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PUBLIC DOCUMENT No. 47

State Geological and Natural
History Survey

COMMISSIONERS

Rollin S. Woodruff, Governor of Connecticut (Chairman)
Arthur Twining Hadley, President of Yale University
Bradford Paul Raymond, President of Wesleyan University
Flavel Sweeten Luther, President of Trinity College (Secretary)
Rufus Whittaker Stimson, President of Connecticut Agricultural College

SUPERINTENDENT
William North Rice

Bulletin No. 10

Hartford
Printed for the State Geological and Natural History Survey

1908

A PRELIMINARY REPORT

ON

THE ALGJE OF THE FRESH WATERS
OF CONNECTICUT

By
HERBERT WILLIAM CONN, Ph.D.,

Professor of Biology in Wesleyan University
AND

LUCIA WASHBURN (HAZEN) WEBSTER, M.S.

Hartford
Printed for the State Geological and Natural History Survey

1908

A Preliminary Report on the Alga? of the Fresh
Waters of Connecticut.

INTRODUCTION.

The present report is designed to accompany the previous
report upon the Fresh-water Protozoa, Bulletin No. 2 of this
Survey. Like that report, it is not claimed to be complete,
nor by any means to contain all of our Algae. But, the work
having covered considerable parts of four years, it is thought
that it will be found to contain most of the common Algae in
this state, and will therefore be useful as a guide to students of
the microscopy of our waters. To wait until all omissions
could be rilled would clearly postpone unduly the publication
of any report. For these reasons this preliminary report is
issued at the present time.

Work upon the Algae is scattered somewhat widely in books
and in journals. We have found most valuable, The British
Fresh-zvater Alger, by West. Wolle's Fresh-water Algce of
the United States, and his similar work on the Desmids, have
also been found extremely useful. The magnificent work of
Engler and Prantl has been found of great value, as has also
Die Mikroskopische PHanzenwelt des Siisstvassers by Kirchner,
and the Analytical Keys of Genera and Species of the Fresh-
zvater Algce by Stokes. The most useful publication upon a
single group has been that of Hazen — The Ulotrichacece and
Chcetophoracecv, in the Memoirs of the Torrey Botanical Club,
XXII, 1902.

The key that we have adopted in this Bulletin is based upon
that given by West. We have used this because in our experi-
ence it has been found to be the most practical and useful.
We have, however, modified it in several respects to make it
correspond to the key used in the Bulletin on the Protozoa.
As so modified, we think it will be found very easy of use for
microscopists who are beginning the study of the Algae.

6 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull.

We have adopted the plan used in the Bulletin on the Pro-
tozoa of indicating by a * in the analytical keys the genera that
have been found in our waters. In a number of cases the
genera thus indicated have not yet been found by ourselves,
although known to occur in Connecticut. We have given de-
scriptions of all the genera likely to be found in this vicinity,
whether already known to occur in Connecticut or not.

So far as possible we have determined the species of the
forms studied and figured. While there is considerable varia-
tion among the individuals of the same species of Alg3e, it is
less than among the Protozoa, and it is less difficult to deter-
mine species. In most cases there has been little difficulty
in affixing specific as well as generic names to the Algae found.
In some genera the determination of species is nearly im-
possible without the whole life history of the specimen under
consideration. In the genus Spirogyra, for instance, the
species are determined with certainty only when one has the
zygospores for study. The ordinary student of Algae is seldom
so fortunate as to have the zygospores, and must in these
cases make his determination from other characters. We have,
therefore, in these cases determined the species as well as
possible from the general structure of the plant, thinking this
to be more practical than to rely upon the more rarely seen
zygospores.

The figures have all been drawn from nature, and all from
specimens found by ourselves in our waters. A majority of
them have come from the immediate vicinity of Middletown.
Collections have been made from other parts of the state, but
these other localities have not yet yielded many forms not
represented in this immediate vicinity. The Algae have not
been to a very large extent obtained from city reservoirs, since
these localities are not very profuse in this kind of life. Road-
side pools, ditches by railroads, swamps, stagnant pools, etc.,
have been more prolific sources of Algae.

The late Isaac Holden made during his life large collec-
tions of Algae in the state. The largest number of the types
that he collected were marine, but he also made quite exten-
sive collections of the fresh-water forms. A list of the species
identified by him in this state has been recently published by

No. IO.] FRESH-WATER ALGJE. 7

F. S. Collins (Phycological Notes of Isaac H olden, in Rhodora,
vol. 7, p. 222, 1905). Since he identified quite a number of
species that we have not found, we have, for the purpose of
making this report as complete as possible, included in this
list all the species reported by him which we have not ourselves
identified. These have been appended to our own list, and
are distinguished by being inclosed in square brackets [ ].
We have not given any figures of his species, however, all of
the species figured having been personally found by ourselves.
In a few cases we have noted the collection of certain species
in this state by Hazen and by Setchell. No other extensive
collections of Algse are known to us as having been made in
the state.

The figures of plates I to XXXI were drawn by Mrs.
Webster, except figures 5, 8, 8a, 10, 28, 31, 45, 47, 49, 54, 54a,
55> 57, 59. 65, 72, 72a, 73, 77, 77a, 102, 125, and 147. These
together with the 'figures of Plates XXXII to XLIV
were drawn by Prof. Conn. Acknowledgment is also made to
H. J. Conn from whose work and sketches many of the figures
of Plates XXXII to XLIV have been drawn.

THE ALG/E.

The Algje are flowerless chlorophyll-bearing water plants.
Although sometimes called seaweeds, they are not confined
to salt water, but are found in every body of fresh water, on
damp stones and soil, and on the trunks of trees. They are,
however, all true water plants, for the few that live out of
water can flourish only in the presence of abundant moisture.

The Algae show the widest variety in form, size, and
structure. They may be unicellular or multicellular ; they may
be solitary, or gathered into larger or smaller families ; they
may grow in all directions to form a spherical thallus, or into
plates only one cell thick, or into branched or unbranched
filaments. When multicellular, all the cells may be alike, or
there may be a differentiation of cells, apical and root cells,
vegetative and sexual cells being found. The filamentous
thallus may present the appearance of a highly developed plant,
as in the Rhodophyceae or Characeae, or may be a single
simple thread, as in the Zygnemaceae.

The coloring matter of the Algae, either diffused throughout
the cell wall, or aggregated in special bodies called chloroplasts,
is predominantly green ; but there is hardly any color known
which cannot be found in these plants, the colors running from
orange and red to purple and black. Their size differs as
greatly as their color ; some are so small as to test the best
microscopes, while others stretch/ two hundred feet from their
marine beds.

The Algae multiply both by the sexual and the asexual
method. The asexual method is universal, the sexual is more
uncommon. They reproduce asexually in three ways: — i,
By simple division of the mother-cell. In the multicellular
forms a small fragment or a branch may separate from the
mother plant to form a new one. 2, By means of spores,
which are formed from the contents of the vegetative cells, and
which have each a ce]l wall, and may or may not be motile. 3,

FRESH-WATER ALG.E. 9

By swarm spores, which lack cell walls and are always motile,
usually provided with cilia. The sexual reproduction is of two
kinds : — I, Conjugation, or the union of two similar or nearly
similar cells called isogamons gametes. These may be either
motile cells, as in Ulothrix, or cells of the thallus, as in the
Conjugatae. They join themselves together, and their con-
tents fuse to form a new cell, a zygote, which, after a short
period of rest, develops into a new plant. 2, Sex union proper,
or the union of two entirely different cells, one of which, the
male or sperm, is many times smaller than the other, the
female or egg — heterogamous gametes. This occurs, for ex-
ample, in Chara.

The Algae are found from the Arctic zone to the Equator,
and no genus is confined to a single latitude. We should
sadly miss these plants if they were all destroyed. They do
much to purify the atmosphere, are used to a considerable ex-
tent in medicine, provide food for fishes and for men, fodder
for cattle, and fertilization for the ground.

The Algae are divided into classes as follows : —

CLASS I. CYANOPHYCE^E ( Schizophyceae, Myxophy-
ceae, or Blue-green Algae). Containing a blue coloring matter
(phycocyanin). Mostly in fresh water, and simple in structure.

CLASS II. BACILLARIE^ (Diatomaceae). Containing
a brown coloring matter (diatomin). Universal both in fresh
and salt water.

CLASS III. HETEROKONT^E (Yellow-green Algae).
Containing a large amount of a yellow pigment (xanthophyll).
The stored product of assimilation is a fatty substance. Found
in fresh water.

CLASS IV. CHLOROPHYCE.E (Green Algae). Con-
taining only the green coloring matter known as chlorophyll.
The product of assimilation is starch. Very largely fresh-
water plants.

CLASS V. CHARACEiE. Having a stem with nodes
and internodes. Sexual reproduction.

CLASS VI. PH^OPHYCE^ (Brown Algae). Con-
taining a brown coloring matter, known as phycophaein.
Mostly marine.

IO CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull.

CLASS VII. RHODOPHYCE^E (Red Algae). Con-
taining a reddish coloring matter known as phycoerythrin.
Mostly marine.

In the study of the fresh-water Algae we are concerned
chiefly with the first five of these classes, the other two being
practically confined to salt water, although a few of them, as
noted at the end of this report, are inhabitants of fresh water.

CLASS I. CYANOPHYCEAE.
( Myxophyceae, Schizophyceae, or Blue-green Algae).

The class Cyanophyceae is unquestionably the lowest class
of the Algae, many of the species resembling the Bacteria.
Their most conspicuous characteristic is the manner in which
the greater number of the genera grow in gelatinous masses
or strata. They are largely filamentous, though some are
unicellular. Some of them grow wherever there is moisture,
as on wet rocks, stones, and trunks of trees. Some of the
filamentous genera form thick, felt-like coverings upon moist
earth and stones. Many of the Cyanophyceae are provided
with heterocysts, which are cells of lighter color and often of
greater size than the other cells of the filament. The hetero-
cysts are almost always solitary on the filaments, and their
use is not known.

The unicellular and simple colonial genera multiply princi-
pally by repeated cell-division, which may occur in every direc-
tion or in certain directions only. Asexual reproduction of
the large forms takes place in a variety of ways. In some
families certain vegetative cells enlarge and form spores ; in
others the contents of the cells divide into a number of small
spores. The Hormogoneae reproduce by hormogones. These
are short filaments arising from the mother plant, which break
away and form new plants. Sexual reproduction is unknown.

Some of the Cyanophyceae unite with Fungi to form
Lichens, in which case they lose much of their distinctive
character.

A few of the Cyanophyceae, of the family Oscillatoriaceae,
are distinguished for their power of spontaneous movement,
which is generally slow, oscillating or gliding. Many of this

No. IO.] FRESH-WATER ALGJE. II

family have a disagreeable odor, giving rise to unpleasant
odors and tastes in drinking-water.
There are two orders, as follows : —

Order I. COCCOGONE.E. Plants unicellular or colonial,
not truly filamentous ; commonly embedded in a gelatinous ma-
trix, more rarely free-floating.

Order II. HORMOGONE.E. Plants filamentous ; filaments
single or branched, generally consisting of one or more rows
of cells within a sheath, attached to a substratum, or free-
floating.

ORDER I. COCCOGONE^E.

The Coccogonese, the lowest form of the Algae, are
unicellular or colonial. The colonies vary much in size and
shape, and the cells, which are of various forms, are disposed
in a variety of ways in the usually hyaline and structureless
envelope. Multiplication is usually by simple cell division.
Rounded asexual spores have been found in some species,
formed inside the wall of the mother-cell.

FAMILY I. CHROOCOCCACE-fE.

This family is composed of unicellular forms of Algae which
divide and form daughter-cells ; often many generations are
involved in one mucilaginous envelope. The envelope varies
from firm and lamellose to hyaline and diffluent. The cells
often contain red, orange, or violet pigments. The members
of this family have been thought to be stages of filamentous
Algse, and Wolle so regarded them ; but more recent algologists
give them a distinct place of their own.

Key to Genera.

i. Cell division in only one direction 2

Cell division in two directions at right angles, form-
ing plate-shaped or irregular masses . .Merismopedia*
Cell division alternate in the three directions of space 4
2. Cells with thin membrane, without a gelatinous or
mucous envelope, single or hanging together in
thick rows Sxnechococcus

12 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull.

Cells with thick, swollen membranes, which merge
into one another and lie in a gelatinous or mucous
bed 3

3. The thick membrane remains present through several

generations, so that the cells are enclosed in several

membranes ; cells elongated Glocothece

Cell membranes fused into a structureless jelly in
which the cells are arranged without order ; cells
slightly longer than broad Aphanothece

4. Cells at the periphery of spherical colonies 5

Cells densely aggregated in spherical, elongated, or

clathrate colonies Microcystis*

Colonies without definite form 6

5. Cells spherical, closely and regularly arranged around

a hollow sphere Ccelosphoerium*

Cells peripheric, sparsely scattered Gomphosphceria

6. Cells enclosed in a thick membrane Gloeocapsa*

Cells not enclosed 7

7. Cells with thick, gelatinous, fusing membranes. . . .

Aphanocapsa*
Cells single or in small groups, with membranes
which do not fuse Chroococcus*

Description of Genera.

Merismopedia Meyen. — Cells spherical, or, at time of
division, oblong. Their regular method of division produces
groups of 4, 8, 16, 32, 64, or 128 cells, associated in a single
stratum, making a flat, freely floating, square thallus.

M. glauca (Ehrb.) Nag., Fig. 3.

M. convoluta Breb., Fig. 4.

Synechococcus Nag. — Cells cylindrical or oblong, found
singly or in series of two or more ; cell wall thin.

Gloeothece Nag. — Cells oblong or cylindrical, with
rounded ends. The cells divide into two nearly spherical
daughter-cells. The colorless gelatinous tegument may con-
tain one or often more cells, and this tegument may, in turn,
be included in a larger tegument with a family.

No. IO.] FRESH-WATER ALGJE. 1 3

Aphanothece Nag-. — Very like Glocothece, with cells
longer than broad ; but the teguments are confluent, forming
a firm gelatinous body which encloses the cells.

Microcystis Kiitz. (Polycystis Kiitz. ; Clathrocystis
Henfrey). — Numerous small cells gathered into globular, ob-
long or irregular families, each with a thin tegument, usually
single but sometimes associated with other families, and all en-
closed in a common tegument. The cells divide alternately in
three directions.

M. ceruginosa (Kiitz.) (?), Figs. 9, ga. Sometimes very
abundant in reservoirs and giving an unpleasant taste to the
water. Frequently thus associated with Anabcrna.

Ccelosphaerium Nag. — Thallus hollow, spherical, with
numerous small spherical cells in families, or scattered at the
periphery, embedded in a gelatinous stratum. Multiplication
takes place by means of enlarged cells which escape and form
daughter-cells, or by constriction and division of the mother-
cells.

C. Kuetsingianum Nag., Fig. 7.

Gomphosphaeria Kiitz. — A globose, free, floating thallus,
composed of wedge-shaped cells, in pairs, associated in radi-
ating families at the periphery of a solid gelatinous sphere, and
furnished with a tegument. The cells divide alternately in
three directions.

Gloeocapsa Kiitz. — Cells blue-green, steel-blue, reddish,
yellowish, etc., spherical or oblong, with a wide, bladder-shaped
integument. The cells divide into two daughter-cells, each
furnished with a tegument and both surrounded by the tegu-
ment of the mother-cell. The cell membrane is very thick,
often lamellated, and the strata frequently separate; either
colorless or colored.

G. arenaria (Rab.) ( ?), Figs. 8, 8a. The specific distinc-
tions in this genus are very uncertain.

[G. violacea (Chorda) Rab.]

Aphanocapsa Nag. — Cells spherical, with a thick, soft
tegument; cell division as in Gloeocapsa, but individual coats
not evident around the cell.

14 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull.

A. GrevillH (Hass.) Rab., Fig. 10. Masses of this jelly-
like plant frequently reach 2mm. in diameter.

Chroococcus Nag. — Blue-green cells, spherical, or an-
gular from mutual pressure, gathered into small families with-
out a distinct tegument. The cells, which are less numerous and
more simple than in Glccocapsa, divide alternately in three
directions.

C. cohccrcns (Breb.)Nag., Fig. 210.

FAMILY II. CHAMJESIPHONIACE^E.

Not represented in the United States.

ORDER II. HORMOGONE/E.

This order contains all the filamentous Myxophyceae.
The filaments usually consist of a single row of naked or
sheathed cells, but in some genera there are two or more rows
in a single sheath. Heterocysts are abundant in some of the
genera. The filaments are often branched or provided with a
false branch system due to the growth of a number of filaments
in close apposition at the base. Asexual reproduction is by
hormogones or, more rarely, by spores. The filaments or
trichomes are usually cylindrical with blunt or narrowed ex-
tremities, but some genera show a gradual attenuation, either
from the base to the apex, or from the centre toward each end.

This order includes two sub-orders.

Sub-order i. TRICHOPHORE.E. Trichomes conspicu-
ously attenuated towards one or both extremities, which are
generally hairy.

Sub-order ii. PSILONEMATEyE. Trichomes cylindrical,
though sometimes narrowed at the extremities.

SUB-ORDER I. TRICHOPHORE.E.

A small group with the filaments always attenuated, either
toward one end or from the middle to both extremities, and
always sheathed. Some genera are provided with heterocysts.
There is an asexual reproduction by means of hormogones, but
in GJccotrichia the basal cells next the heterocysts develop
spores. The threads frequently show hair-like projections
from their sides.

No. 10.] FRESH- WATER ALCE. 15

FAMILY I. RIVULARIACE.E.

Abundant in mountainous regions, found principally on
dripping- rocks, in streams and waterfalls, or on the shores of
rocky lakes. Our collections not having included such locali-
ties, this family is not represented in our figures. The fila-
ments are all attenuated from a long base to a hair-like end.
One or two heterocysts are usually located at the base. The
sheath is yellow or yellowish-brown, gelatinous, tubular, and
often thoroughly lamellated. Asexual reproduction by hormo-
gones, and in Gloeotrichia and Calothrix asexual spores arise
near the basal heterocysts.

Key to Genera.

1. Without heterocysts Amphithrix*

With heterocysts 2

2. Filaments without gelatinous integument, simple,

growing in branched or unbranched tufts, or some-
times singly , Calothrix*

Filaments without gelatinous integument, branched,
several branches in a common sheath Dichothrix*

Filaments with a gelatinous integument, forming a
gelatinous or mucous covering +. . . 3

3. Filaments radially disposed ; thallus spherical or

hemispherical in shape 4

Filaments not radiating; thallus plain, cushion-
shaped Isactis

4. Spores present; single-celled or with heterocysts;

colonies free, floating Glaeotriclvia*

Spores lacking ; colonies attached Rivularia*

Description of Genera.

Amphithrix Kiitz. — The filaments form a thin expanded
stratum of a purple or violet color, which consists of two
layers. The inferior layer is composed of densely intricate
filaments, or of minute radiately disposed series of cells ; the
superior layer of simple erect filaments closely packed and at-
tenuated.

[A. janthina (Mont.) Born, and Flah.]

l6 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull.

Calothrix Ag. (Mastigonema Schwabe; Mastigothrix

Kiitz., in part). — Filaments growing in tufts or soft masses,
rather rigid, straight and spuriously branched. The branches
are younger filaments glued at their bases and part of their
length to the parent stem ; the apex is delicately hair-like.
Heterocysts are normally present and are usually at the base
of the branches.

[C. Braunii Born, and Flah. ; C. fusca (Kiitz.) Born, and
Flah. ; C. parte tina (Nag.) Thur.]

Dichothrix Zanard. Filaments more or less dichotom-
ously branched ; several trichomes with their sheaths enclosed
within an outer common sheath. Heterocysts basal, or inter-
calary, or absent in one species.

[D. gypsophila (Kiitz.) Born, and Flah.; D. Hosfordii
(Wolle) Born, and Flah.; D. Orisiniana (Kiitz.) Born, and
Flah.]

Isactis Thur. The filaments are erect and parallel, at-
tached at the base. They are glued together by a more or less
firm mucilage, and are often encrusted with lime, forming flat
strata.

