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SMITHSONIAN

CONTRIBUTIONS TO KNOWLEDGE.

VOL. XIX.

EVERT MAX II A VALUABLE MEMBER Of SOCIETY, WHO, BY BIS OBSERVATION*, REREAROHE8, AKD EXPERIMENT*, PROCURES

KNOWLEDGE FOR MEX.— SMITIISON.

CITY OF WASHINGTON:
PUBLISHED BY THE SMITHSONIAN INSTITUTION.

MDCCCLXXIV.

>

COLLINS, PRINTER,
705 JAYNE ST.

ADVERTISEMENT.

THIS volume forms the nineteenth of a series, composed of original memoirs on
different branches of knowledge, published at the expense, and under the direction,
of the Smithsonian Institution. The publication of this series forms part of a general
plan adopted fur carrying into effect the benevolent intentions of JAMES SMITHSON,
Esq., of England. This gentleman left his property in trust to the United States
of America, to found, at Washington, an institution which should bear his own
name, and have for its objects the "increase and diffusion of knowledge among
iiu-n." This trust was accepted by the Government of the United States, and an
Act of Congress was passed August 10, 1846, constituting the President and the
other principal executive officers of the general government, the Chief Justice of
the Supreme Court, the Mayor of Washington, and such other persons as they might
elect honorary members, an establishment under the name of the "SMITHSONIAN
INSTITUTION FOR TUB INCREASE AND DIFFUSION OF KNOWLEDGE AMONG MEN." The
members and honorary members of this establishment are to hold stated and special
meetings for the supervision of the affairs of the Institution, and for the advice
and instruction of a Board of Regents, to whom the financial and other affairs are
intrusted.

The Board of Regents consists of three members ex officio of the establishment,
namely, the Vice-President of the United States, the Chief Justice of the Supreme
Court, and the Mayor of Washington, together with twelve other members, three of
whom are appointed by the Senate from its own body, three by the House of
Representatives from its members, and six persons appointed by a joint resolution
of both houses. To this Board is given the power of electing a Secretary and other
officers, for conducting the active operations of the Institution.

To carry into effect the purposes of the testator, the plan of organization should
evidently embrace two objects: one, the increase of knowledge by the addition of
new truths to the existing stock; the other, the diffusion of knowledge, thus
increased, among men. No restriction is made in favor of any kind of knowledge;
and, hence, each branch is entitled to, and should receive, a share of attention.

iv ADVERTISEMENT.

The Act of Congress, establishing the Institution, directs, as a part of the plan of
organization, the formation of a Library, a Museum, and a Gallery of Art, together
with provisions for physical research and popular lectures, while it leaves to the
Regents the power of adopting such other parts of an organization as they may
deem best suited to promote the objects of the bequest.

After much deliberation, the Regents resolved to divide the annual income into
two parts — one part to be devoted to the increase and diffusion of knowledge by
means of original research and publications — the other part of the income to be
applied in accordance with the requirements of the Act of Congress, to the gradual
formation of a Library, a Museum, and a Gallery of Art.

The following are the details of the parts of the general plan of organization
provisionally adopted at the meeting of the Regents, Dec. 8, 1847.

DETAILS OF THE FIRST PART OF THE PLAN.

I. To INCREASE KNOWLEDGE. — It is proposed to stimulate research, ~by offering
rewards for original memoirs on all subjects of investigation.

1. The memoirs thus obtained, to be published in a series of volumes, in a quarto
form, and entitled " Smithsonian Contributions to Knowledge."

2. No memoir, on subjects of physical science, to be accepted for publication,
which does not furnish a positive addition to human knowledge, resting on original
research; and all unverified speculations to be rejected.

3. Each memoir presented to the Institution, to be submitted for examination to
a commission of persons of reputation for learning in the branch to which the
memoir pertains; and to be accepted for publication only in case the report of this
commission is favorable.

4. The commission to be chosen by the officers of the Institution, and the name
of the author, as far as practicable, concealed, unless a favorable decision be made.

5. The volumes of the memoirs to be exchanged for the Transactions of literary
and scientific societies, and copies to be given to all the colleges, and principal
libraries, in this country. One part of the remaining copies may be offered for
sale; and the other carefully preserved, to form complete sets of the work, to
supply the demand from new institutions.

6. An abstract, or popular account, of the contents of these memoirs to be given
to the public, through the annual report of the Regents to Congress.

ADVERTISEMENT. v

II. To INCREASE KNOWLEDGE. — It is also proposed to appropriate a portion of the
in"'iiit\ iinmiitlly, to special objects of research, under the direction of suitable

1. The objects, and tlio amount appropriated, to be recommended by counsellors
of the Institution.

2. Appropriations in different years to different objects; so that, in course of time,
each branch of knowledge may receive a share.

3. The results obtained from these appropriations to t>e published, with the
memoirs before mentioned, in the volumes of the Smithsonian Contributions to
Knowledge.

4. Examples of objects for which appropriations may be made: —

(1.) System of extended meteorological observations for solving the problem of
American storms.

(2.) Explorations in descriptive natural history, and geological, mathematical,
and topographical surveys, to collect material for the formation of a Physical Atlas
of the United States.

(3.) Solution of experimental problems, such as a new determination of the
weight of the earth, of the velocity of electricity, and of light; chemical analyses
of soils and plants; collection and publication of articles of science, accumulated
in the offices of Government.

(4.) Institution of statistical inquiries with reference to physical, moral, and
political subjects.

(5.) Historical researches, and accurate surveys of places celebrated in American
history.

(G.) Ethnological researches, particularly with reference to the different races of
men in North America; also explorations, and accurate surveys, of the mounds
and other remains of the ancient people of our country.

I. To DIFFUSE KNOWLEDGE. — It is proposed to puldish a series of reports, giving an
account of the new discoveries in science, and of the changes made from year to year
in all branches of knowledge not strictly professional.

1. Some of these reports may be published annually, others at longer intervals,
as the income of the Institution or the changes in the branches of knowledge may
indicate.

2. The reports are to be prepared by collaborators, eminent in the different
branches of knowledge.

vi ADVERTISEMENT.

3. Each collaborator to be furnished with the journals and publications, domestic
and foreign, necessary to the compilation of his report; to be paid a certain sum for
his labors, and to be named on the title-page of the report.

4. The reports to be published in separate parts, so that persons interested in a
particular branch, can procure the parts relating to it, without purchasing the
whole.

5. These reports may be presented to Congress, for partial distribution, the
remaining copies to be given to literary and scientific institutions, and sold to indi-
viduals for a moderate price.

The following are some of the subjects which may be embraced in the reports: —

I. PHYSICAL CLASS.

1. Physics, including astronomy, natural philosophy, chemistry, and meteorology.

2. Natural history, including botany, zoology, geology, &c

3. Agriculture.

4. Application of science to arts.

II. MORAL AND POLITICAL CLASS.

5. Ethnology, including particular history, comparative philology, antiquities, &c.

6. Statistics and political economy.

7. Mental and moral philosophy.

8. A survey of the political events of the world; penal reform, &c.

III. LITERATURE AND THE FINE ARTS.

9. Modern literature.

10. The fine arts, and their application to the useful arts.

11. Bibliography.

12. Obituary notices of distinguished individuals.

•

II. To DIFFUSE KNOWLEDGE. — It is proposed to publish occasionally separate treatises

on subjects of general interest.

1. These treatises may occasionally consist of valuable memoirs translated from
foreign languages, or of articles prepared under the direction of the Institution, or
procured by offering premiums for the best exposition of a given subject.

2. The treatises to be submitted to a commission cf competent judges, previous
to their publication.

ADVERTISEMENT. vii

DETAILS OF TDK SECOND PAIIT OF THE PLAN OF ORGANIZATION.

This purt contemplates the formation of a Library, a Museum, and a Gallery of
Art.

1. To carry out the plan before described, a library will be required, consisting,
1st, of a complete collection of the transactions and proceedings of all the learned
societies of the world; 2d, of the more important current periodical publications,
and other works necessary in preparing the periodical reports.

2. The Institution should make special collections, particularly of objects to
verify its own publications. Also a collection of instruments of research in all
branches of experimental science.

3. With reference to the collection of books, other than those mentioned above,
catalogues of all the different libraries in the United States should be procured, in
order that the valuable books first purchased may be such as are not to be found
elsewhere in the United States.

4. Also catalogues of memoirs, and of books in foreign libraries, and other
materials, should be collected, for rendering the Institution a centre of bibliogra-
phical knowledge, whence the student may be directed to any work which he may
require.

5. It is believed that the collections in natural history will increase by donation,
as rapidly as the income of the Institution can make provision for their reception ;
and, therefore, it will seldom be necessary to purchase any article of this kind.

6. Attempts should be made to procure for the gallery of art, casts of the most
celebrated articles of ancient and modern sculpture.

7. The arts may be encouraged by providing a room, free of expense, for the
exhibition of the objects of the ArtrUnion, and other similar societies.

8. A small appropriation should annually be made for models of antiquity, such
as those of the remains of ancient temples, &c.

9. The Secretary and his assistants, during the session of Congress, will be
required to illustrate new discoveries in science, and to exhibit new objects of art;
distinguished individuals should also be invited to give lectures on subjects of
general interest.

In accordance with the rules adopted in the programme of organization, each
memoir in this volume has been favorably reported on by a Commission appointed

ADVERTISEMENT.

for its examination. It is however impossible, in most cases, to verify the state'
ments of an author; and, therefore, neither the Commission nor the Institution can
be responsible for more than the general character of a memoir.

The following rules have been adopted for the distribution of the quarto volumes
of the Smithsonian Contributions : —

1. They are to be presented to all learned societies which publish Transactions,
and give copies of these, in exchange, to the Institution.

2. Also, to all foreign libraries of the first class, provided they give in exchange
their catalogues or other publications, or an equivalent from their duplicate volumes.

3. To all the colleges in actual operation in this country, provided they furnish,
in return, meteorological observations, catalogues of their libraries and of their
students, and all other publications issued by them relative to their organization
and history.

4. To all States and Territories, provided there be given, in return, copies of all
documents published under their authority.

5. To all incorporated public libraries in this country, not included in any of
the foregoing classes, now containing more than 10,000 volumes; and to smaller
libraries, where a whole State or large district would be otherwise unsupplied.

OFFICERS

OF TUB

SMITHSONIAN INSTITUTION.

THE PRESIDENT OF THE UNITED STATES,

O PRESIDING OFFICER OF THE INSTITUTION.

THE VICE-PRESIDENT OF THE UNITED STATES,

SECOND PRESIDING OFFICER.

MORRISON R. WAITE,

CHANCELLOR OF TI1E INSTITUTION.

JOSEPH HENRY,

SECRETARY OF THE INSTITUTION.

SPENCER F. BAIRD,

ASSISTANT SECRETARY.

PETER PARKER,

JOHN MACLEAN, J. EXECUTIVE COMMITTEE.

WILLIAM T. SHERMAN,

B

REGENTS.

HENRY WILSON, Vice-President of the United States.

MORRISON R. WAITE, .... Chief Justice of tJie United States.

HANNIBAL HAMLIN, Member of the Senate of the United States.

JOHN W. STEVENSON, . . . . "

AARON A. SARGENT, "

SAMUEL S. Cox, Member of tJte House of Representatives U. S.

EBENEZER R. HOAR,

GERRY W. HAZLETON, ....

JOHN MACLEAN, Citizen of New Jersey.

PETER PARKER, "of Washington.

WILLIAM T. SHERMAN, ....

ASA GRAY, " o/ Massachusetts.

J. D. DANA, "of Connecticut.

HENRY COPPEE, "of Pennsylvania.

MEMBERS EX-OFFICIO OF THE INSTITUTION.

ULYSSES S. GKANT, President of the United State*.

HKNRY WILSON, Vice- President of the United Stub*.

HAMILTON FISH, Secretary of State.

B. II. BRISTOW, Secretary of the Treasury.

W. W. BELKNAP, Secretary of War.

GEORGE M. ROBESON, Secretary of the Navy.

J. A. J. CRESWELL, Postmaster- General.

GEORGE H. WILLIAMS, Attorney- General.

MORRISON R. WAITE, Chief Justice of the United States.

M. D. LEGGATT, Commissioner of Patents.

HONORARY MEMBER.

COLUMBUS DELANO. The Secretary of the Interior.

SMITHSONIAN CONTRIBUTIONS TO KNOWLEDGE.

241

A CONTRIBUTION

To run

HISTORY OF THE FRESH-WATER KLGM

or

NORTH AMERICA.

BY

HORATIO C. WOOD, JR., M.D.,

r«or«»«OR or IOTAS T. AND CLINICAL LECTURER on DIIBAIBS or TIE HBBTODS ITSTIH in THE
UIIVEBSITT or PEXXIYLVAIIIA ; PBTIICIAIITO THE PHILADELPHIA BOIPITAL, ETC.

[ACCIPTID FOB PDlLICATfO, PKBRPART, 1£72.J

ADVERTISEMENT.

THE following memoir was referred for examination to Dr. John Torrey and Dr.
1 . A. 1'. Barnard, of Columbia College, New York. They recommended its pub-
lication provided certain changes were made in the manuscript. These having
l» TII made by the author, the work is published as a part of the scries of " Smith-
sonian Contributions to Knowledge."

