vestitum, Ralfs. Plate LVI, figs. 28, 29, 30.
Cells rough with minute granules; with this investment
there are also minute emarginate spines; semi-cells fusiform
in front view; seen from the vertex, triradiate, each side
having two slender, forked spines in the middle, and often
accompanied by other smaller ones.
Diameter 62-90 g.
Has a home in many parts of the civilized world, so here
also it is found widely scattered.
St. Sebaldi, (Sancti Sebaldi), Reinsch. Plate LVII, figs. 1-6; 10.
One-fourth to one-half wider than long, coarsely granulate;
margins in part granulate-crenate, and in part spinous.
Semi-cells broad cuneate, base truncate, top convex, with
sides more or less conically produced ; apices bifid or trifid ;
near the top margin a series of emarginate or tricnspidate
spines, which come to view at one or the other end of the
cell as it is more or less inclined from a horizontal position.
End view triangular, angles slightly produced, apices tri-
dentate; sides nearly straight, or slightly convex.
Diameter 75-95 y.152
DESMIDS OF THE EXITED STATES.
A conspicuous species, large, stout and spinous ; variable in
the length of the lateral arms; in some eases short, stumpy; in
others more elongated; the spines are also variously promi-
nent ; in exact horizontal position they are often not notice-
able ; when somewhat turned they become prominent on one
end and indistinct on the other ; the result of their being
arranged not on the margin but within it.
The finest, largest and best developed forms, I found in
small pools and ditches, Pennsylvania and New Jersey.
Tar. spixosfm. Wolle. Plate LYII. fig. 7.
The spine (process') protruding near each lateral margin
of the semi-cell, is the peculiarity of this variety.
Collected near Minneapolis, Minn.
St. Pseudosebaldi. Wille. Plate LYII, figs. 8, 9.
Cells one-fifth part more in width than length, profoundly
constricted: spines of the end of the semi-cells bifurcate;
rays nearly straight, granular, apices tricuspidate: vertical
view, triangular, sides concave, furnished in the middle with
short bifurcate spines.
Diameter about 75 p.
Ponds, Pennsylvania and New Jersey.
St. axatixum, Cooke and Wills. Plate LXII, figs. 1. 2.
Large, granularly rough, or spinous; semi-cells in front
view oval with ends drawn out into diverging arms, apices
trifid. End view triangular, sides slightly concave, with
angles produced into straight arms; margins in both views
ornate with large, emarginate-bifid, or papilliform verrucae.
Diameter bO-SO p.; length about one-half the diameter.
Ponds, Mt. Everett, Mass.
This species differs from St, SiJialcIi, in being more slender,
not so turgid, arms more protracted, and more evenly clothed
with large verrucae.
St. arccvtum. Xord. iYar.) Plate LYII. figs. 13, 11.
In length and breadth about the same: constriction deep:
sinus acute angled, much anrpliated; semi-cells elliptic,
granularly rough, grannies arranged in transverse series ;
base convex, top convex or straight, each end furnished with
large diverging twinned aculei: end view triangular, center
smooth ; arms short with granules in transverse series: sides
furnished with four or more bicuspidate spines; angles with
two aculei. only one of which is clearly visible in exact
horizontal position of cell.
Diameter 3(1-30 p., without the aculei.8TAURASTRUM.
153
Splitrock Pond, Passaic Co., N. J.
Our species differs somewhat from the typical Norwegian
form, but I adopt the name for our variety.
St. subarcuatijm, Wolle. Plate LVTI, figs. 15. 16.
This species is allied to the preceding, St. arcuatum; I have
separated it because it is smaller, the aculei at the terminal
angles are not so long and the marginal granules are only
rarely bifid. In end view, the papilla-like granules are
arranged concentrically, often protruding on the margins.
Since naming this desmid, three years since, I came across
varieties of St. Avicula coarsely granulate, which are very
near to this form. A variety of Avicula would have been
equally appropriate.
St. orescentum, Hast. Plate XLII, figs. 8-11.
Semi-cells subelliptic, or somewhat hexagonal, base trun-
cate convex, undulate; superior lateral margins each with
three teeth or verrucae, the upper two truncate; apex trun-
cate undulate; each lateral angle furnished with two, or
rarely three, diverging aculei, rarely unarmed; end view
triangular, sides sinuous concave, sometimes furnished with
a subulate spine near the angles; angles suddenly attenuate,
rounded and usually furnished with two, sometimes three
aculei, rarely unarmed; center of triangle smooth, sur-
rounded by three pairs of crescentric teeth in a wide circle,
these are surrounded by others, so that each limb of the
triangle bears five crescentric teeth, two, two and one, all
within the margin, the last one sometimes indistinct or ob-
solete.
Diameter, without aculei, 45-50 /J.
From a small pond, Dover, N. H.
This at first view recalls St. arcuatum, also St. forficu/n-
tum, but in end view the crescentric markings, the suddenly
attenuate angles ; the sinuous concave sides aud the lateral
subulate spines make a good specific character.
SECTION III.
MEMBRANE PIEOSE, SPINOUS OR ACULEATED.
Si', aculeatum, Ehrb. Plate LVI, figs. 1, 2, 3.
Cells spinulose; semi-cells with sides somewhat drawn out,
margined with smaller aculei, and terminated by larger ones;
end view usually with three, but sometimes also with four
angles.
Diameter, without aculei, about 50 /<.154
DESMIDS OF THE UNITED STATES.
Pond, near Minneapolis, Minn. Found no good specimens-
elsewhere.
Semi-cells are elliptic or fusiform, thickly spinulose. the
spines usually simple, rarely divided at the apex ; the semi-
cells taper on each side into a short process tipped with three
or four larger aculei.
This form agrees well with St. Saxonicum, Reinsch. Buln-
heim Iras a different form with the same name which I have
adopted in this monograph.
St. teliferum, Ralfs. Plate LYI, fig. 4.
Semi-cells more or less reniform, aculeated; the aculei
larger and most densely set at the angles; end view trian-
gular, sides concave, angles broadly rounded and bristly.
Diameter 33-38 ju.
Not rare in pond waters of New Jersey, Pennsylvania and
Massachusetts.
St. Brebissonii, Arch. Plate LYI, figs. 5, 6.
Cells very near St. teliferum, but much larger; semi-cells
more elliptic and aculei proportionately smaller.
Diameter 62 ju.
Florida, the only habitat hitherto found.
St. setigerum, Cleve. Plate LYI, tigs. 26, 27.
Semi-cells broadly elliptic, bristly; the bristles, or more
properly aculei, have a firm base and sting-like apex; they
are arranged on the margins, with two longer, and stronger,
diverging ones on each lateral angle.
Diameter with aculei 45 /<.; without aculei 25 fj..
Not north of Florida, as far as I could discover.
St. Saxonicu.u. Bulnh. (Not Reinsch’s form.) Plate LVI,
figs. 33, 34.
Large, spinous; semi-cells elliptic, evenly aculeated over
the whole membrane; end view triangular, sides straight or
slightly concave.
Diameter 68-75 //.
Budd’s Lake, N. J. Compare note, St. w.ul.eatum.
Yar. pentagonum. Plate XLII, figs. 14, 15.
St. echixatum. Breb. Plate LVI, figs. 31, 32.
Small, as long as broad, finely aculeated; semi-cells
elliptic; end view triangular, angles broadly rounded, sides
straight or lightly convex; whole membrane except theSTAUEASTRUM.
155
center of the semi-cells, aculeated; 7-10 aculei to a side,
end view.
Diameter 27-30 p.
Not infrequent in pools and ponds, New Jersey, Pennsyl-
vania and other States.
St. Pecten, Perty. Plate LYI, figs. 35, 36.
This looks like and probably is a depauperated variety of
the last, St. echinatum.
Diameter 20 p.
Denmark Pond, Passaic County, N. J.
St. hirsutum, (Ehrb.), Breb. Plate LYI, figs. 19-21.
About as long as broad, more or less densely covered with
thin, short, even, hair-like spines; semi-cells elliptic or sub-
semiorbicular; end view triangular, angles obtusely rounded,
sides straight or moderately convex.
Diameter 40-60 p.
A common species.
St. sociatum, Wolle. Plate LVI, figs. 22, 23.
Separated from the last two, mainly by the arrangement
of the spines which are sociated, or twinned.
Diameter without spines 28-30 p., with spines 40-45 p.
This species has some resemblance to St. geminaturn, Nord.,
but the twinned spines are smaller, and the number twice as
large.
St. xiphidiophorum, Wolle. Plate XLYIII, figs. 21, 22, and
Plate XLIX, fig. 19.
Small, one and one-half to two times as long as broad,
deeply constricted, sinus narrow, widening irregularly out-
wardly ; semi-cells transversely oblong, with lateral margins
notched; the end margins drawn out into a sort of one-sided,
hastate, poignard-like spines or slender points, usually nine
in number; membrane smooth ; with several verrucae; end
view triangular, angles broadly truncate and usually each
showing three prominences, the bases or supports of three
spines, sides concave.
Diameter 25-30 p.; length 40 p. and upward.
Ponds, near Minneapolis and Stillwater, Minnesota.
Yar. Simplex, Wolle, differing from the type-form in having
less spines, usually six; (Plate XLIX, fig. 19,) in end view
the truncate angles have only two prominences each.156
DESMIDS OK THE UK ITED STATES.
Found this form frequent in material collected in small
pools near Lake Tahoe, California, by Mrs. Hanson and Miss
Haggin, of San Francisco.
■St. Mixnesotense, Welle. Plate XLVIII, figs. 7, 8.
Cells large, punctate, spinous, about as long as broad;
semi-cells broadly elliptic, twice as wide as long; lateral
angles each with two large straight or incurved spines or
aculei, three more pairs of similar spines placed within the
margin of the end, one of each pair on opposite sides of the
semi cell; six more, often inconspicuous, arranged around
the center; end view triangular, with two spines at each
angle and two pairs (near the margin) between the angles,
on each side of the triangle; around the center are nine
more spines, often indistinct.
Diameter 65-75 ft. without, and 90-100 ft. with the spines.
Frequent in Minnesota ponds.
St. tridentiferum, Wolle. Plate LVI, figs. 9, 10.
Very small, smooth, sinus ample; semi-cells elliptic, ends
more or less convex, angles furnished with three, firm, di-
verging aculei; end view triangular, sides retuse, angles
with three large aculei.
Diameter 17-20 ft., without spines; with them 25-28 ft.
Sluggish waters, Pennsylvania.
St. cructatum, Wolle. Plate LVI, figs. 11-13.
Small, smooth, front view cruciform, lobes short linear,
ends rounded; sinuses wide, rectangular; end view three or
four lobed, slightly tapering, ends rounded and furnished
with a number of more or less diverging setae, which are
as long as the lobes.
Diameter 25 ft., without setae.
Ponds, Northampton Co., Pa,
St. Cerberus, Bailey. Plate LVI, figs. 7, 8.
“Cells small, deeply constricted, semi-cells three lobed;
lobes with four teeth, two of which project upwards and two
downwards, at each truncate angle.”
Diameter 25-30 ft.
This species is reported by Bailey, from lakes in Florida.
.St. Hystrix, Rail's. Plate LVI, figs. 14-16.
Semi-cells in front view subquadrate, extremities some-
what rounded, end margins nearly straight, furnished withSTAURASTRUM.
157
a few scattered, subulate, acute spines, chiefly confined to-
the lateral extremities; eud view with three or four broadly
rounded angles, the spines scattered, chiefly confined to the
lateral extremities, sides concave.
Diameter 22-25 pi.
Rhode Island, (S. T. Olney) Thwaites.
St. Ravenelii, Wood. Plate LYI, figs. 17, 18. Plate LXIII.
figs. 7, 8.
A little longer than broad; semi-cells from the front, ellip-
tical or oval, not semiorbicular; from the vertex triangular,
with the sides convex or slightly retuse, and the angles
rounded; connecting isthmus obsolete, broad sinus acute-
angled ; cytioderm armed with numerous acute robust spines.
Diameter 25-30 pi.; length 35-38 pi.
Still water, Aiken, South Carolina, collected by H. W.
Raven el.
Although in frequent correspondence with Mr. Ravenel,
and having examined hundreds of specimens gathered by
him the past years, I was not so fortunate as to find this
desmid until December, 1883. The specimens were dried,
and more or less collapsed and shriveled in consequence, but
I was delighted to be able to identify ten to fifteen good speci-
mens. A peculiarity is the somewhat irregular arrangement
of the conical granules. The drawing, front view, of the
semi cells (fig. 18) is singularly incorrect; the inferior angles
should be rounded so as to form a wide, acute-angled sinus.
See Plate LXIII, fig. 8.
St. controversum, Breb. Plate LVI, figs. 24, 25.
Cells spinulose; semi-cells with a short, irregular process
on each side terminated by minute spines; end view with
three or four distorted rays.
Diameter 38-65 pi.; length 75 pi., more or less.
Marsh pool, Minneapolis, Minn.
A variable species in size, in distortions, and in arrange-
ment and size of spines. The lateral angles of the semi-cells
are often much incurved and tipped with minute subulate
spines. In both views, the semi-cells show numerous conspic-
uous spines which are either subulate or forked at the end.
St. aspinosum, Wolle. Plate LXII, figs. 22, 23.
Semi-cells smooth, in front view oval, with each end pro-
tracted into a colorless arm about three times as long as the
breadth of the body, diverging, apices tricnspidate, margins158
DESMIDS OF THE UNITED STATES.
rough with minute, firm, perpendicular, irregularly placed
aeulei; end view triradiate.
Spread of the arm 5S-63 ju.
Pond, Brown’s Mills, New Jersey.
The vertical spines, like the thorns of a rose, give this plant
a distinctive character.
St. quaternium, Wolle. Plate LXII1, figs. 17, IS, 19.
Small, smooth, quadrangular in front view; deeply con-
stricted ; sinus acute-angled, much ampliated; semi-cells
oblong, sides rounded, ends truncate, each angle furnished
with four firm aeulei; end view triangular, sides concave,
angles broadly rounded and furnished witli four aeulei, two
on the margin, somewhat separated, and two within the
margin, one on each side of the cell, and projecting between
the other two. By turning the cells two smaller aeulei may
be detected near the margins of the sides.
Diameter of body 25 /.<.; including aeulei 40-50 /u.
Ponds, near Malaga, N. J., and Wilkes-Barre, Pa.
St. cornutum, Wolle. Plate XLVIII, figs. 3, 4. duplicated on
Plate XL VI, figs. 11, 12.
Cells medium size, about one-fourth longer than broad,
smooth : semi-cell oval or broadly elliptic, with a prominent,
somewhat inwardly curved aculeus at each angle; end view
triangular, angles rounded, each with a firm aculeus, sides
straight or slightly concave.
Diameter 55-60 u.; length about 70 /n, aeulei not included.
In front view resembles a large form of Arthrodesmus con-
vergent, but the triangular end views prove it distinct.
Ponds, Minnesota ; not infrequent.
St. caltxoides, Wolle. Plate XLVIII, figs. 14, 15.
Nearly equal in length and breadth; smooth or finely
punctate; deeply constricted; semi-cells saucer- or calyx-
shaped, bearing on the undulate margin five equally distant
divergent spines; end view pentagonal, each angle produced
and bearing a strong aculeus.
Diameter about 33 /<. without, and 75 /<. with, the aeulei.
Pond, near Manchester, Ocean County, and Green’s Lake,
Warren County, New Jersey.
St. forficulatum, Lund. Plate LXII, figs. 16-19.
Cells rather broader than long; deeply constricted ; sinus
wide; semi-cells subtrapezoid, end truncately rounded; baseSTAURASTRUM.
159
convex, sides somewhat produced and divided into two large
diverging mucros; margins ornate with large emarginate
verrucae, or more or less conspicuous prominences; in ver-
tical aspect three, or more rarely, four or five angled; angles
produced and divided, and sides furnished with spines as in
front view.
Diameter, including aculei, 70-80 ft.
Bamber Pond, New Jersey.
The form of the semi-cells is more elliptic than trapezoid,
but in other points it is a good representative of Lundell’s
Swedish plant.
St. monticulosum, Breb. Var. bifarium, Nord. Plate LXII,
figs. 24-26.
Semi-cells with a forked spine at each lateral angle, and at
the end, two twinned, stout, acute, or furcate prominences;
vertical view usually triangular, angles acute or bifid as the
cell is in a horizontal position, or somewhat turned; sides
with four single or two bifid prominences.
Diameter 38 //.; length 33-35 ft.
Spring Lake, New Jersey.
The form I found is not the typical plant, but answers the
description of Nordstedt’s Norway variety, bifarium.
St. tricornutum, Wolle. Plate LVITI, figs. 1, 2.
Large, as long as wide, smooth, semi-cells broad-elliptic
with angles terminated by three long, stout, colorless, di-
verging, subulate spines; vertical view triangular, sides
somewhat concave, or sometimes slightly convex, angles ter-
minated with three subulate spines.