Gloeotrichia J. Ag. The filaments, with spores in the
lower part, are radiate, sometimes spuriously branched, each
enclosed in a distinct, broad sheath, which is often furrowed
at the base and transversely folded. All the filaments are
enclosed in a more or less spherical jelly.

G. Pisum (Ag.) Thur., Fig. 214.

Rivularia (Roth.) Ag. (Zonotrichia J. Ag. ; Limnactis
Kiitz. ; Schizosiphon Kiitz., in part).

Filaments radiating, with basal heterocysts, but no spores.
A more or less firm mucilage binds the filaments into a hemi-
spherical or bladder-like, well-defined thallus. One species of
Rivularia has been found in our studies, but no figure of it is
given in this report.

FAMILY II. CAMPTOTRICHACE^.

Not found in the United States.

No. IO.] FRESH-WATER ALG^E. 17

SUB-ORDER II. PSILONEMATE/E.

This sub-order contains the greater part of the Hormo-
gonese. The filaments, with or without a sheath, are cylindri-
cal, sometimes showing globular swellings. The sheath may
be very thin, hyaline and gelatinous, or tough and lamellose.
The apical cell, or sometimes that and the sub-apical cell, are
occasionally attenuated, or the filaments may end obtusely.

Key to Families.

i. Filaments showing true branching stigonemace.e

Filaments showing false branching; heterocysts

present scytonemace^e

Filaments usually simple, without branching; where
they show false branching they are without hetero-
cysts 2

2. Filaments nearly straight; heterocysts absent

OSCILLATORIACE^

Filaments tortuous; heterocysts present

NOSTOCACE^E
FAMILY I. OSCILLATORIACE^E.

The distinguishing feature of this family, which is the
largest one of the Psilonematese, is the absence of heterocysts.
The trichomes are a single and regular row of cells, although
occasionally false branching is seen. Sometimes the cells are
so closely joined that the whole seems a perfectly homogeneous
cylinder ; but at other times there are constrictions at the ends
of the cells. Apical cell sometimes attenuated. The filaments
are nearly always in sheaths of various character, which some-
times enclose more than one filament. Some of the genera
show gliding or rotary motion. They occur in great profusion,
submerged in ponds and ditches, or form scums upon their
surface.

There are two sub-families, as follows : —

Sub-family I. lyngbye^:. Only one trichome in a
sheath.

Sub-family II. vaginariele. Several trichomes in one
sheath which is often branched.

l8 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull.

SUB-FAMILY I. LYNGBYE.E.

In this sub-family there is never more than one trichome
in a sheath, and the sheath may be thick or thin, or even
wanting. In some genera the trichomes are twisted. The
cells may be of varying thickness and length, but usually the
thicker the trichome the shorter the cell. Oscillatoria, Phor-
midium, and Spirulina exhibit a rotary or gliding motion.

Key to Genera.

1. Trichomes consisting of many cells 2

Trichomes consisting of one cell, spirally twisted. . . .

Spirulina*

2. Filaments simple, or falsely branched ; sheaths firm ;

apices of filament straight 3

Filaments simple ; sheaths thin, always hyaline,
mucous, and more or less readily fusing together;
apices of trichomes straight ; oscillating or rotary
motion evident 4

3. Filaments free, or forming felt-like masses; pseudo-

branches present, often in pairs Plectonema*

Filaments forming er^ct tufts; pseudo-branches often

present and solitary Symploca

Filaments free and unbranched ; free-floating, or

forming a matted stratum Lyngbya*

4. Filaments more or less agglutinated by their mucous

sheaths ; cells of filaments often slightly separated

by a thin mucous layer iPhormidium*

Filaments destitute of sheaths ; free, straight or with

curved extremities Oscillatoria*

Filaments destitute of sheaths ; twisted into a regular

spiral , Arthrospira*

Description of Genera.

Spirulina Turp. — Filaments unicellular, more or less
motile, spirally twisted, usually surrounded by a colorless,
somewhat liquid mucilage.

S. tenuissima Kutz., Fig. 291.

No. IO.] FRESH-WATER ALG.E. IO,

Plectonema Thur. — Filaments branched, singly or in
pairs, quite irregular, each filament enclosed in a separate
sheath ; cell contents deep blue-green.
-[P. Wollei Farlow.]

Symploca Kiitz. — Filaments simple or showing mere be-
ginnings of branches ; in a more or less distinct sheath, rising
from a prostrate base ; glued together into anastomosing or
erect, wick-like clusters.

Lyngbya Ag. (Leibleinia Endlicher; Leptothrix Kiitz.,
in part ; Spirocoleus Mobius, in part) . — Single filaments en-
closed in distinct sheaths, either unbranched or with a sug-
gestion of branching where the filaments break out of the
sheaths. Often forming a membranous stratum.

L. sp. (?), Fig. 13.

[L. ochracea (Kiitz.) Thur.]

Phormidium Kiitz. ( Hyphceothrix Kiitz., in part; Lep-
tothrix Kiitz., in part).— - A genus between Lyngbya and
Oscillatoria. Filaments simple, clothed with a thin, hyaline
sheath. Sheaths often become fused, and the trichomes are
sometimes so numerous as to form mats on damp ground,
stones, etc. The cells are sometimes constricted at the ends,
and the apical cell may be attenuated or even thickened.

[P. Corium (Ag.) Gomont; P. favosum (Bory) Gomont;
P. Retzii (Ag.) Gomont; P. uncinatum (Ag.) Gomont.]

Oscillatoria Vaucher (Oscillaria Bosc). — Filaments
straight or slightly curved ; only in very young specimens are
they coiled ; simple, without a sheath ; mostly bright blue-
green, sometimes changing to violet or steel-blue. When in
good condition, more or less motile, and involved in a thin
mucilage. Found in all sorts of wet places, sometimes even on
damp ground and in hot springs.

O. subtilissima Kiitz., Fig. I.

0. *ccrugineo-ccorulea Kiitz., Fig. 2.

O. chalybea Mertens, Fig. 14.

O. amphibia Ag., Fig. 15.

O. limosa Ag., Fig. 5.

0. percursa Kiitz., Fig. 6.

[O. princeps Vauch. ; O. splendida Grev. ; O. tenuis
Ag.]

20 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull.

Arthrospira Stiz. — Filaments cylindrical, commonly de-
void of a sheath, and twisted into a regular spiral. The latter
character is the only distinction from Oscillatoria.

A. Gomontiwia Setchell. — We have not found this species,
but Setchell has mentioned it as occurring in Bridgeport.

SUB-FAMILY II. VAGINARIE^E

Blue-green Algae, which lack heterocysts, and are distin-
guished by having one or more trichomes in the same sheath.
This sheath is often branched, may be lamellose and colored,
or mucous and uncolored.

Description of Genera.

Microcoleus Desm. (Cthonoblastus Kiitz.). — Trichomes
like Lyngbya, except that two or more are often enclosed in
one sheath, which is at first closed at the end, and later breaks
open, sometimes dividing into shreds. The sheath is colorless,
not lamellose, large, seldom indistinct.

Schizothrix Kiitz. (Inactis Kiitz. ; Hyphaeothrix Kiitz.,
in part). — Sheaths firm, lamellose, hyaline or colored, and
containing few or many trichomes.

[S. lardacea (Cesati) Gomont ; 5\ coriacea (Kiitz.)
Gomont.]

FAMILY II. NOSTOCACE^.

Cells spherical or oval, arranged in simple chains, or,
rarely, with spurious branches. The chain is imbedded in a
more or less copious jelly. Some genera are provided with
spores and heterocysts. The heterocysts are yellow, straw-
colored, or nearly colorless, and are situated at the end of the
chain, or between two vegetative cells. Their function is un-
known. The dark green, granular spores divide after a period
of rest, and then germinate. Many are terrestrial.

Key to Genera.

i. Filaments contorted, within a definite gelatinous

tegument Arostoc*

Filaments more or less straight, free or in a formless
slimy mass, not inclosed in a tegument 2

No. 10.] FRESH- WATER ALG.E. 21

2. Heterocysts terminal, and spores contiguous with

them ; spores long and cylindrical . . . Cylindrospermum*
Heterocysts not terminal 3

3. Filaments aggregated without order Anabcena*

Filaments aggregated in bundles of plate-like masses

Aphanizomenon

Description of Genera.

Aphanizomenon Morren. — Trichomes a little attenuated
towards the apex, glued together parallelly in dense fascicles.
Cells nearly cylindrical, light blue or nearly colorless, and
slightly granular. Thallus somewhat membranaceous, free-
swimming, blue-green, or light pure blue, or at length olive;
spores solitary, smooth, cylindrical, elongated, round at the
ends, pale blue or olive.

Nostoc Vauch. — Filaments necklace-shaped, enclosed in
a more or less distinct gelatinous envelope. The cells are
spherical or elliptical, and more or less closely connected, with
heterocysts rarely terminal. The filaments are clustered to
form thalli, usually surrounded by a membrane, which is some-
times colorless, sometimes dark blue-green, dark brown, light
yellow, or, most often, olivaceous.

N. minutissimus Kiitz. (?), Fig. 211.

N. sp. (?), Fig. 18.

N. rupestre Kiitz., Figs. 16, 17.

N. comminiitum Kiitz., Fig. 19.

[N. commune Vauch. ; N. microscopicum Carm. ; N. par-
melioides Kiitz. ; N. pruniforme Ag.]

Cylindrospermum Kiitz. — Filaments sheathless, single or
glued together in an indefinite gelatinous stratum ; occasionally
a number enclosed in a tegument. Cells spherical, oblong,
elliptical, or compressed. Heterocysts single, on the ends of
the filaments; spores next the heterocysts very long and
cylindrical.

[C. majus Kiitz.]

Anabaena Bory ( Sphaerozyga Ag. ; Trichormus Allman ;
Dolichospermum Thwaites). — Filaments similar to those of
Nostoc, only nearly straight ; rarely provided with a* sheath ;

22 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull.

♦

clustered in gelatinous masses, or single. Cells spherical or
nearly so, some of them changing into brownish elongated
spores, which are solitary, or one on either side of a heterocyst,
or, rarely, in a short series. Heterocysts not terminal.

A. gigantea Wood, Fig. n.

A. Flos-aqua? Kiitz, or circinalis (Rab.) Kirch., Fig. 12.

[A. osciUarioides Bory.]

A nab ana is very common in reservoirs, and sometimes in
combination with Microcystis is so abundant as to give the
water a very bad taste and smell, and a distinct color. It is
one of the most troublesome Algae in our city reservoirs.

FAMILY III. SCYTONEMACEJE.

This family is known by its method of branching. Each
filament is enclosed in a sheath of uniform thickness, and at
intervals penetrates this sheath to form long, flexuose branches
which are provided with their own sheaths. The filaments are
cylindrical, but thickened toward the growing end, and con-
tain heterocysts. The sheath may be colorless, or yellow, or
brown. Reproduction is usually by hormogones. though in
some species spores are produced.

Key to Genera.

Branches in pairs, rising between the heterocysts

Scytonema*
Branches single, rising in the region of the heterocysts

Tolypothrix*

Description of Genera.

Scytonema Ag. (Petalonema Berkeley; Schizosiphon
Kiitz., in part; Symphyosiphon Kiitz., in part ; Athrosiphon
Kiitz.). — Each filament enclosed in a sheath ; branches in pairs
produced by a fold of the filament, which breaks through the
sheath between the heterocysts. The heterocysts are scattered
irregularly throughout the filament. The filaments produce in-
terwoven mats of larger or smaller size. The sheath is lamel-
lose, and yellow or brown in color, generally of an even thick-
ness, but occasionally the margins are irregular.

[S. crispum (Ag.) Bornet ; 5\ Hofmanni Ag. : S. myoch-

No. IO.] FRESH-WATER ALG^. 23

thous (Dillw.) Ag. ; S.Gguratum Ag. ;S. ocellatum (Dillw.)
Thur.]

Tolypothrix Kiitz. (Hassallia Berkeley). — Filaments
branched, with a distinct sheath. The branches usually ap-
pear where heterocysts occur, the trichome breaking through
the sheath just below the heterocyst and continuing its growth.
The sheaths are thinner than in Scytonema. The heterocysts
are sometimes two, three, or four in a row.

[T. lanata (Desv.) Wartmann.]

FAMILY IV. STIGONEMACE.E.

The cells of this family are arranged in a single row or in
several irregular rows, in a strong, thick sheath, which is
brown and very uneven. The filaments are branched, and
grow by repeated division of the cells near the apex. The
heterocysts are never terminal, and they are placed in a lateral
position when there is more than one filament in a sheath.

Key to Genera.

Normal reproduction by means of hormogones, de-
veloped on the extremities of the branches. .Stigonema*
Normal reproduction by spores Hapalosiphori

Description of Genera.

Stigonema Ag. (Sirosiphon Kiitz.). — Cells of the fila-
ments in one, two, or many rows, owing to the lateral division ;
the older filaments often having as many as ten series, while
the younger have only one or two. The cells are surrounded
by a membrane which is always distinct, but especially so in
the older filaments. The sheath is large, irregular, and usually
brown or golden yellow. The generally short, thick branches
are irregularly disposed. Found mostly on damp or wet rocks,
but sometimes free-floating in lakes or ponds.

[S. mamillosum Ag. ; S.minutum (Ag.) Hass. ; S. panni-
forme (Ag.) Born, and Flah.]

Hapalosiphon Nag. — Filaments attached or floating ;
olive-green, blue-green, or, when older, bright or dark brown.
The branches rise singly at right angles to the prostrate stem,

24 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull.

and sometimes bear secondary branches. The cells are granu-
late, and grow in a single series, rarely in two; they are
distinct or, sometimes, continuous. Heterocysts are frequent.
The sheaths of the branches, usually colorless, are always
thinner than those of the primary filaments. Spores are
formed from the ordinary vegetative cells. The plants grow
in fresh and salt waters.

CLASS II. BACILLARIE.E (DIATOMACEiE).

We have, as yet, given no attention to the Diatoms, and
they are, therefore, omitted from this report.

CLASS III. HETEROKONT^E.

The Algae of this class are unicellular, multicellular, or
colonial, appearing as rounded single cells, filaments, or large
colonies. The cell walls are usually very thick, and contain
many chromatophores of a yellow-green color, without pyre-
noids or starch. The ordinary asexual reproduction is by
means of zoogonidia, which are pear-shaped bodies furnished
with one long and one short cilium. Non-motile spores are
also sometimes found with thick walls.

Sexual reproduction takes place by fusion of two similar
motile gametes which probably resemble the zoogonidia in
having two cilia. Since these gametes are alike they are said
to be isogamous. This class contains only a single order.

ORDEfR CONFERVALES.

The various forms are divided into two families, as
follows : —

Family i. botrydiace;e. Plant body large, globose.
Family ii. tribonemace^. Plant body unicellular or
filamentous.

family i. botrydiace^:.

Each plant is globose, attached by rhizoids to the damp
earth ; the chromatophores are numerous and the reproduction
varied. This family contains only one genus, which we have
not vet found in Connecticut.

No. 10.] FRESH-WATER ALG.E. . 25

Botrydium Wall. — Small, non-cellular, green, globose
plants, with colorless, much divided roots, descending into the
moist earth, upon the surface of which this Alga lives. The
zoogonidia are small, ovoid, and provided with a long cilium.
If the plant becomes submerged, the whole may turn into a
zoogonidiangium, and the zoogonidia escape through an open-
ing in the apex. Non-motile spores are often produced in
great numbers in the rhizoids. If the plant becomes too dry,
the green portion migrates into the rhizoids, and a number of
spores are produced.

FAMILY II. TRIB0NEMACE.E.

Plants unicellular or filamentous ; cells spherical, cylindri-
cal, or elongated, often united to form filaments, and spirally
coiled. The cell wall is always firm, and usually thick.
Asexual reproduction by zoogonidia. Aplanospores occur in
Tribonema. Sexual reproduction by isogamous (i. e., similar)
gametes.

Key to Genera.

1. Plants unicellular 2

Plants filamentous, cell wall firm, splitting into H-

shaped pieces Tribonema*

2. Cells globose, aggregated in mucilaginous colonies

Chlorobotrys
Cells elongate, usually shortly stipitate and often
spirally coiled Ophiocytium*

Description of Genera.

Tribonema Derbes and Solier (Conferva, as used by
Lagerheim). Filaments composed of cylindrical cells, covered
with a thick cell wall which frequently breaks up into H-shaped
pieces. The cells each contain one or two nuclei and several
chromatophores. Asexual reproduction by zoogonidia with
two unequal cilia, and by non-motile spores which escape from
the broken filaments. Sexual reproduction by isogamous
gametes, one of which comes to rest and rounds off before
another conjugates with it.

This genus covers many of those forms previously called
Conferva, a name that is now given up. Hazen places it with

26 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull.

the Ulotrichaceae, but we follow West in placing- it here be-
cause of its yellowish-brown color. The plants are abundant
in all waters.

T. bombycinum (Ag.) Derbes and Sol., Fig. 48.

T. minus (Wille) Haz., Fig. 21.

Chlorobotrys Bohlin. — Plants are formed of solitary
globose cells, or of 2, 4, 8, or 16 cells associated in a family.
Each family has surrounding it an ample hyaline mucous tegu-
ment. The cell walls are thick and smooth. Six to thirty
parietal chromatophores are disposed on the wall of each cell.
Sometimes a red pigment spot appears in each cell.

Multiplication by cell division, at first in two directions,
afterwards in three.

Ophiocytium Nag. (inclus. Sciadium A. Br.). — Cells
cylindrical, variously curved, attenuated at one end into a thin,
short stem ; sometimes both ends rounded, with or without a
spine. Propagation by non-motile spores or zoogonidia, which
are formed by division of the cell contents. The cell wall has
a lid fitted to the apex of a long tube. In the attached species
the zoogonidia come to rest on the rim of the empty cell and
develop into full-grown cells. A repetition of this process gives
a curious branched appeal ince.

O. parvulum (Perty) A. Br., Fig. 20. The two different
sizes are, perhaps, two species. None of our specimens showed
the terminal spine.

CLASS IV. CHLOROPHYCEyE.

This class contains all the green Algae and numbers more
species than all the other classes of Algae together. The forms
are very diverse in size- and structure, and include unicellular,
filamentous, and colonial plants, some furnished with rhizoids,
others with hairs, and some with spines. Cell division usually
takes place in all the cells of a thallus, but occasionally there
is a growing point. Both sexual and asexual reproduction are
found in most of the families of the Chlorophyceae. This class
flourishes most abundantly in fresh water, though many are
marine, and members of it are to be found in every damp or wet
situation.

No. IO.] FRESH-WATER ALG/E. 2"J

The class may conveniently be divided into orders, as in-
dicated by the following key : —

Key to Orders.

i. Thallus coenocytic (». e., non-cellular but with many

nuclei) SIPHONALES

Thallus filamentous and septate, or unicellular, or
expanded 2

2. Thallus filamentous, though filaments may unite in a

plane. In the Conjugatse some are unicellular and

not filamentous 3

Thallus expanded, membranous ULVALES

Thallus neither expanded nor filamentous '.

PROTOCOCCALES

3. Cell division by intercalation of new cells producing

transverse striation CEDOGONI ALES

Cell division of ordinary type 4

4. Filaments attenuated and commonly ending in a

bristle CH^TOPHORALES

Filaments not ending in a bristle 5

5. Chloroplasts single, substellate, with one pyrenoid.

Filaments may fuse in a plane: . . . .SCHIZOGONIALES
Chloroplasts single, reticulated or band-shaped, with-
out pyrenoids MICROSPORALES

Chloroplasts numerous, parietal, each with a pyre-
noid CLADOPHORALES

Chloroplasts single or several, large and of some
definite shape, with pyrenoids. The entire contents
of two cells unite to form a single zygote. .CONJUGATE

ORDER I. PROTOCOCCALES.