JOSEPH HENRY,

Secretary, S. I.
WASHINGTON, October, 1872.

(iii)

PREFACE.

OK ;ill the various branches of Natural History, none has been more enthusias-
tically and more successfully prosecuted in the United States than Botany. The
whole field has been most thoroughly occupied, save only as regards certain of the
ln\vcr i-ryptogams, and amongst the latter, it is the fresh-water Alga; which alone
ran he said to have been almost totally neglected. In this fact lies my apology for
ottering to the scientific public the following memoir.

lu lining this, so far from thinking that the work contains no error, I hasten to
disarm criticism, and to ask with solicitude for a favorable reception, in view
of the difficulties of the investigation, which I have conducted alone, and almost
maided

The. investigation was first undertaken in connection with my elementary studies
of Materia Medica and Therapeutics, and has since been prosecuted at intervals
amidst the distractions of medical teachings and practice, and in some cases with-
out immediate access to authorities. The field covered is so wide that it is almost
impossible to exhaust it, and, if it were not for rapidly increasing professional
engagements, I would gladly devote more time to the subject; but, as it is, I must
leave to others to carry on the work thus begun.

N\ i. :!•• - \ing this, it is but just to state that nothing here published has been
done hastily, but that all is the result of arduous and conscientious investigation.

A very large part of my material has been of my own gathering, and was
studied whilst fresh ; but I am indebted to several persons for aid by collections.

First of all, I desire to offer my thanks to Dr. J. S. Billings, U. S. A., and to
Professor Ravenel, of South Carolina; to the former for assistance in various
ways, and for collections made nfar Washington City; to the latter for very large
collections made in Texas, South Carolina, and Georgia. I am also indebted to
M r. C. F. Austin for a large collection gathered in Northern New Jersey, to Mr.
William Canby for some beautiful specimens obtained in Florida, to Professor
•10 Watson for Rocky Mountain plants, and to Dr. Frank Lewis for a number
of White Mountain desmids.

These various collections were partly dried and partly preserved in a watery
solution of carbolic acid or of acetate of alumina, both of which I have found more
or I.--., satisfactory preservatives.

The present investigations embrace all families of the fresh-water algcc except
the Dialomacea, which, as every one knows, are so numerous as to constitute in

(v)

vi PREFACE.

themselves a special study. As I have paid no attention to these plants, they are
of course not included in this memoir.

In the synonymy I have generally followed Prof. Ilabenhorst. The original de-
scriptions of the forms, especially those of the older authorities, are very frequently
so meagre and obscure, that the species cannot be recognized by them with any cer-
tainty. Prof. Ilabenhorst has gone over the ground most carefully, with access to
the whole literature of the subject and probably to all extant type specimens, and his
decisions are, no doubt, as accurate as the circumstances will allow. To attempt to
differ from them, to go behind his work to the original sources and make fresh
interpretations, would cause endless confusion. I have, therefore, nearly always
contented myself with his dictum, and have referred to him as the authority for the
names used.

The following references were omitted through a misunderstanding from the first
portion of the text.

Tage 14. Ceelosphserium dubium, GRUNNOW. RABENHORST, Flora Europ. Algarum, Sect. I. p. 55.

" 15. Merismopedia convoluta, BREBISSON. RABENHORST, Flora Europ. Algarum, Sect. I. p. 58.

" 18. Oscillaria chlorina, KUTZING. RABKNIIORST, Flora Europ. Algarum, Sect. I. p. 97.

" 18. 0. Frohlichii, KUTZING. RABENHORST, Flora Europ. Algarum, Sect. I. p. 109.

" 19. 0. nigra, VAUCHER. RABENHORST, Flora Europ. Algarum, Sect. I. p. 107.

" 19. 0. limosa, AGARDH. RABENHORST, Flora Europ. Algarum, Sect. I. p. 104.

" 21. Chthonoblastus repens, KUTZING. RABENHORST, Flora Europ. Algarum, Sect. I. p. 132.

" 22. Lyngbya muralis, AGARDH. HARVEY, Nereis Boreali- Americana, pt. III. p. 104.

In the text after the " Habitat" a name is quoted as the authority therefor ; if
such a name be in brackets, it signifies that the specimens were simply collected by
such individual, but that the identification was made by some one else ; when there
is not a name uninclosed in brackets, it is meant that the identification was made by
the author of this memoir.

Since the present memoir has gone to press, I have received from the author a
copy of " Algae Rhodiacese. A list of Rhode Island Algae, collected and prepared
by Stephen T. Olney, in the years 1846-1848, now distributed from his own her-
barium."

In the introduction to this list, Mr. Olney says: "Of the fresh-water species, I
have few for distribution. These were obtained mainly in the environs of this
city, and were placed in twenty-seven small vials in Goadsby's solution, and sent
to Prof. Harvey, who submitted them to the judgment of the most learned Eng-
lish botanist in this particular department, G. H. K. Thwaites, Esq., then of Bris-
tol, England. The large number of species found in this collection, in so limited
a range, and collected within a very short period, is surprising, and shows what
moie persistent collections will develop. I have not time to collate the numerous
publications of the lamented Prof. Bailey, or I might have made the list of this
portion of Rhode Island plants more complete."

The chlorosperms of this list are as follows: —

Porphyra vulgaris, AG.-HARV. Ner Bor. Am. 3. 53. Newport.

Banyia fuscopurpurea, LYNGB.-HARV. Ner. Bor. Am. 3. 54. Southern Rhode Island.

I'llKlACK. M,

nil. .*•!,, ,<il,.*, I.y\<;ii HAKV Nrr. lUr. Am. 3. 50. Providence to Newport.
k'nti r»iiK»-j l,n com/, i, *,..•. \ ||.\i:\ NIT l!,.r. Am. a. ."iii. Southern Khode Island.
EnicroiHurjihu tlatltrata, (JuKV.-H.VKV. Ner. i;..r. Am. 3. 56. Newport.
i lati.-i*iuni, L.-lI.Miv. Nrr. l!<>r Am. '.', ;">'.>. I'r»viilr;
lii,-tin;i, I, -Il.uiv. NIT. IJi.r. Am :! r.n. I'ruviili -nee.

la< MMM, I'M AI \ II M:V .N.-r. Bor. Am. 3. 61. T. perforata, BAILEY Mas. Providence.

-/xil-lt lulirnil, AI.. 1'rovidrnri-.

Batrac/u>!<i><:r>iiuiH fiui-lirrrimiint, HAS.S. 1'rnviili'iicc.

•iiim muiiili/nriiK-, lli'in -ll.\u\ N.T. linr. Am. 3. 63. Providence.
Chect»i>lt>jra eitilu-n foliu, Ati.-llAiiv. NIT 15nr. Am. .'!. (','.». I'rovidcncr
ijlunn-riilu, Aii.-ll.\u\. Nrr. Bor. Am. 3. 72. Providence.

miiuttum, Ki r/. Provideiu-f.

i- I. -ll.\uv. Nor. Bor. Am. 3. 74. Newport.

Cliiiliij,li<,rn ijl • , GBIFF.-HABV. Ner. Bor. Am. 3. 77. Ilhode Island.

Cla<l<>i>lioni rrfrnrta, IloTii.-IlAKV. Ner. Bor. Am. 3. 79. Soutlicrn Ithodc Island.
<.'ltt'l"j'h<>ni Itii'luli'hiana, Aa.-HARV. Ner. Bor. Am. 3. 80. Providence.
Cladojihora ijriKilo, (JKUK.-HAKV. Ner. Bor. Am. 3. 81. Little Compton.
' 'I'hora fracta, HARV. Ner. Bor. Am. 3. 82. Rhode Island, Bailey.
Chsetomorpha xren, Du.i.w.-IlAR. Xcr. Bor. Am. 3. 86. Newport, etc.

nnrjiha Olni-iji, ILvuv. Ner. Bor. Am. 3. 86. Little Compton.
Chtctomoriiha 1'nnjiiirlirulata, HARV. Ner. Bor. Am. 3. 86. Little Compton.
rnr. rru.^.-i',r. HAKV. Ner. Bor. Am. 3. 86. Little Compton.

•HiorjiliH sutoria, BEIIK.-HAKV. Ner. Bor. Am. 3.87. Newport.

malfnrmatum, HASS. 1. 147. Providence.
/" .-eforme, HASS. 1. 147. Providence.

X>j'jn<-\nii Tliii-iiii,-sii, OLNEY, n. s. NearZ. subventricosum, Providence.
Xyijntmn I'lixjnlnm, HASH. 1. 151. Providence.
Z'/'jnrma striata, OLNEY, n. s. " Cells evidently striated," Tliwaites. Providence.

''iriilea bicornis t ILvss. 1. 162. Providence.
Tyndaridea insignis ? UASS. 1.163. Providence.
Ifesocarjnis /xzriru/us, HASS. 1. 1C9. Providence.
M">i(jeotia yenuflexa, Ao.-IlASS. 1. 173. Providence.
Vesiculif era concatenates, HASS. 1. 201. Providence.

•ulifera teqttalis, HASS. 1. 205. Providence.
Vesiculifera bombycina, HASS. 1. 208. Providence.
Vesiculiftra Candollii, HASS. 1. 208. Providence.
Jlnlbochtste Thwaittgii,Oi.tiiT, n. s. Providence.
Lynybya majuscula, HARV. Bor. Am. 3. 101. Providence.
Spheeroplea virescens, BERK. Providence.
Sphteroplea pvnctalig, BERK. Providence.
Tolypothrix dittorta, KuTZ.-IlASS. 1. 240.

Calothrix confervicola, Ao -HARV. Ner. Bor. Am. 3. 105. Providence.
Calolhrix scopulorum, AO.-HARV. Ner. Bor. Am. 3. 105. Providence.
Uyalotheca dissiliens, BREV.-RALFB. DCS. 51. (Qloeoprium.) Providence.
Hijdlotheca mucosa, EnRn.-IlALFS. DCS. 53. Providence.
Ih'lymoprium Orevillii, KiJTZ.-RALrs. PCS. 61. Rhode Island, Bailey.
Didymoprium Borreri, RAI.FS. DCS. 58. Rhode Island, Bailey.
Desmidium Sicartzii, AO.-RALFS. DCS. 61. Throuphont United States, Bailey.
Aptogonum Baileyi, RALFS DCS -209. Worden's Pond, Rho<le Island, Bailey.
Micrcuterias rolata, RALFS. DCS. 71. Providence.
Micrasteriat radiosa, Ao.-RAi.F8. DCS. 72. Maine to Virpinia, Bailey.
Mii-rasterias furcala, RAI.FS. DCS. 73. Worden's Pond, Rhode Island, Bailey.

'•astering Crur-Melil>-n>si*, RAI.FS. Des. 73. Maine to Virprinin, Bailey.
ificraisleriaslrnncata, BREB.-UAI.FS. DCS. 75. United States, Bailey.

via

PREFACE.

Micrasterias foliacea, BAILEY-RALFS. Desm. 210. Worden's Pond, Rhode Island, Bailey.

Micrasterias Bayleyi, RALFS. Desm. 211. Rhode Island, Bailey.

Euastrum oblongum, RALFS. DCS. 80. Rhode Island, Bailey.

Euastrum crassum, KUTZ.-RALFS. Des. 81. Rhode Island, Bailey.

Euastrum ansatum, EHRH. -RALFS. Des. 85. E. binale KNTZ. Providence.

Euastrum elegans, KUTZ.-RALFS. Des. 89. Providence.

Euastrum binale, RALFS. Desm. 91. Providence.

Cosmarium cucumis, CORDA.-RALFS. Desm. 93. United States, Bailey.

Cosmarium bioculatum, RALFS. Des. 95. Providence.

Cosmarium MenegMnii, BREB.-RALFS. Des. 96. United States, Bailey.

Cosmarium crenatum, RALFS. Des. 96. Providence.

Cosmarium amcenum, BREB. -RALFS. Des. 102. Providence.

Cosmarium ornatum, RALFS. Des. 1 04. Providence.

Cosmarium connatum, BHEB. -RALFS. Des. 108. Providence.

Cosmarium Cucurbita, RALFS. Des. 109. Providence.

Cosmarium grandiluberculatum, OLNEY, n. s. ; "near C. cucumis, but with large tubercles on tho
frond." Providence.

Staurastrum orbiculare, RALFS. Des. 125. Providence.

Staurastrum hirsutum, RALFS. Des. 127. Providence.

Stauraslrum Hystrix, RALFS. Des. 128. Providence.

Staurastrum gracile, RALFS. Des. 136. Providence.

Staurastrum tetracerum, RALFS. Des. 137. United States, Bailey.
Staurastrum cyrtocerum, BREB. -RALFS. Des. 139. Providence.

Telmemoras Brebissoni, RALFS. Des. 145. Providence.