Diameter of body 90-100 ft.; with the spines 175-200 ft.
Frequent in Hammonton and other ponds of southern New
Jersey.
St. Novje (Iesar^:, Wolle. Plate LVIII, figs. 3, 4.
Cells as long as broad, or somewhat longer, coarsely gran-
ulate; semi-cells in front view elliptic, margins crenulate,
angles produced into two long subulate, divergent spines;
vertical view quadrangular, at angles somewhat constricted,
often producing a mammiform appearance, and drawn out
into two, long, subulate spines.
Diameter without spines 36-40 ft.-, with spines 62-70 ft.
This species, hitherto found only in a pond near Hammon-
ton, N. J., proves to have a home in Florida also. The plant160
DESMIDS OF THE UNITED STATES.
differs somewhat from the more northern form, in having the
subulate spines at the angles not so long, and the cell itself not
quite so large. Jas. L. Bennett reports this plant from Provi-
dence, R. I., with end view triangular.
St. eongispinum, Bailey. Plate LII, fig. 7.
Large, smooth, triangular, with two long spines at each
angle.
Diameter of body 75 g.-, with spines 150 g.
Lakes in Florida (Bailey).
St. quadrangulare, Breb. Plate LII, figs. 1-4.
Cells smooth, nearly scpiare, divided by a deep, linear
constriction into rectangular-oblong semi-cells with a few
marginal spines or teeth; end view quadrilateral, sides more
or less concave, angles truncate and emarginate or dentate.
Diameter 23-30 g.
Not infrequent in ponds of Pennsylvania, New Jersey and
Florida.
St. Brasiliense, Xord. Plate LIX, figs. 1, 2, 3.
Semi-cells short cuneate, top truncate, or moderately
rounded, angles terminating in three firm, diverging aculei;
end view pentangular; each angle produced into three more
or less elongated firm subulate diverging spines, sides con-
cave; membrane punctate.
Diameter 87-130 //., including the spines.
Three localities only have been developed for this species ;
Florida furnishes the smaller form figured ; the other is from
pond, Passaic County, New Jersey, and from vicinity of
Mobile, Alabama. The original form from Brazil, is described
by the author as usually quadrangular, and angles often
furnished with four spines.
Var. TRIQUETRUM, Wolle. Plate XLIX, figs. 39, 40.
The form hitherto found here is pentangular in vertical
view ; the form first discovered and described by Xordstedt,
is quadrangular, found in Brazil. The present variety from
California is triangular in vertical view ; it appears so nearly
related in character of cell, arrangement and character of
aculei, think it best described as a variety of the same
species.
Diameter of cells, including aculei, 63-67 g.
Smaller than the pentangular form, but about the same
size as the original quadrangular form.
Collected in small pools near Lake Tahoe, by Mrs. Hanson
and Miss Haggin, San Francisco, California.ST AURA STRUM.
161
Section IV.—Cells furnished with numerous processes usually divided at the
ends.
St. furcigerum, Breb. Plate LIX, figs. 12-14; Plate LXIII,
figs. 23, 24.
Cells constricted at the middle, angular, -with six processes
to each semi cell; in end view, triangular, one process at
each angle and one within the angle, about half way between
it and the center of the triangle, Plate LIX, fig. 12, Plate
LXIII, fig. 24; semi-cell in front view somewhat elliptic,
Plate LIX, fig. 13; Plate LXIII, fig. 23; each end drawn
out into a short process, margins serrate, ends furcate or
toothed; three other processes are usually in view, two on
the end margin, and one intermediate. Cytioderm granular;
granules arranged in transverse lines.
Diameter 50-62 p.
Occurs in many localities, Rhode Island and southward to
South Carolina and Florida.
Foreign authors report a form, quadrangular in end view ;
such would have eight processes to a semi-cell.
I find considerable diversity in the specimens of this species,
particularly in the arrangement of the processes on the tops
or ends of the cells ; typically they are attached away from
the center, and are directed towards the angles; a variety
(Plate LIX, tig. 14), has them coming from the center and
directed transversely, or at right angles with the sides.
St. eustephanum, ( Ehrb.), Ealfs. Plate LIX, figs. 9-11.
Of nearly equal length and breadth, granular, margins
more or less serrate; semi-cells elliptic (fig. 9) with angles
produced, furcate; end view triangular, furnished with nine
processes, counting the three somewhat produced, and bi-
furcate angles; the other six are on the upper surface,
attached, usually between the center and the margins, ends
elevated above the surface ; the processes extend to margins,
or slightly over them; in front view, these present them-
selves on the outer margin in two pairs; the third pair is
either under the cell, or stands towards the eye, and is in-
visible.
Diameter varies from 50-75 p.
Var. a. fig. 11 represents a foi'in with more elongated
processes.
Var. b. figs. 4-6 is another variety, very distinct; it is
smaller in size and has spreading, swallowtail-like ends of
processes.
11162
DESMIDS OF THE UNITED STATES
The latter was collected in Minnesota; the others occur
frequently in small ponds and ditches, New York, (Bailey;
Ehrenberg) ; Pennsylvania, New Jersey, South Carolina,
Massachusetts. Figs. 4-6 may represent a new species ; it
needs further verification.
St. senarium, (Ehrb.), Ealfs. Plate LXIII, fig. 1.
Smooth, each semi-cell furnished with fifteen processes;
in end view triangular, each angle a process, two on each
side, and six radiating, on the upper surface within the
margins.
I have found no form to answer this description satisfac-
torily. Ehrenberg and Bailey report it from New York.
St. pseudoftjrcigerum, Reinscli. Plate LXIII, figs. 27, 28.
Cells smooth; semi-cells broadly elliptic, sides produced
into a short, stout process, with margins smooth and apices-
bifurcate; end view triangular; one process at each angle,
and two near the margin of each side, extending beyond it,
making nine processes to each semi-cell.
Diameter 37-40 g.
Minnesota.
I am aware that this name is usually applied to a different
plant, which has a granular cytioderni and margins undulate-
serrate. Reinsch’s figures indicate an absolutely smooth
membrane, and in his description he writes membrana glabra.
Satisfied I have Reinsch’s prototype in size, and detail of con-
struction, it is but just to retain the name given by him. The
plants generally recorded for psrudofurcigerum would prob-
ably be better placed with St. eustcphanum.
St. ctjneatum, Wolle. Plate L1X, figs. 7, 8.
As long as wide, divided by a deep constriction into two-
broadly cuneate semi cells; base convex, broad; sides, each
with three to six sharp teeth, converge from the base to a
concave-truncate end ; superior angles somewhat produced,
making a short process, apex bifid or trifid; end view tri-
angular, sides slightly convex, angles bisected; on the top
six processes radiating from the center and extending to, or
slightly over the margins.
Diameter 44-46 g.
Ponds, Pennsylvania.
In front view, this form bears much similarity to a plant
found on the Island of Spitzbergen and named St. megalono-
tum, Nord., but in end view it is entirely distinct.STAUKA STRUM.
163
St. spongiosum, Breb. Plate LVIII, figs. 5-8.
Thickly covered with short spines which are forked at the
apex; semi-cells semiorbicnlar, spinulose; end view trian-
gular, angles rounded; sides slightly convex and bordered
with forked spines or short processes.
Diameter 45-50 pi.
This species appears to be sparsely but widely distributed.
The specimens vary considerably in different localities ; figs.
7, 8, represent the more frequent form; Naegeli supposed it
to be a new species and named it St. Griffitheanum.
St. aectiscon, Elirb. Plate LVIII, figs. 9, 10.
Cells about one-fourth longer than broad, moderately con-
stricted, sinuses obtuse angled; semi-cells subglobose, slightly
depressed, furnished in the middle with (usually) nine
straight divergent processes; above these another whorl con-
sisting, usually, of six similar, but shorter processes, apices
trifid. Membrane punctate.
Diameter 100-120 pi.
In addition to the forms represented on Plate LVIII, figs.
9, 10, I add another, apparently more highly developed, Plate
XLVI, fig. 4, distinct in the large, wide-spreading points of
the trifid apices of the arms.
Green Lake and other waters of New Jersey.
Wood describes St. munition as a new species, but evidently
it is the same as St. cvrctiscon. He had it from New Hamp-
shire ; I found it frequently in Massachusetts, Pennsylvania,
New Jersey. No doubt it will turn up in all parts of the
United States. Ehrenberg had his specimens from New York.
St. Wolleantjm, Butler. Plate XLVIII, figs. 1, 2.
Medium size, membrane punctate, about one-half longer
than broad, moderately constricted, sinuses obtuse-angled;
semi-cell broadly oval or subhexagonal; superior and lateral
angles produced into subcylindrical, somewhat swollen pro-
cesses or arms, slightly notched at the apices; four more
similar processes within the margin ; in vertical view regular
hexagonal, each angle furnished with an arm in appearance
as those in front view; within the margin, arranged in a
circle around the center, are six, more or less conspicuous
processes.
Diameter of body 40-50 pi.; with processes 65-83 pi.
This species was discovered, identified as new and named
by Miss E. Butler, Minneapolis, Minnesota, where it was
found.164
DESMIDS OF THE UNITED STATES.
Yar. Kissimhense, Wolle. Plate XLYII, figs. 1, 2, 3.
Front, lateral and vertical views; a large, smooth and
beautiful form fully one-half larger than the original type
from Minnesota; the arms are similarly constructed and ar-
ranged, but in proportion with the body, are much longer,
nearly equal in length to the diameter of the body; apices
not notched but tipped with several small spines.
Diameter, including arms, 100-125 p.
Grassy shores of Lake at Kissimme, Florida, March, 1885.
St. Eloiseanum, Wolle. Plate LII, figs. 17, 18.
Small, equal in length and breadth, smooth or finely punc-
tate; sinus an acute angle; semi cells subhexagonal, basal
and superior angles produced into short, bifurcate processes;
sometimes two, but oftener only one discernible at each
angle; end view circular, margin furnished with (usually)
nine, short processes, ends notched.
Diameter 22-30 p.
This form has some resemblance to iS't. spinosum, Breb., but
in front view the processes are less conspicuous, the apices less
distended ; in end view, circular, not triangular.
St. Tohopekaligense, Wolle. Plate XLYII, figs. 4, 5.
Cells smooth, semi-cell in front view oval with radiating
arms; in end view triangular, each angle drawn out into a
smooth arm nearly as long as the diameter of the body ; two
similar arms on each side; all at nearly equal distances and
bifurcate at the apices.
Diameter, including arms, 75 p.
This species occurs frequently in small coves of Lake
Tohopekaliga, at Kissimme, Florida. It bears features in
common with St.furcatum, Breb., but is about twice the size,
has more arms, and has them differently arranged; the de-
scription “one spine at each angle, with two accessory spines
at the base,” or “.three spines at each angle,” does not apply.
St. duplex, Wolle. Plate LXIY, figs. 6, 7.
Small, subquadrangular, constriction deep, sinus acute-
angled ; semi-cell twice as broad as long, rectangular; angles
truncate and furnished with two short, stout processes with
ends truncate granulate-spinous; end view triangular, sides
straight or concave, angles truncate, divided and drawn out
into two short, somewhat diverging processes, apices finely
toothed.
Diameter 20-25 p.STAURASTRUM.
165
Numerous in small pools, on the banks of river, Bethlehem,
Pennsylvania.
The end view has a resemblance to Nordstedt’s St. gemelli-
parum, but front view is quite distinct.
St. distentum, Wolle. Plate LII, figs. 15, 16.
Small, smooth; semi-cell obovate, end convex crenulate,
sides in upper portion laterally produced into nearly straight
elongated arms, margins smooth; apices divided into three
parts aud distended ; end view five or six radiate; rays taper
from a broad base to a distended trifid end. Between each
two of the bases is a deep linear sinus.
Diameter 40 p., more or less.
Ponds, Denmark, Splitrock, Passaic County, N. J.
St. Kitchelii, Wolle. Plate LI, figs. 35, 36.
Cells smooth, about as long as wide; semi-cells subelliptic,
bases more inflated than the ends, the angles produced into
bifurcate processes; semi-cells furnished with three addi-
tional processes; end view triangular, angles produced,
apices bisected ; on the top surface three bifurcate processes,
one extending over each of the three sides; membrane
smooth or finely punctate.
Diameter 38-50 p.
Collected by Itev. H. D. Ivitchel, in Gilder Pond, Mount
Everett, Mass.
St. npinosurn, Ralfs, bears some similarity, but is separated
by having two or more spines on each side besides the one
terminating each angle. St. furca/um, Ehrb., also appears
related, but is possessed of more spines.
St. furcatum, (Ehrb.), Breb. Plate LI, figs. 40, 41; Plate LIX,
figs. 15, 16; Plate LXIII, fig. 34.
Cells smooth, about as long as wide, sometimes shorter,
furnished with numerous processes always more or less
widely furcate at the apices; end view triangular, angles
somewhat produced and furcate; sides each with two, or
rarely three, furcate processes; normally a semi-cell has nine
processes, one at each angle and two on each side between
the angles; in front view, more or less broadly elliptic,
angles drawn out and furcate; the end margin has usually
four processes visible, projecting over the margin.
A variable form separated from furcigerum, ewstephanum
and others not only by the smooth, or punctate membrane166
DESMIDS OF THE UNITED STATES.
which is very striking in contrast with the granular surface,
and serrate margins of the others, but by the processes, par-
ticularly evident in end view, which do not spring from the
upper surface more or less distant within the margin, but from
the margin itself. This feature not evident in St. paeurtofur-
cigerum, Reinsch, gives it a position for itself. The form,
Plate LIT, figs. 8, 9, from Minneapolis, Minn., is Ralfs’ St.
spinoxum, now properly transferred to this “old name,” has
besides the marginal processes some smaller accessory ones
within the margin, Plate LXIII, tig. 34 Plate LXIII, figs.
25, 26, is another variety from the same locality of unusual
size and very marked in the wide-spreading forks of the pro-
cesses ; Ralfs admits of “ sometimes three marginal spines, as
seen in end view.”
St. ENORME, Ralfs. Plate LII, figs. 19-25.
Cells irregular or quadrate, spinous; end view three or
four lobed; lobes broad, more or lessemarginate or bifid, and
terminated by spines which are either simple or branched.
Ralfs, the author of this species, says of it, it “is by far
the least symmetrical plant in this family, especially in front
view, and it is very difficult to trace any division into the
cells.”
Some of the forms, as figs. 21, 25, may properly belong to
this genus, but the others would be better placed under
Polyedrimn.
These forms occur frequently in ponds of New Jersey,
Pennsylvania, Massachusetts.
St. leptauanthum, Nord. Var. tetroctocerum, Wolle. Plate
LX II. figs. 29, 30.
Cells about as long as broad; deeply constricted; semi-
cells suborbicular, furnished with eight long thin rays,
deeply forked, or clawed at the ends; this whorl is rather
below the middle, and another above it with four similar
rays; end view octangular, each angle produced into a long,
thin ray, deeply clawed at the end ; between the margin and
the center four more similar rays go out; membrane smooth.
Diameter of body 25 /c; including the processes 75-80 g.
Pond near Malaga, N. J.
The only essential distinction between this form, and the
typical, Brazil plant, is that it has six rays in the larger whorl,
and ours has eight.
St. Pottsii, Wolle. Plate LXII, figs. 8, 9.
Small, smooth, sinus gaping; semi-cells in front view
broadly elliptic, furnished on each side with three divergentSTA U UA8TRUM.
167
processes, whose apices are rounded, bearing two small di-
verging aculei; end view triangular, sides concave, angles
broadly truncate and produced into two processes with a
wide, rounded sinus between, a third process from a position
somewhat back of the sinus, rising at an angle of about 40
•degrees,.projects between the other two, thus constituting
three divergent processes at each of the angles of the triangle.
Diameter, including the aculei, 30-38 )-i-
Collected by Ed. Potts in Harvey Lake, near Wilkes-Barre,
Pa., where it appeared in numbers.
The three diverging, aculei-tipped processes at each angle
make this form a distinct species.168
PEDIASTRUMS OF THE UNITED STATES.
Family, PROTOCOCCACE^.
Cells chlorophyllous, strictly unicellular, without terminal
growth, either single, segregate or associated in families.
Propagation by means of gonidia, which are of two kinds,
macrogonidia the larger kind, and microgonidia the smaller forms;
they are ovate ; the smaller, anterior end, somewhat protruding
and colorless, is provided with two ciliae; the posterior end is
broadly rounded and green.
This family is subdivided into a number of subfamilies, and
these again into genera. There remains for us to treat merely of
the subfamily Pediastreae, and genus Pediastrum. The features
of the subfamily and of the genus being, in this case, the same,
therefore
Genus, PEDIASTRUM, Meyen.