Single-celled green Algae, without terminal growth or
branches, and without vegetative generation of cells ; either
single or in flocks or families. Sometimes the cells of the
families indefinitely increase in number, and form daughter-
families. At other times there is a definite number associated
together to form colonies called cocnobia. Even when ap-
parently closely united, each cell has the power of reproduction,
and therefore the plants are essentially unicellular.

28 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull.

The order is a very large one, and contains an immense
variety of forms which can hardly admit of a general descrip-
tion. The order is divided into eight families, the following
six of which are known in the United States : —

Key to Families.
i. Unicellular, or of a definite number of ciliated motile

Cells VOLVOCACEyE

Cells not ciliated or motile 2

2. Cells formed in flat plates or in a network

HYDRODICTYACE.E

Cells not in a plate or a network 3

3. Unicellular and solitary; cell with differentiation of

base and apex characiace^e

Cells without differentiation of base and apex 4

4. Unicellular and globular, or consisting of short, few-

celled filaments (not truly filamentous) ; firm cell
walls ; no autospores pleurococcace^;

Cells free or colonial, without copious gelatinous en-
velope, forming autospores protococcace^e

Cells spherical and indefinite in number, embedded in
a copious gelatinous envelope palmellace^e

FAMILY I. PALMELLACE^E.

Unicellular Algae, free-floating or attached, single or in
families, with a conspicuous mucous envelope, which is with-
out definite form, and is either structureless or differentiated
into concentric envelopes. Cell contents at first homogeneous,
later granular, green or reddish. Multiplication by cell division
in two or three directions, and cells often grouped in twos or
fours. Asexual reproduction by biciliated zoogonidia, several
of which arise from an ordinary cell. Sexual reproduction has
been observed in some species.

This family is divided into three sub-families, as follows : —

Key to Sub- families.

Cells grouped in twos or fours within a lamellose
mucous investment glceocystide^e

Cells grouped, in fours, irregularly disposed in a
mucus ; cells with a non-motile hair tetraspore^e

No. IO.] FRESH-WATER ALG.E. 29

Cells irregularly grouped within a structureless

mUCUS PALMELLE^E

SUB-FAMILY I. GLCEOCYSTIDE/E.

Plants formed of colonies of cells in a common mucila-
ginous envelope. Ordinarily concentric coats of mucus can
be seen around single cells or groups of cells. Multiplication
by division of the mother-cell into four parts.

Key to Genera.

Colonies irregular Glccocystis*

Colonies cylindrical and branching (Palmodictyon

Colonies subspherical Botrydina

Description of Genera.

Glceocystis Nag. (Chlorococcus Fries., in part). —
Spherical or oblong cells associated in globose families of an
indefinite number of cells. Teguments gelatinous, formed in
layers. Cells spherical or ellipsoidal.

G. vesiculosa Nag., Fig. 28.

[G. rupestris (Lyng.) Rab.]

Palmodictyon Kiitz. — The cells and surrounding tegu-
ment are in the shape of cylindrical masses which branch and
anastomose. The outer covering is often hard and of a
reddish brown color. Reproduction by means of resting spores
with brown cell walls.

Botrydina Breb. — A genus little investigated. The
colonies are subspherical, made of cells enveloped in a thick,
gelatinous integument, which may be as large in diameter as
five hundred microns.

SUB-FAMILY II. TETRASPORE/E.

Cells grouped in fours or very irregularly scattered towards
the outside of a structureless mass of jelly. The cells of this
family are frequently provided with delicate non-vibratile hairs
called pseiidocilia.

Description of Genera.
Tetraspora Ag. — Thallus gelatinous, thick, at first baggy,
then lengthening; scattered through the jelly are numberless

30 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull.

green cells, dividing in one or more directions, grouped in
twos or fours without order near the periphery. Isogamous
planogametes — *. e., provided with cilia, — biciliated zoogoni-
dia, and resting spores with thick brown cell walls, are de-
veloped.

T. lubrica (Roth) Ag. var. lacanosa Chand., Fig. 212.

T. gelatinosa (Vauch.) Desv., Fig. yy.

[T. bullosa (Roth) Ag.]

Apiocystis Nag. — Thallus small, of various or changing
color, fastened by a stem-like base. Cells spherical, sometimes
scattered, sometimes eight in a circle; contents homogeneous
or slightly granular, with a distinct colorless vacuole. Propa-
gation by globose zodgonidia, each bearing two cilia, and
isogamous gametes.

SUB-FAMILY III. PALMELLE^E.

A large number of globose cells are aggregated in a struc-
tureless mass of jelly, which is of indefinite extent except in
Palmodactylon, in which it is more or less cylindrical and
variously branched. The outer layers of the firm, thin cell
walls are thrown off from time to time in one or many pieces.

Description of Genera.

Palmella Lyng. — A shapeless mass of jelly, holding cells
which are spherical, oval, or oblong, green, red, or brown.
Multiplication by repeated division of the cell contents, accom-
panied by decided gelatinization of the wall of the mother-cell.
Reproduction by macro- and macro-zoogonidia and also by
small isogamous planogametes.

P. mucosa Kiitz. ( ?) , Fig. 72. Fig. J2a is the gelatinous
colony, natural size.

Schizochlamys A. Br. — Found with Tetraspora, and like
it, except that in this genus the cell wall often splits into four
parts. The cell contents afterward divide into two or four
daughter-cells.

Palmodactylon Nag. — Small round cells, dull green, en-
closed in a cylindrical bladder-like membrane. Several of
these membranes are often joined together at one end, spread-

No. IO.] FRESH-WATER ALG.E. 3 1

ing radially. One, two, or four series of cells in each mem-
brane.

FAMILY II. PROTOCOCCACE.E.

The vegetative cells are green, strictly unicellular, and are
not provided with cilia. Propagation either sexual or asexual.
In the latter case the cells divide into many parts, the whole
assuming the form of a new colony. These are called auto-
spores and autocolonies. Division of vegetative cells lacking.
In some genera the cells are united into definite regular forms
called cccnobia, in others into a pseudocoenobium, which differs
from the true coenobium in that the cells are not all of the same
generation; other genera have the cells scattered or congre-
gated into irregular forms.

Key to Sub -families.

i. Cells elongated, frequently curved; solitary or in

definite, loosely coherent colonies selenastre^:

Cells angular, with a definite number of angles, two,

four, six, eight, or more; cells solitary. . . tetraedre^e
Cells variable, united in a regular flat plate. . crucigenie.e
Cells globose or sub-globose 2

2. Cells strictly globose, united in a spherical colony

(coenobium) ccelastre.e

Cells globose or sub-globose, not united in a spherical
coenobium 3

3. Cells with two or more attenuated bristles. . .phythelie^:
Cells without bristles 4

4. Cells generally retained within enlarged wall of

mother-cell oocystidelf:

Cells joined in colonies by persistent walls of mother-
cells, which sometimes become transformed into
connecting threads dictyosph^rie.e

SUB-FAMILY I. DICTYOSPH^ERIEJE.

Cells globose, ovoid, or ellipsoid, and associated to form
indefinite colonies. The cells are held in position, usually, by
the wall of the mother-cell, which in some genera breaks up
into connecting threads. Multiplication by simple vegetative

32 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull.

division, or by the formation of four daughter-cells in a mother-
cell, which at length ruptures to let them out.

Key to Genera.

i. Cells indefinitely disposed 2

Cells in grape-like clusters, freely exposed in a

thin gelatinous envelope Botryococcus

2. With well-marked. subdichotomous connecting

threads ; chloroplast parietal Dictyosphcerinm*

Cells in radiating series ; connecting threads scarcely
visible ; chloroplast axile Dictyocystis

Description of Genera.

Botryococcus Kiitz. — Sixteen or thirty-two cells clustered
like a bunch of grapes in an irregularly lobed mucous thallus.
Cells oval, spherical, or elliptical, densely packed in families
within a thin tegument. Clusters free-swimming, green, at
length pallid or brown.

Dictyosphaerium Nag. — Cells green, kidney-shaped or
egg-shaped, gathered into a hollow, somewhat spherical family,
and usually surrounded by a gelatinous envelope; free-swim-
ming. Cells covered bv thick coats which are confluent;
joined by a fine tegument. Division of cells at first in all
directions, later only radially. Biciliated zoogonidia rarely
occur.

D. Ehrenbcrgianum Nag., Fig. 22.

Dictyocystis Lagerh. — Oblong or cylindrical cells, held in
radiating series by delicate threads, to form a small, free-
floating colony, the series often branching.

SUB-FAMILY II. TETRAEDRE/E.

Solitary unicellular plants, flattened and angular with a
definite number of angles. The angles may be rounded,
notched, or furnished with spines. Only one genus, sometimes
divided into two, according to the depth of the lobulation.

Tetraedron Kiitz. (Polyedrium Nag.). — Cells green,

single, free-swimming, three-, four-, or eight-angled ; angles

pounded, sometimes notched, mostly armed with a spine.

No. IO.] FRESH-WATER ALG/E. 33

Propagation by means of autospores, which are formed, usu-
ally to the number of four or eight, in the mother-cell.

T. minimum (A. Br.) Hansg., Fig. 23.

T. trigonum var. punctatum (Kirch.), Fig. 24.

T. trigonum var. pentagonum (Rab.), Fig. 25.

SUB-FAMILY III. OOCYSTIDE.E.

Cells spherical or elliptical, often retained within the swollen
wall of the mother-cell. There may be one or several parietal
chloroplasts. The cell wall of all but Palmellococcus is firm.
Multiplication by means of autospores, which often develop
and grow to full size in the mother-cell.

Key to Genera.

1. Cells curved, subcylindrical or sublimate. .Nephrocytium*

Cells ellipsoidal Oocystis

Cells spherical 2

2. Cells large, solitary and free-floating. . . . Eremosphcera
Cells minute, forming a thin stratum. . . .Palmellococcus*

Description of Genera.

Nephrocytium Nag. — Two, four, eight, or sixteen oblong
or kidney-shaped cells, associated in a free-swimming family,
surrounded by an oval or kidney-shaped covering. Of variable
size ; cells bright green. Frequent in ponds. Multiplication by
autospores, which are often spirally disposed around the inside
of the wall of the mother-cell.

N. Ncegelii A. Br., Figs. 26, 29.

AT. Agardhianum Nag., Fig. 27.

Oocystis. This genus differs from Nephrocytium in
having cells ellipsoidal and showing polar nodules. There are
usually several parietal chloroplasts in each cell.

Eremosphaera D. By. ( Chlorosphaera Henfrey). — Large,
spherical, free-swimming cells, with firm walls, showing a
colorless border. Cell contents green, granulose; each cell
containing large numbers of small parietal chloroplasts. Mul-
tiplication into two or four parts, which escape through the
cell wall. Found in small pools.
3

34 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull.

Palmellococcus Chodat (Protococcus Ag., in part). —
Strictly unicellular Algae, globose, green, sometimes changing
to red upon exposure. Cells formed singly or in clusters,
growing in water, or on damp soil, flower-pots, trunks of trees,
etc. ; 8, 16, 32, or 64 spores formed within a mother-cell, the
wall of which ruptures and sets them free. Very rapid multi-
plication by cell division.

P.sp. (?), Fig. 30.

P. Gigas (Kutz.), Fig. 31.

SUB-FAMILY IV. SELENASTRE^.

Cells elongated and attenuated, sometimes lunate ; solitary,
or joined into fragile families. A single chloroplast, which
may contain one or many pyrenoids, is found in each cell.
The cell wall is delicate but firm. Multiplication by autospores
or autocolonies.

Key to Genera.

1. Colonies enveloped in mucus Kir c line riclla*

Colonies almost destitute of mucus 2

2. Cells attenuated to acute apices 3

Cells sublunate or ellipsoidal, arranged in groups of

four in a plane ; groups forming irregular colonies

Dimorphococcus

3. Cells forming definite colonies of a row of cells in one

plane Sccnodesmus*

Cells solitary or loosely grouped in irregular bundles

A nkistrodesmus*

Cells lunate, arranged back to back Selenastrum*

Cells dividing, oblique ; daughter-cells remaining at-
tached loosely by their apices Dactylococcus

Description of Genera.

Kirchneriella. — The cells are bent like a bow, often until
their apices almost touch each other ; loosely aggregated within
an enveloping mass of jelly. The cell wall is thin, the chloro-
plast parietal ; multiplication by autospores, four or eight of
which are produced in a mother-cell. The genus differs from
Selenastrum in the presence of jelly.

K. obesa (West) Schmidle, Fig. 54.

No. 10.] FRESH-WATER ALGM. 35

Selenastrum Reinsch. — Cells lunate, attenuated on both
ends to a fine point, with firm, thin walls; arranged back to
back to form four- to eight-celled colonies. Multiplication by
autospores.

S. acuminatum Lagerh., Fig. 46.

S. sp. (?) (perhaps acuminatum), Fig. 43.

Scenodesmus Meyen. — Cells elliptical, cylindrical, oblong-
spherical, often drawn out into longer or shorter spines. One,
sometimes two, rows of cells are commonly joined laterally
into a ccenobium. Propagation by repeated division of the
cell contents into brood-families, which are set free by rupture
of the mother-cell wall.

S. obtusus Meyen, Fig. 38.

S. caudatus Corda, Fig. 36.

S. caudatus var. abundans Kirch., Fig. 32.

5\ caudatus var. typicus Kirch., Fig. 33.

S. caudatus var. setosus Kirch., Fig. 34.

S. acutus Meyen, Fig. 37.

6". dimorphus Kiitz., Figs. 42, 44.

S. antennatus Breb. var. rectus Wolle, Fig. 39.

S.sp. (?), Fig. 35.

Dimorphococcus A. Br. — Cells united more or less in
fours on short branches ; the two intermediate, contiguous cells
oblique, obtuse-ovate; the two lateral, opposite and separate
from each other, lunate; families free-swimming, in irregular
clusters.

Ankistrodesmus Corda (Rhaphidium Kiitz. ; Schroderia
Lemmermann). — Finely granulate, cylindrical cells, usually
tapering at both ends and variously curved. The cells occur
singly, or gathered into groups, several radially joined, two
crossing each other, rarely two united at the end; covering
thin and smooth; division in only one direction.

A. falcatus (Corda) Ralfs, Fig. 45.

A falcatus var. acicularis West, Fig. 47.

A. falcatus var. mirabilis West, Fig. 41.

A. Braunii (Nag.) (?), Fig. 40.

SUB-FAMILY V. CRUCIGENIE^.

Cells gathered into flat coenobia. The cells are generally
rounded and sometimes furnished with spines. The groups of

36 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull.

four are held together by a tough mucilage. Multiplication by
autocolonies. The only American genus is the following: —

Crucigenia Morren (Staurogenia Kiitz. ; Lemmer-
mannia Chodat; Willea Schmidle). — 4, 8, 16, or 32 sub-
quadratic cells, gathered into a flat ccenobium held in a mucila-
ginous envelope. As many as 128 cells in groups of four have
been discovered. The cell walls are smooth, and each cell is
furnished with a single chloroplast. Multiplication by auto-
colonies.

SUB-FAMILY VI. PHYTHELIE^E.

Unicellular or grouped in a more or less definite ccenobium,
freely floating. Almost devoid of a mucous envelope and fur-
nished with bristles.

SUB-FAMILY VII. CCELASTRE.E.

The cells are either globose or polygonal, provided with
processes by which they are united into a hollow sphere ; or
broadly lunate, and united at the centre by short stalks.
Propagation by autocolonies which are formed in each cell of
the ccenobium.

Key to Genera.

Ccenobium hollow Coclastrum*

Ccenobium solid So rostrum*

Description of Genera.

Ccelastrum Nag. (Hariotina Dang.). — Ccenobium a
hollow globe formed of a single layer of green, spherical or
angular cells ; later the ccenobium appears to be reticulately
pierced ; in older growths the cells have become polygonal
through continued pressure. Daughter-ccenobia are developed
within the mother-cell, and escape by breaking the walls of the
latter. Found in ponds.

C. micro porum Nag., Fig. 51.

Sorastrum Kiitz. (Selenosphaerium Colin). — Differs
from Ccelastrum in that the ccenobium is solid. It is composed
of 4, 8, 16, or 32 wedge-shaped stalked cells, radially disposed,
with spines (usually two) on each end. Propagation by auto-
colonies.

No. IO.] FRESH- WATER ALG.E. $J

S. spinulosum Nag. (?). — The common form of Soras-
trum in this region is shown in Fig. 213. It shows only one
spine at each corner. A less common form which may be a
different species is shown in Fig. 55.

FAMILY III. HYDRODICTYACEyE.

These plants are free-floating, non-motile ccenobia, com-
posed of cells arranged like a net or in a flat plate. Pediastrum
may have fifty cells and Hydrodictyon many hundreds. Multi-
plication by autocolonies. Reproduction by spores, which be-
come quiescent within the mother colony and then unite by
their extremities to form a new ccenobium. A fusion of
isogamous gametes to form a zygospore also sometimes occurs.
The two sub-families are probably not closely related.

Key to Sub-families.

Cells in a flat plate pediastrEyE

Cells form a network hydrodictye^:

SUB-FAMILY I. PEDIASTRE^.

Microscopic plants composed of a number of small cells
united into a flat disk. Zodgonidia formed in the mother-cell
are liberated into an external vesicle, and there form new
ccenobia.

Description of Genus.

Pediastrum Meyen. — The plane, discoid or stellate, free-
swimming ccenobium is formed of a single, rarely a double,
layer of green cells, perforated or continuous. The cells are
polygonal, with four or more sides ; the central cells are entire,
while the marginal cells are often bilobed ; the lobes are
wedge-shaped, simple or bidentate, sometimes drawn out into
hair-like ends. The genus is very abundant and variable. The
reproduction is as follows : — The cell contents are at first
homogeneous, later becoming granular. The granular contents
divide into small zoogonidia, spherical or nearly so, which
break away from the mother-cell into an external vesicle.
After they have been motile awhile, they come to rest, and
then divide and redivide ; a gelatinous covering forms around
them, the cells arrange themselves into a single layer, and
gradually take on the shape of the mother plant. Autocolonies

38 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull.

are sometimes found in a single cell. Biciliated gametes are
also found which conjugate.

P.sp. (?),Fig. 65.

P. pertitsum Kutz., Figs. 66, 68, 70, 71.

P. pertusum var. clathratum A. Br., Figs. 50, 52, 57.

P. tetras Ehrb., Fig. 69.

P. Boryamtm (Turp.) Menegh. var. granulatum Kutz.,
Figs. 58, 59, 67.

P. Ehrenbergii A. Br., Figs. 61, 62, 63, 64.

SUB-FAMILY II. HYDRODICTYF^E.

Plants large, composed of a number of large cells, which
are so arranged as to form a net. Zoogonidia swarm and be-
come quiescent within the mother-cell, and there unite to form
new ccenobia.

Hydrodictyon Roth. — Ccenobium large, composed of
oblong cells joined at the ends, forming a reticulated stratum,
at first baggy, then net-like. All the cells are fertile, breaking
up to form large numbers of microgonidia within the mother-
ccenobium. After a period of activity they come to rest and
form a new ccenobium by joining together at their extremities.
Sometimes they become perfectly dry ; but, when moistened,
they form biciliated macrogonidia which join themselves into
daughter-ccenobia within the mother-cell. Motile gametes are
also found which become free and conjugate into a globose
zygote. The only known species is the following: —

H. reticulatum (L.) Lag., Figs. 215, a, b, c.

FAMILY IV. PLEUROCOCCACE.E.

Plants mostly unicellular, sometimes composed of short,
creeping, slightly branched filaments, which are never atten-
uated to hairs. The cell walls are generally very firm, and the
cells aggregate to form indefinite colonies. Multiplication by
division in two or three directions. Asexual reproduction
sometimes by means of biciliated zoogonidia. Of the six
genera of this family we have found only one.

Pleurococcus Menegh. (Protococcus Ag., in part;
Cystococcus Nag. ; Chlorococcus Fries, in part ; Pseudo-
pleurococcus Snow). — The cells are usually globular, some-
times angular from pressure. Division occurs in three direc-

No. IO.] FRESH-WATER ALGvE. 39

tions, so at times a cubical colony is seen, which easily divides
into its respective cells. The plants are occasionally creeping,
branched filaments. A single parietal chloroplast is present,
with or without a pyrenoid. Reproduction by aplanospores —
i. e., without cilia, — by rejuvenescence of the mother-cell con-
tents, by isogamous gametes, or by biciliated zoogonidia.