Tetmemoras granulatus, RALFS. Des. 146. Providence.
Penium margaritaceum, BREB.-RALFS. Des. (Closterium EHR.) Providence.
Penium Digitus, BREB. -RALFS. Des. 151. ( Closterium lamellosum. )
Docidium nodulosum, BREB.-RALFS. Des. 155. Maine to Virginia, Bailey.
Docidium Baculum, BREB.-RALFS. DCS. 158. United States. Bailey.
Docidium nodosum, BAILEY-RALFS. Des. 218. United States, Bailey.
Docidium constrictum, BAILEY-RALFS Des. 218. Worden's Pond, Bailey.
Docidium verrucosum, BAILEY-RALFS. Des. 218. Rhode Island, Bailey.
Docidium verticillatum, BAILEY-RALFS. Des. 218. Worden's Pond, Bailey.
Closterium Lunula, EHRH.-RALFS. Des. 163. New England, Bailey.
Closterium moniliferum, EHRH.-RALFS. Des. 163. New England, Bailey.
Closterium striolatum, EHRH.-RALFS. Des. 173. New England, Bailey.
Closterium cuspidatum, BAILEY-RALFS. Des. 219. Worden's Pond, Bailey.
Pediastrum telras, RALFS. Des. 182. New England, Bailey.
Pediastrum heptactis, RALFS. Des. 183. Providence.

Pediastrum Boryanum, -MENEQH.-RALFS. Des. 187. Maine to Mexico, Bailey.
Pediastrum ellipticum, HASS. -RALFS. Des. 188. Maine to Virginia, Bailey
Scenedesmus quadricauda, BREB.-RALFS. Des. 190. Maine to Virginia, Bailey.
Scenedesmus obtusus, MEYEN.-RALFS. Des. 193. Maine to Virginia, Bailey.

INTRODUCTION.

AiTiioniii beset with difficulties in the outset, no branch of natural science
otter* moiv attractions, \vlim once the study is fairly entered upon, than the fresh-
water ul-j;r. 'Hie enthusiasm of the student will soon be kindled by the variety
and beauty of their forms and wonderful life processes, and be kept alive by their
abundance and accessibility at all seasons of the year; for unlike other plants, the
winter with them is not a period of counterfeited death, but all seasons, spring,
summer, autumn, and winter alike, have their own peculiar species. They have
been found in healthy life in the middle of an icicle, and in the heated waters of
tin- boiling spring; they are the last of life alike in the eternal snow of the moun-
tain summit and the superheated basin of the lowland geyser.

In their investigation, too, the physiologist can come nearer than in almost any
•>:her study to life in its simplest forms, watching its processes, measuring its forces,
and approximating to its mysteries. Sometimes, when my microscope has revealed
a new world of restless activity and beauty, and some scene of especial interest, as
the impregnation of an ocdogouium, has presented itself to me, I confess the
enthusiastic pleasure produced has been tempered with a feeling of awe.

To any on whom through the want of a definite pursuit the hours hang heavy,
to the physiologist who desires to know cell-life, to any student of nature, I can
commend most heartily this study as one well worthy of any pains that may be
spent on it.

An aquarium will often, in the winter time, give origin to numerous interesting
forms, but it is not a necessity to the fresh-water algologist; besides his microscope
and its appliances, all that he absolutely needs is a few glass jars or bottles and
the fields and meadows of his neighborhood.

The great drawback to the investigation of these plants has been the want of
accessible books upon them. In the English language there is no general work
of value, and the various original memoirs are separated so far and wide in the
Continental and English journals, as to be of but little use to most American
readers. The Flora Europcntm Algantm Aqua; Dulcis ct Submarina^ of Prof. Ra-
benhorst, has done much to facilitate the study, and its cheapness brings it within
the reach of all. It merely gives, however, brief diagnoses of the various species,
but with the present memoir will, I trust, suffice for the American student, at least
until he is vi -r\ far advanced in his researches.

1 November. 1871. f i \

2 INTRODUCTION.

A certain amount of experience and knowledge of the subject greatly facilitates
the collection of these plants, but scarcely so much as in other departments of cryp-
togamic botany, since most of the species are so small that the most experienced
algologist does not know how great the reward of the day's toil may be until he
places its results under the object glass of his compound microscope. In order to aid
those desirous of collecting and studying these plants, I do not think I can do
better than give the following hints as to when and where to find, and how to
preserve them.

There are three or four distinct classes of localities, in each of which a different
set of forms may be looked for. These are : stagnant ditches and pools ; springs,
rivulets, large rivers, and other bodies of pure water ; dripping rocks in ravines,
&c. ; trunks of old trees, boards, branches and twigs of living trees, and other
localities.

In regard to the first — stagnant waters — in these the most conspicuous forms
are oscillatoriae and zygnemacea;. The oscillatorise may almost always be recog-
nized at once, by their forming dense, slimy strata, floating or attached, gene-
rally with very fine rays extending from the mass like a long, delicate fringe.
The stratum is rarely of a bright green color, but is mostly dark; dull greenish,
blackish, purplish, blue, &c. The oscillatoria? are equally valuable as specimens
at all times and seasons, as their fruit is not known, and the characters defining
the species do not depend upon the sexual organs. The zygnemas are the bright
green, evidently filamentous, slimy masses, which float on ditches, or lie in them,
entangled amongst the water plants, sticks, twigs, &c. They are only of scientific
value when in fruit, as it is only at such times that they can be determined.
Excepting in the case of one or two very large forms, it is impossible to tell with
the naked eye with certainty whether a zygnema is in fruit or not; but there are
one or two practical points, the remembrance of which will very greatly enhance
the probable yield of an afternoon's search. In the first place, the fruiting season
is in the spring and early summer, the latter part of March, May, and June being
the months when the collector will be best repaid for looking for this family.
Again, when these plants are fruiting they lose their bright green color and become
dingy, often yellowish and very dirty looking — just such specimens as the tyro
would pass by. The fine, bright, green, handsome masses of these algse are rarely
worth carrying home. After all, however, much must be left to chance; the best
way is to gather small quantities from numerous localities, keeping them separate
until they can be examined.

Adhering to the various larger plants, to floating matters, twigs, stones, &c., in
ditches, will often be found filamentous alga?, which make fine filmy fringes around
the stems, or on the edges of the leaves; or perchance one may meet with rivularisc
or nostocs, &c., forming little green or brownish balls, or indefinite protuberances
attached to small stems and leaves. These latter forms are .to be looked for
especially late in the season, and whenever seen should be secured.

In the latter part of summer, there is often a brownish, gelatinous scum to be
seen floating on ditches. Portions of this should be preserved, as it frequently con-
tains interesting nostocs and other plants.

INTRODUCTION 3

In regard t<> lar^e ;•//>•»•*, the time of \ear in which I have hern most successful
in Mirli localities is tlic latter summer months. Si>i-imjn and smull Inxlics of clear
water may be searched with a hope of reward at any time of the year when
they are not actually frozen up. I have found some exceedingly beautiful and
rare :d^;i- in Mieli places us early as March, and in open seasons they may be col-
lected even earlier than this. '1 he ilesmids an1 most abundant in the spring, and
possibly most beautiful then. '1 hey. hmve\er. rarely conjugate at that time, and
the mo.st valuable specimens are therefore to lie obtained later — during the summer
and autumn months; at least, so it is said; and the experience I have had with this
family semis to confirm it. AVo/A/s should be watched especially in early spring,
and during the summer months.

1 mm the time when the weather first grows cool in the autumn, on until the cold
weather has fairly set in, and the reign of ice and snow commences, is the period
during which the alf,r;r hunter should search carefully all wet, i/i-i/ijiliKj /•«/•.«, for
spi •< imeiis. Amongst the stems of wet mosses — in dark, damp crevices, and little
grnttos beneath shelving rocks — is the algae harvest to be reaped at this season.
Nn-tocs, palmcllas, conjugating desmids, sirosiphons, various unicellular alga?, then
flourish in such localities. My experience has been, that late in the autumn,
ravines, railroad cuttings, rocky river-banks, &c., reward time and labor better than
any other locali:

The vaucherias, which grow frequently on wet ground, as well as submerged,
fruit in the early spring and summer in this latitude, and are therefore to be col-
lected at such times, since they are only worth preserving when in fruit.

In regard to algae which grow on trees, I have found but a single species, and do
not think they are at all abundant in this latitude. Farther south, if one may
judije by I'roh ->-.>r Ilavem 1's collections, they arc the most abundant forms.

Although perhaps of but little interest to the distant collector, yet for the sake
of those living nearrr, I will occupy a few lines with an account of the places
around Philadelphia which will best repay a search for fresh-water alga;. As is
well known, below the city, there is what is known as the "Neck," a perfectly level
ut of ground lying in the fork between the rapidly approaching rivers, Schuyl-
kill and Delaware. This is traversed by numerous large ditches, and, especially
just beyond the city confines, has yielded to me an abundant harvest. My favorite
route is by the Fifth Street cars to their terminus, then across the country a little
to the east of south until the large stone barn, known as " Girard's Barn," is
reached. A large ditch lies here on each side of the road, which is to be followed
until it crosses the Pennsylvania Railroad, then along this to the west, until the
continuation of Tenth Street crosses it. Here the ditches cease, and the steps are
to be turned homeward. From Girard's barn to the crossing just alluded to,
ditches great and small lie all along and about the route, ditches which have often
most abundantly rewarded my search, and enabled me to return home richly laden.
The best season for collecting here is from March to July, and again in October,
when some of the nostocs may be looked for.

Crossing the river Delaware to the low country below and above the city of
Camdcn, the collector will find himself in a region, similar to that just described,

4 INTRODUCTION.

and like it cut up by numerous ditches, in which are pretty much the same forms
'as in the "Neck." But by taking the Camden and Atlantic cars for twenty to
forty miles into New Jersey to what is known as the " Pines," he will get into a
very different country ; low, marshy, sandy grounds, with innumerable pools, and
streams whose dark waters, amber-colored from the hemlock roots over which they
pass, flow sluggishly along. I have been, somewhat disappointed in my collections
in such localities. Fresh-water algae do not appear to flourish in infusion of hem-
lock, and consequently the streams are very bare of low vegetable life. On the
other hand, in pools in the more open places, my search has been repaid by find-
ing some very curious and interesting forms, which apparently are peculiar.

North of Philadelphia are several places, which at certain seasons will richly
reward the microscopist. Along the Delaware River, there is a similar country
and flora to that of the " Neck." But back from the river things are quite dif-
ferent. The North Pennsylvania Railroad passes near Chelten Hills, some eight
miles or so from the city, through some deep rock cuttings, which are kept con-
stantly dripping by numerous minute springs bursting from between the strata.
At the proper season, these will yield an abundant harvest. Besides these, there
is also a stream of water with ponds running along by the road, which should be
looked into. I have seldom had more fruitful trips than some made very early in
the spring to this locality; but then it was in little pools in the woods, and espe-
cially in a wooded marsh or meadow to the left of the road, some distance beyond
the station, that I found the most interesting forms.

The Schuylkill River and its banks have afforded materials for many hours of
pleasant work. In the river itself a few very interesting forms have been found;
but it is especially along its high banks that the harvest has been gathered.

The dripping rocks and little wood pools in the City Park are well worth visiting ;
but the best locality is the western bank, along the Reading Railroad, above Mana-
yunk, between it and the upper end of Flat Rock tunnel. Down near the river, at
the lower end of the latter, will be found a number of beautiful, shaded rocky pools,
which, in the late summer, are full of Cliaetophora and other algce. Along the
west rocks of the river side of the bluff, through which the tunnel passes, are to
be found, late in the fall, numerous algae. It is here that the Palmella Jessenii
grows in such abundance.

West of the city, in Delaware and Chester Counties, is a well wooded and
watered, hilly country, in which, here and there, numerous fresh-water algae may
be picked up.

As to the preservation of the algae — most of the submerged species are spoiled
by drying. Studies of them should always, when practicable, be made whilst fresh.
Circumstances, however, will often prevent this, and I have found that they may
be preserved for a certain period, say three or four months, without very much
change, in a strong solution of acetate of alumina.

An even better preservative, however, and one much more easily obtained, is
carbolic acid, for I have studied desmids with great satisfaction, which had been
preserved for five or six years in a watery solution of this substance. In regard
to the strength of the solution I have no fixed rule. Always simply shaking up

I N T lit) I" rcTION. 5

a f« w drops of the arid with the water, until the latter is very decidedly impreg-
nated with it, as indicated by the senses of smell and taste.

Almost all species of alga? which are linn and semi-cartilaginous, or almost
woody in consistency, are best preserved by simply dning them, and keeping them
in the ordinary manner for small plants. The fresh-water alga? which bear this
treatment well belong to the /'////« </(/o;;/r/y</(//oea', such as the Nwtocs, Scyloncma,
the true confervas not enduring such treatment at all. When dried plants
are to he studied, fragments of them should he soaked for a few minutes in warm,
or for a longer time in cold water.

The only satisfactory way that alga? can he finally prepared for the cabinet is by
mounting them whole or in portions, according to size, for the microscope. Of the
methods of doing this, the present is hardly the time to speak; but a word as
to tin1 \\ .!} of cleaning them will not be out of place. Many of them, especially
the larger filamentous ones, may be washed by holding them fast upon an ordinary
microscope slide, with a bent needle or a pair of forceps, and allowing water to
llow or slop over them freely, whilst they are rubbed with a stiffish camel's-hair
pencil or brush. In other cases, the best plan is to put a mass of the specimens in
a bottle half full of water, and shake the whole violently; drawing off the water
from the plants in some way, and repeating the process with fresh additions of
water, until the plants are well scoured. At first sight, this process would seem
• dingly rough, and liable to spoil the specimens, but I have never seen bad
results from it, at least when practised with judgment. The water seems so to
envelop and protect the little plants that they arc not injured.