Cells united into definite families, known as coenobiums; they
are plane, discoid or stellate, swimming free. A coenobium is
formed of cells in a single or rarely, in part, double stratum,
which is continuous dr perforated. Cells are polygonal, with
four or more sides; those of the center entire or often emargi-
nate. and those of the periphery often bilobed ; the lobes cuneate,
either simple or bidentate, often produced into short hair-like
ends. Cell contents green, primarily homogeneous, then granular.
In the propagation of the species the granular chlorophyllous
contents of the cells break up into small snbspherical bodies;
these constitute the macrogonidia, which break through the
membrane. After a short period of motile life, they come to
rest, then divide and redivide, and become invested with a gela-
tinous covering ; the cells unite in a single layer, then gradually
develop into the form of the matured, or mother plant.
P. simplex, Meyen. Plate LXIY, figs. 17-20.
Coenobium variously composed of from one to three circles
of subquadrilateral cells, those of the periphery with apex
more or less conically produced, cuspidate.
Var. a. Composed of six simple cells radiately connected,
fig. 17.
Var. b. (P Sturmii, Reinsch.) Composed of six cells, with
an open space in the center, fig. 18.PEDIASTRUM.
169
Var. c. (P. duodenarius, Bailey), fig. 20; composed of
twelve cells in the periphery, and a circle of four cells in the
middle, with open spaces between the two, and open center.
Yar. d. A new form, with three circles of cells, of four-
teen, seven, and four; the four constitute the center. The
openings, or lacunae, first circle seven, second four.
The only good locality found for this species and varieties
is the Croton water supply of the City of New York. Bailey’s
specimens, collected more than thirty years ago, were from
the same source.
P. MUTICUM, Kg. Plate LXIV, fig. 36.
Coenobium circular or oval, composed of two to five circles
of cells, entire, smooth, regular; peripheric cells emarginate
or with two slight protuberances.
Pond waters, Pennsylvania, New Jersey.
. ANGULOSUM, (Ehrb.), Menegh. Plate LXIY, figs. 28, 37.
Minute, consisting of one or more circles of cells. Not
perforated; marginal cells with angular lobes which are not
extended into rays. A small form (fig. 37) has the center
open.
Frequent in ponds, New Jersey.
P. forcipattjm, (Corda.), A. Br. Plate LXIY, figs. 21, 30, 31.
Coenobium orbicular, entire, marginal cells bilobed;
lobules with apices acute, converging, leaving an oval sinus
between; usually smooth or punctate, but sometimes coarsely
granular, probably when in older condition.
Ponds, Pennsylvania, New Jersey.
P. Boryanum, (Turpin), Menegh. Plate LXIV, figs. 22, 29, 32.
Coenobium orbicular, oblong or elliptic, bright green,
variable in size, composed of 8-16-128 cells. Marginal cells
two lobed, each drawn out into a colorless horn-like process,
short or long, rather obtuse, sometimes a little thickened at
the ends- Cells closely united, four to six angled. Mem-
brane punctate.
Sometimes the cells and the horns are distinctly granulate.
These constitute the variety granulatum, Kg.
Frequent, Massachusetts to Florida.
P. pertusum, Kg. Plate LXIV, figs. 33, 34.
Coenobium, more or less orbicular, pierced with many
lacunae; variable in size; composed of 16-32-64 cells. All
the cells more or less loosely connected; attached at the
angles only, leaving an opening between the sides, and be--170
PEDIASTUUMK OF THE UNITE]* STA'l'ES.
tween the connecting end of one. and the base of the adjoin-
ing cells. Cells of the periphery deeply bilobed; lobes
conical or horn-like, sometimes acute, sometimes obtuse or
truncate.
Frequent in pools everywhere.
Var. beachyeobum, A. Br. Plate LXIV, fig. 35.
Differs from the typical form in having the cells of the
periphery emarginate, notched, or shortly two lobed, or
lobes almost obsolete; cells of the disc perforated with
smaller openings.
Var. OLATHRATUii, A. Br. Discs pierced with larger openings;
the lacunae being often as large as the cells.
P. Ehrenbergij, i Cord a. 1, A. Br. Plate LXIV, figs. 25-27.
Marginal cells closely united, bilobed, medianly deeply
incised; each lobule with ends truncate and notched or in-
cised. Coenobium not perforated, composed of 4-8-16-32
cells.
Var. cuspidatuji. A. Br. Plate LXIV, fig. 25.
A small form, with lobes of cells finely, and often indis-
tinctly bidentate.
Not so frequent as the preceding forms, but widely dis-
tributed.
P. tetras, Ehrb. Plate LXIV, fig. 24.
Coenobium very small, four-celled, separated by colorless
interstices which form a cross.
A. Braun, has a variety of P. Elirenbergii, var. truncation,
very near this form, but differs in having the ends of the
lobes notched—our form, as far as observed, is perfectly
square, hence I retain the old name.
Occurs frequently from Rhode Island to Florida.
P. Selenjea, Kg.
Coenobium orbicular; cells crescent-shaped, arranged in
one or more circles round one or two central cells.
A form reported by Bailey from Rhode Island.
P. CONSTRICTUM, HaSS.
Coenobium nearly orbicular, continuous, composed of
16-32 cells; cells of the periphery two lobed, or suddenly
contracted into two short cylindrical, obtuse processes.
Bailey reports this species from South Carolina, Georgia
and Rhode Island. It is very nearly allied to Boryamim and
is probably a variety of that species.ADDENDA.
In addition to note on page 16 the following may be quoted
from the “Journal of the Boyal Microscopical Society of Lon-
don,” Feb., 1884. It relates to the motion of granules in the
vacuoles of Glosterium.
The occurrence of crystals of calcium sulphate, endowed with
a peculiar dancing motion, has long been known in the terminal
vesicles of Glosterium and in other desmids; the phenomenon has
now been carefully investigated by A. Fisher. Their chemical
constitution was clearly established by different tests. They
are always quite isolated from one another, and occur in all
parts of the cells, though in the greatest quantity in the terminal
vesicles; they are either carried along passively by the currents
of protoplasm, or they swarm in the space filled with cell-sap, be-
tween the cell wall and the radiating chlorophyl bodies; these
vesicles are not true vacuoles, but portions of cell-sap space.
The crytals are not formed, nor do they grow, in the vesicle,
but reach it in a mature condition from some other part of the
cell, being formed apparently in the furrows between the bands
of the chlorophyl bodies; from here they are carried to the ter-
minal chambers of the protoplasmic currents.
Fisher found these crystals in all species of Glosterium which
he examined, also in various species of Cosmarium (though indi-
viduals are often entirely destitute of them) their form being
the same as in Glosterium. They occur in Micrasterias, Euas-
trum, in which genera also they are not invariably present, and
always in Pleurotaenium, Penium and Tetmemorus, but were absent
from all the specimens examined of Staurastrum, Desmidium and
Hyalotheca. They appear to be entirely confined to the Des-
midieae, other fresh water Algae containing calcium oxalate,
especially species of Spirogyra, but not calcium sulphate.
Desmidium diagonum (Aptogonum diagonum).
Filaments compressed, perforated, twisted, not vaginate;
cells in end view oblong elliptic.
Diameter 32 /a.; thickness 14 g.; length of cell about half
the diameter.
171172
ADDENDA.
Found in Lake Jessup, five miles from Sanford, Florida.
This species described by Delponte in his Desmidiacearum
Subalpixarum is, in front view, scarcely separable from D.
aptogonum, but in lateral view it is distinct. The cells ob-
long elliptic, in end view not triangular. The filaments are
twisted, and being more than twice as wide as thick, present
an irregular outline, parts showing the broad front and parts
the narrow sides of the filaments. The margins of cells are
notched, and the ends excavated as in D. aptogonum.
Sphaerozosma pulchrum, var. constrictum, Wolle. Plate
SLYII, fig. 12.
Cells half as long as wide, with a decided constriction in
each lobe between the axis and the apex.
Diameter 70-75 g.
Lake near Kissimme, Florida.
Gonatozygon sexspixiferum, Turner. Plate XLIII, fig. 15.
Joints variable in length, ten to thirty times the breadth;
base swollen, apex either rotundo-truncate or quite rounded;
spines, or rather setae, very short and arranged longitudi-
nally in six linear series. Forming long filaments.
Length of joints S8-1S0 g\ diameter 6-8 g.
Minnesota.
Closterittji Brebissonii, Delp. Plate YI, fig. 17.
Cells sublinear, ends attenuated, moderately curved, apfces
rounded; about thirty times longer than broad; cytioderm
smooth.
Diameter 18 g.
Observed occasionally, Minnesota and Pennsylvania.ERRATA.
Page 37, 16th line from below, strike out Plate XXXVII.
“ 40, insert C'. Brebissonii, Plate VI, tig. 17.
“ 41, third line, change Plate V to VI.
“ 42, fourteenth line, insert Plate VI, fig. 12.
“ 43, fourteenth line, change VII to VI.
“ 45, twelfth line, change LIV to XLIII.
“ 46, twenty-fifth line, change LIV to XLIII.
“ 90, eighteenth line, change Laoense to Lagoense.INDEX
Addenda,..........................171
AlGjE—Characteristics of,	.	xi
Color of, .... xii
Fresh-Water—How to find,
collect and preserve, .	. xiii
Signification of term,.	.	xi
Uses of,.....................xii
Varieties of,	.	xii
Akthrodesmcs, Ehrb.,	.	. 103
“	eonvergens (Ehrb.),Ralfs,	11'3
“	fragilis, Wolle, .	103
“	incus (Ehrb.), Hass.,	104
“	incrassatns, Lagh., .	.	105
Var. cycladatus, Lagh.,	105
“	notochondrus, Lagh.,	105
“	orbicularis, Wolle, .	104
“•	octncornis, Ehrb., .	104
“	ovalis, Wolle, .	103
“	pachycerons, Lagh.,	105
“	quadridens, Wood, .	104
“	Eauii, Wolle.	103
“ subulatus, Kg., .	.	104
“	triangularis, Lagh.,.	105
Authors and Books—Names of. viii
Bambusina, Kg.—Characteristics
of, .	.	.	24 ;
“	BrebisM>nii Kg., .	.	24
Var^gracilescens,Nord.,	25
“	gracileseens, Nord,.	25
“	delicatissima, Wolle,	25
Calocylindrus, D. By.—Descrip-
tion of, ...	58
1	Clevei, Wolle, .	60
“	connatus, (Breb.), Kirch.,	59
'Tar. minor, Nor,d.,	60
“	Cordanum, .	.	.59
175
Calooylindrus, costatus, Wolle,. 61
“	Cucurbita (Breb.), Kirch.,	59
“	cnrtus (Breb.), Kirch.,	59
“ De Baryi, .	.	.58
“	diplospora, Lund.,	60
“	minutus (Ralfs), Kirch.,	59
“	pseudoconnatus, Nord.,	60
“	Ralfsii (Kg.), Kirch.,	58
“	Thwaitesii, Ralfs,	60
Closterium, Nitsch. — Observa-
tions concerning,	.	. 38
“	acerosum(Sehrank),Ehrb.	42
“	acuminatum, Kg., .	47
“	acntum, Breb.,	46
“	amblvonenia, Ehrb.,	.	46
“	angustatum, ICg.,	41
“	areolatum, Wood,	.	46
“	attenuatnm, Ehrb., .	44
“	Brannii, ...	45
Brebissonii, .	.	.	72a
“	cosiatnm, Corda, .	45
Cucnmis, Ehrb, .	42
“	decorum. Breb., .	.	45
“	decussatnm, Kg.,	41
“	Delpontei, .	45
“	Dianse. Ehrb., .	.	47
“	didymotocnm, Corda,	.	40
“	Ehrenbergii, Menegh.,	48
Var. immane, Wolle, . 48
ensis, ...	40
“	gracile, Breb., .	.	.40
“	Jenneri, Haifa,	.	47
“	juncidum, Ralfs,	.	39
forma gracillima laevis-
sima, Breb., .	.	.39
‘	Kuetzingii, Breb., .	50
“	lanceolatum, Kg., .	.	40176
INDEX.
Closterium, Leibleinii, Kg., .		PAGE 49
	Yar. curtum.	49
tl	lineatum, Ehrb.,	45
	Yar. eostatum,	45
It	Lunula, Ehrb.,	42
	Yar. striatum, Wolle, .	42
tl	macilentum, Breb.,	40
It	monilifernm, Ehrb.,	48
it	nasntum, Nord.. .	43
“	obtusum, Breb.,	39
it	parvulum, Naeg.,	47
it	prolongum, Delp., .	43
It	pronum, Breb., .	50
it	Ralfsii, Breb., .	49
“ *	robustum, Hast.,	4S
“	rostratum, Ehrb., .	49
	Yar. brevirostratum,	
	West, .	49
it	setaceura, Ehrb., .	50
“	strigosum, Ehrb.,	44
It	striolatum, Ehrb.,	44
	snbcostatum, Nord.,	43
“	subdirectum, West,	46
It	subtile, Breb., .	42
It	turgidum, Ehrb.,	43
It	Yenus, Kg..	47
Conjugate—Family of,		21
Cosmarium. Conla—Divisions of,		62
	aculeatum, Wolle. .	71
ft	amcenum, Breb., .	85
	Var. tumidum. Wolle,.	86
it	Americanum, Lagh., .	64
a	anceps, Lund.,	63
it	anisochondrum Nord.,	78
tt	ansatum Kg., .	74
it	Raileyii, Wolle,	69
ti	bireme, Nord.,	89
it	biocuhitum, Breb.,	66
ti	bireturn, Breb., .	93
	Var. Floridense, Wolle,	93
ti	Blytiii, Wille,	95
ti	Botrytis, Menegh., .	81
	Var. tumidum, Wolle,	82
tl	Braunii, Reinsch., .	72a
it	Brebissonii, Menegh.,.	82
it	Broomei, Thwaites,.	93
it	caelatum, Ralfs, .	93
ft	circulare, Reinsch, .	68
Cosmarium c>> spersnm, Ralfs,		PAGE. 82
	Var. retusum,	82
it	constrictum, Delp.,	63
ti	commisurale, Breb.,	91
tl	Cordanum, Breb.,	59
it	contractum, Kirch.,	68
a	crenatum, Ralfs, .	73
	Var.crenulatum,W olle,	73
a	cruciatum.Breb.,	89
tt	Cucumis, Corda,.	62
“	DeBaryii, Arch.,	62
it	dentatum, Wolle,	83
it	depressumfNaeg.), LuDd.,	69
it	DoDnellii, Wolle,	77
it	elegantissimum, Land., .	86
tt	Eloiseanum, Wolle, .	92
it	Everettense, Wolle,	92
a	excavatum, Nord.,	85
	Var. trigonum, .	85
	Var duplo major, .	85
“	exiguum, Arch.,	72
tt	galeritum, Nord.,	75
u	globosum. Bulnh., .	65
tt	granatum, Kreb.,	64
ti	Hammeri, Reinsch,	86
it	Holmiense, Lund.,	74
	Var. integrum, Lund ,.	74
tt	homalodermum, Nord.,	88
t.	inflatuuj, Wolle,	67
it	intermedium, Delp., .	83
it	Kitchelii. Wolle,	79
t.	Kjellmanii, Wille,	94
“	laeve, Rab.,	72a
	Var septemtrionale, .	72a
tt	lagoense, Nord.,	90
u	latum, Breb.,	84
a	lobatulum, Wolle, .	66
it	lunatum, Wolle, .	71
tt	margaritiferum, Menegh.,	81
	margaritum, Wolle, .	88
it	Meneghinii, Breb., .	70
	Var. simplicissimum,	71
“	m icrosph in etum,	81
	Var. parvula, Nord.,	81
ti	moniliforme, Ralfs,.	65
“	Naegelianum, Breb., .	73
it	nasutum, Nord.,	96
u	nitidulum, Be Not., .	62
“	Nordstedtii, Delp., .	80
<(	notabile, Breb., . . 72, 86	INDEX.