P. vulgaris Menegh., Fig. 73, is a very common form in
the state, growing in damp places, upon stones, etc. We have
not found it in water.

FAMILY V. CHARACIACE^.

Plants unicellular, usually elongated and attenuated at both
ends, the lower end terminating in a stalk, generally furnished
with a disk by which it is attached to larger Algse. A single
parietal chloroplast with one pyrenoid is present. Reproduc-
tion by numerous zoogonidia formed by division of the cell
contents at first transversely, then longitudinally. These por-
tions become rounded off, become biciliated, and escape by
a lateral, or, more rarely, a terminal pore. Each zoogonidium
becomes a new plant on coming to rest.

Characium A. Br. — Coextensive with the family.
C. Nagelii A. Br., Fig. 53.
C. ambiguum Herm., Fig. 56.

FAMILY VI. VOLVOCACE.E.

Plants unicellular, or consisting of ccenobia with a definite
number of cells, always ciliated and motile. Multiplication by
division of the mother-cell into 2, 4, or 8 daughter-cells. Re-
production both by the union of isogamous planogametes and,
in the higher genera, by heterogamous gametes.

The Volvocacese are sometimes found in immense quantities,
and frequently give an oily taste and odor to drinking water.
They are closely related to the Flagellata, and some of them
are frequently classed with the Protozoa.

Key to Sub-families.

Composed of colonies of many cells ; cells with two

cilia volvoce^e

Composed of single cells with two, or rarely four,

cilia CHLAMYDOMONADEyE

40 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull.

SUB-FAMILY I. VOLVOCEJE.

Motile ccenobia; cells varying in number from 4 to 20,000,
globose or ovoiclal, with a distinct but thin cell wall ; cilia two ;
chloroplast one of very variable form, usually including a single
pvrenoid. Cells usually imbedded in a common mucilaginous
investment ; more rarely united by protoplasmic processes.
All the cells may be capable of reproducing the plant, or there
may be a differentiation into vegetative and reproductive cells.
Vegetative reproduction by division of some or all of the cells
to form daughter-ccenobia. Isogamous or heterogamous sexual
reproduction.

Key to Genera.

1. Colonies spherical or circular 2

Colonies flat, cells 4-16, angles rounded, in a color-
less sheath Gonium

2. No gelatinous covering, cells many, in a hollow globe

Volvox*
No gelatinous covering, cells 16, arranged in four

rows Spondylomorum*

With a gelatinous covering 3

3. Colony ovate or spherical 4

Colony of eight cells, in an equatorial zone in a

spherical or ellipsoidal investment Stephanospharra

4. Cells 16-32, globose, not crowded, but scattered at

regular intervals on a colorless sphere Eudorina*

Cells 8, 16, 32, or 64, globose, crowded, often angular
from pressure Pandorina*

Description of Genera.
Gonium Muller (inclus. Tetragonium West). — Four to
sixteen cells so placed in a flat stratum as to form a quadrangle
with rounded angles. A colorless tegument covers all. Cells
globular except when angular from pressure. The cilia all
arise from one surface of the colony. When old, the cells
become granular and are connected by produced angles. Re-
production by repeated division of the cytoplasm into zoogo-
nidia. Multiplication by daughter-ccenobia formed in each cell
of the mother-ccenobium.

No. IO.] FRESH- WATER ALG.E. 4 1

Volvox Ehrb. — Coenobium spherical, hollow, the surface
composed of green cells estimated as high as 22,000, arranged
regularly on the wall, and each provided with two cilia, which
reach through the gelatinous covering and keep the ccenobium
in constant motion. Each green cell is attached to the six sur-
rounding ones by fine threads which are difficult to see even
under high power and with favorable light. Oogonia and
anthcridia are developed from vegetative cells, and a brown,
smooth or star-shaped cell is often found which is supposed to
be a fertilized oospore in a resting stage. Asexual reproduc-
tion takes place by the division of the larger vegetative cells,
which form new families. These after sufficient growth
separate from the mother-cell and begin life independently.

V. aureus Ehrb., Fig. 75.

V. globator (L.) Ehrb., Fig. j6. Fig. 74 is a fertilized
oospore. These are frequently found within the ccenobia, and
also occur free in the water. Ehrenberg named it V . stellata,
but of course this was an error.

Spondylomorum Ehrb. (Uvella Ehrb.; Phacolomonas
Stein.). — Ccenobium of sixteen cells in four alternating rows,
each cell with four cilia.

6\ quateriiariuiu Ehrb., Fig. 288.

Stephanosphaera Cohn. — Eight green cells, each having
two vibrating cilia, are arranged at regular intervals in an
equatorial circle, enclosed in a colorless sphere. Propagation
by macrogonidia, formed by eight-fold division of the green
cells, each bearing two cilia and a lateral red spot, and gathered
into families of eight ; or by microgonidia, each provided with
four cilia, formed by repeated division, and at first revolving
within the common sphere, afterwards escaping singly. In
hollow rocks and pools after rain.

Eudorina Ehrb. (Eudorinella Lemmermann). — Cceno-
bium somewhat oval or spherical, composed of 16 or 32 globular
green cells, each with two cilia, arranged around the color-
less sphere at nearly regular intervals. Usually four of the
32 cells develop antheridia and the rest oogonia for the sexual
reproduction. Asexual reproduction by the division of the
cells into 16 or 32 parts to form daughter-ccenobia.

E. elegans Ehrb., Fig. 285.

42 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull.

Pandorina Bory. — Coenobium spherical, covered by a
colorless jelly. Cells 8, 16, or 32, green, spherical, each covered
with a thin membrane and furnished with two widely divergent
cilia, often so crowded as to be angular. Propagation sexual,
by the conjugation of isogamous gametes. Cells of a coenobium
divide into eight daughter-cells ; these become two-ciliated
gametes, and are scattered and conjugate with similar cells
from other coenobia ; they flow together and produce a
zygospore, which, after a season of rest, develops one to three
biciliate macrospores, and these in their turn develop new
coenobia. Asexual multiplication by formation of a daughter-
ccenobium from each of the cells of the mother-coenobium.
P. morum (Mull.) Bory, Figs. 286, 287.

SUB-FAMILY II. CHLAMYDOMONADE^.

The plants are unicellular, spherical or ovoid, with thin
walls, and two or rarely four cilia. The chloroplast is in the
posterior end of the cell and usually contains one pyrenoid.
Reproduction by division of the resting cell into 2, 4, or 8
daughter-cells. Non-motile spores sometimes occur. Sexual
reproduction by conjugation of ciliated gametes, either isoga-
mous or heterogamous, which are similar to the vegetative
cells, though smaller. They arise by division of the contents
of the mother-cell, sometimes as many as 64 resulting from one
cell.

Key to Genera.

Contents of cell close to cell wall Chlamydomonas*

Contents of cell connected with cell wall by threads

Spharella

Description of Genera.
. Chlamydomonas Ehrb. — Vegetative cells ovate, green,
enclosed in a narrow, colorless tegument, frontal extreme some-
times produced to a beak with two cilia, other end with large
chloroplast, and with or without a red lateral spot. Gametes
formed by continued division of cell contents of vegetative
cells, numerous, oblong, or ovate, pale green or yellow, after-
wards brownish. Zygospores globular, red or brownish.

Chlamydomonas is abundant in the reservoirs of the state.

C. pulvisculus Ehrb., Fig. 289.

No. IO.] FRESH- WATER ALG^E. 43

According to West the forms with four cilia should be
named Carteria, Fig. 290. Both the two- and the four-ciliate
forms are common in our waters.

Sphserella Sommerfeldt ( Chlamydococcus A. Br.;
Haematococcus Ag.). — Like Chlamydomonas, except that
the cell walls are outstanding and joined to the cell contents by-
fine threads. There is always more or less red coloring matter
present.

[S. lacustris (Girod.) Witter.]

ORDER II. ULVALES.

Thallus expanded and parenchymatous; attached when
young by rhizoids. Each cell is furnished with a single nucleus
and a parietal chloroplast, often quite large, containing one
pyrenoid.

FAMILY I. ULVACE^E.

Most of the genera of this family are inhabitants of salt
or brackish water. The thallus consists of an expanse of cells
arranged compactly with their longer axes at right angles to
the plane of the thallus ; either flat or, more rarely, tubular.
The cells are uninucleate, with a single parietal, often ragged,
chloroplast, containing one pyrenoid.

Asexual reproduction by zoogonidia with 4 cilia, and by
gemmae. Sexual reproduction by isogamous gametes. The
contents of a vegetative cell divide into 8 (sometimes 4 or 16)
gametes, smaller than the zoogonidia, which are pear-shaped,
with a pigment spot and two long cilia. As a result of conjuga-
tion a rounded cell with two pigment spots and 4 cilia is
formed, which becomes a zygospore on losing its cilia.

Enteromorpha Lk. — Thallus tubular, membranaceous ;
at first fixed, then floating; sometimes branched. It is either
green or pale olive-colored. Reproduction as in the family.
Found in salt or fresh water.

ORDER III. SCHIZOGONIALES.

The thallus, often attached by rhizoids, is filamentous,
sometimes several filaments being joined laterally to form a flat

44 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull.

plate. Each cell contains one nucleus and a central stellate
chloroplast with one pyrenoid. The cells, especially of young
plants, often divide in two or three directions.

FAMILY I. PRASI0LACE.E.

Coextensive with the order.

Prasiola Ag. (inclus. Schizogonium Kiitz., and Hor-
midium Kiitz., in part). — Found on moist earth, trunks of
trees, rocks, stones, etc. ; some species require very little
moisture. The cells of the filamentous thallus are broader than
long, and those of the flat plates quadrate or polygonal. The
cell walls are strong and colorless. Reproduction by gemmae,
by resting spores liberated at the margin of the thallus, and by
tetraspores.

ORDER IV. C1EETOPHORALES.

Thallus filamentous, simple or usually branched. Branches
generally attenuated and bearing long hairs. The uninucleate
cells possess each, except in Trentepohliacccv, a single parietal
chloroplast with one or more pyrenoids. Asexual reproduction
by resting spores or zoogonidia with two cilia. Sexual repro-
duction by isogamous planogametes with two cilia, or by
heterogamous gametes.

Key to Families.

i. Plant entirely filamentous, simple 2

Plant of branched filaments forming a flat cushion-
like expansion enveloped in mucilage

COLEOCHJETACE.^

2. Filaments branched 3

Filaments not branched 5

3. Gametes arise from special cells only

TRENTEPOHLIACE.E

Gametes arise from any cell of the filament 4

4. Small creeping filaments upon water plants; cells

globose or cylindrical herposteirace^e

Like the above, but with flask-shaped cells

chjetosph^eridiace.e
Plant not creeping ch.etophorace^e

No. IO.] FRESH-WATER ALCE. 45

5. Cells with thick lamellose coats, in a series inside a

lamellose sheath cylindrocapsace^e

Cells without lamellose coat ulotrichace^:

FAMILY I. TRENTEPOHLIACE.E.

Thallus filamentous and branched, filaments erect or creep-
ing-, growing on the ground or on tree trunks. The cell walls
are firm and lamellose. The cells are uninucleate, and possess
one or many parietal chloroplasts with or without pyrenoids.
The color of the plants is usually brown or reddish. Zoogo-
nidia are developed only in cells especially set apart, either on
the ends of the branches or intercalated. These motile spores
sometimes conjugate. Spores are sometimes produced which
rest for a period before germinating, called resting spores or
hypnospores.

Key to Genera.

Terrestrial or arboreal ; chloroplasts several

Trentepohlia*
Aquatic ; cells that produce zoogonidia are terminal

Gongrosira
Aquatic ; cells that produce zoogonidia not terminal

Leptosira

Description of Genera.

Trentepohlia Mart. (Chroolepus Ag.). — Filaments
irregularly branched, often so dense that the branches and
stem cannot be easily distinguished ; primary branches and
stem of same thickness. Cell contents reddish brown, golden-
yellow, or olive-colored. About 32 red-brown or golden-yellow
zoospores in a cell which is set apart especially for the purpose,
usually on the end, sometimes on the side of the filament.
[T. aurea (L.) Mart.; T. Iolithus (L.) Wittr.]
Gongrosira Kiitz. (inclus. Pilinia Kiitz., in part). — The
plant is attached by a mass of cells, formed by a confluence
of creeping branches. From this mass, which may be of one
or many layers of cells, numerous erect branched filaments
arise. The whole is frequently encrusted with lime. The cell
walls are thick and lamellose, and the chloroplast is parietal
with one or many pyrenoids. Zoogonidia are found in flask-

46 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull.

shaped, terminal zoogonidiangia. The spores are ordinary
cells from the recumbent branches which become detached.

Leptosira Borzi. — Very much like Gongrosira. The
thallus is in the form of a minute bright green cushion. The
cells are light yellow-green, the terminal cells being elliptical
or irregular. The zoogonidiangia are intercalated and not
terminal. The zoogonidia either germinate directly, or con-
jugate in pairs and form resting spores. The ends without
cilia fuse first in conjugation.

FAMILY II. CH.'ETOPHORACE^E.

The thallus is branched, and the branches are attenuated
sometimes into long hyaline hairs ; it is usually differentiated
into creeping and erect portions. The creeping portion is at-
tached by rhizoids, is branched, and is more or less torulose.
The cells of the creeping portion are more or less swollen, and
the branching is irregular. Each cell, except those of the
terminal hairs, is provided with a parietal irregular chloroplast,
containing a single pyrenoid.

Zoogonidia, from I to 16, may be produced in each cell of
the thallus except those of the rhizoids and the terminal hairs.
They possess a red pigment spot and 2 or 4 cilia, and vary
much in size. Spores of a red-brown color are produced in all
the genera of the Chaetophoraceae. The gametes possess only
two cilia, conjugate in pairs, and produce zygospores which
rest for a short period before germinating.

Key to Genera.

1. Plants less than 1 mm. high, without setae

Microthamnion*
Plants larger, branches attenuated, and with seta?. . . 2

2. Filaments fine, showing little difference in character

of stem and branch, not in tufts in gelatinous
masses Myxonema*

Filaments fine, in tufts in a dense gelatinous substance

Chcctophora*

Filaments and main branches large, bearing tufts of
small branchlets Draparnaldia*

No. IO.] FRESH- WATER ALG.E. 47

Description of Genera.

Microthamnion Nag. — Filaments articulate, variously
branched, straight; end cell at first linear, then obtuse, and
finally swollen into a sporangium. The plants are at first fixed,
but later free-floating. The branches arise just below a trans-
verse cell wall. The chloroplast is parietal, long and entire, and
lacks a pyrenoid.

This genus is frequently placed with the Trentepohliacece ;
but Hazen states that the zoogonidia may be produced in any
cell of the filament, and hence it has its relationship near
Myxonema. Two species are found in Connecticut, according
to Hazen.

[M. Kuetzingianum Nag. ; M. strictissimum Rab.]

Myxonema Fries (Stigeoclonium Kiitz.). — Filamentous,
simple, branched, articulate ; the branches not in tufts, in ap-
pearance much like the main stem, with the end cells often
drawn out into long, colorless bristles. The chloroplasts are
scattered or arranged as in Drapamaldia. One to many zoogo-
nidia, each with two or four vibrating cilia, formed from the
contents of one cell. Gametes with 4 cilia. Zygospores smooth
or stellate.

M. attenuatum Haz., Fig. 220.

.1/. tenue (Ag.) Rab., Figs. 79, 82.

M. nanum (Dillw.) Haz., Fig. 284.

M. lubricum var. varians Haz., Fig. 81.

M. sp. (?), Fig. 78.

[M. Hagelliferum (Kiitz.) Rab.]

Chaetophora Schrank. — Plants enveloped in a hard, gela-
tinous covering of a globose, plane or lobed form. Thallus
filamentous, articulated and branched. Stems radiately dis-
posed, dividing into short branchlets, sometimes ending in a
bristle. The zoogonidia have two or four cilia, and resting
spores are generally developed from terminal cells and are
brown.

C. incrassata (Huds.) Haz., Fig. 221.

C. pisiformis (Roth) Ag., Fig. 222.

[C. attenuata Haz.]

Drapamaldia Ag.— Filaments articulate, much branched.
The stem is thick and composed of sterile cells, colorless

48 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull.

except for the chloroplast, which is in the shape of a trans-
verse band. The filaments are furnished more or less densely
with alternate or opposite, tufted branches. These are com-
posed of smaller, green, fertile cells, the end cell often a color-
less spine. From one to four zoogonidia, with four cilia apiece,
arise from each cell of the lateral branches. Usually all the
cells of one tuft form zoogonidia at the same time, and the
whole process occupies but a few minutes. A gelatinous
sheath, soft and slippery, covers the whole. Found in clear
streams, attached to stones or water-plants.

D. plumosa (Vauch.) Ag., Figs. 83, 84.

D. glomerata (Vauch.) Ag., Fig. 217.

[D. acuta (Ag.) Kutz.]

FAMILY III. CYLINDROCAPSACE^E.

Filamentous green Algae, without branches or roots, living
either in water or air. The filaments are covered with a thick,
lamellose sheath, and the cells are lamellose and are in a
single series.

In an ordinary vegetative cell the contents mass together to
form one oosphere. The antherozoids, which change from
green to red or orange are each provided with two short
cilia. After the oosphere is fertilized, it also changes to red or
orange, and lies resting for some time before it germinates.

Cylindrocapsa Reinsch. — With the characters of the
family. They are at first attached, then floating.

FAMILY IV. ULOTRICHACE.E.

Filaments simple, composed of cylindrical or of rounded
cells. The cell wall is always colorless, though of varying
thickness. Each cell contains a single parietal chloroplast
with irregular margins and one pyrenoid. Asexual reproduc-
tion takes place in various ways. Both motile and non-motile
.spores are produced; of the former some are large (macro-
zoogonidia) and some small (microzoogonidia). The plants
also multiply by dismemberment of the filament into single
cells or series of cells. Sexual reproduction by isogamous
gametes.

No. IO.] FRESH- WATER ALG^E. 49

Key to Genera.
Filaments attached; chromatophore a homogeneous

zonate band, with one to several pyrenoids. . . Ulothrix*
Filaments not attached; chromatophore a parietal

disk or plate, with one pyrenoid Stichococcus*

Filaments generally not attached; chromatophore
granular, covering more or less completely the
whole cell wall, containing starch but no pyrenoids

Microspora*
Description of Genera.

Ulothrix Kutz. (Hormiscia, as used by Rabenhorst,
Hansgirg, and De Toni). — Filaments simple; each cell except
the basal cell capable of reproduction. The chloroplast is
parietal with one or many pyrenoids. Asexual reproduction by
zoospores. Sexual reproduction by conjugation of gametes,
of which eight or more may be formed in a cell.

U. zonata (Web. and Mohr) Kutz., Fig. 94.

U. tenerrima Kutz., Fig. 93.

Figures 86 to 91 are specimens of Ulothrix of which we
have not determined the species.

[U. implexa Kutz. ; U. flacca (Dillw.) Thur.]

Stichococcus Nag. (Hormococcus Chodat). — Very like
Ulothrix, but unlike it in being almost wholly aerial, and in
the fact that the filaments easily and commonly dissociate into
cylindrical cells or small groups. The dissociation frequently
occurs first on the one side and then on the other, giving a
zig-zag appearance. Each cell has a parietal chloroplast,
usually occupying a part of the cell wall and containing a
small pyrenoid. Propagation by cell division, breaking up of
the filaments, by non-motile spores, and by biciliated zoogonidia.

6". Uaccidas (Kutz.) Gay, found but not figured.

[S. rivularis (Kutz.) Haz.]

Microspora Thur. — Filaments composed of cylindrical
or slightly swollen cells. The firm, sometimes lamellose cell
walls occasionally break up into H-shaped pieces, each piece
composed of a transverse wall and portions of the lateral walls
of the two adjoining cells. The cells are uninucleate, and a
more or less reticulated chloroplast occupies the cell wall.
4

50 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull.