After all, in many instances it appears impossible to clean these algtc without
utterly ruining and destroying them — the dirt often seeming to be almost an inte-
grant portion of them; so that he who despises and rejects mounted specimens,
simply because they are dirty and unsightly, will often reject that which, scienti-
fically speaking, is most valuable and attractive.

In finally mounting these plants, the only proper way is to place them in some
preservative solution within a cell on a slide. After trial of solution of acetate of
alumina and various other preservative fluids, I have settled upon a very weak
solution of carbolic acid, as the best possible liquid to mount these plants in.
Acetate of alumina would be very satisfactory were it not for the very great
tendency of the solution to deposit minute granules, and thus spoil the specimens.
As every one knows, the great difficulty in preserving microscopic objects in the
moist way is the perverse tendency of the cells to leak, and consequently slowly to
allow entrance to the air and spoil the specimen.

As I have frequently found to my great chagrin, the fact that a slide has re-
mained unchanged for six months, or even a year, is no guarantee that it will remain
so indefinitely. It becomes, therefore, exceedingly important to find some way of
putting up microscopic objects that can be relied on for their preservation. Where
carbolated glycerine jelly or Canada balsam can be used, the solid coating which
they form around the specimens constitutes the best known protection. Except in
the case of the diatoms, however, these substances so shrivel and distort the fresh-
water alga? immersed in them as to utterly ruin them. I lost so many specimens

6 INTRODUCTION.

by the old ways of mounting, that, becoming disheartened, I gave up all idea of
making a permanent cabinet, until a new cement, invented by Dr. J. G. Hunt, of
this city, was brought to my notice. This is prepared as follows: —

" Take damar gum, any quantity, and dissolve it in benzole ; the solution may be
hastened by heat. After obtaining a solution just thick enough to drop readily
from the brush, add enough of the finest dry oxide of zinc— previously triturated
in a mortar with a small quantity of benzole— until the solution becomes white
when thoroughly stirred. If not too much zinc has been added, the solution will
drop quickly from the brush, flow readily, and dry quickly enough for convenient
work. It will adhere, if worked properly, when the cell-cover is pressed down,
even when glycerine is used for the preservative medium. Keep in an alcohol-
lamp bottle with a tight lid, and secure the brush for applying the cement in the
lid of the bottle."

Its advantages lie in the circumstance, that the glass cover can be placed upon
the ring of it whilst still fresh and soft, and that in drying, it adheres to both cover
and slide, so as to form a joint between them of the width of the ring of cement,
and not, as with asphaltum, gold size, &c., simply at the edge and upon the outside
of the cover. It is readily to be seen how much less liability to leakage must
result from this. The method of mounting with it is as follows: A ring of any
desired size is made, by means of an ordinary Shadbolt's turn-table, upon a slide,
which is then placed to one side to dry. When required for use, the specimen,
cover, &c., being all prepared and ready, the slide is again placed upon the turn-
table and a new ring of cement put directly upon the old one. The specimen is
immediately placed within the cell thus formed, and the requisite quantity of the
carbolated water placed upon it. The cover, which must be large enough to entirely
or nearly cover the cement ring, is now picked up with the forceps, the under side
being moistened by the breath to prevent adhesion of air-bubbles, and placed care-
fully in position. It is now to be carefully and equably pressed down with some
force. By this, any superfluous water is squeezed out and the cover is forced down
into the cement which rises as a little ring around its edge. The pressure is best
made with a stiff needle, at first on the centre and then upon the edges of the cover,
which may finally be made slowly to revolve underneath the needle point. The
slide may then be put aside to dry; or, better, an outside ring of the cement thrown
over its edge in the usual manner. Where a deep cell is required, several coats of
the cement should be placed one over the other, each being allowed to dry in
turn. If time be an object, and only a shallow cell be necessary, the first ring of
cement may be dispensed with, and the whole mounting of the specimen be done
in a few minutes. Even with this cement and the utmost care in mounting, the
cabinet should be occasionally inspected, for there will always be some slides into
which air will penetrate. When such are found, efforts may be made to stop the
leak by new rings of cement overlaid upon the old, but very often entire remount-
ing of the specimen is the only satisfactory cure.

The classification which I have adopted in this memoir is that of Professor Ra-
benhorst. I have finally selected it, not as being absolutely natural, but as conve-
nient, and as rarely doing much violence to the natural relations of the various species.

INTRODUCTION. 7

Our knowledge of the life-history of the alga; must make very many advances
!M Lire the trui- >\>tein can I»c devclojM'd, and abstinence from adding to the present
numerous classitication-, i> an exhibition of self-control not very common.

There are, lio\\. \,T, certain great groups, which are already plainly foreshadowed,
and which no doubt will he prominent points in the perfected classification.
Amongst these are the Con^uijattr, or those plants in which sexual reproduction
occurs \}\ the union of two similar cells. In the present paper all the plants of
this family described are together, since the diatoms are not noticed ; but in Raben-
h' list's work the latter plants are very widely separated from their fellows, and this
to me the weak point of the Professor's system.

1 Ki:>ll-\VATKR Al.d.K 01- THE I'MTKI) STATKS.

CLASS rilYCOCIIKOJIOI'IIYCEjE.

uni- vcl multiccllul:iiv<. in ;i«|ii;i vigcntes vcl extra aquam in
iicali nidulantcs, plcruiuquc fumilias per ccllularum generationes

urta-- lunimntCS.

nun silieeum, combustil>ile.
([t/ti,,/,lnx/iHt phjoocbrootate coloratum, nuclco destitutum, granulis

aim laeeis i>lenimqur niillis.

Propagatio divisioue vegetativa, gonidiis immobilibus vcl sporis tran-

(inillis.

or multi-cellular plants living in water, or incased in a mater-
nal jelly out of it, mostly in families formed from successive generations
of cells.

not siliceous, combustible.

an endochrome, brown, olivaceous, fuscous, &c., destitute
of nucleus, mostly without starch granules.

1'i-niHnjntion by vegetative division, by immovable gonidia or tranquil
spoi

The phycochroms arc plants at the very bottom of the scale, distinguished by
the simplicity of their structure and the color of their protoplasm, which, instead
of being of the beautiful green that marks chlorophyll, is fuscous, or yellowish,
bluish, brownish, or sometimes particolored, and rarely greenish, but of a shade
very distinct from the chlorophyll green, more lurid, bluish or yellowish, or oliva-
ceous in its hue. The nucleus appears to be always wanting. The cell wall is
oftriitimes distinct and sharply defined, but in many instances it is not so, the
walls of different cells being fused together into a common jelly in which they are
imbedded. In a large suborder the wall is replaced by a sheath, which in some
genera surrounds cells with distinct walls, in others, cells without distinct walls,
and in still others, a long cylindrical mass of endochrome, which may be looked
upon as a single cell.

Many of the phycochroms are unicellular plants in the strictest sense of the word,
but more often the cells are conjoined, so as to form little families, each cell of
which is in a sense a distinct individual capable of separate life, yet the whole
bound together into a composite individual. Rarely the phycochrom is a multi-

2 January. 1878. ( 9 )

10 FRESH-WATER ALG^ OF THE UNITED STATES.

cellular plant in the stricter use of the term. Increase takes place by the multiple
cation of cells by division, and also by the formation of enlarged thick-walled cells,
to which the name of spores has been given, although it is entirely uncertain
whether they are or are not the result of sexual action. There are numerous
peculiar forms of cell multiplication by division occurring in these plants, the dis-
cussion of which will be found scattered through the remarks on the various
families and genera.

The method of reproduction, and in fact the life history in general, of the phy-
cochroms, is still involved in such mystery, that I am not aware that absolute
sexual generation has been demonstrated in any of them. This being the case, it is
not to be wondered at that many have conjectured as possible, and some have roundly
asserted as true, that the phycochroms are merely stages in the life history of higher
plants ; that they are not species, and, consequently, that any attempt at describing
such is little more than a busy idleness. In regard to some of them it has certainly
been rendered very probable that they are merely fixed stages of higher plants.
On the other hand, in the great bulk of the forms, no proof whatever has been
given that they are such. They all certainly have fixed, definite characters, capa-
ble of being expressed and compared, so that the different forms can be defined,
recognized, and distinguished. If, therefore, future discoveries should degrade
them as subordinate forms, names will still be required, and definitions still be
necessary to distinguish them one from the other, so long as they are common
objects to the microscopist.

If Nostoc commune, for example, were proven to be a peculiar state or develop-
ment of Polytricum commune, I conceive it would be still known as Nostoc commune.
But, as previously stated, no proof whatever has as yet been furnished for the vast
majority of the plants of this family, to show that they bear any such relation to
higher plants ; and until some such proof is forthcoming, certainly the only scien-
tific way to act, is to treat them as distinct species.

ORDER Cystiphortc.

Plantse unicellulares. Cellulae singulae vel plures in familias consociatse.
Unicellular plants. Cells single or consociated in families.

In this order the cells are oblong, cylindrical, spherical, or angular. They are
sometimes single, or more commonly are united by a common jelly into families,
which sometimes are surrounded by distinct coats. The mucus or jelly, in which
the cells are imbedded, is mostly, but not always, colorless, and varies in firmness
from semifluid to cartilaginous. The division of the cells may take place either in
one, two, or three directions or planes.

FAMILY CHROOCOCCACE^E.

Character idem ac ordine.
Characters those of the order.

FIIESH- WATER A LG £ OF Til E U NI TK D ST ATE S. H

(i. mis CHROOCOCCUS, N^GELI.

CcllulsD globose ovalcB vcl a pressione inutua plus minus angulosa;, solitaritc vcl in fumilias con-
Fuciuue, liber a; (a vesica matricali non involute) ; cytiodcriuate achromatico, bomogeneo, sajpe in niuco
plua minus lirmo couliucnte; cytioplasmate a.Tuginoso vcl pallide ca:ruleo-viridi, non rare luteolo Tel
auruiitiat-o, iiiterdutu purpurasccute.. Ocneratiouuni successivarum divisio altcruatim ad dircctioncs

Syn. — Frotococms, Ao. ct KTZ., Ac., ex parte. Pleurococcus, MENOH.

Olobulinae ct Frotosjiharriee, TUKPIN, ex part.

Cells globose, oval, or from mutual pressure more or less angular, solitary, or consociatcd in free
families (not involved in a maternal vesicle); Cytioderm achromatic, homogeneous, often confluent
int.' a more or le.ss linn mucus; cytioplasiu a?ruginous or palo bluish-green, not rarely yellowish or
orange, sometimes purplish. Successive generations arising by alternate division in three directions.

C. refraclus, WOOD.

('. eellulis in families solidas arete consociatis, plcrumquc subquadratis, sxpiiis triangularibu*,
rare angulosis; familiis sa-piua lobatis; cytiodcrmato tcnui, vix visibile, achroo; cytioplas-
mate subtiliter granulate, subfusco vel subluteo vel olivacco, yalde refrangente.

Z>iam.— Cell JB'OU" — suW. rare in eellulis singulis nW; famil. -rA»"— ilo"
Syn. — C. refractua, WOOD, Prodromus, Proc. Amcr. Philos. Soc., 1869, 122.
JIab. — In rupibus irroratis grope Philadelphia.

Cells closely associated together into solid families, mostly subqnadrate, very often triangular,
rarely multiangular ; families often lobcd ; cytioderm thin, scarcely perceptible, transparent ;
cytioplasm finely granular, brownish, olivaceous, or yellowish, highly refractive.

/,'< marks. — The color of this species varies from a marked almost fuscous brown
to a light yellowish-brown, the lighter tints being the most common. The cells
arc remarkable for their powerful refraction of the light, resembling often oil as
seen under the microscope, especially if they be the least out of the focus. They
arc MTV closely joined together to form the families, many of which are composed
only of four cells. Often, however, a large number of the cells arc fused together
into a large, irregular, more or less lobatc family, and these sometimes arc closely
joined together into great irregular masses. I have occasionally seen large single
cells with very thick coats, whose protoplasm was evidently undergoing division.
Arc such a sort of resting spore ? The color of the protoplasm varies. Perhaps the
more common hue is a sort of clay tint. Bluish-olive and a very faint yellowish-
brown are not rarely seen. The species grows abundantly on the wet rocks along
the Reading Railroad between Manayunk and the Flat Rock tunnel.

Fig. 5, pi. 5, represents different forms of this species; those marked a, magnified
750 diameters ; J, 470 diameters ; c, 950 diameters.

C. multicolorntiiH, WOOD.

C. in strato mncoso inter algas varias sparsns ; eellulis singulis ct sphtericis, vcl 2-4 (rare 8) aut
angulis ant scmisphicricis ant abnormibns in familias oblongas eonsociatis ; cytioderraate crasso,
hyalino, hand laraelloso; tegumentis plerumque nullis, interdum snbnullis; cytioplasmate plc-
rumque homogeneo, interdum subtiliter granulato, vel lutco-viridc vcl ca;ruleo-viride vel lutco
Tel subnigro, vel brunnco, vel saturate aurantiaco, sa;pe ostro tincto.