177
PAGK. Cosmarium Nymannianum,Grun., 87		
“	obsoletum, Reinsch, .	70
“	ochthodes, Nord,	84
“	octogonum, Delp.,	71
«	oculiferum, Lagh,	76
tt	ornatum, Ralfs, .	89
	Var. protractum, Wolle,	90
“	orbiculatum, Ralfs,	85
“	orthosticum, Lund.,	86
((	ovale, Ralfs,	62
tt	pachydermum. Lund.,	75
tt	Pardalis, Cohn, .	83
(t	parvulum, Breb.,	64
*•	Pectinoides, Wolle,	96
u	perforatum, Lund., .	65
11	Phaseolus, Breb.,	89
“	polygonum, Naeg., .	71
u	polymazum, Nord.,	76
tt	polymorphum, Nord.,	80
(1	Portianum, Arch.,	84
“	protractum(Naeg.),Arch.,	90
“	protuberans, Lund., .	91
	Var.granulatum, Wolle,	91
“	Pseudobroomei, Wolle,	93
“	pseudonitidulum, Nord., .	72a
it	Pseudopectinoides, Wolle,	96
It	pseud og ran at um, Nord., .	64
it	pseudopyramidatum,Lund., 75	
tt	pseudotaxichondrum,Nord.,77	
“	puleherrimum, Nord.,	97
't	punctulatum, Breb.,	80
“	pyramidatum, Breb., ,	74
	Var. stenonotum,	74
“	pycnochondrum, Nord., .	97
“	quadratum, Ralfs,	63
tt	quadrifarium, Lund.,	94
it	Quasillus, Nord,	92
“	Quimbyii, Wood,	66
	quinarium, Lund.,	78
“	radiosum, Wolle,	97
“	Ralfsii, Breb.,	75
“	Regnesi, Zeinsch, .	70
tt	reniforme, Ralfs,	,84
“	Reinschii, Arch.,	73
(I	retusum, Perty, .	87
“	rhombusoides, Wolle,	66
it	scenedesmus, Delp., .	63
it	Sch liephackeanum.Grun.,	89
it	Seelyanum, Wolle,	80
“	sejunctum, Wolle, .	68
12
PAGE.
Cosmarium sendtnerianum, .	72a
“	sexangulare, Lund.,	69
“	sinuosum, Lund.,	.	70
“	Smolandicum, Lund.,	72
“	speciosum, Lund.,	.	95
“	splialerostichum, Nord.,	.	76
“	Sportella, Breb., .	.	90
“ stenonotum, Nord., .	. 74
“	subcrenatum, Ilantzsch,	91
“	subcruciforme, Lagh.,	.	94
“	sublobatum, Arch.,	.	87
“	suborbiculare, Wood,	.	85
“	supraspeciosum, Wolle,	95
“	taxichondrum, Lund.,	.	77
Var. bidentatum,Lagh.,	77
“	tetrophthalmum (Kg.),
Breb., .	.	.	.82
tinctum, Ralfs,	.	67
“	tithophorum, Nord.,	.	88
“	traehypleurum, Lund.,	79
“	triplicatum, Wolle,.	.	79
“	tumidurn, Lund.,	67
“	Turpinii, Breb., .	.	87
“	undulatum, Corda,	.	72
Var. crenulaturu,.	73
“	variolatum, Lund.,	.	68
“	venustum, Rab., .	.	73
“	Wolleanum, Lagli.,	.	64
Var. granuliferuin,Lagh. 64
Crystals in Desmids,
DESMiDiBiE—How generated and
	multiplied, .	17
Desmidium, Ag.—Description of,.		25
It	aptogonium, Breb.,	27
tt	Baileyii, Ralfs,	27
tt	cylindricum, Grev.,	25
“	diagonum, Delp., .	171
tt	longatum, Wolle,	26
tt	quadrangulatum, Kg.,	27
tt	quadratum, Nord,,	26
tt	Swartzii, Ag.,	26
Desmids—Characteristics of,		16
	Ilow multiplied,	17
	Regeneration of,.	18
	Of the United States,	21
	Voluntary movements of,	16
	Where found,.	15
Didymopkium, Kg.,		23178
INDEX.
Docidium, Breb.—Why name is
retained, .	.	.50
“	Archerii, Delp., .	.	51
“	Baculum (Breb.), D.By.,.	52
Var. Floridense, Wolle,	52
“	breve, Wood. .	.	.54
“	clavatum (Kg.), D.By.,	51
“	constrictum, Bail., .	54
1 coronatum, Rab.,.	.	53
■'	coronulatum, Grun.,	.	53
“	costatum, Wolle,.	.	57
“	crenulatum (Ebrb.), Rab.,	51
“	dilatatnm (Cleve), Lund.,	55
‘	Ehrenbergii, Ralfs, .	53
Var. Floridense, Wolle,	53
‘	Flotowii, Rab.,	52
"	gracile, Breb.,	58
“	Georgicum,	55
“	hirsutum, Bail.,	56
‘	minutum, Ralfs,	.	57
“	nodosum, Bail., .	54
“	nodulnsum,	.	51
“	rectum, Delp., .	52
“	repandum, Wolle,	.	54
“	sinuosum, Wolle,	55
Var. breve, Wolle,	55
“	spinosum, Wolle,	56
“	Trabecula (Ehrb.), Naeg.,	51
“	tridentulum, Wolle, .	57
“	truncatum, Breb.,	52
“	undnlatum, Bail.,	55
“	verrucosum(Bailey),Ralfs,	56
‘‘	vertieillatum, Bail., .	57
Var. turgidum, Wolle,	58
'	Woodii,	.	55
Euastrum, Ehrb.,	. 106
“	abruptum, Nord.,	1)8
‘‘	affine, Ralfs, .	110
“	ampullaceum, Ralfs, .	110
“	ansatum (Ehrb ), Ralfs,	109
“	altenuatnm, Wolle,	113
“	binale (Turpin), Ralfs,	117
“	circulare, (Hass.), Ralfs,	112
“	compactum, Wolle,.	117
“	crassicolle, Lund.,	115
“	crassum (Breb.), Kg.,	.	106
Var. scrobiculum,	106
“	cuneatum, Jenner,	108
“	cuspudatum, Wolle, .	115
page.
Euastru-m didelta (Turpin.), Ralfs, 109
“	divaricatum, Lund.,	114
“	Donnellii, Wolle,	114
“	elegans, Kg.,	116
“	erosiun, Lund.,	115
“	Everettense, Wolle,	112
“	formosum, Wolle,	114
“	gemmatum, Breb.,	112
“	Hastingsii, Wolle, .	113
“	humerosum, Ralfs,	107
“	inerme, Lund.,	116
1	insigne, Hass.,	.	113
“	insulare, Wittr.,	115
integrum, Wolle.	.	117
“	intermedium, Cleve, .	108
Var.cuspadatum, Wolle,	103
“	magnificum, Wolle, .	108
Var. crassioides, Hast.,	108
“	mammillosum, Wolle,	.	113
‘	multilobatum, Wood,.	107
“	Nordstedtianum, Wolle, .	116
“	oblongum (Grev.), Ralfs,	106
“	obtusum, Wolle,	.	117
“	ornatum, Wood,	106
“	pectinatum, Breb.,	109
“ pingue, Elf., .	.	116
“	pinnatum, Rails, .	.	107
“	Pokornyanum, Grun.,.	114
“	purum, Wolle,	.	110
rostratum, Ralfs,	116
“	simplex, Wolle,	.	117
‘‘	spinosum, Ralfs, .	116
“	urnaforme, Wolle,	.	Ill
“	ventricosum, Lund.,	.	110
“	verrucosum(Ehrb.),Ralfs,	111
Var. alatum, Wolle,	111
“ Crux Africanum,
Lagh., .	.	Ill
“ reduetum, Nord.,	112
“ simplex, Joshua,.	Ill
“	Wollei, Lagh ,	.	108
Var. quadrigibberum,
Lagh., .	.	108
“ cuspidatum, Wolle 109
GoNATOZYQON.D.By.—Description, 22
‘‘	asperum (Ralfs), Rab.,	22
“	pilosum, Wolle, .	.	22
“	Ralfsii, D. By., .	.	22
‘	sexspiniferum, Turner,	172INDEX.
179
PAGE. Hyai.otheca, Ehrb.—Character-			Micrasterias, oscitans, Ralfs,		’AGE. 12H
	istics of,	22	tl	papillifera, Breb., .	120
	How to find and collect.	xiii	“	pinnatifida (Kg.), Ralfs,	128
«	dissiliens (Smith), Breb.,	22	ft	pseudofurcata, Wolle,	122
	Var. hians, Wolle, .	22		Var. minor, Wolle, .	122
((	dubia, Kg.,	24		Pseudotorreyi, Wolle,	118
	mucosa (Mert.), Ralfs,	23	“	quadrata, Bailey,	129
“	undulata, Nord.,	23	“	Rabenhorstii, Kirch.,	131
			It	radiosa (Ag ), Ralfs, .	119
Mesotjenium, Naeg.—Generation				Var punctata, West, .	119
	of, ...	31	“	ringens, Bailey, .	123
ff	Braunii, D. By., .	31		Var. serulata, Wolle, .	123
*	Clepsydra, Wood,	33		rotata (Grev.), Ralfs, .	120
“	Endlicherianum, Naeg.,	32	((	speciosa, Wolle,	119
(I	micrococcum, Kg., .	32	(t	Swainei, Hast., .	119
			If	Torreyi (Bailey), Ralfs, .	118
Micrasterias, Ag.,		118	(f	triangularis, Wolle,	127
G	Americana (Ehrb.), Kg.,	124	tl	truncata (Corda), Ralfs,	126
	Var. spinosa, Tur.,	124 ‘	it	verrucosa, Roy, .	120
	'* Hermanniana, Rh.	124	it	Multiplication of,	17
	‘‘ recta, Wolle,	124	II	Names of Authors,	ix
((	alata, Wall,	125			
if	apiculata, Menegh.,	124	PEDiASTRUM.Meyen.—Description		
M	arcuata, Bailey, .	129		of,	168
ft	Baileyi, Ralfs,	130	a	angulosum, Menegh., .	162
u	brachyptera, Lund.,	121	it	Boryanum (Turpin),	169
it	conferta, Lund.,	126	“	braehylobum, A. Br., .	170
<(	crenata (Breb.), Ralfs)	126		Var. clathratum, A.Br.,	170
((	Crux-Melitensis, Ehrb..	123	“	constrictum, Hass.,	170
(1	decemdentata, Naeg.,	126	“	duodenarius, Bailey,	169
ff	denticulata (Breb.), Ralfs,	120	if	Ehrenbergii, A. Br., .	170
((	dichotoma, Wolle, .	123		Var cuspidatum,	170
«(	expansa, Bailey, .	129	“	forcipatum (Corda) A. Br.,	169
	fimbriata, Ralfs,	121	it	muticum, Kg.,	169
Forma, genuina,		121	“	pertusum, Kg., .	169
	“ apiculata, Menegh., .	121	it	Selena* a, Kg.,.	170
	“ Elephanta, Wolle,	121	“	simplex, Meyen, .	168
	“ nuda, Wolle,	121	n	Sturmii, Reinsch,	168
	“ simplex, Wolle,	121	“	tetras, Ehrb.,	170
If	foliacea, Bailey,	130			
ft	furcata (Ag.), Ralfs, .	122	Pentum, Breb.—Description of, .		33
	Var. simplex, Wolle, .	122	“	Brebissonii(Mengh.),Ralfs, 37	
a	hamata, Wolle,	127	a	Clevei, Lund.,	38
“	Jenneri, Ralfs,	127	it	closterioides, Ralfs,	36
“	Kitchelii, Wolle,	129	it	crassa, D. By.,.	36
it	laticeps, Nord.,	128	“	cruciferum, (D.By.) Wittr	38
“	Mahabuelshwarensis, Ho.	124		Digitus (Ehrb.),	34
(i	mamillata, Tur.,	125	t	interruptum, Breb.,	36
ft	muricata, Bailey,	130	“	Jenneri, Ralfs,	37
it	Nordstedtiana, Wolle,	125		lamellosum, Breb.,	34180
INDEX.
Page.
Penium, margaritaceutu, Breb., .	35
“	minutum, Cleve,.	3G
“	Navicula, Breb.,	37
“	oblongum, D. By..	35
“	polymorphum, Pertv, . 37
“	rupestre, Kg., .	38
"	spirostriolatum, Barker,	35
“	tumidum, F. Gay,	38
“	truncatum, Ralfs^	36
Phymatodicis, Nord., .	.	28
“	Nordstedtianum, Welle,	28
Pletrotaenium, see Docidium.
Regeneration,	.	.	18
Sphaerozosma, Oorda—Wherein
it differs from Phymatodocis	28
“	excavatnm, Ralfs,	30
“ filiforme, Rab.,	.	29
moniliforme, Lund.,	30
“	Nordstediana, Turner,	31
“	pnlchellum (Areh.l, Rab.,	29
“ pulebrmn, Bailey, .	29
Var.constrictum,Wolle,	172
•“ inflatnm, Wolle, .	29
“ planum, Wolle,	29
11	rectangulare. Wolle,	31
“	serratum, Bailey,	30
“j	spinulosum, Help., .	31
“	vertebratum(Breb.), Ralfs,	30
“	Wallacbi? Jacobson, .	31
SpiROTyENTA, Breb., .	.	33
“	bryophila (Breb.), Rab.,	34
“	condensata, Breb.,	33
“	obscura, Ralfs,	33
Staurastrum, Meyen,	. 119
“	aculeatum, Ehrb., .	153
“	alternans, Breb., .	.142
“	anatinum, Cooke—Wills,	152
“	angulatum, West, .	. 132
“	ankyroides, Wolle, .	150
Var. hexacerum,Wolle,	151
“	Arachne, Ralfs,	143
“	arctiscon, Ehrb., .	163
“	arcuatum, Nord.,	152
“	aristiferum, Ralfs,	. 135
“	asperum, Breb., .	140
“	aspinosum, Wolle,	157
Staurastrum, Avicula, Breb.,.
‘	baoillare, Breb.,
“	Bieneanum, Rab.,
“	botrophiluni, Wolle,
“	brachiatum, Ralfs,
“	Brebissonii, Arch.,	.
“	brevispina, Breb.,
Var. inerme, Wille,
“	Brasiliense, Nord.,
Page.
136
132
137
145
136
. 154
134
134
160
Yn r. triquetrum, Wolle, 160
calyxoides, Wolle,	158
Cerastes, Lund., .	147
Cerberus, Bailey, .	156
eommutatum, Kg.,	136
comptum, Wolle, .	143
controversum, Breb., .	155
cornutnm, Wolle,	158
eoronulatum, Wolle, .	148
Var. Floridense, Wolle, 149
cosmarioides, Reinsch, 139
crenatum, Bailey,	13S
crenulatum,(Delp.),Naeg. 140
crescentnm, Hast., .	153
crncintum, Wolle,	156
cuneatum, Wolle,	.	162
euspidatum, Breb., .	135
crytocerum, Breb., .	.142
Var. major, Wlole, 142
“ pentacladum,Wolle 143
dejectum, Breb.,	134
Var mneronatum,Ralfs, 134
“ eonvergens, Wolle, 134
Dickiei, Ralfs, .	135
dilatatnm, Ehrb, .	142
distentum, Wolle,	165
Donnellii, Wolle,	.	146
duplex, Wolle, .	164
echinatum, Breb.,	154
Eloisianurn, Wolle,	.	164
elongatum, Barker,.	.	143
Var. tetragonum, Wolle	143
enorrne, Ralfs,.	.	166
erasum, Breb., .	.	139
Var. espinulosa, Lund., 139
eustephanum, Ralfs, 161
fasciculoides, Wolle,	.	144
forficulatum, Lund.,	.	158
Franconium, Reinsch, 145
furcatum, (Ehrb.), Breb., 165
furcigerum, Breb.,	.	161INDEX.
181
	Page.		Page.	