Resting spores with thick walls are produced, usually one
in each cell, and also two- to four-ciliate zoogonidia.

M. Wittrockii (Wille) Lag., Fig. 216.

M. Stagnorum (Kutz.) Lag., Fig. 92.

[M. abbreviates (Rab.) Lag.; M. amcena (Kutz.) Rab. ;
M. crassior (Hansg.) Haz.]

FAMILY V. HERPOSTEIRACE.E.

The thallus is a creeping filament, sometimes branched,
and growing on larger Algae or other water plants ; most of the
cells have a bristle on the back, which is bulbous at the base and
separated from the cell by a septum.

In the sexual reproduction, cells in the centre of the thallus,
devoid of bristles, form the oogonia. One oosphere is formed
in each oogonium, and is ejected through an opening in the
wall. The oosphere is large and slowly motile, provided with
four cilia. Smaller cells on the end of the thallus, frequently
colorless, form the antheridia. One or two swiftly moving
antherozoids, pear-shaped, each with four cilia and two pul-
sating vacuoles, are produced in each antheridium, and they
unite, outside the oogonium, with the oosphere.

Herposteiron Nag. (Aphanochaste A. Br., Berth.,
Huber). — Coextensive with the family.

H. Confervicola Nag., Fig. 80b.

[H. vermiculoides Wolle.]

FAMILY VI. CH^TOSPH^RIDIACE^E.

Thallus creeping, composed of flask-shaped cells more or
less loosely joined, and each bearing a very long and slender
seta, sheathed at the base. Cell division horizontal, the lower
daughter-cell migrating to the side.

Asexual reproduction by zoospores, formed to the number
of four or more (?) in a cell.

Chaetosphaeridium Klebahn. — Coextensive . with the
family.

FAMILY VII. COLEOCH^ETACE^E.

Small, bright green water-plants. The thallus forms small
green cushions or discs. The cells in the common species often

No. IO.] FRESH-WATER ALG^E. 5 1

form a flat, more or less circular plane, or are arranged as fila-
ments radiating from one point. The cells are oblong, more
or less dilated at the anterior end, and some of them bear a
colorless bristle fixed in a long and narrow sheath.

The oogonium is round, on a slender neck — the continua-
tion of the end cell of the plant. Antheridia found either on a
neighboring cell or on a separate thallus. The oospore rests
for the winter, and develops in the following spring. Asexual
reproduction by zoogonidia, which are larger than the anthero-
zoids and may be developed in any cell.

Coleochaete Breb. — Coextensive with the family.

C. irregularis Pringsh. (?), Fig. 800.

C. scutata Breb., Fig. 243.

ORDER V. GEDOGONIALES.

Thallus of simple or branched filaments, fixed. The cells
are uninucleate, and with a parietal, more or less anastomosing
chloroplast containing one or more pyrenoids. In the vegeta-
tive division new pieces of the cell wall are intercalated.
The zoogonidia are possessed of a circle of numerous cilia
around the anterior end. Antheridia and oogonia are present.

FAMILY I. CEDOGONIACE.E.

Filaments branched or unbranched, attached in early stages.
Cell multiplication by transverse division, shown by transverse
striae, usually at the end of the mother-cell.

The oogonia are developed in a series of vegetative cells,
and are at first green, then orange, and finally dark red or
almost black. There are two kinds of male plants, dwarf and
elongated ; the dwarf males are attached to female plants, and
the elongated males are composed of a short series of cells
forming an independent thread.

Asexual reproduction by zoogonidia. The entire contents

of a cell gather in one mass, the cell wall splits near one end,

and the mass, with a small colorless protuberance on one end

surrounded by numerous cilia, escapes and swims away to

form a new plant.

Key to Genera.

Cells long, without a laterally placed bristle. CEdogonium*
Cells short, with a laterally placed bristle. . . .Bulbochate*

52 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull.

Description of Genera.

CEdogonium Lk. — Filaments simple, articulate ; the end
cell sometimes setiform, sometimes with an acute conical cap;
cells enlarged at the upper extremities. The oogonia and
antheridia are either on the same or on different filaments.
Dwarf males, shaped like inverted flasks, are parasitically sit-
uated near the oogonium. The elongated males are inde-
pendent and shorter than the female plant. When a cell has
reached maturity, it splits below the top by a circular line, the
top is raised by growth, and a new cell formed. This may
split again, and a new growth push the top up and leave an-
other ring ; this may be repeated five or six more times, leaving
a new ring each time.

O.sp. (?),Fig. 96.

O. cardiacum (Hass.) Wittr. (?), Fig. 228. Male and
female specimens.

[0. crenulato-costatum Wittr.]

Bulbochaste Ag. — Filaments much branched ; almost all
the cells thickened upwards, and bearing on that end long,
thin, transparent bristles, bulbose at the base. Reproduction
as in CEdogonium. The plants are more often mixed than in
CEdogonium, and are i nveloped in a quantity of mucus.

B. sp. (?), Figs. 97, 98.

[B. intermedia DeBary.]

ORDER VI. CLADOPHORALES.

Three families, very like the Siphonales, comprise this
order. The thallus is simple or branched, incompletely divided
into cells. Each portion contains many nuclei and parietal
chloroplasts, with single pyrenoids. Asexual reproduction by
resting spores, cysts, or zoogonidia with two or four cilia.
Sexual reproduction by heterogamous or isogamous gametes.

The order is divided into families, as follows : —

Key to Families.
1. Filaments unbranched, compound or elongated coeno-

CyteS SPH^ROPLEACE^E

Filaments branched 2

No. IO.] FRESH-WATER AIXLE. 53

2. Producing barrel-shaped and fusiform resting spores

PITHOPH0RACE.E

Without the barrel-shaped resting spores

CLADOPHORACE.E
FAMILY I. SPH^ROPLEACE^E.

The thallus is nnbranched, composed of cells from one to
ninety times as long as wide, each with several nuclei, and
parietal chloroplasts in the form of rings. Any segment of the
filament may form an oogonium or a bright red antheridium.
These sometimes alternate in a filament. Many antherozoids
are formed on the breaking up of the antheridium, and they
penetrate the oogonium through the transverse walls. Bright
red oospores with thick walls are produced, which hibernate in
the oogonium, and on germination from two to eight zoospores
are set free, which produce young plants, simple, fusiform, at-
tenuated to a fine point on each end.

Sphaeroplea Ag. — Coextensive with the family. Its fila-
ments are 36-62 microns in diameter.

FAMILY II. PITHOPHORACE.E.

Thallus much branched, segments six to twelve or more
times longer than broad. Usually many nuclei in a segment,
chloroplast parietal; growth apical; attached below by a
rhizoid. Asexual, green resting spores with thick walls are
produced here and there; when intercalated, cask-shaped;
when terminal, ovoid or fusiform. They develop on germina-
tion at both ends.

Pithophora Wittr. — Coextensive with the family. It is
almost exclusively tropical.

FAMILY III. CLADOPHORACE.E.

Thallus large, filamentous, incompletely septate, branched
in Cladophora. Each segment contains several nuclei and one
reticulated parietal chloroplast or several smaller ones, each
with a pyrenoid. In Cladophora and Chcetomorpha asexual re-
production is by zoogonidia, formed in great numbers in the
mother-cell. Rhizoclonium produces thick-walled cysts. Clado-
phora has also an isogamous sexual reproduction.

54 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull.

The Cladophoraceoe secrete very little or no mucus, and
are, therefore, a resting place for epiphytes.

Key to Genera.

i. Filaments unbranched; cells often slightly swollen

Chcetomorpha

Filaments commonly branched ; cells not swollen ... 2
2. With branched rhizoids Rhisoc Ionium*

Without rhizoids Cladophora*

Description of Genera.

Chaetomorpha Kiitz. — Wide, simple filaments of thick-
walled, swollen segments ; fixed at the base, the basal segments
being shorter than the rest. The cell wall is firm and lamellose.
Mostly marine or in brackish water.

Rhizoclonium Kutz. — Filaments slightly branched, with
branched rhizoids at the base ; articulate, somewhat contorted,
having here and there short branches composed of from one
to three cells.

[R. lacustre forma Americanum Wille ; R. hieroglyphicum
var. macromeres Nordst.]

Cladophora Kiitz. — Filaments much branched, the last
branches much thinner tnan the main stem ; cell walls thick,
cells longer than broad. Propagation by zoogonidia, which
develop in large numbers within the cells.

C. glomerata (L.) Kutz., Fig. 274.

[C. callicoma Kiitz.]

ORDER VII. SIPHON ALES.

Plant composed of an elongated ccenocytic filament (cceno-
cyte), which is much branched. The order inhabits salt water
almost exclusively. The only family living in fresh water is
the Vaucheriacece.

FAMILY I. VAUCHERIACE/E.

Thallus elongated, somewhat branched, ccenocytic, usually
attached. The protoplasm contains many minute nuclei. The
oval chloroplasts are small and numerous. The cell wall is
thin and easily broken ; after which the injured part is cut off
by a septum, and the uninjured parts develop into new plants.

No. IO.] FRESH-WATER ALG.E. 55

Vaucheria D. C. — Many filaments growing from one
root, green, rather stout. A single filament usually more or
less branched, with chlorophyll quite evenly distributed on the
inside of the cell wall, forms one plant. Sexual reproduction
by oospheres and spermatozoids ; asexual reproduction by
zoospores. One zoospore, provided with many cilia, is formed
in a swelling at the tip of the thallus, cut off from the rest of
the cell by a wall. The oogonia and antheridia, either sessile
or on short pedicles, grow in various numbers on the same
tube and usually close together.

V. sessilis (Vauch.) D. C, Figs. 200, 201. Sexual organs
of this species are shown in Fig. 206.

[V. aversa Hass. ; V. geminata (Vauch.) D. C]

ORDER VIII. CONJUGATE.*

The Conjugates are green or brownish Algae, sometimes
single-celled, but usually composed of many cells closely joined.
They are named from the peculiar mode of propagation. Two
cells unite their entire contents to form a zygospore ; rarely
two zygospores result from such a union. Resting spores or
cysts are produced in the Zygnemacece without copulation.
Non-motile spores are sometimes formed. All the Conjugates
are very slimy to the touch.

Key to Families.

Unicellular; cells commonly constructed of two
symmetrical halves ; of very many forms, though
rarely cylindrical; single, or, very rarely, bound
together in a loose thread ; two to eight germs de-
velop from a single zygospore desmidiace^e

Thallus a thread of many similar cells ; each zygo-
spore produces only one germ plant zygnemacece

* Our work upon the remaining orders of Chlorophyceae is as yet quite in-
complete. These Algae are abundant in our waters. In the filamentous forms it
is difficult or impossible to identify the species from the vegetative stages; and,
since in ordinary waters it is usual to find these stages only, specific determination
is frequently impossible. The family of Desmidiacea is very abundant; and,
while our list contains a large number of them, doubtless a longer study will show
many more species. The common species are, however, fairly well represented.

56 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull.

FAMILY I. DESMIDIACE^.

Cells of various forms, but symmetrical, single, or, in a few
genera, loosely united into threads. Often a constriction in
the middle of the cell divides it into halves, called semi-cells ;
the cell contents nearly always divided. The cell wall is often
provided with granules, spines, or other protuberances, which
are usually arranged in a definite pattern. These projections
serve as a protection from aquatic animals, and as an
anchor in times of flood. Conjugation of two cells results in
zygospores. Asexual multiplication by transverse division or
separation of semi-cells. The Desmidiacece are surrounded by
a mucus exuded through pores in the cell wall, and often may
be found embedded in a mass of jelly.

They are not free-swimming, but are able under certain
conditions of light and gravitation to glide along a hard sur-
face.

Desmids are extremely abundant the world over; there are
several thousand known species, living in all degrees of tem-
perature, and found most abundantly in soft water.

The following key, modified from West, includes all the
known genera of Desmids, four of which (Ichthyocercus,
Triploceras, Phymatodo is, and Streptonema) are exclusively
tropical, and one (Ancylonenta) is exclusively arctic. We
have identified certainly as yet only a part of the Connecticut
species, but have indicated by an asterisk the genera, and have
figured the species thus far observed.

Key to Sub-families.

Cell wall not evidently divided into two parts, and
without pores saccoderm^e

Cell wall showing two segments, and with a differ-
entiated outer porous layer placoderm^:

SUB-FAMILY I. SACC0DERM.E.

Cell wall unsegmented and without pores. Point of division
of cells indefinite, and unknown previous to the actual division.
The young half of the cell is developed obliquely, and its walls
are absolutelv continuous with the walls of the older half.

NO. 10.] FRESH-WATER ALG.E. 57

Key to Tribes and Genera.

Tribe I. gonatozygele. Cells elongate, cylindrical, and
unconstricted, forming loose filaments. Cell wall with a differ-
entiated outer layer, of which the small roughnesses and spines
form a part.

Chloroplasts axile Gonatozygon

Chloroplasts parietal and spirally twisted .... Genicularia
Tribe II. spirot^nie^:. Cells solitary, relatively short,
and mostly unconstricted. Cell wall a simple sac, without a dif-
ferentiated outer layer. The cell becomes adult by periodical
growth.

i . One chloroplast in each cell 2

Two chloroplasts in each cell 4

2. Chloroplast spirally twisted, axile or parietal. .Spirotcenia
Chloroplast plane, axile 3

3. Cells solitary M esotcenium,*

Cells forming short filaments Ancylonema

4. Chloroplasts star-shaped, radiating from a central

pyrenoid Cylindrocystis

Chloroplasts ridged with longitudinal serrated ridges

Netrium*

Description of Genera.

Gonatozygon D. By. — Cells long and straight, not con-
stricted, forming filaments which break up at maturity. The
cell wall is smooth or covered with minute granules. The
two chloroplasts are axile, thin and waving or twisted ; they
contain four to sixteen equidistant pyrenoids. The zygospores,
which quickly separate from the empty cells, are smooth.

Spirotasnia Breb. — Cells straight, fusiform, ends rounded,
not constricted in the middle; cells single or several, covered
by a gelatinous envelope. Chloroplasts spiral bands on the
inside of the cell wall.

Mesotaenium Nag. — Cylindrical cells, straight or slightly
curved, without median constriction. The ends are broadly
rounded. The chloroplast is a flat plate, extending from one
end of the cell to the other ; occasionally there are two chloro-
plasts.

M. micrococcum (Kiitz.) Roy and Biss., Fig. 219.

58 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull.

Netrium Nag. — Cylindrical, straight, or fusiform cells,
without constriction. Chloroplasts two (or four) in each cell,
each with longitudinal serrate ridges.

N. interraptum (Breb.) Lutkem, Fig. 281.

N. Digitus (Ehrb.) Itz. and Roth., Fig. 282.

SUB-FAMILY II. PLACODERM^E.

Cell wall mostly constricted, with a differentiated outer
layer. Cell division follows a fixed type, with interpolation of
the younger halves between the old ones. The younger por-
tions of the cell wall are joined to the older portions by an
oblique surface.

Key to Genera.

1. After division the cells remain free and solitary. ... 2
After division the cells remain attached to form

colonies 14

2. Cells more or less constricted at the middle 5

Cells not constricted 3

3. Cells of moderate length, straight, cylindrical. . .Peniam*
Cells elongate, generally curved and attenuated 4

4. Cells almost cylindrical, scarcely attenuated ; chloro-

plast single, without apical moving granules .... Roya*
Cells strongly attenuated towards each extremity;
two chloroplasts in each cell, with apical moving
granules Closterium*

5. Cells elongated and cylindrical, constriction slight. . 6
Cells relatively short ; deeply constricted 10

6. Apices of cells truncate or rounded, entire 7

Apices of cells cleft, incision open or narrow 8

7. Base of semi-cells plicate Docidium*

Base of semi-cells plane Plenrotcenium*

8. Cell wall adorned with rings of furcate processes. .

Triploceras
Cell wall plane 9

9. Apical incision widely open, each apical angle

furnished with a spine Ichthyocercus

Apical incision narrow Tetmemorus

10. Cells compressed (at right angles to the plane of the

No. IO.] FRESH- WATER ALGM. 59

front view), in the vertical view fusiform or el-
liptical ii

Cells in vertical view radiating, triangular, quadran-
gular, or radiate; rarely fusiform Staurastrum*

ii. Cells mostly oblong or elliptical; moderately lobed;

margins wavy, the depressions rounded .... Euastrum*

Cells very much compressed, mostly orbicular or
broadly elliptical, deeply lobed or incised . Micrasterias*

Cells with a more or less entire margin, often
furnished with warts or spines 12

12. Cell wall with regularly arranged spines of consider-

able length 13

Cells without spines Cosmarium*

13. Spines several, commonly in pairs ; a central pro-

tuberance always present .Xanthidium*

Spines 4 or 8, occasionally 16, no central protuberance

Arthrodesmus*

14. Colonies spheroidal ; cells not in contact, but joined

by gelatinous bands 15

Colonies thread-like ; cells attached by their apices to
form long filaments 16

15. Gelatinous bands narrow; few cells forming a micro-

scopic colony Cosmocladium

Gelatinous bands very broad, many cells forming a
macroscopic colony. Oocardiium

16. The line of division of the cell, where the new and

old parts of the cell wall are obliquely fitted to-
gether, develops a girdle during division 21

The line of division does not develop a girdle during
division 17

17. Cells attached by special apical processes 18

Apices of cells plane and flat 19

18. Apical processes very short Spharozosma*

Apical processes long and overlapping the apices of

the adjoining cells Onychonema*

19. Cells deeply constricted 20

Cells slightly constricted Hyalotheca*

20. Cells in vertical view elliptical Spondylosium*

Cells in vertical view quadrangular with produced

angles Phymatodocis

60 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull.

21. Cells joined by special apical processes Streptonema

Cells joined by their flat apices or by flattened apical

projections 22

22. Cells short, in vertical view fusiform, triangular, or

quadrangular (rarely circular with produced

angles) Desmidium*

Cells elongate, cylindrical Gymnosyga

Description of Genera.

Penium Breb. — Cells straight, cylindrical or fusiform,
without median constriction, ends rounded ; free or collected
in a gelatinous membrane. Cell wall smooth, or minutely
granular, colorless or sometimes red, often finely striate.
Chloroplast axile ; when seen in cross section star-shaped, with
arms often forking. Multiplication by division, and by zygo-
spores formed by conjugation.

P. closterioides Ralfs, Fig. 172.

P. polymorphum Perty, Fig. 173.

P. margaritaceum (Ehrb.) Breb., Fig. 175.

P. Navicula Breb., Fig. 218.

Roya West. — Cells curved but not attenuated. Cell wall
without pores, chloroplast single, without dancing granules.

R. obtusa (Breb.) West, Fig. 145.

Closterium Nitzsch. — Cells simple, elongated, crescent-
shaped or lunately curved, entire. The centres are not con-
stricted, but often bear a few transverse striae. The cell walls
are smooth or finely striate, colorless or brown ; at each end of
the cell is a vesicle, colorless or straw-colored, containing
numerous granules. The chloroplasts are arranged in longi-
tudinal rows broken in the middle by a transverse, colorless

band.

C. acuminatum Ktitz., Fig. 147.

C. lanceolatum Kiitz., Fig. 148.

C. Cucumis Ehrb. (?), Fig. 149.

C. acerosum (Schrank) Ehrb. (?), Figs. 150, 151.

C. Lunula Ehrb., Fig. 152.

C. turgidum Ehrb., Fig. 153.

C. strigosum Ehrb., Fig. 154.

C. costatum Corda, Fig. 155.

C. Delpontei Klebs, Fig. 156.

No. 10.] FRESH-WATER ALG^. 6l

C. prelongum (Breb.) Delp., Fig. 157.

C. lineatum Ehrb., Figs. 157a, 158.

C. decorum Breb., Fig. 159.

C. areolatum Wood, Fig. 161.

C. Diana Ehrb., Fig. 162.

C. Jenneri Ralfs, Fig. 160.

C. parvulum Nag., Figs. 163, 164.

C. moniliferam (Bory) Ehrb., Fig. 165.

C. Leibleinii Kutz., Fig. 166.

C. Leibleinii var. curium West, Fig. 167.

C. rostratum Ehrb., Fig. 168.

C. rostratum var. breviro stratum West, Fig. 169.

C. subcostatum Nord., Fig. 170.

C. Brebissonii Delp., Fig. 171.

Docidium Breb. — Cells straight, cylindrical or fusiform ;
ends rounded, truncate or smooth, constricted in the middle ;
each semi-cell furnished with a basal inflation. The base is
plicate with a granule under each plication. Chlorophyll axile
and an axile row of pyrenoids. The ends have a vacuole con-
taining dancing granules.