Dinm.— Cell., sing, sine togm., „*„„" cum teg. uVa"; cell, in famil. sing. „*„,,"—
Fara. long. i.V'-^S,"; Iat- «o»"-«V-

12 FRESH-WATER ALG^ OF THE UNITED STATES.

Syn.—C. multicoloratus, WOOD, Prodromus, Proc. Amer. Philos. Soc., 1869, 122.

Hab.—in rupibus humidis prope Philadelphia.

C. occurring scattered in a mucous stratum with other algae; cells spherical and single, or else
angular semi-spherical or irregular and associated together in oblong families of from 2-4
(rarely 8) ; inner coat thick, hyaline, not lamellate ; outer coat generally wanting, sometimes
indistinctly present; endochrome mostly homogeneous, sometimes minutely granular, either a
yellowish-green or bluish-green, or yellowish or brown, or blackish, sometimes tinged with
bright lake.

The cells of this species do not appear to have any tendency to unite to form
large masses or fronds. On the contrary they are generally very distinct. Their
color varies very much, in a larger number of instances they were a decided yellow-
ish-green, tinged at some point or other with a beautiful lake. When several cells
are formed by division out of one cell, a similar division of the very thick surround-
ing gelatinous coat follows separating them finally entirely one from the other. I
have seen a single cell which appears to be an encysted form of this, of which I give
a drawing.

Fig. 6, pi. 5, represents different forms of this species magnified 260 diameters.

C. thermophilns, WOOD.

C. cellulis singulis aut geminis vel quadrigeminis et in familias consociatis, oblongis vcl sub-
globosis, interdum angulosis, haud stratum mucosum formantibus; tegumento crassissimo,
• achroo, haud lamelloso, homogeneo ; cytioplasmate viride, interdum subtiliter granulato, inter-
dum homogeneo.

Diam. — Cellulse singulse sine tegumento longitudo maximaT^T'', latitude maxima ^V^"-

Syn. — C. thermophilus, WOOD, American Journal Science and Arts, 18G9.

Hob. — Benton Springs, Owen Co., California (Mrs. Parz.).

Cells single, geminate, or quadrigeminate and consociated into families, oblong or subglobose,
sometimes angular, not forming a mucous stratum ; tegument very thick, transparent, not
lamellate, homogeneous ; cytioplasm green, sometimes minutely granulate, sometimes homo-
geneous.

RemarTcs. — Remarks upon this species will be found under the head of Nostoc
calidarium, Wood.

Genus GLOEOCAPSA, KTZ.

" Cellulae sphericae aut singulse aut numerosse in familias consociatse ; singular tegumento vesiculi-
forme (cytiodermate tumido) inclusae, post divisionem spontaneam in cellulas duas filialcs factam
ntraque tegumento se induit, dam ambae tegumento matricali involute remanent; cellularum harum
filialium iterum in duas cellulas divisione continuo repetita, tegumentnm atavise restat et sese exten-
dens familiam totam circumvelat. Cytioderma crassnm, saepe crassissimum, cellules lumen crassitie
sequans vel superans, achromaticum vel coloratura, plerumque lamellosum ; lamellae vel strata non
raro discedentia. Cytioplasma aeruginosum, cseruleo-viride, chalybeum, rufescens, luteo-fuscum, &c.
Cellularum divisio directione ad tres dirnensiones alternante. Cellulae generationum ultiuiarum
minores quam priorum sunt." (Rab.)

Syn. — Olobulina et Bichatia, TURPIN, ex part.
Gloeocapsa, KTZ., ex part.
Microcystis, MENEGH., ex part.

Cells spherical, either single or associated in numbers into families; the single cell included a
vesiculiform tegument (the tumid cytiodcrm); this cell then undergoing division into two daughter-

FRESH-WATER A L G .E OF THE UNITED STATES. 13

cells, each of which has a distinct tegument, the whole luring surrounded with that of the old mother-
cell. This process of division i- tlien repeated airain and again, the original cell-wall remaining and
surroumliiitr the family thus funned. (.'ytiudenu thick, ofti-n very thick, e([ii;illing, or exceeding in
diameter the cavity of the cell, achromatic or colored, mostly laraellated, lamcllie or strata not rarely
si-parating. Cytioplasm of various colors, icruginniis, dlni-li-grecn, chalybeate, reddish, yellowish-
fuscous, Ac. Division of the cells occurring in three directions. The last generation of cells smaller
than the earlier ones.

CJ. «par*n, WOOD.

U. in strato mucoso sociis algis variis sparsa; cellnlis sphiericis, vel oblongis vel ovatis, 2-8 in

familia* consiwiatis; fumilii.s subglobosis vel subovntis, interdnm nnmeroso-aggregatig ; tegu-

racntis inti-rnis aureofu-cin, firmis, rarissime coloris expertibus, homogcncis, vel lamellosis;

tepnnu-nti • exiiTiiis uehromaticis, rare subachromaticis, plernuiqae vix visibilibus; cytioplas-

mate homogcnco.
Diam. — Max. cell, oblong, sine tegnm. long., yjvv"; lat, 75*05"; cell, glob., sine tcgum.,

„>„«"; cum tcgura., TI'Ti"; fam., 7}j".

.s'yn. — f!. sparta, WOOD, Prodromus, Proc. Amcr. Philos. Soc., 1869, 123.
IM>. — In rupibus irroratis prope Philadelphia.

ii scattered in a mucous stratum composed of various algae ; cells spherical, or oblong, or ovate,
associated tiijrcther in families of from 2-8; families subglobose or subovate, sometimes aggre-
gated loir. .||ii-r in large numbers; inner tegument yellowish-brown, Grin, rarely colorless, homo-
geneous or lamellate ; external tegument achromatic, rarely subachromatic, generally scarcely
visible.

/,'< marks. — This species was found in a rather firm, grumous or gelatinous coat-
ing of a light brown color, growing on the rocks at Fairmount Water Works,
chiefly composed of a very minute nostochaceous plant, but contained numerous
other alir;i\ The color of the tegument is yellowish-brown, sometimes with some-
red in it, sometimes with something of a greenish tint. This inner colored coat
is not generally more than once or twice lamellate, often it is not at all so. This
species seems somewhat allied to 0. 8(i/<>j>fi!ln, but differs slightly in the form of
tin- cell, and more especially in not having a distinct thallus, and iu the families
beiiii,' small and containing but few cells.

Fig. 7, pi. 8, represents this species, magnified 750 diameters.

Genus CLELOSPH^ERIUM, NJEGELI.

Thallns parvns, c cellulis minimis in familias peripheries consociatis vel in stratum pcriphcricum
simplex et in muco tegamcntis celerrimc con fluent! bus formato nidulautibus compositus. Ccllu-
larum divisio, initio generationum serierum, in omnem Gt dircctionem, turn deoiqae alternatim
ad superficiei splncricic utramque directioncra.

Thallns small, composed of very small cells consociated into peripheral families, or in a simple
peripheral layer, inclosed in their quickly confluent teguments. Division of the cells at first in all
directions, afterwards only in each direction on the surface of the sphere.

C. dubium, GRIN. ?

C. thallo microscopico, snbgloboso vel cnorme, natante, congregate; cellnlis globosis ant sub-
globosis; cytioplasmate pallide airngineo, snbtiliter granulato.

Diam.— Cell, plemmqnc „'„*" — -00016"; rare ,^5" = .00025"; fara. T»W»"
.00083"— .0033".

14 FRESH-WATER ALG;E OF THE UNITED STATES.

Hob. — In aquis stngnis, prope Philadelphia.

Thallus microscopic, subglobose or irregular, floating, aggregated in great numbers; cells glo-
bose or subglobose; cytioplasm finely granulate, pale aurugiuous greeu.

Remarks. — I found this beautiful little plant forming a dense scum on a stag-
nant brick-pond, below the city, in the month of July. The scum was of the
" color of pea-soup," and so thick was it, that I think a quart of the plants might
have been readily gathered. The fronds were of various sizes, and many of them
were apparently undergoing division — some of them seemed to have little fronds
in their interior. They were composed of an exceedingly transparent firm jelly, in
which the cells were placed, often so as to leave the central parts of the frond
empty, merely forming a sort of filament-like layer around the edge. Earcly they
were in such numbers as to be crowded together over the whole surface of the
frond. In some of the younger fronds the cells formed a little ball within the jelly,
instead of being scattered through its outer portion. I have seen some large single
cells three or four times the size of the ordinary frond cell, swimming amongst the
plants, of which they are apparently the reproductive gonidia. Their cell-coats
are very firm and thick. The fronds themselves are often closely aggregated
together into little masses, and I think it. probable that there is a state of the
plant, in which the jelly becomes softened and the fronds more or less fused together
in protococcus-like masses. This plant appears to be the same as the European C.
dubium, but differs from 'the description in the fronds not attaining to anything
like the size. It is very probable, however, that this depends upon age or circum-
stances of growth, and that American plants may be found as large as the
European.

Genus MEKISMOPEDIA, MEYEN.

Cellulaj globosas, aut oblongse, aut ovales, tegumentis confluentibus, 4, 8, 16, 32, 64, 128 in fami-
lias tabulatas, unistratas consociataa. Thallus planus, tennis, plus minus quadratus, in aqua libere
natans. Cellularum divisio in planitiei utramque directionem.

Cells globose, oblong, or oval, joined together by their confluent coats into tabular families of 4,
8, 16, 32, 64, 128. Thallus, a more or less quadrate plane, swimming free in the water. Division
of the cells occurring in all directions in the one plane.

M. nova, WOOD.

M. thallo membranacco, distincte limitato, cellulis numerosissimis composite; cellulis ovalibus,
arete approximatis, 16 in familias consociatis, dilute cajruleo-viridibus, iuterdum medio con-
strictis; thalli margiuibus rectis, integris.

Syn. — M. nova, WOOD, Prodromns, Proc. Amer. Philos. Soc., 1869, 123.

Diam.— Cell. ad. ^vv" = 0.0025".

Eab.— In flumiue Schuylkill, prope Philadelphia.

Thallus membranaceous, distinctly limited, composed of very numerous cells ; cells oval, closely
approximated, consociate in families of 16, light blnish-grco.n, sometimes constricted in the
middle ; margin of the thallus straight and entire.

Remarks — The only specimens I have ever seen of this species were found grow-
ing in the Schuylkill Iliver adherent to, or entangled in, a lot of filamentous alga3.

r.BBSB-WATIB ALQ.E OF Till: r N I T K D STATES. 15

The frond is \{-r\ sharply <1< lim d, and, uutlrr a !<>\v pm\er. i- nf a uniform bluish-
M tint. The celK an- a--neiated in primary families of lii.nl' a number of .
which the thallu* k composed. The species appears to be most closely allied to
M. nniliti /•/••(//«<*, Na u' . tVuiii whirh it ditiers \ery I'ssrntiully in tin- M/e of the fronds,
and perhaps even more closely to M. ylnnm. tbe only character .separating it from
which is the straight margin. 1 have m\self some doubts whether it ought not to
he considered as merely a I'onji of M. ijluiu-n.

Fig. 8, pi. s, represents this sp, ., -i, -s, magnified 400 diameters.

JTI. ronrolutn, I!ur.n.

M. tluillo ini'inliranacco, oculis nudis visiKili, plus minus convoluto; faniillis c celluli-< ^nninis ct
in Milifamilms i|i~|^'-;!i-, •J.'ii'i oniipositis, inti-nluia familiis cluabus in familia gi'ininu CUIIJUDC-
tis; ct-llulis .-pli;i-rici.s aut obluiigis; cytioplosmate homogcnco, viridi.

Diam.— Cell. „/„„" = 0.00017"; fam. long. ,!„" - .06"; lat tfa" - 0.04".

//,//, — In acpiis quietis propc Philadelphia.

Tlmllus mriiilirnniiiis, visible to tho naked eye, more or less folded; families composed of 250
p'Miinntf crlls, arranp'il in siilifainilios, sometimes two of these families conjoined with a com-
posite family ; cells spherical or oblong; cytioplasm homogeneous, green.

/,'< murk*. — "When my Prodromus was published, the only specimens of this plant
which I had seen were contained in a mounted slide given me by my friend Dr. J.
(iibboiis Hunt, of this city. Since then I have found it growing in a very shallow,
quiet, but fresh, sweet pool at Spring Mills, making a distinct green layer upon the
mud many feet in extent. Of course, there were millions of specimens in this layer.
The fronds are irregular in shape, often somewhat ovate, sometimes subquadrate,
varioush torn, and not rarely somewhat lobate. Their edges are frequently very
sharply defined and rendered firm and prominent by several rows of cells being
en iwded closely together along them. The cells in the body of the frond are arranged
in larijr parallelogrammatic families, composed of 256 cells. There are 16 cells on
cadi sidc% the- families being parallelogrammatic rather than square, owing to the
oblong shape of the cells. This cell family is composed of four subfamilies, each
containing <!4 celK These arc again subdivisible into four more or less distinct
groups of 16 cells each. The cells are, finally, generally closely geminate, each
pair being very distinctly separated from its neighbors. In certain stages of growth,
as immediately after a general division of the cells, two of the large cell-families
spoken of are often temporarily joined together to form a huge family of 512 cells,
but soon separate one from the other.