Staurastrum, fusiforme, Wolle, .		150	Sta URASTURUM,pseudofurcigerum,	
«	gracile, Kalfs,	147	Reinsch,	162
ll	grande, Bulnh.,	133	“ psendopachyrhynchum,	
ll	grallatorinin, Nord., .	150	Wolle, . .	137
	Yar. ungnlatura,Wolle,	150	‘ Pseudosebaldi, Wolle,	152
It	Haaboeliense, Wille, .	147	“ pusillum, Wolle,.	144
ll	Heleneanurn, Wolle,	146	“ punctulatum, Breb.,	141
“	hirsutum (Ehrb.), Breb.,	155	“ pygmamm, Breb.,	141
“	Ilvstrix, Ralfs,	156	Forma—genuina, Breb.,	141
((	incisum, Wolle,	146	“ rhomboides,Wolle,	141
ll	inconspicuum, Nord.,	137	“ truncata, Wolle, .	141
ll	iotanum, Wolle, .	150	“ quadrangulare, Breb., .	160
It	Kitchelii, Wolle,	165	‘‘ quaterninro, Wolle,	158
ll	leptacanthum, Nord.,	166	“ Ravenelii, Wood,	157
“	leptocladum, Nord.,	149	“ rotula, Nord., .	148
“	Lewisii, Wood, .	135	1 rugulosum, Breb.,	140
“	longispinum, Bailey,	160	“ scabrum, Breb.,	143
(C	luteolum, Lagh.,.	139	“ Saxonicum, Bulnh.,	154
ll	maamense, Arch., .	139	Var. pentagona,	154
ll	macrocernm, Wolle,	148	“ Sebaldi, Reinsch,	151
ll	magnum, Wolle,	133	Var. spinosum, Wolle,	152
“	majusculum, Wolle,	133'	‘ senarium, Ralfs, .	162
a	margaritaceum, Ehrb., .	138	“ setigerum, Cleve,	152
“	megaeanthum, Lund.,.	134	“ silatatum, Nord, .	142
<>	megalonotum, Nord.,	141	“ sociatum, Wolle,	155
n	Meriani, Reinsch,	146	“ spongiosum, Breb.,	163
“	Minneapoliense, Wolle, .	141	*• striolalum, Naeg., .	138
“	Minnesotense, Wolle, .	156	‘ subarcuatum, Wolle, .	153
it	monticulosum, Breb.,	159	“ teliferum, Ralfs,	154
	munitum, Wood,	163	“ tetroctocerum, Wolle,.	166
((	muricatum, Breb.,	140	“ Tohopekaligense, Wolle,.	164
u	muticum, Breb., .	131	“ tricorne, Breb., .	138
	Yar. minus,.	131	“ tricornutum, Wolle,	155
	“ ellipticum,	132	“ tridentiferum, Wolle, .	155
a	nanum, Wolle,	151	“ trifidum, Nord.,	136
ti	Novie Cfesarete, Wolle,	159	“ trihedrale, Wolle,	136
n	odontatum, Wolle, .	148	“ tumidum, Breb.,	133
“	Ophiura, Lund., .	147	“ ungulatum, Wolle,	150
	Var.pentacerum,Wolie,	148	“ vesiculatum, Wolle,	132
	“ tetracerum, Wolle,	148	“ vestitum, Ralfs, .	151
“	orbicnlare (Ehrb.), Ralfs,	132	“ Wolleanum, Butler,	163
n	paniculosum, Wolle,	136	Var.Kissimmense,Wolle, 164	
“	paradoxum, Meyen, .	143	“ xiphidophorum, Wolle,	155
	Var. Osceolense, Wolle,	132	Irar. simplex, Wolle, .	155
u	Pecten, Perty,	155		
it	pentacladura, Wolle,	149	Tetmemokus, Ralfs—Description	
ii	polymorphum, Breb., .	139	of,		98
	Pottsii, Wolle,	166	“ Brebissonii (Menegh.),	
“	Pringlei, Wolle, .	145	Ralfs, .	98
it	pseudocrenatum, Wolle, .	139	“ giganteus, Wood,	99182
INDEX.
Page.
Tetememohtjs, granulatus, Ralfs, 98
“	lsevis (Kg.), Ralfs,	98
“	minutus, D. By.,	.	99
“ turgidus, Ralfs, .	.	98
Xanthtdium, Ehrb.............99
“	aculeatum (Ehrb.),	Breb.,	99
antilopaeum (Breb.), Kg, 101
Var.polymazum, Nord., 101
“ triquetrum, Lund., 101
‘ Canadense,Joshua, 102'
“ truncatum, Hast., 101
asteptum, Nord., .	100
Page.
XANTHiDruM, armatum(Breb.),Ralfe,99
“	bisenarium, Ehrb., .	100
“	Columbianum, Wolle,	100
cristatum (Breb.), Ralfs,.	100
‘	fasciculatum(Ehrb.)Ralfs	101
Var.hexagonum,Wolle,	101
“ minus, Wolle, .	101
“ subalpinum,Wolle,	101
“	Minneapoliense, Wolle, .	101
“	rectocornutum, Wolle,	102
“	tetracentrotum, Wolle, .	102
Zyoosporea::—Order of,	.	. 21EXPLANATIONS AND REFERENCES.
PLATE I.
Figures magnified 500 diameters.
Page.
Fig. 1. Gonatozygon Asperum, (Ralfsii), filaments and developed zygo-
		spore,	22
“ O	((	PILOSUM, .....	22
Figs. 3-5.	Hyalotheca dissiliens; three forms, normal condition,		22
“• 6,8.	“	“ end views of two cells,	22
Fig. 7.	((	“ a cell separated from the filament,	22
9.	((	“ first stage of conjugation, one cell in	
		front view, the other in end view,	22
Figs. 10,11	1.	“ advancing stages; chlorophyl of the	
		two cells concentrating in the gelati-	
		nous connecting tube, .	22
Fig. 12.		the developed zygospore, .	22
13.	Hyalotheca	MUCOSA, ...	23
“ 14.	Hyalotheca	DUBIA, . .	24
“ 15.	Bambusina Brebissonii,		24
“ 16.	>(	“ a developed zygospore,	24
“ 17.		“ first stage of development from a zygo-	
		spore; undeveloped cells enclosed in	
		a gelatinous envelope, .	24
“ 18		“ a second condition, the gelatinous en-	
•		velope largely dissipated,	24
“ 19.	U	“ early form of a developing filament,	24
“ 20.	It	“ more advanced stage; appearance of	
		notch at the middle of the cells,	24
“ 21.	“	“ central inflation begins to show, .	24
“ 22. Bambusina delicatissima, fully developed,	.	25
“ 23.	“	“	earlier stage,	.	25
“	24.	“	“	younger still, .	.	.	.25PLATE I
22PLATE II.
Figures magnified 500 diameters.
Page.
Figs. 1, 2. Desmidiom Swartzii.	Two forms ; filaments in vegetative con-	
	dition, .....	26
Fig. 3. “	Filament in fruit; the spores, and empty	
	ceils forced apart by the growth of the	
	spore, .....	26
Figs. 4, 5. “ “	End view of cells, showing the triangular	
	form of the filaments,	26
Fig. 6. Desmidiom Aptogonium, a vegetative filament,		27
« l( it	the triangular end view of the same, .	27
Figs. 8, 9. Desmidiom Bailf.yi.	(Aptogonum Baileyi.) 8. the normal	
	vegetative condition of the chlorophyl;	
	9. the same concentrating for the forma-	
	tion of the spores, (left hand figure is an	
	end view),	27
Fig. 10. “	the fully developed spores,	27
“ 11.	spores matured and separating from the	
	filaments, .....	27
“ 12. “ “	end view of filament,	27
“ 13. Desmidium quadrangulatom ; part of a filament,		27
“ 14. “ “	end view of filament,	27PLATE IIPLATE III.
Figures magnified 500 diameters.
Page.
Fig. X.	Desmidium cyeindricum, (Didymoprium Gremlli), part of a	
	vegetative filament, .	25
“ 2.	*• “ end view of a cell,	25
‘ 3.	“ r “ two cells copulated; chlorophyllous contents passing through a gelatinous	
	tube, from one cell to the other,	25
“ 4.	“ “ Two developed zygospores; the two	
	empty cells still connected, .	25
“ 5.	Mesotaenium Braunii, D. By. [Palmoglcea maerococca. Kg.),	
	a group of three vegetative cells,	32
Figs. 6-9.	1 “ advancing stages of copulation and spore formation to the fully developed	
	zygospore, ....	32
Fig 10.’	Mesotaenium micrococcum, a group of seven cells.	32
“ 11.	Mesotaenium Enduicherianum, a group of four cells,	32
12.	Mesotaenium ceepsydra, three vegetative cells, .	32
Figs. 13-15.	two cells copulating and two devel- oped spares, husks remaining at-	
	tached.	33
“ 16-19.	Spirotaenia obscura,	33
“ 16,17.	“ young stages of development in gela-	
	tinous envelopes,	33
“ 18, 19.	“ “ more matured forms,	3S
Fig. 20.	Spirotaenia Bryophila, (S. muscicola), a group of four,	34
Figs. 21, 22.	Spirotaenia condensata,	33PLATE IIIPLATE IV.
Figures magnified 500 diameters.
Page.
Figs. 1, 2. Sphaerozosma pulchrum, filament enveloped in a colorless
gelatinous sheath; the irregular
breadth is produced by the twist of
the filament, .	. 29
"	3, 4,	“	“	Var. planum,	.	.	29
“	5,	6.	Sphaerozosma filiforme,	...	29
Fig. 7.	SrHAEROZOSMA serratum. See	also Plate XLTII,	30
“ 8. Sphaerozosma excavatum, with gelatinous sheath, .	. 30
“ 9.	“	“	with sheath partially dispersed, 29
Figs. 10 12.	“	“	developed spores with empty cells
attached, .	.	.	.29
Fig. 13.	Sphaerozosma vertebratum ; with a decided twist, .	30
“	14.	Sphaerozosma spinulosum ?	.	31
“ 15.	Sphaerozosma Wallachii? .	...	31
For additional varieties see—
Plate LX. S. pulchrum, Var. inflatum,	. 29
Plate XLVII. S. var. constrictum,	Addenda, 172
Plate LX. S. rectangulare,	31
Plate XII. S. PULcnELLUM.	.	29
Plate XLVII. S. moniliforme, .	.	.30
Plate XLIII. S. Nordstehtiana,	.	31PLATE IVPLATE V
22PLATE VI.
Figures magnified 250 diameters.
Page.
Figs. 1,2. Closterium Dianas, .	.	.	.	.	.47
“	3,4.	Closterium tdkgidum,	.....	43
“	5-8.	Closterium striolatum,	.	.	.	.	.44
Fig.	9.	Closterium Delpontii,	.....	45
“	10.	Closterium didymoticum,	.	.	.	.	.41
“	11.	Closterium subcostatum,	.....	43
“	12. Closterium Lunula. Var. 9triatum, .	. 42
Figs. 13,14.	Closterium ensis, ......	40
“	15,16. Closterium prelongum,	.	.	. 43
Fig. 17. Closterium Brebissonii, (Addenda, p. 172),	.	.	24
Figs. 18,20. Closterium lanceolatum, (also Plate IX, fig. 14),	.	. 40
Fig. 21. Closterium juncidum, Var. gracillima-loevissima,	39
“	22. Closterium pronum, .	.	.	.	.50PLATEPLATE VII.
Figures magnified 250 diameters.
Pace.
Fig. 1. Closterium obtusum,	...	39
“	2.	Clostericm jcncidcm,	.	.	39
“	3.	“	“ two cells with developed zygospore, .	39
Figs. 4,5.	Closterium gracile, .....	40
Fig. 6.	Closterium macilektum,	.	. 40
“ 7.	Clostericm acerosum, zygospore and empty cells, .	42
“	8.	Closterium striolatum,	.	.	.	.44
Figs. 9, 10. Closterium decussatum, .	.	.	41
Fig. 11.	Clostericm acerosum, vegetative cell,	.	.	42
“	12.	Closterium masutum,	.	.	43
Figs. 13,14.	Closterium strigosum,	...	.	44
Fig. 15.	Closterium turgidum, ...	.43
“ 16.	Clostericm lineatcm,	two cells, (see Plate IX,	fig. 15),	.	45
Figs. 17, 18.	Closterium cuccmis, ....	42
Fig. 19.	Clostericm costatdm, .	.	... 45
‘	20.	Clostericm striolatum,	(compare	fig. 8, and	Plate	VI,
figs. 5-8),	.	.	,	44
Figs. 21-23.	Clostericm angcstatum, and variety decussatum, .	41PLATE VIIPLATE VIIIPLATE DC
17PLATE X.
Figures magnified ,500 diameters except Closterium, only 250 diameters.
Page.
Figs. 1, 2. Closterium acerosum, forma striolatum with single ami twin
zygospores, .	.	.	.42
Fig. 3. Closterium lineatum, Var. costatum, with twin zygospores, 45
Figs. 4, 5. Arthrodesmus notochondrus, in front and vertical views, . 105
Fig. 6. Asthrodesmus lncrassatus, Var. cycladatus, .	.	105
Figs. 7, 8. CosmArium oculiferum, front and lateral views, .	. 76
“	9-11. Penium crucieerum, in different stages of division, .	38
“	12, 13. Arthrodesmus pachycerus, front and lateral views, .	. 105
“	14,15. Arthrodesmus triangularis, front and vertical views, .	105
Fig. 16. Docidium Georgicum,	.	.	.	.	.55
“	17. Penium spirostriolatum, var., .	35
“	19.	“	..... 35
18. Docidium verticillatum, .	58
Figs. 20, 21. Docidium rectum, ...	. 52PLATE XIPLATE XI.
Figures magnified 500 diameters.
Page.
Fig. 1.	Docidium crenulatum—(C. iwdulosum),	.	. 51
Figs. 2, 3,4. Docidium Trabecula. Compare Plate XV, figs. 1-7,	.	51
Fig. 5.. Docidium Flotowii, Variety, .	.	.	.	.52
Figs. G, 7 Docidium truncatum, .	.	.52
Fig. S. Docidium ulavatum,	.	51PLATE XIPLATE XII.
Figures magnified 500 diameters.
Page.
Fig. 1. Tetmemoros gigahteus,	.	99
“	2. Docidiuh Archeeii, ...	51
“	3. Docidium nodtjxosum, .	. 51
“	4. Docidium WooDn, .	.	.55
“	5. Docidium Baculum, Var. Floridense, .	.	.	.53
Figs. 6,7. Statjrastrum yesiculatum, .	.	.	132
“	8, 9. Sphaerozosma petechellum, Var. bambusioides, .	. 29
“	10-13. Euastrum PECTINATUM, front, lateral and transverse views, 109
“	14-16. Hyalotheoa dissiliens, Var. liians, .	.	. 22PLATE XIIPLATE XTII.
Figures magnified 500 diameters.
1.	Docidium
2.	Docidium
3.	Docidium
4.	Docidium
5.
6.	Docidium
7.
8.
9.	Docidium
10.	Docidium
11.	Docidium
12.	Docidium
13.	Docidium
Page.
VERTICILLATUM,	.	.	.57
COSTATUM, .	.	57
gracile, large form; whorls evidently composed of two
rows of teeth,	...	58
verrucosum, vegetative state,	.	. 56
“	empty semi-cell, shows the arrangement oi
the verrucae,	...	56.
gracile, empty semi-cells,	...	58
“ empty semi-cell, older condition before breaking
into parts, .	...	58
“ small form, ...	.58
minutum. Yar. See Plate LXI, figs. 29-31. .	.	57
TRIDENTULUM, .	.	.57
verticillatum, Var. turgidum,	...	57
seinosum, .	.	.	. 56
HIRSUTUM,	...	.56PLATE XIII
■'MAM
\ \ A A-i

f\M/l
\/\ \ A A A A*)
yV\r\ \ /\A\KA /v&jji
&\^N\Aa A \vm


:^r.rj»v;-i-•;.•:i:-’V;'•• •;'^v•	-v
WliS
SMS#	PLATE XIV.	
	Figures magnified 500 diameters.	Page.
Fig. 1.	Docidium repandum, ...	. 54
“ 2.	Docidium CONSTRICTUM, . . / .	54
Figs. 3,4.	Docidium Bacct.um, two forms, .	. 52
Fig. 5.	Docidium undulatum, ....	55
Figs. 6-8.	Docidium sinuosum, .....	. 55
“ 9, 10.	Docidium coronatum, two forms,	53
Fig. 11.	Docidium nodosum, falling to pieces through decay,	. 54PLATE XIV
11PLATE XV.
Figures magnified 500 diameters.
Figs. 1-3.
Fig. 4.
Figs. 5, 6.
Fig. 7.	
H	8.
it	9.
“	10.
it	11.
ti	12.
((	13.
“	14.
t<	15.
a	16.
u	17.
u	18.
it	19.
“	20.
Page.
Docidium Trabecula ; two conjugated cells, pouring out the
cytioplasm, or granular ehlorophyllous
contents and forming a zygospore, . 51
“	“	a developed zygospore, .	51
“	“	a cell dividing, .	.	.	.61
u	“	early stage of outgrowth, or new semi-
cells,	.	.	.	.	.51
Calocylindrus connatus, very near Delps. C. ellipticum,	59
“	“	..........................59
“	“ Var. minor, ...	60
Calocylindrus pseudoconnatus,	.	.	.	.	.60
Calocylindrus minutus, .....	59
Calocylindrus costatus, .	.	.	.61
Calocylindrus cucurbita, .....	59
Calocylindrus curtus, larger form,	.	.	.59
x'
“	“ smaller form, ....	59
Calocylindrus Ralfsii—C. cylindrieum, .	.	.58
Calocylindrus diplospora, .	.	.	.	.61
Calocylindrus Thwaitesii,	.	.	.	.	.60
Docidium nodosum. (Compare Plate XIV, fig. 12), .	.	54PLATE X.VPLATE XVI.
Figures magnified 500 diameters.
Page.
Figs.	1, 2.	Cosmarium margaritiferum ;	normal, front view, and empty
semi-cells, transverse view,	81
Fig. 3.	-	“	zygospore with the empty semi-
cells, .	.	. .SI
4. Cosmarium punctulatum,	.	.	.	.	81
Figs. 5-7. Cosmarium Botrytis, three forms. (Compare Plate XXVII,
fig. 27),	.	.	81
“	8, 9. Cosmarium ovale, smaller and larger form, .	.	62
“	10, 11. Cosmarium Brebissonii, two forms, .	.	. 82
Fig.	12.	Cosmarium intermidium, .	...	83
“	13.	Cosmarium tetropthalmum,	.	...	82
“	14.	Cosmarium latum, ends too convex for typical form,	84
“	15. Cosmarium dentatum, .	.	.	.	.	.83PL,ATE- XVi:jlj.