D. Baculum (Breb.), Figs. 103, 223.

D. verticillatum (Bailey) Ralfs, found but not figured.

Pleurotsenium Nag. — In shape much like Docidium,
without plications at the base of the semi-cells. The ends are
truncate and usually furnished with a ring of tooth-like pro-
jections. The parietal chloroplasts are longitudinal and are
provided with several pyrenoids. The centre of the cells usually
contains large vacuoles, and in the apical ones moving granules
are often seen.

P. crenidatum (Ehrb.) Rab., Fig. 224.

P. Archerii Delp., Fig. 225.

P. Trabecula (Ehrb.) Nag., Fig. 226.

P. nodosum (Bail.) Lund., Fig. 283.

P. sp. (?), Fig. 101. .

Tetmemorus Ralfs. — Cells like Penium, except that the
ends are slightly cut and the middle is constricted. One
central chloroplast with a single row of pyrenoids is present.
Cell wall mostly punctate or granulose.

62 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull.

Staurastrum Meyen. — The second largest genus of
Desmids. Cells in front view oblong, cylindrical, elliptical, or
orbicular, with margins notched or smooth, always constricted
in the middle, ends rounded, entire. End view with three to
six obtuse, acute, or horn-like angles. Chlorophyll more or less
central, zygospores commonly furnished with spines (see
Fig. 261).

S. orbicular e (Ehrb.) Ralfs, Figs. 123, 124.

S. dejectum (Breb.) var. convergens Wolle, Fig. 122.

S. dejectum var. mucronatum Ralfs, Fig. 125.

6\ megacanthum Lund., Figs. 126, 127.

5". hirsutum (Ehrb.) Breb., Figs. 133, 263, 263a.

5\ brevispinum Breb., Fig. 128.

S. leptocladum Nord., Figs. 264, 264a.

S. erasum Breb., Figs. 130, 131.

S. arctiscon Ehrb., Figs. 268, 268a.

S. odonatum Wolle, Fig. 132.

5. coronulatum Wolle, Figs. 267, 267a.

5*. Ravenelii Wood, Figs. 134, 135.

S. dejectum Breb., Figs. 233, 236.

S. furcigerum Breb., Fig. 136.

5. crenulatum (Delp ) Nag., Fig. 231.

5. margaritaceum Ehrb., Fig. 235.

5\ iotanum Wolle, Fig. 143.

5". eustephanum Ralfs, Fig. 144.

S. pygmceum Breb., Fig. 261. Conjugating.

S. muricatum Breb., Fig. 129.

Four* species, names unknown, Figs. 137-142.

S. gracile Ralfs, found but not figured.

Euastrum Ehrb. — Cells elliptical or oblong, deeply con-
stricted ; semi-cells usually cut at the ends and wavy or lobed
at the sides, the number of lobes being uneven; usually
furnished with circular inflated protuberances.

E. integrum Wolle, Fig. 105.

E. verrucosum _ (Ehrb.) Ralfs, Fig. 104.

E. oblongatum (Grev.) Ralfs, Fig. 229.

E. ampullaceum Ralfs, Fig. 230.

E. elegans Kiitz., Fig. 232.

E. Nordstedtianum Wolle, Fig. 234.

No. IO.] FRESH-WATER ALG^. 63

E. sp. (?), Fig. 227.

E. ansatum (Ehrb.) Ralfs, found but not figured.

Micrasterias Ag. (Holocystis Hass. ; Tetrachastrum
Dixon) . — Cells simple, flattened, in the form of a double-con-
vex lens, deeply constricted in the middle. Front view
orbicular or broadly elliptical ; end view spindle-shaped, with
acute ends. Each semi-cell three- to five-lobed ; lateral lobes
entire, or irregularly cut into large, deep lobes ; the end lobes
entire, or more slightly cut, sometimes with angles pro-
nounced, and two-cleft. Zygospores seldom found, large,
globular, with stout spines which are at first simple and later
branched.

M. radiosa (Ag.) Ralfs var. punctata West, Fig. 106.

M. apiculata Menegh., Fig. 108.

M. rotata (Grev.) Ralfs, Fig. 238.

M. furcata (Ag.) Ralfs, Fig. 239.

M. Americana (Ehrb.) Kiitz., Fig. 240.

M. muricata Bailey, Fig. 241.

M. truncata (Corda) Ralfs, Fig. 242.

M. Crux-Melitensis (Ehrb.) Hass., Fig. 107.

Arthrodesmus Ehrb. — Cells simple, deeply constricted in
the middle; each half-cell is wider than long, and furnished
with several spines. This genus is distinct from Xanthidium
by the absence of the protruding area in the centre of the semi-
cells. There are usually fewer spines, and the zygospores are
either smooth or spinous.

A. octocornis Ehrb., Fig. 260.

A. convergens (Ehrb.) Ralfs, Fig. 259.

Cosmarium Corda ( Dysphinctium Nag.; Calocylin-
drus (Nag.) Kirch.; Cosmaridium Gay; Pleurotaeniopsis
(Lund.) Lagerh.). — The largest genus of Desmids. The
single cells circular, elliptical, or oblong, usually one and one-
half diameters in length, always more or less constricted in
the middle. Ends usually entire, rounded or truncate. The
margins are smooth, dentate, or crenate, the cell wall smooth,
punctate, warty, or even covered with spines. End view
oblong or oval, with sometimes a swelling in the middle of
the longer sides. Zygospores usually spherical, sometimes
cubical or angular, smooth or furnished with spines.

64 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull.

C. Botrytis Menegh., Figs. 115, 116.

C. Broomei Thwaites, Figs. 99, 258.

C. suborbiculare Wood, Fig. 113.

C. granatum Breb., Fig. 109.

C. crenatum Ralfs, Fig. no.

C. contractum Kirch., Fig. 117.

C. tumidum Lund., Figs. 100, iooa.

C. ornatum Ralfs, Fig. 102.

C. ovale Ralfs, Fig. 245.

C. undulatum Corda, Fig. 244.

C. pyramidatum Breb., Fig. 246.

C. Meneghinii Breb., Fig. 247.

C. octhodes Nord., Fig. 248.

C. perforatum Lund., Fig. 249.

C. Ndgelianum Breb., Fig. 250.

C. intermedium Delp., Fig. 251.

C. Portianum Arch., Fig. 252.

C. orbiculatum Ralfs, Fig. 253.

C. tetrophthalmum (Kiitz.) Breb., Fig. 254.

C. galeritum Nord., Fig. 255.

C. Cucurbita Breb., Fig. 256.

C. pseudobroomei Wolle, Fig. 257.

Xanthidium Ehrb. — ■ Cells single, or two joined end to
end ; deeply constricted ; semi-cells wider than long, entire,
furnished with spines, and with a round, truncate, or toothed
arm projecting from the centre. The spines are either simple
or with two or three forks at the end. In the centre of each
semi-cell is a roughened protruding area of variable size.
Zygospores spherical and spinous.

X. fasciculatum (Ehrb.) Ralfs var. subalpinum Wolle,
Figs. 121, 266.

X. antilopceum (Breb.) Kiitz., Fig. 262.

X. cristatum (Breb.) Ralfs, Fig. 265.

X. aseptum Nord., found but not figured.

Sphaerozosma Corda. — Filaments of cells closely united
by a narrow isthmus or by a granular process. Cells deeply
constricted, thus forming bilobed cells.

5\ Uliforme Rab., Figs. 118, 119.

No. IO.] FRESH-WATER ALG/E. 65

6\ spinosum Delp., Figs. 120, 277.
S. pulcrum Bailey, Fig. 271.

Onchonema Wall. — Like Spharozosma except that the
granular processes are long.

0. serratum (Bailey) Wall., Fig. 272.

Hyalotheca Ehrb. — Cells short, cylindrical, usually
blunted, constricted in the centre; joined in long filaments en-
closed in an ample mucilaginous sheath. The end view of the
cell is round and shows the chloroplast to be eight- to ten-rayed.

H. dissilicns (Sm.) Breb., Fig. 273.

Spondylosium Breb. (Leuronema Wallich). — Like
Spharozosma except that instead of being united by lateral
processes, the cells are joined in filaments merely by the close
apposition of the cells.

5". papillatum West, found but not figured.

Desmidium Ag. (Didymoprium Kiitz.; Aptogonum
Ralfs). — Cells incised or entire, with two chloroplasts barely
touching in the middle ; triangular or quadrangular in end
view; united into fragile, elongated filaments, regularly
twisted, and enclosed in a mucous envelope.

D. cylindricum Grev., Fig. 276.

D. Swartzii Ag., Fig. 275.

Gymnozyga Ehrb. (Bambusina Kiitz.). — 1 Cells barrel-
shaped with one or more narrow bands around the middle ;
closely united into articulate filaments. Chlorophyll bodies as
in Hyalotheca. Zygospores smooth, ellipsoidal.

FAMILY II. ZYGNEMACE^E.

Unbranched filaments composed of single cells or of a
simple series of cells. Chloroplasts in the shape of spiral
bands, axile plates, or twin stellate bodies.

Key to Sub-families.

Conjugation producing a zygospore which, after a
period of rest, develops directly into a new gameto-

phyte ZYGNEMEiE

5

66 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull.

Conjugation producing a zygospore which immedi-
ately develops a sporocarp of several cells, one of
which is the spore. The gametophyte is developed
from this spore after a period of rest. . . . mesocarpe^e

SUB-FAMILY I. ZYGNEME,E.

Filaments unbranched. A lining of protoplasm is in each
cell, and the nucleus is held in the centre by quite prominent
bands of protoplasm. The chloroplasts containing numerous
prominent pyrenoids are twin stellate bodies in Zygnema and
spiral bands in Spirogyra.

Vegetative multiplication by breaking of filaments into
separate cells or groups of cells. Asexual reproduction
by spores. Sexual reproduction by conjugation between
cells of different filaments which lie close together. Each
cell puts out a tube on the side nearest the other fila-
ment, and these meet with similar tubes from the cells
of the other filament. The ends of the tubes join, and an
open " conjugating tube " is formed. The contents of the
cells separate from the cell walls, and the mass from one cell
flows into the other, there to unite with the mass in that cell
and form a zygospore. The zygospores are usually all found
in one of the two filaments. Occasionally lateral conjugation
between two cells of the same filament is observed.

Key to Genera.

Cells containing two star-shaped chlorophyll bodies

near the nucleus Zygnema'*

Cells with spirally twisted bands of chlorophyll. . .

Spirogyra*
Cells with nearly straight bands of chlorophyll. Choaspis*

Description of Genera.

Zygnema Ag. (Zygogonium Kiitz.). — Cells with two
star-shaped chlorophyll bodies near the nucleus, each chloro-
plast bearing a starch grain.

Z. leiospermum D. By., Fig. 176.

Z. stellium Ag., Figs. 177, 178.

Z. stellium var. genuinum Kirch., Fig. 179.

No. IO.] FRESH-WATER ALG^E. 67

Z. pectinatum (Vauch.) Ag., Fig. 279. In conjugation.

Z. cruciatum (Vauch.) Ag., Fig. 180.

Spirogyra Link. — Cells with from one to many bands of
chlorophyll in the cell wall, winding to the right. The* zygo-
spores are always inside the walls of one of the conjugating
cells.

The length and width of the cells, the form of the
dividing wall (which may be plane or replicate, i. e., with an
annular ingrowth of cellulose), the number of spirals, and the
number of turns each spiral makes in a cell, are all points for
consideration ; but the zygospores form the only decisive
factor in the determination of species. In the determination
of the species given below, we have chiefly relied on the
vegetative thread.

Found in low-lying ponds and ditches.

5\ varians (Hass.) Kutz., Figs. 181, 182.

S. Weberi Kutz., Figs. 183, 184.

S. maxima (Hass.) Witt., Fig. 185.

5". jugalis (Dillw.) Kutz., Figs. 186, 187.

5". inflata (Vauch.) Rab., Fig. 269.

6\ calospora Cleve, Fig. 105.

S. dubia Kutz., Fig. 188.

5". qninina (Ag.) Kiitz., Figs. 189, 190.

S. Grevilleana (Hass.) Kiitz., Fig. 191.

S. majuscula Kutz., Fig. 192.

5\ adnata Kiitz., Fig. 193.

5\ Spreeiana Rab., Fig. 194.

5\ decimina (Mull.) Kutz., Fig. 196.

S. communis (Hass.) Kiitz., Fig. 197.

S. Huviatilis Hilse, Figs. 198, 199.

5". mirabilis Hass., Fig. 202.

6". bellis (Hass.) Cleve, Figs. 203, 204, 270.

5*. Havescens (Hass.) Cleve, Fig. 205.

5\ crass a Kiitz., Fig. 60.
[S. nitida (Dillw.) Link.]

Choaspis S. F. Gray (Sirogonium Kiitz.). — Fila-
mentous. The only genus of Conjugatae without a mucous
coat. Sterile cells much like Spirogyra; conjugating cells
arise by unequal division of the cells of the filaments, and,

68 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull.

bending knee-like towards each other, grow together; zygo-
spores elliptical.

• SUB-FAMILY II. MESOCARPE^E.

The plants of this sub- family are often narrower than those
of Zygnemese, with thin cell walls. The chloroplast is a thin
axile plate, and all those of a filament usually lie in one
plane. The chloroplasts change their position according to
the degree of light, turning the edge to bright light and the
face to dim light. Reproduction as in Zygnemese.

Key to Genera.

Plants reproducing by conjugation Mougeotia*

Reproduction by non-sexual methods only . .Gonat one 'ma

Description of Genera.

Mougeotia A. Br. ( Staurospermum Kiitz. ; Mesocarpus
Hass. ; Craterospermum Braun ; Plagiospermum Cleve). —
Cells long, cylindrical, with axile chloroplasts. Conjugation
scalariform ; zygospores spherical or quadrate and more or
less flattened with rounded angles.

M. sp. ( ?), Fig. 85. The method of conjugating is shown
in Fig. 280.

[M. robusta (De Bary) Wittr. ; M. genuftexa (Dillw.)
Ag.]

Gonatonema Wittr. — Cells similar to Mougeotia, but re-
production only by means of non-sexual spores. Spores pro-
duced without conjugation, formed by division of the mother-
cells, which are afterwards often burst and bent angularly
and alternately at the point of fructification.

CLASS V. CHARACEiE.

Algse with a peculiar odor; often encrusted with lime.
Thallus a stem with nodes and internodes. The plants grow
from a few inches to over a foot in height by means of an
apical cell. Whorls of leaves, on which may be borne antheridia
and oogonia, grow at the nodes.

Zoospores are wanting. The organs of reproduction are
conspicuous in color and form. The antheridia are spherical,

No. IO.] FRESH-WATER ALG^. 69

red when mature, the wall consisting of eight shields or plates.
The spermatozoids are spirally coiled. The oogonium is situ-
ated on a nodal cell from which five other cells grow and coil
around the oogonium, covering it closely. They divide once
or twice at the top, so that a crown of five or ten small cells
is formed.

Description of Genera.

Chara Vaill. — The crown consists of five cells. The
stems are covered with a cortex.
C. sp. (?), Figs. 207-209.

Nitella Ag. — The crown consists of ten cells ; cortex
lacking.

CLASS VI. PrL^OPHYCE^ (FUCOIDE^).

The Algse of this class are almost exclusively salt-water
forms, known as the Brown Seaweeds, and include the most
highly developed of the Seaweeds. The vegetative cells are
uninucleate, and the chromatophores are distinctly brown.

Asexual reproduction by means of motile cells or zoogonidia.
Sexual reproduction by isogamous or heterogamous gametes.
Copulation always takes place outside the plant, and the re-
sulting spore germinates directly. The motile cells always
possess two laterally placed cilia, one directly forward and the
other backward.

While the class is made up mostly of marine plants, there is
one order that is found in fresh water.

ORDER I. SYNGENETIC^.

Exclusively fresh-water forms. Plants unicellular, solitary
or colonial, or multicellular ; free-swiming or motionless. The
cells are either naked or surrounded by a mucilaginous en-
velope. The cells are uninucleate, possess one or more pul-
sating vacuoles, one or two yellow or pale brown chromato-
phores, and occasionally pyrenoids.

The order as thus defined includes about seven families.
But at least four of the seven are frequently classed with the
Flagellate Protozoa, and are described in the report upon the
Protozoa of our waters. These include the following genera :

yo CONNECTICUT GEOL. AND N%\T. HIST. SURVEY. [Bull.

Cryptomonas, Synura, Uroglena, Dinobryon. (See Bull. No. 2
of this Survey.)

The only other family known to us to occur in our fresh
water is the following : —

FAMILY I. HYDRURACEvE.

The plant consists of an attached colony, from two to twelve
inches long. The cells have each one chromatophore, lack a
cell wall, and are embedded in a large mass of jelly. Cells
brown at one end, colorless at the other; arranged in irregular,
longitudinal families ; at first globose, then elliptical. Division
at first in one, later in two directions.

Asexual reproduction by uniciliated tetrahedral zoogonidia.
Two or four of them are produced from each cell of the
branches, and germinate at once. Resting spores have been
observed.

Hydrurus Ag. — Coextensive with the family.

CLASS VII. RHODOPHYCE/E (FLORIDE^).

Plants generally rosy red or purple, dark reddish-brown, or
blackish. Most closely related to salt-water Algae. Crust-
aceous, filamentous, variously branched.

Asexual propagation by means of motionless spores. In the
sexual reproduction, which is wanting in some of the genera,
the female cell, called the carpogonium, is fertilized by a mass
of protoplasm, called spermatium, derived from a male cell.
The result of fertilization is called a cystocarp, and the method
of its formation determines the different groups of Rhodo-
phyceae.

Sometimes the cystocarp is developed directly, and some-
times the fertilized carpogonium puts out growths, known as
0 obi a sterna-filaments, which conjugate with auxiliary cells, the
result being the cystocarp. The carpospores are always de-
veloped on a tuft of filaments which spring from the fertilized
cells and are called gonimoblasts.

Of the four orders of this class, two are found in fresh
water. They are distinguished as follows :

No. IO.] FRESH-WATER ALG.E. 71

Key to Orders.

Carpogonium developing directly NEMALIONALES

Carpogonium developing a filament of which two
cells conjugate with each other CRYPTONEMIALES

ORDER I. CRYPTONEMIALES.

A long branched filament is sent out from the fertilized
carpogonium. Each terminal cell of the filament unites with
an auxiliary cell, and from the latter the gonimoblasts arise.

FAMILY I. SQUAMARIACE.E.

A small group, mostly marine, but with a few fresh-water
species. The thallus consists of dense, upright cell-filaments,
which form minute, flat, gelatinous or membranous expanses.
Cavities in the upper surface of the thallus hold the sexual
organs, and, after the fertilization of the carpogonia, are
filled with cystocarps.

Hildenbrandtia Nardo. — Thallus crustaceous,- firmly ad-
hering, formed of subcubical, blood-red, dark red, rose, or
brown cells, placed in close vertical series. Sexual organs in
cavities in the upper surface.

ORDER II. NEMALIONALES.

The gonimoblasts are developed in tufts, directly from the
fertilized carpogonium.

Key to Families.
Thallus with a basal attached portion, from which
arise tufts of simple or branched filaments

LEMANEACE^E

Thallus filamentous, simple or branched, with sec-
ondary axes often in whorls. . .helminthocladiace^e

FAMILY I. LEMANEACE^E.