ORDER Nematogeiieas

Plant® multicellnlarcB vel pscudo-mnlticellnlares. Ccllulic filnm (trichoma) formantes et pic-
rnmque vagina tubulosa horaogenea vcl lamellosa inclusw. Trichomata aut simplicia aut ramiflcata.

Plants multicellular or psendo-mnlticellalar. Cells forming a filament, nnd generally included in
a tubular lamellate or homogeneous sheath. Filaments either simple or branched.

16 FRESH-WATER ALG^E OF THE UNITED STATES.

FAMILY OSCILLARIACEJE.

Trichomata simplicia baud vero multicellularia, sed distincte articulata, plcrumque vaginata, mo-
tionibus variis prsedita.

Filaments simple, not strictly rnulticellalar, but distinctly articulate, mostly vaginate, moving in
various ways.

Genus OSCILLARIA, Bosc.

Trichomata simplicia, plernmque distincte articulata, rigida, recte vel parum curvata, rarius cir-
cinata vol spiraliter convoluta, plcrumque Isete colorata, motu triplici pa;dita, in muco matricali
nidulantia vel vaginula tubulosa angustissima utroque fine aperta inclusa ; articuli fronte disciformes.
(R.)

Filaments simple, mostly distinctly articulate, rigid, straight, or somewhat curved, very rarely
circinate or spirally convolute, capable of three motions, floating in a maternal jelly, and shut up
in a fine tubular sheath, open at both ends ; joints from the front disciform.

The oscillaria are very peculiar plants, which flourish almost in every situation
in which fresh water is to be found. The purest springs are not always free from
their presence, although they occur most abundantly in stagnant pools and ditches,
where animal or vegetable matters are undergoing decay. When viewed in mass,
floating upon some foul pool, few objects in the vegetable world are better calcu-
lated to excite disgust. A dark, slimy scum reeking with its putrescent surround-
ings, they seem to offer nothing of pleasure or interest. But, when brought home
to the table of the microscopist and placed beneath his object-glass, they startle
the observer by the wonders of their life-history. Living rods, writhing, twisting,
bending, curling, creeping, gliding hither and thither ; incessant, apparently cause-
less, motion, occurring too in what to most minds is the very type of fixity and
passivity — a plant. No marvel, then, that they are so famous.

The structure of an oscillatoria is about as simple as it can be. An outside
colorless cellulose sheath, which is probably in the uninjured filament closed at the
end, although, as seen by the microscope, violence and age have often torn it open.
Within is a long rod of variously colored endochrome, distinctly articulated by, at
great or less intervals, breaks in the color, which appear as dark lines under a low
power, but, under a higher objective, are revealed as narrow linear portions of
protoplasm lighter and more transparent than the rest. Frequently at the joints
there is a marked tendency to separation between the successive articles, and a very
decided contraction of the endochrome on each side, so as to leave a little gutter,
or dividing trench. The endochrome is sometimes homogeneous, sometimes con-
tains numerous granules, which are, however, never amyloid in their nature.

The color of the endochrome varies very greatly in the different species. Slate
color, blue, greenish, olivaceous, are among the most common hues. According
to Ur. Ferdinand Cohn (Botan. Zeitung, 1867, p. 38; Sitzung, 13th Dec. 1866,
der Schlesischen Gesellschaft fur vaterlandische Cultur), the coloring matter of the
oscillatoria consists of true chlorophyll, and a substance which he calls Phycocyan,
but which he states to be different from Phylcolcyan of Kiitzing, the Plitjcliochrom
of Naegeli, and also from Phycocyan of the latter authority. The chlorophyll is,

FH K.-II \v .\ TI: i: .\ M; .1: or TII i: r \ ITEP STAT n

of course, soluble in ether and alcohol hut not in water; lint the fVii/n*-y<in (Cohn)
is insoluble in alcohol and ether, l>nt soluble in water after the death of the oscil-
latoria. It is precipitated out of its solution by acids, alcohol, and metallic salts,
as a blue jelly, but potash and ammonia throw it down as in a colorless, gelatinous
mass. I ha\e mvself frequently noticed that oscillatoria after death will yield a
bluish coloring matter to water, but thought that such coloring matter was the
re>ult of a partial decomposition, and 1 think that Professor Cohn has by no means
.hlished as a faet that his /'////.•,„•//,(/, exists in the oscillatoria during life.

As to the method of reproduction of these plants, we are as yet almost entirely
in the dark. Individuals do multiply by the breaking up of the internal endo-
rhroine into masses or sections through a separation at the joints. These little
masses frequently grow immediately into new individuals. Sometimes, however,
they roll themselves into a ball, but whether they then have the power of coating
themselves with a protective wall and passing into a sort of resting spore or not, I
cannot say.

The specific characters of the oscillatoria arc derived from the color, form, mode,
and place of growth, &c., of the large common mass, its thickness, consistency,
the absence or presence of radii, &c. Descending to the individual filament, t he-
characters are drawn from the size, the color, the length of the articulations, and
the shape of the uninjured ends. Thus, it is to be noted, whether the latter arc
gradually narrowed (attenuated), or preserve their size to the very point, whether
they are acntish or obtuse, rounded or truncate, whether they are straight or con-
stantly curled. The activity and modes of motion are also to be remarked. Some
lea merely glide across the field of the microscope, some are constantly curling
and uncurling at their ends, some bending to and fro almost like a pendulum, some
are very sluggish, others very active and restless.

After all, however, it must be confessed that the specific characters are very un-
satisfactory, much more so than in any other phycochroms which I have studied.

A very large number of European forms have been described, some few of which
1 have been able to recognize. I have also ventured to name a few forms appa-
rently distinct, but have refrained from going farther into their specific study,
because I have found it so unenticing, and my time has been so limited.

Professor Bailey, in Silliman's Journal, N. S., vol. iii., states that he has identified
a few species of this family, although with great hesitation and doubt. At the
time he wrote there were really no known grounds upon which specific unity could
be predicated in these plants, and I therefore think that his identifications arc of
but little value, although holding the most profound respect for his abilities as a
naturalist. The list he gives is as follows: —

0. tenuitsima, Ag. Warm Springs of Washita.

O. fcntiw, Ag. Providence, Rhode Island. "NVcst Point, New York. Culpcpper
County, Virginia.

O. decortieans, Gener. Common everywhere on pumps, &c.

O. muscorum, Ag. West Point, New York.

O. nigra, Vauch. West Point, New York.

O. cortuwi, Ag.

3 February. 1871

18 FRESII-WATER A L G .E OF THE UNITED STATES.

O. clllorilia, KUTZINO.

O. interdum in strato sordidc viridi natante, iuterdum in aqua diffusa; trichomatibus rectis,
vividc moventibus, vel articulatis et cum cytioplasmate granulate, vel inarticulatis et cum
cytioplasmate baud granulate; cytioplasmate byalino, interdum colons fere expertibus,
interdum dilutissime viride; apiculo baud attenuate, obtuse rotundato, recto ; articulis dia-
metro subaequalibus.

- .00014"-.0001".

jjab. — In stagnis prope Philadelphia.

Sometimes swimming on the water as a dirty-greenish stratum, sometimes diffused in the water;
filaments straight, actively moving, either articulated and having the cytioplasm filled with
blackish granules, or else neither articulate nor granulate, cytioplasm hyaline, almost colorless,
or with a faint greenish tint ; ends of the filaments not attenuate, straight, obtusely rounded ;
joints about equal to the diameter.

Remarles. — I found this species in the month of August, 1869, in one of the
stagnant brick-ponds below the city. It occurred as a sort of floating scum, or
else diffused through the water, which was then opaque and greenish. It resembled
so a protococcus in gross appearance that I did not think of its being an oscilla-
toria until I placed it under the microscope. The filaments are almost colorless,
and, in most instances, are very distinctly granulate and articulate. The dissepi-
ments are in such cases clear and transparent, perfectly free from granules. This
form is very close to the descriptions of the European 0. chlorina, Ktz., but differs
somewhat from descriptions, chiefly in habit of growth. The filaments, when in
mass, are often seen to be curved under the restraining force of the glass cover,
but when free I think always straighten themselves.

Fig. 1, pi. 1, represents a single filament, magnified 750 diameters.

O. Frohlichii, KTZ. ? .

O. strato indefinite, tenue, viride ; trichomatibus loete viridibus, subrectis, vivide oscillantibus,
ad genicula nonnihil pellucidis et leviter contractis et rarissimc granulatis; articnlis diametro
2, 3, 4 plo brevioribus ; cytioplasmate obscure aut distincte minutissime granulate ; apiculo
haud attenuate, late rotundato.

Diam.— ssV— YsW" = 0.00066"— 0.0004.
Hob. — In flumine Schuylkill.

Stratum indefinite, thin, green ; filaments bright green, straightish, vividly oscillating, some-
what pellucid at the joints, where they are slightly contracted and very rarely granulate ;
articles 2, 3, 4 times shorter than the diameter, cytioplasm obscurely or distinctly very mi-
nutely granulate ; apex not attenuate, broadly rounded.

RemarJcs. — I found this species growing upon the bottoms of the shallows in the
Schuylkill Eiver and its larger tributaries, forming a somewhat badly defined
stratum, rather, indeed, a coating on the mud than a definite stratum. The motion
is exceedingly active, the filaments bending and gliding, and their apices con-
stantly curling and extending in all directions. The apices are very blunt. The
filaments are not often seen woven and twisted together into a mass composed
simply of themselves, but are stuck together loosely, each filament remaining
straightish, with numerous little masses of mud between them. I have not been

FUKS n -\Y.\TI-: i: AI.U.I: oi TIN: UNITED BTAT1 19

;ililc to identif) tin- ^|>< < -ir- pi'siti\i-I\. hut li;i\<- ivfrrn-d it \vitli doubt to ft. /•';'//<//-
chii.

'J, pi. 1, represents tin- mil nf a filament.

O. uigra, VAI I-H.

1 ' ' ruto plus niiiiu-! fiinipucto, aiii]il.>. plrruinquc iiatniitr, atro-viride, cum rodiia longie ; trirlio-
in:itiiiiis p!rruin<|iif lli-MiuM.s; npicr .>litii-r mi uiiilatu ; urtiriilis diauielro I plo brevioribus;
-rpiiuciilis di.stinrtt- gruiiululN ; r\ iioplaMuatu pullidu ta'sio.

l»um.— si'oa"— lo'oo"-

IMi. — In fossis stu^nis prupr Phil;ulr!|iliia.

Strntuni in. .re or Irss compart, aniplr, l>r»ail, mostly floating, blnckMi-grcrn, with long radii ;
filamfiits innstly ll«'\ii'>us; npin-s nliiii-cly rouiiil.-<l; joints j shorter tliun l)road ; dissepi-
ments ili.-tini-tly frranuliiti'; rytinplusm paJe-grayish.

lt< murk* — Tliis sjM-cirs is foU7i<l in tliick, rathrr loose strata, floating, especially
\vlifii old. mi stagnant waters, or adhering to plants, &c., or the muddy shores and
bottom of ditches, lo>d aquaria, «fcc. The color of tlie stratum is a very dark
l)I.icki>h-green, with a ]>ee\diar. L'l"-->. repid-»ive appearance. The single filaments
are iif a pale-liluMi neutral tint, sometimes a little greenish, very much curved
and entangled, or more rarely straightish. Their motion is active. The measure-
ments do not quite equal those given by European authorities, but otherwise the
plant agrees \vrll with their descriptions.

l-'i:,'. on, pi. 1, n IIIVM iits the mass of the plant as seen with flic naked eye; fig.
:;/-, shows a number of filaments slightly magnified; fig. Ic, a broken portion of a
filament magnified '.Ml diameters, with the sheath projecting beyond the cndo-
eliioiiie; fig. !«/, the end of a filament still more highly magnified.

O. limoxa. A.. MIL n.

0. trichomatilms subripidis ct subrcctis, vividc oscillantibns, cscrnlco-viridibus, in stratum muco-
suni ln?tc saturate viridc ct nmdicc longc radians ct natans collectis ct intcrtoxtis, diatincte
arliculiitis; artieulis diamctro sulucqiialibiit. interdnra dnplo brcvioribns (post divisionem),
ad pcnirulu distinctc coiistrirtis ; dissi-pimcntia baud granulatis ; apiculo obtuso, baud atten-
nato, interdum recto, intcrdum rurvato ; cytioplasmate granulato.

Hub. — In stagnis propc Camden, New Jersey.

Filaments straigbtish and soraewbat rigid, yividly oscillating, bluish-green, interwoven into a
bluish-green, floating stratum, with moderately long radii, distinctly articulate; articles about
equal to the diameter, or after division one-half shorter, at the joints distinctly constricted ;
dissepiments not granulate; apices obtuse, not attenuate, sometimes straight, sometimes
curved; cytioplasm granulate.