82
84
84
85
85
86
84
84
84
84
84
93
74
74
85
PLATE XVII.
Figures magnifled 500 diameters.
C'OSMARIUM CONSPERSUM ; two forms,
C'OSMARIUM OCRTHODES,
“	“	empty cell of smaller form, .
COSMARIUM AMCENUM,	.	.	.	.
“	“	Var. tumidum, .
COSMARIUM ELEGANTISSIMUM, ,	.
C'OSMARIUM RENIFORME, ....
“	“	smaller form, empty cell, .
Cosmarium Portianum, .....
“	“	cell dividing,
“	“	zygospore and emptied semi-cells,
Cosmarium Broomei, Var. (Compare Plate XX, figs. 6-9),
Cosmarium pyramidatum, two forms, one cell empty,
“	“	Var. stenonolnm,
Cosmarium orbiculatom,PLATE XVII
Sfe.b'j
l&v*
’B°o °o J
°G o ° ° O OoO qx
??0o0o00o"°ooto
o o°oo O O
o QOO O o O O 6 ° °:j
AiiM *\u
wjoooomJ
hmcoomm
WoooMPotyj
tboQOQOOOOQ^
iptoiDNu
Poojoooi
4(1(100 Ora
©MOW
MOOOOOC
IPOOOQ1.


5o° ^o o0,,0o0o0oOo^3i
te,=?o%L"o;;00°°gl
Oo° O O O 0®oO^^J-
55o°°o o o %oo9rf>f^

PLATE XVIII.
Figures magnified 500 diameters.
Fig. ]. COSMARIUM Ralfsii, .	.	.
Figs. 2-4. Cosmarium pachydermum ; three forms,
Fig. 5. Cosmarium De Baryi. (Compare Plate XLV, fig. 12),
Figs. 6-9. Cosmarium Cucumis, four sizes,
Fig. 10. Cosmarium laeve, a variety. (Compare Plate XLI1I, fig. 14), 70a
Figs. 11, 12. Cosmarium pseudopyramipatum (Compare Plate XIX, figs.
Page.
. 75
75
62
62
5, 6),	. 75
Fig. 13.	“	“	zygospore, and husks of cells, 75
Figs. 14, 15. Cosmarium granatum, Var. elongatum, for typical form See
Plate LX I, fig. 13,	.	64
“	16, 17. Cosmarium moniliforme, two forms,		64
Fig.	18.	after division, new semi-cells en-	
		larged, ....	64
«	19.	zygospore,	64
«(	20. Cosmarium globosum;	a variety; See typical form, Plate	
		LX, figs. 14-17,	65
It	21. Cosmarium bioculatum,		66
“	92 << c<	zygospore, .	66
. 67
23.
Cosmarium tumidum,PLATE XVIIIPLATE XIX.
Figures magnified 500 diameters.
Page.
Fig. 1.	COSMARIUM CONTRACTCM,	.	.	68
“	2.	COSMARIUM SINUOSUM,	.	.	70
Figs. 3, 4. COSMARIUM VARIOLATUM,	.	.	.	68
“	5-6. Cosmarium pseudopyramidatum, smfil 1 variety. (Compare
Plate XVIII),	75
Fig. 7.	Cosmarium Meneghinii, four forms,	76
Figs. 8, 9.	Cosmarium sexangulare. (Compare Plate LX, fig. 13),	69
Fig. 10.	Cosmarium undulatum, Var, crennlatum, ...	73
“ 11.	Cosmarium notab ile,	.	.	.	72,86
“ 12. Cosmarium Reinschii, .	.	73
Figs. 13, 14. Cosmarium exiguum, .	72
Fig. 15.	Cosmarium aculeatum,	.	71
“ 16.	Cosmarium lunatum,	71
Figs. 17,18. Cosmarium Baileyi; (C. depressum, Rail.),	.	69
“	19,20. Cosmarium undulatum ; and Var. crenulatum, .	72
Fig. 21.	“	“	a zygospore,	72
“ 22. Cosmarium ansatum, .	. 74
Figs. 23-25. Cosmarium Holmiense, varieties,	.	74
“	26, 27. Cosmarium trachypleurum, normal state and cell dividing, 79
“	28, 29.	“	“	transverse and side views,	79
Fig. 30.	Cosmarium polygonum, .	71
“ 31.	Cosmarium tinctum, .	67
Figs. 32-34.	Cosmarium taxichondrum ; two forms and	lateral	view of
empty cell,	.	.	77
“	35, 36. Cosmarium Smolandioum, .	.	.	72
Fig. 37.	Cosmarium venustum, ...	73
Fsgs. 38^10.	Cosmarium polymazum, front, end and lateral views,	76
“	41, 42.	Cosmarium Donnellii, ...	77
“	43-45.	Cosmarium antsochondrum, front, end and side views,	78
“	46-48.	Cosmarium galeritum, three varieties,	.	.	.75PLATE XIXPLATE XX.
Figures magnified 500 diameters.
Page.
Figs. 1,	2.	Cosmakium biketcm, front and end view,	.	.	.93
“	3,	5.	Cosmaridm Botrytis, Var. tumidum, Wolle,	front	and side
views, .	.	.	.82
Fig. 4.	“	“	zygospore, husks attached, .	.	82
Figs, 6,	7.	Cosmaridm Broomei, front and end views,	.	.	.93
“	8, 9.	“	“ smaller variety and zygospore, .	93
“	10-12.	Cosmaridm Everettense ; front, end and lateral views,	.	92
13-15.	Cosmaridm qdasillus ; front, lateral and end views,	.	92
“	16-18.	Cosmaridm quadrii arium ; front, lateral and end views,	.	94
“	19,20.	Cosmaridm homalodermum ; front and end views,	.	88
“	21-33. Cosmaridm Wolleanum (C. pseudogranatum), front, trans-
verse and lateral views,	.	64
“	24-26.	Cosmaridm Turpinii ; front, end and lateral views, .	.	87
“	27, 28.	Cosmaridm protractdm ; front and end views, .	.	90
Fig. 29.	Cosmaridm ornatdm, Var. minor, (Protractum f)	.	.90PLATE XXPLATE XXI.
Figures magnified 500 diameters.
Page.
Figs. 1 -3.	Cosmarium	Kitchelii, front, end and lateral views,	.	. 79
‘‘	4, 5. Cosmarium orthosticum, front and lateral views, .	.	86
“	6,7.	Cosmarium	subcrenatum, front and lateral views,	.	. 91
“	8, 9.	Cosmarium	quadratum, front and end views,	.	.	63
Fig. 10.	“	“	larger form.	.	63
“ 11. Cosmarium anceps, .	.	.	.63
Figs 12, 13.	Cosmarium	parvulum, front and side views, .	.	.64
“	14,	15.	Cosmarium	Schueipacheanum, front and end views,	.	89
“	16-18.	Cosmarium	nitidclum; a form; ends not usually so	convex, 72a
Fig.	19.	Cosmarium	pseudonitidueum, ....	72a
20.	Cosmarium	tumidum, a coarsely granulate variety,	82
Figs.	21,	22	Cosmarium	sublobatum, .	87
“	23,	24.	Cosmarium	cruciatum, front and end aspect,	.	89
“	25,	26	Cosmarium	retusum, front and end aspect,	.	88
Fig 27. Cosmarium Hammeri, Var. intermedium,	.	86
Figs. 28-30. Cosmarium Phaseolus, three views,	.	89
“	31,32,	‘	“	smaller variety;	zygospore with husks
of cells attached,	.	.	89
“	33-35.	Cosmarium	Seelyanum, front, end and side views,	.	. 80
“	36, 37.	Cosmarium	Hammeri, Var. inflated sides,	.	.	86
Fig. 38.	“ zygospores with remains of cells, .' 86
Figs.	39-42.	Cosmarium	ornatum, two sizes, four views,	.	.	89
“	43-45.	“	“ a variety, front, side and end views, 89
46-48. Cosmarium caelatum, front and side views; transverse view
of an empty semi-cell, .	.	.93
“	49,	50.	Cosmarium	commisurale, front and transverse views, .	91
Fig. 51.	“	“	zygospore, husks of cells not de-
tached, .	.	.	.91PLATE XXIPLATE XXII.
Figures magnified 500 diameters.
Page.
Figs. 1, 2.	Cosmarium Eloiseanum, front and end views,.		92
“ 3-6.	C’OSMAKICM	triplicatum, front, lateral and end views, and	
		zygospore,	79
“ 7, 8.	COSMARIUM	SPECIOSUM,	95
Fig 9.	l(	“ smaller form,	95
Figs. 10, ll.	CoSMARIUM	pycnochondrum, front and lateral views,	97
“ 12, 13.	COSMARIUM	Pecttnoides, front and side views,	96
“ 14, 15.	COSMARIUM	speciosum, small variety,	95
“ 16-18.	Cosmarium pseudopectinoides ; two in front view, one in side		
		view,	96
Fig. 19.	Cosmarium	NASUTUM,	96
“ 20.	Cosmarium	subcrenatum. (Compare Plate XXI, figs, tf, 7),	91
Figs. 21-22.	Cosmarium	RADIOSUM, .	97
“ 23, 24.	Cosmarium	bireme, in three views, front, side and end*,	89
“ 25, 26.	Cosmarium	marqaritum, in three views,	88
Fig. 27.	<	zygospore, with the remains of the	
		semi-cells attached,	88
Figs. 28-30.	Cosmarium	tithophorum, from three points of view,	88
“ 31-33.	Cosmarium	Blyttii, front, side and end views,	95PLATE XX UPLATE XXIII.
Figures magnified 500 diameters.
Page.
Fig. 1. Tetmemorus Brebissonh, long form, .	98
“ 2.	“	“	shorter and more usual form, .	98
“ 3. Tetmemorus LAEvrs, .	.	.	.	.	.98
Figs. 4, 5. Tetmemorus Brebissonh, Var. turgidus, two forms, front view, 98
Fig. 6. Tetmemorus giganteus, (See also Plate XII), .	.	.99
Figs. 7, 8. Tetmemorus minutus, conjugating and more advanced condition
of spore, .	.	.99
Fig. 9.	“	“ zygospore fully developed.	99PLATE XXIII
7PLATE XXIV.
Figures magnified 500 diameters.
Page.
Fig. 1. Xanthidium armatum, from Mount Everett, Mass.,	. 99
Figs. 2, 3.	“	“ more common forms and sizes, .	99
Fig. 4.	“	“ transverse view of a semi-cell,,	.	99
Figs. 5-7. Xanthidium cristatum, three forms, ....	100
Fig. 8.	“	“ end view, .	100
Figs. 9, 10. Xanthidium asteptum, two forms, ....	100
Fig. 11.	“	lateral view,	.	. 100PLATE XXIV
frrj
’rffotrsyl;: iPLATE XXV
Figures magnified 500 diameters.
Page.
Fig. 1. Xanthidiom	Antilopaeum, Var. triquetrum, front view,	101
“ 2.	“ triangular end view,	101
“ 3.	zygospore with the empty semi-	
	cells attached,	101
“ 4. Xanthidium FASCICULATUM,		101
“ 5.	“ in process of dividing,	101
Figs. 6, 7. “	a seini-ceil in two views, develp- ing a sort of spore without con-	
	jugation; an abnormal process,	102
Figs, s, 9. Xantiiidium	tetracentrotum, front and end vi*"ws	li'2
“ 10, 11.	rectocornutum, front and end views,	102PLATE
XXV101
101
101
101
101
101
100
99
103
103
103
103
PLATE XXVI.
Figures magnified 500 diameters.
Xanthidium antilopaeum, typical form, front view,
“	**	transverse view of	semi-cell,
u	“	Var. polymazum, front	view,
“	“	lateral view,
Xanthidium fasciculatum, Var. hexagonum,
“	“	lateral view,
Xanthidium bisenarium, front, side and end views,
Xanthidium aculeatum, front, side and end views,
Arthrodesmus Kauii, front, end and side views,
Arthrodesmus fragilis, two front and one end view,
Arthrodesmus convergens, two front and one end view,
“	“	variety with short aculei, .PLATE XXVIPLATE XXVII.
Figures magnified 500 diameters.
	Page.	
Fig, 1-	Arthodesmus Incus, large form,	104
“ 2.	“ “ smaller form,	104
“ 3.	“ “ long spined variety,	104
“ 4.	'• “ depressed variety,	104
'• 5.	“ “ quadrate variety,	104
“ 6.	'■ “ quadrate variety, smaller,	104
“ 7.	“ “ crenate-cuneate,	104
“ 8.	“ “ two cells conjugating,	104
“ 9.	“■ “ zygospores doveloped,	104
“ 10.	“ “ end view of cell,	104
Figs. 11, 12.	Arthrodesmus subulatus, front and end view,	104
“ 13, 14.	Arthrodesmus ovai.is, front and end view,	103
“ 15, 16.	Arthrodesmus orbicularis, front end view,.	104
“ 17, 18.	Arthrodesmus quadridens, front and end view,.	104
“ 19, 20.	Arthrodesmus octocornis, Var. twin spined,	104
21-23.	“ “ larger and smaller typical form,	104
Fig. 24.	COSMARIUM SUBORCULARE, ....	85
“ 25.	Desmidum cylindricum, (Compare Plate HI, fig. 1,) to illus- trate the division of » cell in the	
	process of growth,	26
“ 26.	Hyalotheca dissiliens, (Compare Plate I, figs. 4, 5, etc.), the middle cell is normal, the other two enlarging preparatory to division in	
	the process of growth,	22
“ 27.	Cosmarium Botrytis, two cells, opening on one side, putting	
forth cytioplasm, uniting, thus perform-
ing the first act of conjugation,	81
“	28. The whole contents, cytioplasm, of the cells, poured out com-
mingled and formed into the zygospore,	.	19
“ 29. The tubercles on the membrane formed around the fnass of
cytioplasm (fig. 28,) developed into spines. In the process of
further development the membrane breaks, lets out some of the
cytioplasm ; (fig. 29,) this assumes a spherical form, (fig. 30,)
membrane increases in thickness and number of layers; the
contents divide in one direction, (fig. 31,) then subdivided in
a transverse direction, (fig. 32). Two or four daughter cells
are thus formed in all respects like the mother cell, except in
the granules of the membrane ; these develop later,	19
33. A cyst containing a number of small Closteriums; supposed to
be the development of a zygospore by another process,	19PLATE XXVIIPLATE XXVIII.
Figures 3, 7, 10, 12 magnified 150 diameters; others 500 diameters.
Euastrum crassum,
“	“	semi-cells of very large form,
“	“	transverse view of semi-cell,
Euastrum ornatum, a form of “ E. crassum,"
Euastrum oblongum, two forms,
“	“	transverse view of semi-cell,
Euasarum ansatum, two forms,
“	•* transverse view of semi-cell,
Page.
106
106
. 106
106
. 106
106
109
109
. 110PLATE
: viirPLATE XXIX.
Figures magnified 500 diameters.
Page
Fig. 1-3. Eoastrum ventricosum, zygospore, lateral and end views of
cell,	.	.	.	.110
Figs. 4, 5. Euastrum crassum, Var. scrobicdlatdm, front and lateral
views,	.	. 106, 108
“	6-8. Edastrdm magnificum, front, lateral and end views,	.	108
“	9-11. Euastrdm PDRUM, two front and one lateral view, .	110
“	12, 13. Euastrdm cdneatdm, front and lateral views, .	.	108xi xx aivadHjHi.
Ill
111
111
111
111
114
116
116
116
116
113
114
113
114
PLATE XXX.
Figures magnified 500 diameters.
Euastrum verrttcosum, typical form,
“	“	Var. Crux Africanum, .
“	“	Var. reductum,
“	“	Var. alatum,
“	“	transverse view,
Euastrum Donnellii,
Euastrum Nordstedtianum, .
“	“	Var. minor,
“	“	typical varieties,
“	“	lateral view,
Euastrum mammillosum; front and end views,
Euastrum formosum,
Euastrum attencatum,
Euastrum divarioatum, front and end views,PLATEPLATE XXXI.
Figures magnified 500 diameters.