Exclusively fresh-water Alga, growing in very rapid
water. The thallus consists of a basal attached portion from
which arise dense tufts of erect branched filaments. From
these grow the fructiferous branches which are the most con-
spicuous part of the plant. After the growth of this part, the

72 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull.

vegetative portion of the thallus generally dies away, and
these branches become fixed by rhizoids of their own. The
fructiferous branches are long, filamentous, cartilaginous, and
swing freely in the water; they are olive-green or greenish
black. Each thread is built up of an axile row of tubular
cells surrounded by rows of smaller cells ; at short, more or
less regular, distances along the entire length are distinct
swellings or nodes.

Only sexual multiplication is known. The antheridia are
short and cylindrical, growing on whorled eminences or on the
widest part of the nodes. The carpogonium possesses a long,
simple or branched process for the reception of the male
gamete, called a trichogyne. After fertilization the car-
pogonium puts out an ooblastema-filament, at the extremity
of which a bunch of jointed moniliform filaments arises, each
of the swollen cells of which becomes at maturity a carpo-
spore. The carpospores are produced on the inside of the
thallus, filling up the space between the axile cells and the
cortical cells. The carpospores in turn produce the vegetative
thallus.

Lemanea Bory. — Large, simple or somewhat branched,
bristle-like threads of drrk or brownish color; hollow except
for the axile series of cells which is held in place by transverse
threads at regular intervals.

[L. fucina var. rigida (Sirdt.) Atk.]

Tuomeya Harvey. — Thallus much branched, upright,
five cm. high, rosette-like.

[T. Hiiviatilis Harvey.]

FAMILY II. HELMINTHOCLADIACE.E.

The plants consist of a filamentous thallus, simple or
branched, with the secondary axes often arranged in whorls.
The main filament may consist of a single row of cells or of an
axile row surrounded by cortical rows of smaller cells.

The terminal cells of the gonimoblasts, which are short
tufts of filaments, generally form the carpospores. When the
carpospore has become detached, the supporting cell grows
through the old cell wall and produces a new spore-forming
cell. The cystocarp has no. definite wall.

No. IO.] FRESH- WATER ALG.E. 73

Key to Genera.

i. With clustered tufts of branches. .. .Batrachospermum*
Without clustered tufts 2

2. Thallus three to seven mm. in length Chantransia

Thallus thirty to sixty cm. in length Thorea

Description of Genera.

Batrachospermum Roth. — A wholly fresh-water genus.
The plants are dioecious, of a violet or bluish green color. Thal-
lus is from sixteen to twenty cm. in length, moniliform, gela-
tinous, slippery, consisting of an axile series of cells growing by
means of a hemispherical apical cell, and an accessory parallel
series, covered with clustered tufts of branches which are more
or less scattered. The carpogonium grows in a cell at the
extremity of a short branch which stands out directly from the
main branch; it possesses a short, straight trichogyne, and
after fertilization develops a dense mass of exposed carpo-
spores.

B. vagum (Roth) Ag., Fig. 278.

\B. anatinum Sirdt. ; B. Boryannm Sirdt. ; B. Corbula
Sirdt. ; B. ectocarpnm Sirdt. ; B. moniliforme var. typicum,
and var. chlorosum Sirdt. ; B. pyramidale Sirdt. ; B. virga-
tum Sirdt.]

Chantransia Fries. — Dioecious, red, steel-blue, or purp-
lish violet, growing in fresh and salt water. Filaments articu-
late, branched ; branches simple or compound ; mucilage
lacking.

The carpogonium develops, after fertilization, numerous
gonimoblasts in small clusters, upwards and on one side.
Asexual multiplication by tetraspores developed on ends of
cells.

Thorea Bory. — This genus possesses but one species, T.
ramosissima Bory. The thallus is round, filamentous, much
branched, the thickness of a horse hair, of a purple-brown or
dark brown color, very mucous, and reaching the length of
thirty to sixty cm. The branches are short and compact,
slightly attenuated, and the cells are from two to five times
longer than their diameter. The cells possess starch-like
granules, and the spores are naked and non-motile.

FRESH-WATER ALG^E.

75

INDEX.

Amphithrix, 15.
Ancylonema, 57.
Ankistrodesmus, 34, 35.
Aphanocapsa, 12, 13.
Aphanochsete, 50.
Aphanothece, 13.
Apiocystis, 30.
Aplanospores, 39.
Aptogonum, 65.
Arthrodesmus, 59, 63.
Arthrosiphon, 22.
Arthrospira, 18, 20.
Autocolonies, 31.
Autospores, 31.

Bacillariae, 9, 24.
Bambusina, 65.
Batrachospermum, 73.
Botrydiaceae, 24.
Botrydina, 29.
Botrydium, 25.
Botryococcus, 32.
Bulbochaete, 51, 52.

Calocylindrus, 63.
Calothrix, 15, 16.
Camptotrichaceae, 16.
Chaetomorpha, 54.
Chaetophora, 46.
Chaetophoraceae, 44, 45.
Chaetophorales, 27, 44.
Chaetosphaeridiaceae, 44, 45.
Chaetosphaeridium, 50.
Chamaesiphoniaceae, 14.
Chantransia, 73.
Chara, 9, 69.
Characeae, 9, 68.
Characiaceae, 28, 39.
Characium, 39.
Chlamydococcus, 43.
Chlamydomonadeae, 42.

Chlamydomonas, 42.
Chlorobotrys, 25, 26.
Chlorococcus, 29, 38.
Chlorophycese, 9, 26.
Chlorosphasra, 33.
Choaspis, 66, 67.
Chroococcaceae, 11.
Chroococcus, 12, 14.
Chroolepus, 45.
Cladophora, 54.
Cladophoracese, 53.
Clathrocystis, 13.
Closterium, 58, 60.
Coccogoneae, II.
Coelastrese, 31, 36.
Ccelastrum, 36.
CcElosphserium, 12, 13.
Coenobia, 27, 31.
Coleochseta, 51.
Coleochsetaceae, 44, 50.
Conferva, 25.
Conjugate, 9, 27, 55.
Cosmaridium, 63.
Cosmarium, 59, 63.
Cosmocladium, 59.
Craterospermum, 68.
Crucigenia, 36.
Crucigenieas, 31, 35-
Cryptonemiales, 71.
Cthonoblastus, 20.
Cyanophycese, 9, 10.
Cylindrocapsa, 45, 48.
Cylindrocapsacese, 45, 48.
Cylindrocystis, 57.
Cylindrospermum, 21.
Cystococcus, 38.

Dactylococcus, 34.
Desmidiaceae, 55, 56.
Desmidium, 60, 65.
Diatomaceae, 9, 24.

76

CONNECTICUT GEOL. AND NAT. HIST. SURVEY.

[Bull.

Diatomin, 9.
Dicothrix, 15, 16.
Dictyocystis, 32.
Dictyosphserieje, 31.
Dictyosphaerium, 31, 32.
Didymoprium, 65.
Dimorphococcus, 34.
Docidium, 58, 61.
Dolichospermum, 21.
Draparnaldia, 46, 47.
Dysphinctium, 63.

Enteromorpha, 43.
Eremosphsera, 33.
Euastrum, 59, 62.
Eudorina, 40, 41.
Eudorinella, 41.
Gametes, 9.
Genicularia, 57.
Gloeocapsa, 12, 13, 14.
Gloeocystideae, 28, 29.
Gloeocystis, 29.
Gloeothece, 12, 13.
Gloeotrichia, 14, 15, 16.
Gomphosphaeria, 12, 13.
Gonatonema, 68.
Gonatozygon, 57.
Gongrosira, 45.
Gonium, 40.
Gymnozyga, 60, 65.

Hsematococcus, 43.
Hapalosiphon, 23.
Hariotina, 36.
Hassallia, 23.

Helminthocladiacese, 71, 72.
Herposteiracese, 44, 50.
Herposteiron, 50.
Heterocysts, 10.
Heterokontas, 9, 24.
Hildenbrandtia, 71.
Hormidium, 44.
Hormiscia, 49.
Hormococcus, 49.
Hormogoneae, 10, 11, 14:
Hormogones, 10.
Hyalotheca, 59, 65.

Hydrodictyacese, 28, 37.
Hydrudictyon, 37, 38.
Hydrurus, 70.
Hyphoeothrix, 19, 20.

Ichthyocercus, 58.
Inactis, 20.
Isactis, 15, 16.

Kirchneriella, 34.

Leibleinia, 19.
Lemanea, 72.
Lemaneaceae, 71.
Lemmermannia, 36.
Leptosira, 45, 46.
Leptothrix, 19.
Leuronema, 65.
Limnactis, 16.
Lyngbya, 18, 19, 20.
Lyngbyese, 17, 18.

Mastigonema, 16.
Mastigothrix, 16.
Merismopedia, II, 12.
Mesocarpeae, 68.
Mesocarpus, 68.
Mesotaenium, 57.
Micrasterias, 59, 63.
Microcoleus, 20.
Microcystis, 12, 13, 22.
Microspora, 49.
Aiicrosporales, 27.
Microthamnion, 46, 47.
Mougeotia, 68.
Myxonema, 46, 47.
Alyxophyceae, 9, 10.

Nemalionales, 71.
Nephrocytium, 33.
Netrium, 57, 58.
Nostoc, 21.
Nostocacese, 17, 20.

CEdogoniales, 27, 51.
CEdogonium, 51, 52.
Onchonema, 59, 65.
Oocardium, 59.
Oocystidese, 31, 33.

No. 10.]

FRESH-WATER ALG^.

77

Odcystis, 33.
Ophiocytium, 25, 26.
Oscillaria, 19.
Oscillatoria, 18, 19, 20.
Oscillatoriacese, 10, 17.

Palmella, 30.
Palmellaceae, 28.
Palmellese, 29, 30.
Palmellococcus, 33, 34.
Palmodactylon, 30.
Palmodictyon, 29.
Pandorina, 40, 42.
Pediastrese, 37.
Pediastrum, 37.
Penium, 58, 60.
Petalonema, 22.
Phaeophyceae, 9.
Phormidium, 18, 19.
Phycocyanin, 9.
Phycoerythrin, 10.
Phycophsein, 9.
Phymatodocis, 59.
Phythelieae, 31, 36.
Pilinia, 45.
Pithophora, 53.
Placodermae, 56, 58.
Plagiospermum, 68.
Planogametes, 30.
Plectonema, 18, 19.
Pleurococcaceae, 28, 38.
Pleurococcus, 38.
Pleurotaeniopsis, 63.
Pleurotaenium, 58, 61.
Polycystis, 13.
Polyedrium, 32.
Prasiola, 44.
Protococcaceas, 28, 31.
Protococcales, 27.
Protococcus, 34, 38.
Pseudocilia, 29.
Pseudoccenobia, 31.
Pseudopleurococcus, 38.
Psilonemateae, 14, 17.

Raphidium, 35.
Rhizoclonium, 54.

Rhodophyceae, 10.
Rivularia, 15, 16.
Rivulariaceae, 15.
Roya, 58, 60.

Saccodermae, 56.

Scenodesmus, 34, 35.

Schizochlamys, 30.

Schizogoniales, 27, 43.

Schizogonium, 44.

Schizophyceae, 9.

Schizosiphon, 22.

Schizothrix, 20.

Schoderia, 35.

Sciadium, 26.

Scytonema, 22, 23.

Scytonemaceae, 17, 22.

Selenastreae, 31, 34.

Selenastrum, 34, 35.

Selenosphaerium, 36.

Sex union, 9.

Siphonales, 27, 54.

Sirogonium, 67.

Sirosiphon, 23.

Sorastrum, 36.

Sphasrella, 42.

Sphaeroplea, 53.

Sphserozosma, 59, 64.

Sphaerozyga, 21.
Spirocoleus, 19.
Spirogyra, 66, 67.
Spirotaania, 57.
Spirulina, 18.
Spondylomorum, 40, 41.
Spondylosium, 59, 65.
Spores, 8.
Squamariaceas, 71.
Staurastrum, 59, 62.
Staurogenia, 36.
Staurospermum, 68.
Stephanosphasra, 40, 41.
Stichococcus, 49.
Stigeoclonium, 47.
Stigonema, 23.
Stigonemaceae, 17, 23.
Streptonema, 60.
Swarm spores; 9.

78

CONNECTICUT GEOL. AND NAT. HIST. SURVEY-

Symphysiphon, 22.
Symploca, 18, 19.
Synechococcus, 11, 12.

Tetmemorus, 58, 61.
Tetrachastrurn, 63.
Tetraedrefe, 31, 32.
Tetraedron, 32.
Tetragonium, 40.
Tetraspora, 29.
Tetrasporeae, 28, 29.
Thorea, 73.
Tolvpothrix, 22, 23.
Trentepohlia, 45.
Trentepohliacese, 44, 45-
Tribonema, 25.
Tribonemacese, 24, 25.
Trichormus, 21.
Trichophoreae, 14-
Triploceras, 58.
Tuomeya, 72.

Ulothrix, 49.

Ulotrichaceae, 48, 49.
Ulvaceae, 43.
Ulvales, 27.

Vaucheria, 55.
Vaucheriaceae, 54.
Vaginarieae, 17, 20.
Volvocaceae, 28, 39.
Volvoceae, 39, 40.
Volvox, 40, 41.

Willea, 36.

Xanthidium, 59, 64.
Xanthophyll, 9.

Zonotrichia, 16.
Zygnema, 66.
Zygnemaceae, 65.
Zygnemeae, 66.
Zygogonium, 66.
Zygote, 9.

Plate I : Figures i to 6; Au. Magnified i.ooo Diameters
Fig-, i

Fig.

2.

Fig.

3

Fig.

4

Fig.

5

Fig.

6

Oscillatoria subtilissima Kutz. .

oerugineo-ccerulea kutz.
Merismopedia glauca Nag.

" convoluta I'>reb. .

Oscillatoria limosa Ag.

" percursa Kiitz.

page 19

12

!9

PLATE I.

QP

f\r\ ^

flaw go

f I Q&Gu

y yyao

;18 '

Goai

-1*4

\ .%\

E eV

Oi tffc&.

i- Ji!

Plate II; Figures 7 to 10; All (except Fig. 8a) Magni-
fied 1000 Diameters.

Fig. 7. Ccelosphcerium Kuetsingianum Nag. page 13

Fig. 8. Glococapsa arenaria ( ? I

Fig. 8(7. " " A mass of the plant,

natural size .....
Fig. 9. Microcystis aeruginosa Kiitz. (?). -In a

mucilaginous mass ....
Fig. ga. Microcystis ccntgiiiosa Kiitz. Without

the mucilaginous mass
Fig. 10. Aphanocapsa Grcvillci (Hass.) Rab. 14

PLATE II.

g# % <*# ^S> 4 a fl&fi©

Plate III; Figures ii to 15; All Magnified iooo

Diameters.

Fig. 11. Anabana gigantea Wood . . page 22

Fig. 12. Flos-aquce Kiitz. or circinalis

(Rab.) Kirch "

Fig. 13. Lyngbya sp. (?).... 19

Fig. 14. Oscillatoria chalybea Mertens
Fig. 15. amphibia Ag.

PLATE III.

Plate IV; Figures 16 to 19; Fig. 18 Magnified 500 Diam-
eters ; the others iooo Diameters.

Fig. 16. Nostoc rupcstrc Kiitz.

Fig. 17. " "...

Fig. 18. " sp. (?)

Fig. 19. comminutum Kiitz.

ige

21

«

ti

u

it

«

(i

PLATE IV.

*SL

£

.ar

%r^JLr

big.

20.

Fig.

21.

Fig.

22.

Fig.

23-

Fig.

24-

Fig.

25-

Fig.

26.

Fig.

27.

Fig.

28.

Fig.

29.

A. Br.

page

26

26

Nag.

a

32

rlansg.

a

33

Plate V; Figures 20 to 29; Figs. 26 and 29 Magnified 500
Diameters; all others iooo Diameters.

Ophiocytium parvulum (Perty)
Triboncma minus (Wille) Haz.
Dictyosphcerium Ehrenbergianum
Tetraedron minimum (A. Br.)

trigonum var. punctatum

(Kirch.) "

Tetraedron trigonum var. pentagonum

(Rab.) "

Nephrocytium Naegelii A. Br. .

Agardhianum Nag. .
Glcrocystis vesiculosa Nag. . . 29

Nephrocytium Ndgelii .A. Br. . . 33

PLATE V.

Plate VI; Figures 30 to 49; All Magnified iooo

Diameters.

big.

30

Fig.

31

Fig.

32

Fig.

33

Fig.

34-

Fig.

35-

Fig.

36.

Fig.

37-

Fig.

38.

Fig.

39-

Fig. 40

Fig.

4i

Fig.

4^

Fig.

43

Fig.

44

Fig.

45

Fig.

46

Fig.

47

Fig. 48

Fi£- 49

Si

pic us
tosus

Pcdmellococcus sp. ( ?) .

Gigos (Kiitz.).
Scenodesmus caudatus var. dbundans
Kirch. ......

Scenodesmus caudatiis var. ty
Kirch. ....

Scenodesmus caudatus var
Kirch. ....

Scenodesmus sp. (?)

caudatus Corda
acutus Meyen
obtusus Meyen .
aiitcuuatus Breb. var.
rectus Wolle ....

Ankistrodesmus Braunii fXag.) (?)

falcatus var. mira-

bilis West .....

Scenodesmus dimorphus Kiitz. .
Sclcnastrum sp. ( ?) .
Scenodesmus dimorphus Kiitz.
Ankistrodesmus falcatus (Corda) Ralfs.
Sclcnastrum acuminatum Lagerh.
Ankistrodesmus falcatus var. acicu-
laris West .....

Tribonema bombycinum (Ag.) Derbes
and Sol. ......

Scenodesmus sp. (?)

page 34

35

ti

(<

it

a

a

a

26

35

PLATE VI.

Plate VII; Figures 50 to 56; All except Fig. 54a Magni-
fied 1000 Diameters.

Fig. 50. Pediastrum pertusum var. clathratum
A. Br

Fig. 51. Coelastrum microporum Nag'.

Fig. 52. Pediastrum pertusum var. clathratum
A. Br

Fig. 53. Characium Naegelii A. Br.

Fig. 54. Kirchneriella obesa (West) Schmidle.
Fig. 54a represents a single cell

Fig. 55. Sorastrum spinulosum Nag.

Fig. 56. Characium ambiguum Herm. .

page

38

a

36

a

3«

a

39

a

34

a

37

a

39

PLATE VII.

Plate YIII; Figures 57 to 60; All Magnified 500 Diam-
eters.

Fig. 57. Pediastrum pertustim var. clathra-

tinn A. Br page 38

Figs. 58, 59. Pediastrum Boryamtm (Turp.)

Meneg. var. granulatum Kiitz. . " "

Fig. 60. Spirogyra crassa Kiitz. ... "67

PLATE VIM.

Plate IX ; Figures 6i to 71 ; Fig. 68 Magnified 500 Diam-
eters ; ALL OTHERS IOOO DlAMETERS.

Figs. 61-63. Pediastriim Ehrenbergii A. Br. . page 38
Fig. 64. " " var.

truncatiim Braun .... " "

Fig. 65. Pcdiastrum sp. ( ?) . . . . " "

Fig. 66. pcrtusum Kiitz. . . " "
Fig. 67. Boryanum (Turp.) Meneg.

var. granulatum Kiitz. . . " "

Fig. 68. Pediastrum pcrtusum Kiitz. . . "

Fig. 69. " tetras Ehrb. ... " "

Figs. 70, 71. " pcrtusum Kiitz. . . "

PLATE IX.

Plate X ; Figures 72 to 77.

Fig. 72. Palmella mucosa Kiitz. ( ?) (250
diameters) .....

Fig. 72a. A colony of the same, natural size .

Fig. 7$. Pleuro coccus vulgaris Menegh. (500
diameters) .....

Fig. 74. Volvox. A young colony. (500
diameters) .....

Fig. 75. Volvox aureus Ehrb. (200 diameters)

Fig. 76. globator Ehrb. ( 125 diam-

eters) ...