Remark*. — I have found this species floating on foul ditches near Kaighn's
Point, New Jersey, in the month of May. The color of the stratum is a very pure
deepgrcen; the single filaments vary from a rather bright deep-green to a pale blue-
green, according to the power under which they are seen. The apices are not at all
attenuate. The constriction at the articles is scarcely visible with a lower power than
The stratum is rather thin, with a good deal of dirt adhering to its bottom.

20 FRESH- WATER ALG^E OF THE UNITED STATES.

When grown in a bottle, the plant appears as a very thin stratum growing up the
sides. The agreement of this plant with the descriptions of the European 0. limosa
is very close, so that I do not think it can be separated from it, although in 0.
limosa the dissepiments are said to be distinctly granular.

Fig. 4, pi. 1, represents a filament of the American plant magnified 1250 dia-
meters. The color and form are closely counterfeited, but the characteristic sepa-
ration of the endochrome into parts at the joints is decidedly exaggerated.

O. ncglectn, WOOD.

O. trichomatibus modice brevibus, aut dilute purpuraceo-plumbeis aut plumbeo-cinereis, pler-
umque rectis, aut stratum mucosum atro-purpureum baud distincte radiante formantibus, aut
in strato gelatinoso baud radiante subplumbeo dispersis et cum algis aliis intermixtis, rare
oscillantibus sed lente sese moventibus ; articulis diametro fere 4 plo brevioribus ; dissepi-
mentis plerumque baud granulosis, rare indistincte granulosis; apiculo obtuse rotuiidato,
interdum breviter nonnibil attenuate.

Syn. — 0. neglecta, WOOD, Prodromus, Proc. Amer. Philos. Soc., 1869, 124.

Diam.—f&a" = .0066.

Hab. — In stagnis prope Philadelphia.

Filaments rather short, of a dilute purplish-lead color, or leaden-gray, generally straight, either
forming a mucous, blackish-purple stratum without marked rays, or diffused with other algte
in a gelatinous mass, rarely oscillating but gliding ; articles about four times shorter than
broad; joints for the most part not granulate, rarely indistinctly granulate; ends obtusely
rounded, occasionally short, somewhat attenuate.

RemarJcs. — I have found this plant in the shallow ditches along the track of the
Norristown Railroad above Manayunk, growing in two different ways. In the one
it forms a distinct, soft, gelatinous, floating stratum of a very dark purplish color,
consisting of nothing but interwoven filaments, and provided with long rays. In
the other, the plant is largely mixed with diatoms and other algae into a thick,
gelatinous stratum without rays, whose color is a dirty slaty tint, which, however,
is not all distinctive, and often varies as the proportion of the different constituents
varies. The color of the single filaments is a slaty, almost neutral tint. The
cytioplasm is remarkable for the numerous very minute spots more transparent and
with less color than the surrounding parts. The ends of the filaments are often
abruptly obtuse, frequently however there is a very short taper. Motion docs not
appear to be very active, and seems especially to be gliding, rather than a bend-
ing to and fro of filaments.

Fig. 5a, pi. 2, is an outline drawing of a filament magnified 450 diameters ; 56
is a portion of a filament.

O. imperator, WOOD.

O. in strato mucoso, plerumque natante, olivaceo-atro, longe radiante ; trichomatibus rectis aut
subrectis, tranquillis, dilute viridibus vel saturate olivaceis, haud oscillantibus, sed ambulan-
tibus; apiculis nonnihil attenuatis, late rotundatis vel subtruncatis, curvatis; articulis diame-
tro 5-12 plo brevioribus, ad genicula indistincte contractis ; cytioplasmate homogeneo,
olivaceo-viride ; vaginis firmis, ad genicula distincte transverse striatis.

Syn.—O. imperator, WOOD, Prodromus, Proc. Araer. Philos. Soc., 1869, 124.
Diam.— .002".

i -i; i:< ii- w ATI-: u A !.<;.!•: OF THI: IMTED STATES. 21

Ilnli. — In sta^nis |irojn- riiiluilcl]ihi;i.

i ' • •.•.-urriiig in an nliv.--l.hirk. mucous stratum, mostly swimming and with long rays; filaments

htruijjlit or »trui}:liiisli, lijjlit-frr.-rn or ilcc|i-olivc. ir;iii.|iiil, nut oscillating, but moving with a

gliding motion ; mils M.mi-uluit attriiiiatr, l.n.iully rnundi-d or sulitruncatc, cum-d ; articles

I liin.-.-. -h-r.i r ili.in liroinl, slightly contracted at tin- joints; cytioplasui homogeneous,

olive-green ; .shcutLs linn, ili.-tiuetly transversely grooved at tho joints.

/,'• inn >•/.-*. — The strata <>f tins species are often of great extent, and resemble
more masses of spim^vra than of the ordinary oscillatoria. They arc very loose in
texture anil arc vi-ry slimy, whilst their eil^es arc fringed by the long tranquil
In certain conditions of growth, the endochrome of the filaments is so dense
ns to render them very opaque and the articulations very obscure. The sheaths
when emptied show the marks of the joints very distinctly ; but, at times, when
gorged with (\tioplasm, scan-.-ly can the sheath itself be seen. The color of the
filament is also affected by the state of the protoplasm, so that it varies from a
liijhtish-u'recn with an olive tint to a very decided dark olive. This species seems
ti> he closely allied to the European O. printvfM, from which, however, it differs in
its motion, which is always very slow and merely gliding, its color, the distance of
the dissepiments, and the much longer curvature of the ends. It grows everywhere
in the ditches around the city ; when mature, generally floating upon the surface
with an adherent nnder-stratum of dirt, but, in its earlier history, often adhering

to the bottom.

I'ig. Grt, pi. 1, is a drawing of the end of a filament; fig. 66, represents a small
fragment of a filament, showing the tendency to take a roundish or barrel shape;
much of the endochrome has been squeezed out by the injury which has broken

the filaments.

Genus CHTIIOXOBLASTUS, KTZ.

Phormitlii trichomaU fasciatim congests ct vagina rommuni mncosa apice clnusa vel aperta inclusa.
Tales fasciculi numcrosi in stratum (quasi thulium) gclatinosum, passim araoso-dmsum aggrcgati.
:i8D communes achromatictc, saspe lumellosic, plus minus ampliatac, rarins indistincUe et subnulla-,
evacnatic, plerumque valdc intumcscentes. Trichomata Phormidii modo oscillantia, articulata et
vaginata, rigida, recta vel parum curvula, in fascicules funiformes plus minas dense contorta, apico
soluta et divaricata. Cellulas propagatorias observarc mihi contigit. (K.)

Filaments fasciately placed together and included in a common mucous sheath with open or shot
apex. A number of these fasciculi aggregated in a gelatinons stratum (pseudothallus), which is
gelatinous, and here and there ramosely divaricate. Common sheath colorless, often lamellate, more
or less enlarged, rarely indistinct and nearly wanting, when empty mostly markedly intumescent.
Filaments oscillating like to those of Phorraidium, articulate and vaginate, rigid, straight, or a little
curved, more or less densely entangled into cord-like fasciculi, with the apex dissolved and dis-
severed.

C'h. rrpens, KTZ.

Ch. terrestris, strato plus minas expanse, satnnxtc aeniginpo-chalybeo aut olivaceo-fuscescente,
mncoso-mcmbranaceo ; trichoniatibus equalibus in fascicules filiformcs, soepe valde elon-
gatos, e vaginae communis apertura penieillatirn cxsertos congestis; articnlis diametro tequali-
lni-i disscpimcntis granulatis, apiculo obtuse recto. (R.)

Species, mihi ignota.

22 FRESH-WATER ALGJR OF THE UNITED STATES.

Hab.— Common on damp earth. West Point, New York ; Bingluun, Massachusetts ; Provi-
dence, Rhode Island; Baily, Silliman's Journ., N. S., vol. iii.

Terrestrial, stratum more or less expanded, deep aeruginous chalybeate, or olivaceous fuscous,
mucous membranaceous ; filaments equal, in filiform fasciculi, which are often much elongate
and penicillately exserted from the open common sheath ; joints as long as broad, the dissepi-
ments granulate ; the apex obtuse, straight.

Genus LYNGBYA, AGARDH.

Trichomata inarticulata vel breve articulata, cellulis perdurautibus instructa. Yaginse ssepe colo-
ratae, crassse, ssepe Iamellona3.

Filaments not articulate, or shortly so, furnished with heterocysts. Sheaths often colored, thick,
often lamellate.

"L. muralis, Aa.

Filaments somewhat rigid, thickish, tortuous, very long, interwoven in a bright, grass-green
stratum; annuli strongly defined. Ag. Syst., p. 74 ; Harv. Man. Ed., p. 160; Conf. muralis.
Dillw., tab. 7, E. Bot. t. 1554. |3. aquatica.

Hob. — Var. j3. in pools of fresh water, Whalefish Island, Davis Straits. Dr. Lyall.

The specimens are mixed with turfy soil. Except in the submerged habitat, this agrees with
the ordinary form. Intermixed with threads of the usual size and structure are others
cohering in pairs, as in L. copulala, Ilarv., which is obviously only a state of this widely
dispersed species. I have not received specimens of the ordinary L. muralis from America ;
but no doubt it is common on damp walls, &c., as in Europe generally."

I have never identified this species, and have simply copied Harvey's account
of it from the Nereis Boreali Americana, pt. III. p. 104.

I;, bicolor, WOOD.

L. trichomatibus simplicibus, in csespites nigro-virides vel caaruleo-virides dense intricatis, varie
curvatis, plerumque inarticulatis, intcrdum breviter articulatis et ad genicula contractis; cytio-
plasmate dilute cseruleo-viride, plerumque copiose granulate, ssepe intcrrupto ; cellulis perdu-
rantibus cylindricis, ssepe elongatis, saturate brunnejs, sparsissimis; vagiuis firmis, achrois, in
trichomata matura modice crassis.

Syn. — L. bicolor, WOOD, Prodromus, Proc. Amer. Philos. Soc., 18G9, 124.

Diam.— T7V5"-

Hab. — In flumine Schuylkill prope Philadelphia.

L. with the filaments closely interwoven into a blackish or bluish-green mat ; filaments variously
curved, simple, mostly inarticulate, sometimes shortly articulate with the joints contracted ;
endochrome light bluish-green, mostly very granulate, often interrupted ; heterocysts cylin-
drical, often elongate, deep brown, very few; sheaths firm, transparent, in old filaments
moderately thick.

Remarks.— This species is abundant in the shallow water of the Schuylkill
River, near Spring Mills, where it forms dark waving tufts a half inch or more in
height, which are adherent either to the bottom of the stream or to some firm sup-
port, such as large growing plants, sticks fixed in the mud, &c. When examined
with the microscope, these tufts are seen to be composed of innumerable, very long,
motionless, greatly curved filaments. They do not seem to be attached to their
support, but in the denser parts are woven into a very thick mat, which apparently
adheres en masse to the fixed body. These filaments are very rarely articulate,

FBB8H-WAT1B ALG.E OF T 11 E UNITED STATES. ;>3

hut, when they arc, the joints arc shorter than broad. The endochrome is mostly
\< iy ^'iMiiulate ; sometimes, ln>\\r\cr, it is niucli more honiogvncnns. The sheaths
in the old filaments are rather tliick, and freqiu 'iitly partially empty; the exterior
i if such sheaths has often a roii^'h, ra^ed look. The larger cells are very few in
numher. They are elongated cylinders with concave ends. I have found this plant
in the Schuylkill Hiver, just above 1 airmount dam, in a younger state, and appa-
rently without heterocysts. The threads near their ends had their endochrome
distinctly articulate, like an oscillatoria, but elsewhere the protoplasm was continu-
ous. It often contains numerous large granules resembling minute starch grains,
which however fail to exhibit the reaction with iodine.

l-'ig. ~. ". pi. 1, represents a portion of the filament slightly magnified; fig. 7, 6, a
heterocyst from the same specimen more magnified ; fig. 7, cam! <I, are drawings from
another specimen from the same locality, each magnified 800 diameters ; fig. 8,
pi. 1, represents the form alluded to in the text as having been found ill the
Schuylkill River just above the dam.

FAMILY NOSTOCHACELE.

Trirhomata simpliciix, c cellulis distinct!* composita, interUum vaginata, articuluta, in gclatina
immrrsa, ccllulis pcrdurantibus, ct intcrdum sporis porro instructa.

Filaments simple, rmiipii.-cil «.f di.-tinct cells, sometimes vaginate, imbedded in jelly; furnished
with lictcroeysts and sometimes with spores also.

/,'• murk*. — The nostochacere are plants of simple construction, consisting of a
more or less firm jelly in which arc imbedded serpentine filaments, composed of
numerous cells. These cells are mostly more or less globose, especially in the true
no-toes, so that the filament has amoniliform aspect. They have not distinct walls,
or at least any that can be distinctly seen by ordinary powers of the microscope,
and arc sometimes closely connected, sometimes rather widely separated. No
nuclei are usually discernible ; I have, however, seen in some instances central
spots, which were possibly of that nature. The filaments themselves arc of various
length, almost always tortuous, sometimes widely separated, sometimes closely in-
terwoven. The gelatinous portions of the fronds are of various consistence — some-
times semifluid, sometimes very firm, almost cartilaginous.