		Page	
Figs. 1-3.	Euastrum	pingue, front, side and end views,	116
“ 4-6	Euastrum spinosum, three forms, .		116
Fig. 7.	CC	“ lateral view, ....	116
Figs. 8, 9.	Euastrum rostratum, . . .		116
“ 10-15.	Euastrum	ELEGANS,	116
Fig. 16.	((	“ zygospore,	116
“ 17.	Euastrum	spinosum, side view of cell.	116
Figs. 18-22.	Euastrum	INTEGRUM,	117
“ 23, 24.	Euastrum	BTNALE, ...	117
“ 25, 26.	Euastrum	ELEGANS,	116
Fig. 27.	Euastrum	rostratom, a form of,	116
Figs. 28, 29.	Euastrum	COMPACTUM,	117
“ 30, 36.	Euastrum	INERME, ...	115
Fig. 31.	Euastrum	OBTUSUM,	117
“ 32.	Euastrum	C'USPIDATUM, . . .	115
Figs. 33-35.	Euastrum	POKORNYANUM,	114
Fig. 36.	Euastrum	INERME, ....	115
Figs. 37, 38.	Euastrum	CRASSICOLLE,	115
“ 39-42.	Euastrum	INSIGNE, . .	113
Fig. 43.	U	11 end view, showing the cruciform apex and the quadrate base of the semi-cell,	113PLATE XXXIPLATE XXXII.
Figure* magnified oOO diameters.
Page.
Figs. 1, 2. Euastrum circueare. front and transverse views of semi-cell, 112
Fig. 3. Euastrum gemmatdm, .	.	. 112
“	4.	“	“	transverse view of semi-cell,	112
“• 5.	Euastrum Everettense .	.	. 112
Figs, 6, 7.	“	“	transverse and lateral aspect of
semi-cell,	.	. 112
“	8-10. Euastrum ampullaceum, three forms,	.	.	110
Fig. 11.	“	“	transverse view of semi-cell. .	110
“ 12. Euastbttm humerosum, .	.	.	107
“	13.	“	“ basal view of semi-cell, .	.	107
Figs. 14, 15. Euastrum pixnatum,	.	107
Fig. 16.
107
basal aspect of semi-cell,plate XXX uPLATE XXXIII.
Figures magnified 500 diameters.
			Page.
Fig. 1.	Ecastrom	WoLLEI,	. 108
“ 2.	((	“ transverse view of semi-cell. .	108
“ 3.	U	“ Var. cuspidatum, .	108
Figs. 4, 5.	“	lateral and end views,	108
“ 6-8.	Euastrdm	inerme, three forms,	. 115
“ 9, 10.	Euastroti didei/ta, two forms,		109
“ 11, 12.	Euastrum	astsatum—E. Ralfsii,	. 109PLATE XXXIII.
10PLATE XXXIV.
Figures magnified 375 diameters.
Page.
.1-8. Micrasterias Torreyi, in eight varieties, each represented by
one-fourth of a cell. The varieties
effected by the process of multiplication
by division ; two semi-cells of entirely
different outline being in many cases
united, as part of the same plant,
118PLATE XXXIVPLATE XXXV.
Figures magnified 375 diameters.
Page.
Fig. 1. Miorasterias radiosa, larger form containing about forty biparted
lobelets, with apices furcate or bidentate, 119
“ 2.	“	“	smaller form of about twenty bipartite
lobelets, .	.	.	.	.119
“ 3.	“	“	anotherform with about twenty-foursimilar
lobelets, some of the apices indicating by
the smaller indentations a further division, 119
“ 4 Micrasterias muricata, small variety,	.	130
“ 5.	“	‘	larger form,	.	.	.	130
transverse view of semi-cell,	130
•• tiPLATEPLATE XXXVI.
Figures magnified 375 diameters.
Fig. 1. Micrasterias	PSEUDOTORREYF,	Page. . 118
“ 2. Micrasterias	Americana, .	124
“ 3.	“ Vnr. recta,	124
“ 4.	“ transverse view, .	124
“ 5.	Var. Hermanniana, .	. 124
Figs. (5,7. Micrasterias	brachyptera, two semi-cells varying	somewhat
in details, .	121
“	8, 9. MiCRAsTERIAs PAPILLIFERA, two forms,
120PLATE XXX VIPLATE XXXVII.
Figures magnified 375 diameters.
Page.
Fig. 1. Micrasterias Jenneri, ...... 127
“ 2.	“	“ Var. angulosa, .	.	127
Figs. 3, 4. Micrasterias oscitans, two semi-cells, varying mainly in the
apices of the polar lobes; in the one
simple, in the other divided, .	.	128
“	5, 6. Micrasterias decemiientata. a large form, two sizes, .	126
“	7, 8. Micrasterias crenata, two forms,	.	.	.	126PLATE XXXVII
7PLATE XXXVIII.
Figures magnified 875 diameters.
		Page.	
Figs. 1, 2.	Micrasterias rotata, two forms,		120
Fig. 3.		Var. simplex,	120
* 4.	Micrasterias	DENTICDLATA, circular form,	120
“ 5.	U	“ more oblong in outline,	120
“ 6.	“	larger variety, near M. angulosa	
		of Reinsch,	120
Figs. 7, 8,	u	semi-cells of two smaller forms, .	120
	
	
	
	
8PLATE XXXIX.
Figures magnified 375 diameters.
Page.
Figs. 1, 2. Micrasterias ringens, two forms, .	.	. 123
Fig. 3.	Micrasterias Crux Melitensis, ....	123
“ 4.	Micrasterias pseodofurcata, .	.	122
Figs. 5,6. Micrasterias furcata, two forms, .	.	.	128PLATE XXXIXFig. 1.
“ 2.
“ 3.
“ 4.
Figs. 5, 0
Fig. 7.
“ 8.
PLATE XL.
Figures magnified 375 diameters.
Page.
Micrasterias fimbriata, semi-cell, typical form,	.	121
“ other semi-cell, VTar. apiculata, .	121
“	one-fourth cell, Var. Elephantine, .	121
“	“ Var. nuda, .	,	.	121
“	“ two varieties of polar lobes, .	.121
Micrasterias subfimbriata, has the form of lobelets, but not
the specific number, .	.	121
Micrasterias simplex, unlike all other forms in the simple,
acute, ultimate division of the lobules, 121PLATE XL.PLATE XLI.
Figures magnified 375 diameters.
Page.
Figs. 1, 2. Micrasterias Kitchelii, two forms, .	.	129
Fig. 3.	“	“ lateral view, .	.126
Figs. 4, 5. Micrasterias laticeps,—M. disputa, Wood,	.	128
Fig. 6. Micrasterias Baieeyi, .	130
Figs. 7, 8. Micrasterias pinnatifida, two forms, .	.	.	129
Fig 9.	“	“	Var. inflata, .	.	.	129
“ 10. Micrasterias Mahabci.eshwarensis,	124
“ 11. Micrasterias pseudofurcata, Var. minor,	.	122
“ 12. Micrasterias expansa, .	.	.	. 129PLATE XL1
- •V.-t • • -i.1


X'iVJPLATE XLII.
Figures magnitied 500 diameters, excepting the Micrasterias only about
one-half as much.
Page.
Fig. 1.	Micrasterias	Swainei, Hastings, .	.	,	.119
“	2.	Micrasterias	Kitchelii, Wolle, variety.	Pond, Malaga,
New Jersey,	.	.	.	129
Figs. 3-5. Xanthidium antelopaeum, Kg., ....	101
Var. truncatum, Hastings, front,
lateral and end	views,	.	101
“	6,7. Staurastrum	megalonotum, Nord.,	.	.	.141
Var. obtusum,	Hastings,	.	141
Nord.’s Spitz., Des. Arcto. and Des. Groen.
“	8-11. Staurastrum cresceetum, Hast., front and end views, . 153
“	12,	13.	Euastrum	verrucosum, Ehrb., ....	Ill
Var. simplex, Joshua, .	. Ill
“	14,	15.	Staurastrum	Saxonicum, Bulnh.,	.	154
Var. pentagonum, Wolle, front
and end views,	.	.	. 154
“	16, 17. Eq a strum Hastingsii, Wolle, .	.	.	.	113PLATE XL.IIPLATE XLIII.
Figures magnified 500 diameters, except the Micranterias and Ctosterium-i only
about one-half.
Page.
Fig. 1. Micrasterias radiosa, Ralfs, Var. punctata, West, .	119
Figs. 2, 3.	Xanthidium antilopaeum, Kg., ....	101
Var. Canadense, Joshua, front
and end views, .	102
Fig. 4. Cosmarium Regnesi, Reinsch, .	.	70
Figs. 5, 6. Staurastrum angulatum, West,	.	.	132
“	7,8.	.Sphaerozosma serratum, Bailey ; two varieties from Florida, 30
“	9, it),	Sphaerozosma (Onvchonema), Nordstedtiana, Turner,	31
“	11-13. Cosmarium Meneghinii, Breb., forma octangularis, Wille,
Var. simplicissimum, Wille,	70
Fig. 14.	Cosmarium laeve, Rab., Var Septemtrionale, Wille, .	72a
“ 15. Gonatozygon sex-spiniferum, Turner, .	. 172
“ 16. Calocylindrus Cucurbita {Breb.), Kirch., .	.	59
Figs. 17, 18.	Cosmarium (Caloevlindrus) Cordanum, Breb.,	59
Fig. 19.	Closterium Braunii, Reinsch, .	.	45
“ 20. Closterium subdirectum, West, .	.	.	.46
“ 21.	Closterium rostratum, Ehrb., .	49
Var. brevirostratum, West,	.	49
“ 22.	Closterium Leibleinii, Kg., ....	49
Var. curtum West, .	.	.49PLATE XLIV.
Figures magnified 375 diameters.
Page.
Micrasterias triangularis, Pennsylvania and New Jersey form, 127
127
Fig. 1.
,{ 2.	“	“	Florida variety,
/
Figs. 3, 4. Micrasterias conferta, Var. hamata,
127
Fig. 5.	Micrasterias	ARCUATA,		129
6.	Micrasterias truncata		>	126
“ 7.	U	it	Var. semiradiata, Naeg.,	126
“ 8.	<(	u	Var. concatenata, Wolle,	126
“ 9.	u	«	Var. minor, Wolle,	126
“ 10.	Micrasterias	FOLIACEA,	a single cell,	130
“ 11.	a	it	part of a series of more than forty cells,	130PLATE XLIVPLATE XLV.
Figures magnified 875-500 diameters.
Page.
Figs. 1, 2. Micrasterias speciosa,	.	.119
Fig. 3.	Micrasterias apiculata,	.	124
Figs. 4, 5.	Micrasterias Crux Melitensis,	123
Fig. 6.	Micrasterias Rabenhorstii, Var.,	.	131
Figs. 7, 8. Cylindrocystis tumidum,	.	.	38
Fig. 9.	Xanthidium fasciculatum, Var.	Subalpinum,	101
Figs. 10, 11. Xanthidium Columbianum,	. 100
Fig. 12.	Cylindrocystis De Baryi,	58
Figs. 13, 14. Xanthidium Torreyi. (See Fresh-Water Alga-, p. 35),PLATE XPLATE XLVI.
Figures magnified .500 diameters; the Micrasterias 375 diameters.
Page.
Fig. 1. Micrasterias A lata, .	.	.	. 125
“ 2. Micrasterias mamullata,	.	.	125
“ 3. Micrasterias denticulata, zygospore,	.	120
“	4. Staurastrum arctiscon, Var., .	.	.	163
‘‘	5. Cosmarium conspersum, Var. retusum, front view, .	.	82
“ 6. Cosmarium biretcm, Var. Floridense, front view,	.	S3
Figs. 7. 8. Staurastrum cosmarioibes, front and vertical views,	139
“	9,	10. Staurastrum brevispina, Var. inerme,	.	.	134
“	11, 12. Staurastrum cornutum, front and vertical views, .	. 158PLATE XL VI

IIPIPLATE XLVII.
Figures magnified 500 diameters.
Page.
Fig. 1-3.	Staurastrum Wolleanum, Var. Kissimense,	.	.	163
Figs. 4, 5.	Staurastrum Tohopekaligense, front, lateral and end views,	164
“	6,7.	Micrasterias furoata, Var. simplex,	.	122
“ 8, 9. Staurastrum parodoxum, Var. Osceolense, .	.	143
Fig. 10.	Micrasterias verrucosa, .....	120
“ 11.	Sphaerozosma moniliforme, ...	30
“ 12.	Sphaerozosma pulchrum, Var. constrictum,	.	.	172
Figs. 13, 14. Bambusina gracilescens, with zygospores,	.	.	25
Fig. 15.	Micrasterias ringens, Var. serrulata, .	.	.	123PLATE XL.VII
mm
10PLATE XLVIII.
Figures magniiied 500 diameters.
Page.
Figs. 1, 2. Staurastrum Wolleanum,	... 163
“	3,4. Staurastrum cornutum,	.	.158
“	5, 6. Staurastrum bacillare, .	.	132
“	7,8. Staurastrum Mixnesotense, .	.	.	.	156
“	9, 10. Staurastrum pseudocrenatum,	.	.	. 139
“ 11-13. Staurastrum Minneapoliense,	.	.	141
“	14, 15. Staurastrum cauyxoides,	.	.	. 158
“ 16, 17. Staurastrum erasum,	.	.	139
“	18-20. CoSMARIUM INFLATUM, .	.	67
21, 22.	Staurastrum xiphediophorum,	155
“	23-25.	Cosmarium	Nordstedtii,	80
“	26, 27.	Cosmarium	sphalerostichum,	.	76
“	28, 29.	Cosmarium	Braunii, forma major,	72a
“	30, 31.	Cosmarium	Sexdtnerianum,	72a
Fig. 32.	Cosmarium	perforatum,	65
Figs. 33, 34. Cosmarium lobatulum, .	.	66
“	35, 36.	Cosmarium	loeve,	72a
Fig. 37.	Cosmarium	circulare,
68■Mm
PLATE
XL. VIIIPLATE XLIX.
Figures magnified 300 diameters.
Page.
Figs. I, 2. COSMARIUM WoLLEANTTM, Var. granuliferum, front and
lateral views,	.	. 04
“	3—3. Cosmarium Parualis, front, lateral and transverse views, S3
“ G, 7. Cosmarium RHOMBUsoides, front and transverse views,	06
“	8, 9. Staurastrum Noy.e C.esarea:, front and vertical views, 159
“	10,11. Cosmarium quinarium, front and vertical views,	78
“	12-14. Cosmarium subcruciforme, front, lateral and vertical views, 94
“	15, 16. Cosmarium Americanum, front and vertical views,	64
“	17, IS. Cosmarium taxk hoxorum, Var. bidentulum, front and
vertical views,	77
Fig. 19. Staurastrum xiphidiophorum, Var. simplex, front view, 155
Figs. 20, 21. Cosmarium microsphinctum, front and vertical views, . 81
“	22, 23. Staurastrum luteolum, front and vertical views,	.	139
“	24, 25. Cosmarium excavatum, Var. trigonum, front and vertical
views,	.	85
“	26, 27. Cosmarium lagoense, front and vertical views, .	. 90.
Fig. 28. Cosmarium coriiaxum, front view, .	59
“	29. Euastrum Woli.ei, Var. quADRio ibrrrum, vertical views, 108
“ 30.- Micrasterias Americana, Var spikixa, front view of
semi-cell,	.	. 124
Figs. 31-33. Cosmarium polymorphum, front, lateral and vertical view, 81
“	34, 35. Cosmarium octogoxum, front and vertical views, .	71
“	36-38. Staurastrum orbicut.are, Var. oblique and front views, 132
“	39, 40. Staurastrum Brasiliense, Var. trr;uetum, front and
vertical views, .	. 160
41, 42. Staurastrum mutu um, Var. ellipticum, front and vertical
views,	,	132PLATE XL1XPLATE L.
Figures magnified 500 diameters.
Page.
Figs. 1, 2.	Staurastrum tumidum, front and end views,	.	, 133
“	3, 4.	Staurastrum	grande front and end views, .	133
“	5, 6.	Staurastrum	majusuulum, front and end views,	133
“	7, 8. Staurastrum magnum, front and end views,	.	133
*' 9, 10.	Staurastrum orbiculare, front and end views,	.	. 132
“	11,12.	Staurastrum	muticum, front and end views, .	131
Fig. 13	“	“ Var. ellipticum, .	.	. 132
Figs. 14, 15.	“	“ Var. minus, ...	131PLATE L.PLATE LI.
Figures magnified .500 diameters.
Page.
Figs. 1, 2.		Staurastrum	brevispina, Var., front and end views,	. 134
U	3,4.	il	“ Var. inerme,	134
U	5. 6.	Staurastrum	Dickiei, two aspects,	135
(t	7, 9,10,	11. Staurastrum	dejectum, Var. convergens, .	134
Fig. 8.		“	“ Var mucronatum,	. 134
Figs. 12-14.		Staurastrum	trihedrale, in three aspects,	136
il	15, 16.	Staurastrum	aristiferum, .	. 135
i(	17-22.	Staurastrum	dejectum, four forms and a zygospore,	134
U	23, 25.	Staurastrum	CUSPEDATUM, . . . .	, 135
ii	26, 27.	Staurastrum	Lewisii, front and end views, .	135
it	28, 29.	Staurastrum	trifidum, front and end views,	136
a	30, 32	Staurastrum	AVICULUM,	136
u	33, 34.	Staurastrum	COMMUTATUM,	. 136
i i	35, 36.	Staurastrum	Kitchelii, two views, .	165
u	37-39.	Staurastrum	BRACHIATUM,	. 136
u	40, 41	Staurastrum	furcatum, a form of a variable species,	165I'l tl.i.V'MPLATE LII.