Fig. 77. Tctraspora gelatinosa (Vauch.) Desv.
(250 diameters) ....

Fig. 77a. A colony of the same, natural size

page 30

it

39

4i

30

PLATE X.

'V?' * * ''

77a

Plate XI; Figures 78, 79; Magnified 250 Diameters.

Fig. 78. Myxonema sp. ( ?) . . . page 47

Fig. 79. " tenue (Ag.) Rab. . "

PLATE XI.

Plate XII ; Figures 80 to 82.

Fig. 80a .Colcochccic irregularis Pringsh. (?)

(250 diameters) .... page 51

b. Herposteiron Confervicola Nag. . 50

c. Diatom ......

Fig. 81. Myxonema lubricum var. various Haz.

(500 diameters) .... 47

Fig. 82. Myxonema tonne (Ag.) Rab. (250
diameters) .....

a a

PLATE XII.

Peate XIII; Figures 83, 84; Magnified 100 Diameters.

Fig-s. 83, 84. Draparnaldia plumosa (Vauch.)

Ag. page 48

PLATE XIII.

Plate XIV; Figures 85 to 89.

Fig. 85. Mougeotia sp. ( ?) ( 500 diameters) . page 68
Figs. 86 to 89. Ulothrix sp. ( ?) ( 1000 diam-
eters, except 86a, which is 500
diameters) ..... "49

PLATE XIV.

88

/»>A l£& pw>

rsK

"ft I

\hy

Plate XV; Figures 90 to 95; Magnified iooo Diameters,

except Fig. 91.

Fig-. 90. Ulothrix. Young stage . . . page 49

(low power)
Microspore! Stagnorum ( Kiitz.) Lag. 50

Ulothrix tenerrima Kiitz. . . 49

zonata (Web. and Mohr)

Kiitz "

Fig. 95. Ulothrix sp. ( ?)

Fig.

91.

Fig.

92.

Fig.

93-

Fig.

94.

PLATE XV.

rS^jSagi,,,:-

90

if

% ■■■'■ 7 i
<k ft \ % -v ■ '■■

Plate XVI; Figures 96 to 98; Magnified iooo Diameters.

Fig. 96. (Edogonium sp. ( ?) . . . . page 52

Fig. 97. Bulbochccte sp. ( ?) .

Fig. 98. " " Young stage . . "

PLATE XVI.

Plate XVII; Figures 99 to 105; Magnified iooo

Diameters.

Fig.

99.

Fig.

100.

Fig.

1 00a.

Fig.

101.

Fig.

102.

Fig.

103.

Fig.

104.

Fig.

105.

Cpsmarium Broomei Thwaites
tumidum Fund.

•' 1?)
Pleurotcenium sp. (?)
Cosmarium ornatum Ralfs
Pleurotcenium Baculum Breb.
Euastrum vemicosum ( Ehrb. ) Ralfs
integrum Wolle

page 64

61

62

PLATE XVII.

Plate XVIII; Figures 106 to 108; Fig. 107 Magnified
1000 Diameters ; others 500 Diameters.

Fig. 106. Micrasterias radiosd (Ag.) Ralfs

var. punctata West . . . page 63,
Fig. 107. Micrasterias Criix-Mclitcnsis (Ehrb. )

Ha Li.

ass. ......

Fig. 108. Micrasterias apiculata Alenegh.

PLATE XVIII.

Plate XIX; Figures 109 to 121; Magnified iooo

Diameters.

Fig.
Fief.

100.
1 10.

Cosmarium granatum Breb.
crenatum Ralfs
Cosmarium sp. ( ?) .
Cosmarium sub orbicular e Wood
&. .^. sp. ( ?) .

Figs. 115, 116

Figs, in, 112.
Fig 113.
Fig. 114.

Cosmarium Botrytis Menegh.

Fig.

1 1

/■

Cosmarium coutractum Kirch.

Figs. 118, 119. Sphcerozosma Hliforme Rab. .
Fig. 120. Sphcero'zosma spinulosum Delp. ( ?]
Fig. 121. Xanthidium fasciculatum var. sub-

alpinum Wolle .

page 64

65
64

\

PLATE XIX.

Plate XX ; Figures 122 to 133; Magnified iooo Diameters.

Fig. 122. Staurastrum dejectum var. conver-

gens Wolle ..... page 62

Figs. 123,124. Staurastrum orbkulare (Ehrb.)

Rail's "

Fig. 125. Staurastrum dejectum var. mucro-

natum Ralfs .... "

Figs. 126. 127. Staurastrum iiiegacaiithuni Lund.

Fig. 128. Staurastrum brevispinuhi Breb.

Fig. 129. muricatum Breb.

Fig. 130. erasum Breb. . . "

Fig. 131. " '• Show-

ing multiplication by division

Fig. 132. Staurastrum odondtum Wolle .

Fig. 133. hirsutum (Ehrb.) Breb. " "

PLATE XX.

Plate XXI; Figures 134 to 144; Magnified iooo

Diameters.

Figs. 134, 135. Staurastrum Ravenelii Wood (?) page 62

Fig. 136. Staurastrum furcigertim J»reb.

Figs. 137-142. Staurastrum species undetermined

Fig. 143. Staurastrum iotanum Wolle . . " "

Fig. 144. eustephanum Rail's . " "

PLATE XXI.

Plate XXII; Figures 145 to 151; Figures 147, 149, 151
Magnified 500 Diameters; Others iooo Diameters.

Figs. 145, 146. Roya obtusa (Breb.) West . page 60
Fig. 147. Closterium acuminatum Kiitz. .
Fig. 148. lance qlatum Kiitz.

Fig. 149. " Cucumis Ehrb. (?)

Fig. 150. acerosum (Schrank)

Ehrb. (?). With fungous growth
Fig. 151. Closterium acerosum (Schrank)

Ehrb. (?). About to divide .

PLATE XXII.

Plate XXIII: Figures 152 to 159; Figs. 152, 157, 158
Magnified 500 Diameters; others iooo Diameters.

Closterium Lunula Ehrb. . . page 60

turgidum Ehrb. . . "

strigosum Ehrb. .
costatum Corda
Delpontei EClebs .
prelongum ( Breb.) Delp. 61

lineatum Ehrb.

A mul-
tiplication by division
Fig. 159. Closterium decorum F.reb.

Fig.

1 52.

Fig.

!53-

Fig.

154-

Fig.

155-

Fig-

1 56.

Fig.

157-

Fig.

l57a

Fig.

158.

PLATE XXIII.

Plate XXIV ; Figures 160 to 165 ; Magnified iooo Diam-
eters, Except Fig. 161.

Fig. 160. Closterium Jenneri Ralfs. . . page 61
Fig. 161. areolatum Wood (500

diameters) .....

Fig. 162. Closterium Diaiuc Ehrb. .
Figs. 163, 164. Closterium parvulum Nag.
Fig. 165. Closterium moniliferum (Bory) Ehrb

. . ..

PLATE XXIV.

Plate XXY ; Figures 166 to 171 ; Figs. 168, 169 Magnified
500 Diameters ; all others iooo Diameters.

Fig. 166. Closterium Letbleinii Kiitz. . . page 61
Fig. 167. var. curt 11 in West "

Fig. 168. rostratum Ehrb.

Fig. 169. var.

breviro stratum West
Fig. 170. Closterium subcostatum Nord. With

only 6 costae .....
Fig. 171. Closterium Brebissonii Delp. .

11 a

PLATE XXV.

Plate XXVI; Figures 172 to 175; Magnified iooo

Diameters.

Fig. 172. Pen in in closterioides Ralfs . . page 60
Fig. 173. polymorphism Perty .

Fig. 174. " sp/(?) . . . .

Fig. 175. margaritae'eum Breb.

PLATE XXVI.

- "^SkSt :.Br^?*»

.6 **£_»>' jov-u-"^

175 I

M " : fc v

Plate XXVII; Figures 176 to 180; Magnified 500

Diameters.

Fig. 176. Zygnetna leiospertnutn D. By. . page 66

Figs. 177, 178. Zygnetna stellium Ag. .
Fig. i7<). Zygnetna stellium var. genuinum
Kirch. ......

Fig. 180. Zygnetna cruciatum (Vauch.) Ag.

PLATE XXVII.

■ - J : :

179

..-?-

Plate XXVIII; Figures 181 to 187; Figs. 182, 186 Mag-
nified 250 Diameters ; all others 500 Diameters.

Fig. 181. Spirogyra varians (Hass.) Kiitz. . page 67
Fig. 182.

Conjugating ..... " "

Figs. 183, 184. Spirogyra Wcberi Kiitz. . " "

Fig. 185. Spirogyra maxima (Hass.) Witt.
Fig. 186. " ' jugalis (Dillw.) Kiitz. .

Fig. 187.

Conjugating .... " "

PLATE XXVIII.

P \W<

Plate XXIX; Figures 188 to 196; Magnified 250

Diameters.

Fig. 188. Spirogyra dubia Kiitz.
Figs. 189, 190. Spirogyra quiiiina (Ag.) Kiitz.
7i°f. 191. Spirogyra Grevillecma (Hass.) Kiitz.

majuscula Kiitz.

adnata Kiitz. .

Sprcciana Rab.

calospora Cleve

decimina (Mull.) Kiitz.

to

Fig. 192.
Fig. 193.
Fig. 194.

Fig- 195-
Fig. 196.

page 67

PLATE XXIX.

Plate XXX; Figures 197 to 206; Figures 197, 205 Mag-
nified 500 Diameters ; all others 250 Diameters.

Fig-. 197. Spirogyra communis (Hass.) Kiitz. page 67
Fig. 198. " Huviatilis Hilse . "

Fig. 199. " " " Kept in

dishes, the cells elongating without

dividing, and dancing dots of oil

appearing in the ends
Fig. 200. Vaucheria sessilis (?) (Vauch.) D. C. " 55
Fig. 201. " " " "

Fig. 202. Spirogyra mirabilis Hass. . . "67

Fig. 203. bcli.s (Hass.) Cleve. In

state of decomposition ... 67

Fig. 204. Spirogyra bellis (Hass.) Cleve . " "

Fig. 205. iiavescens (Hass.) Cleve " "

Fig. 206. Vaucheria. Showing sexual organs . 55

PLATE XXX.

205

Plate XXXI; Figures 207 to 209.

Fig. 207. Chora sp. ( ? ) Shield of antheri-

dium ( 125 diameters) . . . page 69

Fig. 208. Chora sp. (?) A portion of the

plant, natural size .... " "

Fig. 209. Chora sp. (?). a, antheridium;

b, oogonium 1 50 diameters) . . " "

PLATE XXXI.

Plate XXXII; Figures 210 to 216.

Fig. 210. Chroococcus cohcvrcns (Breb.) Nag. page 14

Fig. 2io<7. (1000 diam-

eters) ......

Fig. 211. Nostoc minutissimus Kiitz. . . 21

Fig. 21 la. Single

thread ( 1000 diameters)

Fig. 212. Tetraspora htbrica (Roth.) var.

lacunosa Chand. .... 30

Fig. 212a. Tetraspora htbrica var. lacunosa
Chand. (1000 diameters)

Fig. 213. Sorastrum spinulosum Nag. (1000
diameters) .....

Fig. 214. Ghrotrichia pisym (Ag.) Thur.

Fig. 215. Hydrodictyon reticulatum (L.) Lag.

a. Natural size

b. Young colony, slightly magnified

c. Full grown colony, highly magnified
Fig. 216. Microspora WittrockU (Wille) Lag.

It

37

11

16

l(

38

PLATE XXXII.

Plate XXXIII; Figures 217 to 220.

Fig-. 217. Draparnaldia glomerata Ag. (250

diameters) page 48

Fig. 218. Penium N:avicula Breb. (1000

diameters) "60

Fig. 219. Mesotcenium micrococcum (Kiitz.)

Roy and Biss. (1000 diameters) " 57

Fig. 220. Myxonema attenuatum Maz. . "47

PLATE XXXIII.

Plate XXXIV ; Figures 221, 222.

Fig. 221. Chcetophora incrassata (Huds.) Haz.
Upper figure, natural size ; lower
figure, highly magnified . . . page 47

Fig. 222. Chcetophora pisiformis (Roth.) Ag.
a, colony, natural size, b, a single
filament "

PLATE XXXIV.

22

H >fWi

/9 a m £&& ,

mm?$^

w

m

Wk

,1 k ■ -^ -:

..«;;v '■

Wm

■&?■&£■.

222 /

?Pf £

f^mMw

Plate XXXV; Figures 223 to 228; Magnified 500 Diam-
eters, except Fig. 228.

Docidiitm Baculum Breb. . . page 61

Pleurotcenium crenulatum (Ehrb.)

Rab « a

Pleurotanium Archerii (Delp.)

Trabecula (Ebrb.) Nag. "
Euastrum sp. ( ?) . . . . "63

Fig. 228. CEdogonium cardiacum (Hass.)

Wittr. (?) " 52

Fig.

223.

Fig.

224

Fig.

22$

Fig.

226

Fig.

227.

PLATE XXXV.

223

Mmm

226

ss; w was? 0g& * ■^.-- &/ mmfml

H

;?#^

:■'••;■' ' '•■''•■'•.'■"X: ijfj.c ft s.* «- .V 'W AtKS "> '■. i*i

•» %*'*.&

mgmmM

'} mm

pCW I

m

m\

«" » nm

/ ■-■ o o <-■<"'-/ >}. ,'■'■• iM /
/,■&' o „ Q.--JU.M m M\ Wm

mv

227

Plate XXXVI; Figures 229 to 23"; Magnified iooo

Diameters.

Fig-. 229. Euastrum oblongatum (Grev.) Ralfs page 62
Fig. 230. " ampullaceum Ralfs . " "

Fig. 231. Staurastrum crenulatum (Delp.)

Nag. End view .... " "

Fig. 231a. Staurastrum crenulatum (Delp.)

Side view .....
Fig. 2^2. Euastrum elegans. Kiitz. .
Fig. 2^. Staurastrum dejectum Breb. .
Fig. 233a. " " End view

Fig. 234. Euastrum Nordstedtianum Wolle .
Fig. 235. Staurastrum margaritaceum Ehrb. .
Fig. 235a.

Side view .....
Fig. 2$(). Staurastrum dejectum Breb. .
Fig. 23<hi. " Side view

Fig. 2$~. gracile Ralfs

Fig. 23-a. Side view

it

..

it

u

li

It

PLATE XXXVI.

8

O-'V

i 231 ^ ,*V

a 32

229 f.

: V--V ?

Plate XXXVII ; Figures 238 to 244 ; Magnified 500
Diameters, except Figs. 243, 244.

Fig. 238

Fig. 239

Fig. 240

Fig. 241

Fig. 242

Fig- 243

Fig. 244

Micrasterias rotata (Grev.) Ralfs

furcata (Ag.) Ralfs .

Americana ( Ehrb. ) Kutz.

m 11 ri cat a Bail.

truncata (Corda) Ralfs
Coleochoeta scutata Iireb.
Cosmarium undulatum Corda (500
diameters) .....

page 63

64

J\0M

*?,';, '5'-1

^

" > #

(

£ & % '

K:--'

fUl: *-.

}

■ ■' $x ■

f

}

f

\

£ V $ '-

■ft

v<pii

.1°

2<H

Plate XXXVIII; Figures 245 to 2=1ti; Magnified iooo

Diameters.

V Ig.

245-

Fig.

246.

Fig.

247.

Fig.

248.

Fig.

249.

Fig.

250.

Fig.

25 1-

Fig.

252.

Fig.

253-

Cosmarium ovale Raits .

pyramidatum Breb.
Meneghinii Breb.
octhodes Nord.

perforatum Lund.
Ndgelianum Breb.
intermedium Delp.
Port'itium Arch.
orbiculatum Ralfs

page 64

I •$% i Jm N

/ iffy, v'tr $••£& ■

/Z

..r£,, ■ -.,,

J? 0

,■ c 0 ^ rt . ..'>• 5^-ipv^; • • ,o

25-0

b^

■a

o°

0v o O Qf-

A«Ai

252

"*-X ' -* J .■..:.,-!... ;vJ

It
a

Plate XXXIX; Figures 254 to 260; Magnified iooo

Diameters.

Fig. 254. Cosmarium tetrophthalmum (Kiitz.)

Breb page 64

Fig. 255. Cosmarium galeritum Nord. . " "

Fig. 256. Cucurbit a Breb. .

Fig. 25-. pseudobroomei Wolle .

Fig. 257a.

End view "

Fig. 258. Cosmarium Broomci Thwaites. End

view "

Fig. 259. Arthrodcsmus convergens (Ehrb.)

Ralfs "63

Fig. 260. Arthrodcsmus octocornis Ehrb. . " "

PLATE XXXIX.

O 0 00o5)

0 o oo<>5

O 0 O 0 Og i

Oj3 JL&OftSj

< €L. 0 O ■ © O Q

\-r *£

** "257

157*

258

Plate XL; Figures 261 to 266: Magnified iooo Diameters.

Fig". 261. Staiirastriaii pygmceum Breb. Con-
jugating ..... page 62

Fig. 262. Xanthidium antilopceum (Breb.) Kutz.

Fig. 263. Staurastrum hirsutum ( Ebrb. ) Breb.

Fig. 2f^a.

Side view .....

Fig. 264. Staurastrum leptocardium Nord.

Fig. 264a.

End view .....

Fig. 265. Xanthidium cristatum (Breb.) Ralfs 64

Fig. 266. fasciculatum (Ehrb.) Ralfs

var. subalpinum Wolle

PLATE XL.

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Plate XLI ; Figures 267 to 270: Magnified 500 Diameters.

Fig. 2(^7. Staurastrum coronulatum Wolle . page 62
Fig. 2671;.

End view .....

Fig. 268. Staurastrum arctiscon Ehrb. .
Fig. 268a. " " " End

..

view-

Fig. 269. Spirogyra infiata ( Vauch. ) Rab. .
Fig. 270. he// is (Hass.) Clev.

67

PLATE XLI.

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Plate XLTI; Figures 271 to .277 ; Magnified 500

Diameters.

Fig. 271. Spharozosma pulcrum Bailey . . page 65
Fig. 2-J2. serratum (Bailey) Wall.

</. Side view : b, end view : c, view
from above ....

Fig. 273. Hyalotheca dissiliens (Sm.) Breb.
Fig. 274. Cladophora glomerata ( L. ) Kiitz. 54

Fig. 2/$. Desmidium Sivartzii Ag. a, Side
view ; />, end view ; c, side view-
less magnified .... 65
Fig. 2j(). Desmidium cylindricum Grev. Side
view ......

Fig. 2ytm. Desmidium cyliudricum Grev. End

.. it
view ......

Fig. 2~~. Sphitrososma spiuosum (Del]).) Wolle

PLATE XLII.

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271

272

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273

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Plate XLIII ; Figures 278 to 280.

Fig. 278. Batrachospermum vagum Ag. . page ~$

Fig. 279. Zygnema pectinatum (Vauch.) Ag. 67

Fig. 280. Mougeotia sp.( ?). Conjugating . " 68

PLATE XLIII.

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278

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280

Plate XLIV; Figures 281 to 291; Magnified iooo

Diam E 1 ERS.

Fig. 281. Netrium interrnptum (Breb.) Lut-

kem page 58

Fig. 282. Netrium Digitus (Ehrb.) Itz. and

Roth "

Fig. 2X3. Pleurotanium nodosum (Bail.) Lund. " 6]
Fig. 284. Myxonema nanum (Dillw.) Eiaz. 47

Fig. 285. Eudorina elegans Ehrb. ... " 41

Fig. 286. Pandorina morum (Mull.) Bory . 42

Fig. 2$/. " " Full-grown colony "

Fig. 288. Spondylomorum quatemarium Ehrb. 41

Fig. 2^\). Chlamydomonas pidvisculus ( Mull. )

Ehrb "42

Fig. 290. Carteria (Chlamydomonas) nudtiUlis

( Fresen. ) ( ? ) . . . "43

Fig. 291. Spirnlina tennissima Kiitz. . . 18

PLATE XLIV.

283

289