Figures magnified 500 diameters.
Page.
Fig.	1.	Staurastrum	qua drangulare, a Minnesota variety,	.	160
“ 2.	"	“	a Pennsylvania and New
Jersey variety, .	.	160
Figs. 3, 4.	“	“	end view of Florida forms, 160
5,6. Staurastrum crenatum, .	... 138
Fig. 7. Staurastrum longispinum,	.	.	.	160
Figs	8, 9,	Staurastrum	spinosum.	See St.furcatum and Kitchdii,	.	152
“ 10, 11. Staurastrum pulchrum,*	....	147
“ 12, 13. Staurastrum incisum,	..... 146
Fig. 14.	“	“ six rayed form, .	.	146
Figs. 15, 16. Staurastrum distentum,	.	. 165
“	17, 18. Staurastrum Eloiseanum,	.	164
“	19-25.	Staurastrum	enorme,	.....	166
“ 26-28. Staurastrum alternans, .	142
“ 29,30 Staurastrum scabrum,	144
“	31-35. Staurastrum margaritaceum,	.	'	138
“ 36-38. Staurastrum tricorne,	.	.138
“	39,40. Staurastrum paniculosum,	.	137
“	41,42. Staurastrum rugulosum, .	.	.	140
11	43-45. Staurastrum punctulatum,	.	.141
* Compare note under SL incisum, p. 146. This species from ponds, New Jersey,
was described in the “ Bull. Tor. Bot. Club, New York, 1880.” Membrane smooth ;
end view five-rayed; apices of rays obtusely rounded, bases wide, separated by a
rounded sinus.PLATE
LIIPLATE LIII.
Figures magnified 500 diameters.
Pigs. 1, 2.		Staurastrum	Bieneanum, Var. ellipticum,	Paoe. 137
<(	3, 4.	Staurastrum	MURICATUM,	140
It	5, 6.	((	“ Var..	140
tt	7, 8.	Staurastrum	ASPERUM,	140
It	9, 10.	Staurastrum	POLYMORPHUM, .	. 139
«	11-13.	Staurastrum	BOTROPHILUM,	145
	14, IB.	Staurastrum	PYGMAEUM,	. 141
<.	16-19.	tt	“ Var. truncatum,	141
K	20, 21.	ft	il Var. rhomboides,	141
u	22, 23.	Staurastrum	SILATATUM, .	142
(<	24, 25.	Staurastrum	POLYMORPH UM, ....	. 139
“	26-29.	Staurastrum	CRENULATUM,	140
a	30, 31.	Sta urastrum	CYRTOCERUM,	. 142
tt	32, 33.	tl	Var. pentacladum minor,	143
«	34, 35.	(	“ pentacladum major,	143
ti	36, 37.	Staurastrum	PA RADOXUM,	143
it	38-42.	Staurastrum	ARACHNE,	. 143
“	43, 44.	Staurastrum	comptum, front and end views,	143
tt	45, 46.		“ Var. major, front and end views,	143
it	47, 48.	Staurastrum	PUSILLUM,	144
tt	49,50.	tt	“ smaller variety, two views,	144
n	51-53.	Staurastrum	Haaboeliense, front and two end views,	147
“	54, 55.	Staurastrum	FASCICULOIDES, front and end views, .	. 144PLATE L'lII
42PLATE LIV.
Figures magnified 500 diameters.
Page
Fig. 1.	Staurastrum cyrtocerum, Var. major, end view, .	142
“ 2.	“	“	Var. major, front view, .	142
Figs. 3-5.	Staurastrum macrocerdm, three views,.	.	.148
“	6, 7.	Staurastrum	cerastes, front and end views,	.	147
“	8, 9. Staurastrum odontodum, front and end views, .	148
"	10, 11.	Staurastrum	Ophiura, front and end views, .	147
“	12, 13, 14. Staurastrum	coronulatum, Var. Floridense,	149
Fig.	15.	Staurastrum	pentacladum,	front	and end views, .	149
Figs. 16, 17.	Staurastrum gracile, front and end views,	,	. 147
PLATE LivPLATE LV.
Figures magnified 500 diameters.
Page.
Figs. 1, 2-	Staurastrum Ophiura, Var. tetracerum, .		148
Fig. 3.	U	“ Var. pentacerum, lighter form than	
		Plate LIV, fig. 13,	148
“ 4	Staurastrum	LEPTOOIiADUM,	149
“ 5.	“	“ Var. divergens,	—
Figs. 6, 7.	Staurastrum	Helene a num, front and end views, .	146
“ 8, 9, 10.	.Staurastrum	nanum, three aspects,	151
“ 11,12.	Staurastrum	CORONULATUM,	148
“ 13, 14.	Staurastrum rotula, end and front views,		148
“ 15, 16.	Staurastrum	pentacladum, end and front views. (Com-	
		pare Plate LIV, fig. 15), .	149
“ 17. 18.	Staurastrum	grallatorium, Var. ungulatum,	150
Fig. 19.	({	“ typical form,	150
Figs. 20, 21.	Staurastrum	fusiforme, front and end views,	150PLATE LVPLATE LYI.
Figures magnified SOU diameters.
11A <. K.
Figs. 1-3. Stadkastedm accleatum, in three aspects,	.	.	153
Fig. 1.	Sta urastrum	teliferum, normal size,	154
“ 5,6.	Staurastrum	Brebissonii,	154
“ 7, 8.	Staurastrum	cerberus, .	156
“ 9, 10.	Staurastrum	tridentiferum,	156
“ 11-13.	Staurastrum	cruciatum, .	156
“ 14-16. Staurastrum Hystrix,	.	.	156
'•	17,18.	Staurastrum	Haven tun. (Compare Plate LX111, figs. 7,8),	157
Fig. 19.	Staurastrum	hirsutum,	155
20.	“	“	dividing,	155
“ 21.	‘	zygospore with empty cells attached, 155
Figs. 22, 23.	Staurastrum	sociatum,	155
“	24, 25.	Staurastrum	controversum, .	157
“	26, 27.	Staurastrum	setigerum,	154
Fig. 28. Staurastrum vestitum, zygospore with remains of cells, .	151
Figs. 29, 30.	“	‘	large form, front and end views, 151
“	31, 32.	Staurastrum	echinatum, front	and	end views,	154
“	33, 34.	Staurastrum	Saxonicum, front	and	end views,	154
“	35, 36.	Staurastrum	pecten, front and	end	views, .	155PLATE LVIPLATE LVTL
Figures magnified 500 diameters.
Figs. 1-6.
Fig. 7.
Figs. 8, 9.
Fig. 10.
“ 1 ]'.
“ 12.
Figs.	13,	14.
“	15,	16.
“	17,	18, 19.
“	20,	21.
Fig. Tl
Staurastrum Sebaldi, six aspects and forms,
“	“ Var. spinosum,
Staurastrum Pseudosebaudi,
Staurastrum Sebaldi, small variety,.
Staurastrum eeongatum, front view,
“	“	end view, .
Staurastrum arcuatum, front and end views.
Staurastrum subarcuatum, front and end views,
Staurastrum Meriani,
Staurastrum grallatorium, a form,
Staurastrum Franconicum, front view,
Page.
.	151
152
. 152
151
.	143
143
. 152
153
. 146
150
145PLATE lviiPLATE LVIII.
Figures magnified 500 diameters.
Page.
Figs. 1, 2.	Staurastrum	tricornutum, front and end views,	.	.	159
“	3, 4. Staurastrum Novas Cass areas, front and end views, .	159
“	5,	6.	Staurastrum	spongiosum, front and end views,	.	.	163
7, 8.	“	“	other form, front and end views, 163
*i 9, 10.	Staurastrum	arcticon,—(M. munitum Wood),	.	163plate
LVII1PLATE LIX.
Figures magnified 500 diameters.
Page.
Fig. 1.	Staurastrum	Brasieienke,	.	.	.160
Figs. 2, 3.	“	“	two end views, Florida and New
Jersey forms, .	.	.	160
“	4,5,6. Stuarastrum eustephanum, Minnesota form, .	161
“	7, 8.	Staurastrum	cuneatum, front and end views,	.	. 162
“	9, 10. Staurastrum eustephanum, (typical form),	161
Fig. 11.	“	“	(elongated processes),	.	161
Figs. 12, 13. Staurastrum furcigerum, end and front views, .	.	161
Fig. 14.	“	“	a variety,	.	.	165
Figs. 15, 16. Stauratrum furcatum, variety, .	.	165PLATE LIX
; Axx i
<?^T'"i' Jl~
- ;PLATE LX.
Figures magnified 500 diameters.
Fig. 1.
“ 2.
Figs. 3, 4.
Fig. 5.
6.
Page.
. 28
“ 8.
“ 9.
“ 10.
“ 12.
“ 13.
Figs. 14-17.
Fig. 18.
“ 19.
Figs. 20, 21.
Fig. 22.
Figs. 23, 24.
Fig. 25.
Figs. 26, 27.
Fig. 28.
Figs. 29, 30.
“	31, 32.
Phymatodocis Nokdstedtianum,
“	“	a cell dividing,.
“	“	transverse view, and front
view of a cell, .
Desmidium (Diclymoprium.) quadratum, front and side views
made evident by the
twist of the filament,
Desmidium (Didymoprium) longatum, front and side views of
cells,
Desmidium aptogonium, partially advanced in process of di-
vision. (Compare normal condition,
Plate II, fig. 6),
Sphaerozosma pulchkdm, Var. inflatum, .
Sphaerozosma rectangulare, .	.	.	. .31
Calocylindruk pseudo< onnatus, Var. (Compare Plate XV), 60
28
28
26
27
27
29
Cosmarium obsoletum, Var. major,
Cosmarium skxangulare, .
Cosmarium globosum,
Colouylindrus connatus, Var. minor,
Cosmarium Kjellmanii,
“	“	end and side views,
Cosmarium ornatum, Var. protractum,
“	“ front and side views,
Cosmarium pulcherrimum, Var. minor,
“	“	side and end views, .
Cosmarium Sportella, ....
“	“	lateral and vertical views,
Cosmarium crenatum,
70
69
65
60
94
94
90
90
97
97
90
90
73PLATE LXPLATE LXI.
Figures magnified 500 diameters.
Pigs 1-4.	COSMARIUM	CONSTRICTUM,	Page. . 63
“ 5, 6.	COSMARIUM	supraspeciosum, front and side views.	95
1 7, 8. 9.	COSMARIUM	scenedesmus, in three views.	63
“ 10, 11, 12.	C’OSMARIDM	depressum, in three views,	69
Pig. 13.	COSMARIUM	granatum,	64
Figs. 14-17.	COSMARIUM	Beckei.*	—
“ 18-20.	COSMARIUM	sejunctum, front, end and side views, .	OS
Fig. 21.	COSMARIUM	Xagelianum.	73
Figs. 22, 23.	COSMARIUM	pseudotaxichondrum,	77
Fig. 24.	COSMARIUM	contractum,	68
“ 25.	Staurastrum Pringlei, in three views,		145
“ 26.	Closterium	: Lunula,	42
“ 27.	Calocylindrus Clever		60-38
•' 28.	Calocylindrus Thiyaitesit,		60
Figs. 29, 30, 31.	Docidium minutum.		57
Fig. 32.	Docidium dilatatum,		55
“ 33, 34.	Tetmemorus granulates, .		. 98
“ 35.	Tetmemorus laevis,		98
“ 36.	Tetmemorus Brebissonii, .		. 95
Figs. 37-39.	Staurastrum (Polyedrium) enorme,		166
* C. Beckei, Willie. (Omitted in proper place.) Cells slightly longer than broad;
semi-cells nearly semicircular, apices truncate five crenate; sides incised crenate;
two series of granules of about 15 and 9 near the margins; center inflated and
sparsely granular; variable in size; larger form about 2S Mic*. M. long; 25 Mic. M.
wide.
Not quite, but nearly in accord with Willie’s diagnosis.PLATE LXI
A1 *«
&rnmrnm
%g0msm0
^SSsSSC.
aSSa*PLATE EXIT.
Figures magnified oUO dianiHer>.
		Page.	
Figs. 1, 2.	Staurastrum	ANATINUM, ,	152
Fig. 3.	Stair a strum	ankyroides, Var. hexaeenim,	151
“ 4.	Staurastrdm	ANKYDOIDES, typical form,	150
Figs. 5 7.	Staurastrum	IOTANUM,	150
“ 8-9.	Staurastrum	POTTSII, .	166
“ 10-12.	Staurastrum	MEGACANTHUM,	134
‘ 13-15.	Gosmarium protuherans, Var. granulatnm, .		91
“ 10, 17.	STAU liASTRUM	forfiuulatum, forma tetragona, .	158
18, 19.	it	forma trigona,,	158
“ 20,21.	Staurastrum	Diukiei, front and end views. (Compare Plate	
		LI, tigs 5, 6), .	135
“ 22, 23.	Staurastrum	ASPINOSCM,	157
" 24-26.	Staurastrum	MONTICULOSUM,	159
- 27, 28.	Staurastrum	STRIOLATUM,	138
“ 29, 30.	Staurastrum	I.EPTAUAnthum, Var. tretroctocerum.	166
Fig. 31.	Staurastrum	elongatum, Var. letragonum,	144
Figs. 32-35.	Staurastrum pseudopachykhynchum, two front ami two		
		end views,	137
“ 36,37.	Gosmarium pseudobroomei, front and end view,		93PLATE LXIIPLATE LXIII.
Figures magnified 50fi diameters, except the Micrasterias 375.
Page.
Fig 1.	Staurastrum sexarium, end view,	.	.	162
“ 2. Micrasterias dichotoma.	.	.	.	.123
“ 3. Mtcrasterias	Xordstedtianum,	125
Figs. 4,5.	“	“•	end and lateral views, .	125
Fig. 6.	Micrasterias Rabenhorstit, .	.	.	131
Figs. 7, 8. Staurastrum	Ravenelii,	157
“	9, 10. COSMARIUM NITIDCLCM,	72a
“	11, 12. Eoastrttm urnaformf, front and transverse views, . Ill
“	13-15. Euastrum Nordstedtiaxum, side, transverse and end views, 116
Fig. 16. Xanthtdium axtilopaefm, Var. Minneapoliense, .	101
Figs. 17-19. Staurastrum	quaterxium, end and front view^,	158
Fig. 20. Staurastrum	Donnellit,	.	146
Figs. 21, 22. Ettastrdm abruptum, variety,	.	118
“	23, 24. Staubastbum	furcigerum, front and end views, .	161
“	25, 26. Staijrastrum	furcatum, (St. spinosum),	165
“	27, 28. Staurastrum	pseudofuroigerum, front and end views,.	165
“	29, 31, Staurastrum	brachiatum, ..... 136
“	32, 33. Staurastrum dilatatum, .	.	.	142
Fig. 34. Staurastrum furcatum, (St. spinosum), .	.	165PLATE LXII1
y~
27PLATE LXIY.
Figures magnified 500 diameters.
Fig. 1.	Penium Digitus,
Figs. 2, 3. Staurastrum rrevispina, front and end views, .
“	4, 5.	Staurastrum inconspicuum,	.
*	6, 7.	Staurastrum duplex,	....
Fig. 8.	Hyalotheca undulata,
Figs. 9, 10.	Closterium strigosum, two	zygospores with	empty	cells at'
tached, .
Fig. 11.	Euastrum multilobatum,
Figs. 12, 13. Micrasterias conferta,
‘‘	14,	15. Cosmarium excavatcm,
Fig. 16. Docidium coronulatum,
“	17.	Pediastrum	simplex,
“	18.	Pediastrum	Sturmii,
“	19.	Pediastrum	simplex, Var.,
“	20.	Pediastrum	dcodenarius,
“	21.	Pediastrum	forcipatuyi.
Figs. 22, 23. Pediastrum Ehrenbergii,
Fig. 24. Pediastrum tetras,
Figs. 25, 26. Pediastrum Ehrenbergii,
Fig. 27.	“	“	variety,
“	28.	Pediastrum	angulosum,
“	29.	Pediastrum	Boryanum,
Figs. 30, 31. Pediastrum forcipatum,
Fig. 32. Pediastrum Boryanum,
Figs. 33, 34. Pediastrum pertusum, ....
Fig. 35.	“	“ Var. braehvlobum,
“ 36. Pediastrum mcticum, .
“ 37. Pediastruyi angulosum, variety, .
Page.
34
134
.	137
164
44
107
126
85
53
168
168
168
168
169
170
170
170
170
162
169
169
169
169
170
169
162plate lx iv