The order is divisible into two families — the Noatocs proper and the Sjtermosirccr.

In the former, the outer portion of the frond is condensed and firm, forming a
sort of outer coat or epidermis, which is sometimes quite distinct, but in other
instances can scarcely be said to exist.

In the filaments of a true nostoc are placed at irregular intervals cells, which
are mostly larger than the others, and have thick, distinct walls. These cells con-
tain very little or no chlorophyllous protoplasm. They arc often, but by no means
always, provided with numerous exceedingly attenuated, hair-like processes, or
quiescent cilia. These bodies were supposed by Kutzing to have some sexual
value, and received from him the name of Sjxrmatia. But, as their functions are
entirely unknown, the name of heterorysts, first applied by M. Allman, is prefera-
ble. They arc the " connecting cells" of Thwaites. No one has as yet demon-

24

FRESH-WATER ALG.E OP THE UNITED STATES.

stratcd the existence of anything indicating sexuality in the nostocs proper, or
shown any body at all worthy to be looked upon as a spore.

Their ordinary method of reproduction is simply a slight modification of that of
growth. If a fragment of an actively growing nostoc is placed under the micro-
scope, the filaments of it are seen to be irregular and distorted, thicker in one
place .than another, the cells misshapen, and sometimes apparently lumped and
fused together. The formation of new filaments is taking place in such cases by
the simultaneous growth and longitudinal segmentation of the cells of the old, and
this may occur through the whole or in only a portion of the length of the latter.
(PL 2, fig. 10.)

The filament of a nostoc is, in other words, capable of a double growth or de-
velopment, the result in one instance being increase in its length, in the other the
production of a new form like itself. The first of these is brought about by a
transverse division of the cells, so that out of each single cell two are formed,
placed end to end, each daughter-cell at first only half the size of their parent, but
soon attaining to its full stature. In the other case great increase in the size of
the cell occurs almost consentaneously with a longitudinal or lateral segmentation,
the cell dividing in the direction of its length, instead of transversely, so as to form
two cells lying side by side instead of end to end. The misshapen filaments alluded
to simply represent different stages of this change, which goes on until two perfect
filaments lie side by side, to be finally more or less widely separated by the jelly
which they secrete around themselves.

This process of growth continues until the plant has arrived at its mature size,
when it ceases. During this time the inner portion of the frond has been be-
coming more and more liquid, and finally the outer epidermis bursts and the
thoroughly softened inner portion is discharged. In this way, innumerable filaments
are set free, which are endowed with a power of motion similar to, but much less
active than, the gliding of the oscillatoria, by means of which they are diffused in
the water. Scattered in this way, carried hither and thither by currents, each
minute thread, fixing itself to some object, at last becomes the centre from which
a new plant is formed in a manner similar to that already described.

In the second division of the NostocJiacece, the jelly is always much less firm
than in the true nostocs, and is not condensed in the outer portions. The fronds
are therefore soft, almost diffluent, and entirely shapeless. The filaments them-
selves also differ from those of the true nostocs. There are no fixed differences
in the vegetable cells or heterocysts, however, although the former are apt to be-
come more cylindrical and the filament consequently less moniliform. It is espe-
cially in the possession of distinct reproductive sporangial cells that the differences
are to be found. These are much larger than the ordinary cells, from which, in
their first appearance, they are not distinguishable ; but, when the frond has attained
a certain age, the spore-cells begin to enlarge both in diameter and length, and
finally assume a form and size apparently fixed within narrow bounds for each
species, and surround themselves with distinct, often quite thick coats. It is very
possible that the production of new individuals may take place by a detachment of
portions of the frond and subsequent growth, as described in the Nostocs proper,

FRESH-WATER ALG.K OF Till: f M T K D STATES. 26

but increase of tin- dot - •-. rtainly occur by means of these so-called spores.

The growth of tin; plant takes place in tin- same way as in tin- true nostocs.
The filaments increase in length by tran>\i rse division and consequent multiplica-
tion of the cells, whil>t new tilaincnts an- formed by the consentaneous longitudinal
division of all the cells of a filament.

The spores of a Cyli»dro»j>ennutn have the power of germinating after prolonged
desiccation, they having been successfully cultivated even from specimens long
preser\ed in the herbarium. Their development lias b.-rn carefully and success-
fully studied by M. Thuret. According to this authority the first change consists
in an elongation of the spore, which ruptures the wall of the sporangium, pushing
a portion of it before it. Directly after this the spore undergoes division, so that
out of it is formed a little torulose filament, composed of four or five cells. Growth
takes place at both ends, but more rapidly at the free one. The new cells formed
are smaller than those which arise directly from the spore, but, finally, all the arti-
<•!.•-< assimilate. The wall of the sporangium remains attached for a long time to
the end of the filament forming a little cap to it. The heterocysts, according to
Thuret, at lirst are indistinguishable from the ordinary cells, but after awhile the
grannies in them begin to disappear, the color to pale, the outer wall to become
apparent and grow thicker, until at last a perfect "connecting cell" is educed.
I have, myself, carefully watched the early development of the spores of a cylin-
(Irospermum, and can confirm, in all essential particulars, the description Thuret
has yiven of the process. Fig. 10, pi. 2, represents a partially formed filament,
to which the empty sporangium is still attached.

As no sexual reproduction has as yet been shown to exist among the XostocJia-
it is very e\ident that their whole life-history is not comprised within the
changes which have been detailed. It has long been known that the gonidia of
many lichens have the power of independent existence, i.e. that when they are
discharged from their thallus they can continue to live and multiply, if circum-
stances favor them, without giving origin to a new thallus. This, and the great
similarity of structure between the nostocs and the lichen genus Collema, has
suggested a possibly close relation between the two. The first observer, I believe,
who asserted that they were different stages of the same plant was Dr. Hermann
It/igsohn.

His observations are, however, rendered of so little value by his own statements
that it is not necessary to review them here. Thus, he says, that after seven years'
rvation he had yet to see a true one called algtc, that the Desmidia; are, at
least, two-celled, &c. &c. The most weighty observations upon this subject are
those of Professor Julius Sachs and of J. Baranetzky — the former published in the
Botanische Zeituny for 18.55, the other in the Bulletin of the St. Petersburg
Academy for 1867.

Professor Sachs states that he watched a whole bed of Noafoc commune deve-
loping into Collema bulbosum. He says that the peculiar Collemoid threads first
appeared as little lateral offshoots or prolongations from the cells of the nostoc
filament, and rapidly developed into well-formed collemoid filaments. Every
possible stage from the typical nostoc to the typical collema was seen repeatedly.

4 r«bru»ry, 1872.

26 FRESH-WATER ALG.E OF THE UNITED STATES.

The development of the distinguishing threads of the collema out of the ordinary
nostoc-cell has never been confirmed by any other observer; but it seems to me
that it must be at least provisionally accepted, although De Bary expresses some
doubt of it. (Morphol. und Physiol. der Pilze, Flechten, &c., p. 290.)

The researches of M. Baranetzky were directed to the developing of a nostoc
out of a collema. Hicks and other observers had previously stated that they had
seen this, but none of them had given sufficient details as to the method of their
observations, to be fully convincing.

M. Baranetzky placed sections of actively growing fronds of Collema pulposum,
Ach, upon smooth, damp earth, using all proper precautions to prevent external
influence. After some days the sections became less transparent and intensely green
from the crowding of the gonidia, which were now arranged in curved rows closely
rolled together into balls. Upon the upper surface of the section appeared little
gelatinous balls or warts, which contained gonidia in rows, and gradually developed
typical nostoc forms, whilst on the edges of the sections appeared little colorless
wart-like masses of jelly, in which, after some time, appeared gonidia, some of
which developed into the typical nostoc form, others into true collemoid plants.

Mr. Baranetzky further states that he watched the body of the section gradually
change by the continual growth and increase of the rows of gonidia, before alluded
to, and by the disappearance of the collemoid threads, until at last the whole
mass of the tissue of the lichen had been converted into a true nostoc, which was
finally identified as Nostoc vesicarium, D. C.1

I have no observations of my own to offer upon this subject; but think enough
has been done to show not only that the nostocs proper have very close relations
with the collemoid lichens, but that they are probably a peculiar phase in their
life-history. This being the case, it may seem a perfectly superfluous work to
indicate species amongst the nostocs. To any one who has given much study to
the fresh-water algae, the reply to this will immediately suggest itself; namely, that
in the present state of the science it seems impossible to avoid it; they are so
commonly thrust at one by collectors, amateurs, &c., arc so distinct, are so often
the subject of tongue and pen, that they must have a name. The idea that at-
taches to the term species is at present not a very definite one; that there are,
however, amongst the nostocs fixed forms, which do not change into one another,
and can readily be distinguished, I have no doubt. Such forms are herein de-
scribed. If they be only life stages of lichens, I have no doubt that it will finally
be found that each so-called species of nostoc has its own peculiar so-called species
of lichen, from which it alone springs, and into which alone it can develop. It
seems to me, then, that as yet no cause for abandoning the specific names of the

1 In order to aid any one desirous of going over this subject more thoroughly, a list of papers is
appended : —

Ventenab und Cassini Opuscula Phytolog., 1817, vol. ii. p. 361.

Dr. Hermann Itzigsohn. Botanische Zeitung, 1854, p. 521.

Prof. Julius Sachs. Botanische Zeitung, 1855, p. 1.

Bayrhoffer. Botanische Zeitung, 1857.

Hicks. Journal of Microscopical Science, 1861, p. 90.

Baranetzky. Bulletin de la Societe des Sciences Nat., St. Petersburg, vol. xii. p. 418.

F R i: S II \V A T K II A L 0 JE OF TUB UNITED S T A T K 8. 27

has In i 11 sli(i\Mi. hut only reason td stiitly also their relations with thv \ari-
eollema.

In n-ijaril t<> tin- >/» / •iiKvii-nt . tin n- i- as yet no direct proof whatever connect-
ing thrin \vitli lirliciis. It i- \< i\ possible that they are not so closely related to
the true nostocs as is tjencrally ln-li«-vril, so that the prohahilitii-s of their being
licln-iis an- at present so remote, tliat for the sy-tt-matist to refuse to take note of
their distinct forms seems to me m.»t unwarrantable.

SIBKAMII.V NOSTOCE^E.

Tliallus JM •riiliTiiintr plus minus distincto instructus, sporis dcstitutus.

Thullns providril with a more or less ili-iim-i int> innm-nt, and destitute of spores.

( ienus NOSTOC, VAUCHEB, (1803.)

Tli.i!''i- iri •l:iiiii<isn<. v:irii- cnlnratus, aut globosus vel Rul>plobo8n8 .nu foliacoo-memhrannceug ct
irr. triilurit.T cxpansus, su-pc Imllutus. Trii-buniuiu plus uiiuus niouiliformia. Cclluto perdurantca
>pli:iTi.-.r vi 1 rare oblongc.

Ttialliis pi'lntinoiis. variiiii-ly colored, pitlirr plohooc or BnbgloboM, or folincoously incmbranoiiB
ami inilriiniiclv expanded, often a liiillu. FiluinenU more or less monilifonuo. HctcrocjsU exactly
hplit-rii-al or rarely oblong.

a. Ttiallus globiisus vel subylobotvt. <;-l tl,.<,-iformi».
Thallus ijl»l*>*f, Hiilxjlobose or discoid.

IH. Auolmii. \V.K)D, (sp. nov.)

.li-_pliil)i>siiiii, |iiirvuni, plornniquo innpnitndinr ovorum piscium, rare ad 2", fuscescente,
vel nigresccnti-, intrnluin durum inlt-riliiin Mihnmlle, superGcie sii'pc corrugata ; tricho-
mntilms varic curratis, dense intrioatis rel dintantibos et lazisHime intricatis, viridibus,
t'u.-r, -. •• -iitilms, suliplunilM-is vcl lutco-brunncis, in thallis minoribus saepc distincte vaginatis,
in thullis majorihus liaud TC-1 inilistiiic-tc vaginatis ; articulis .maturis globosis, saepc didvmis,
crasso granulatis; cellnlis perdurantibus articaloruin diamctro ocqaalibus vcl paulo majoribus,
glol>osis, interjcctis rcl tcrminalibus, plerumquc sparsis.

Diam.— d-ll. V.-p, T^n,"_ TT^Tr" - .002C"— 00033"; cell, pcrdnrant, .00033".

Hob. — in rupibus irroratis, New Jersey. (Austin.)

Sol)jtlolK)so, small, mostly the size of fish-cgga, but reaching the diameter of nearly two lines,
fu-«-ou8 or blackish, sometimes very hard, sometimes much softer; surface often corrugated;
filaments variously curved, densely intricate or distantly and loosely interwoven, greenish,
fuscous, subplumbeis or yellowish-brown, in the smaller fronds often distinctly vaginate, in
the larger indistinctly or not all vnginate ; mature joints globose, often didymons, coarsely
granulate; hetcrocysts equal to the diameter of the other joints or a little larger, globose
interspersed or terminal.

I,'' marks.— The fronds of this distinct species vary greatly in appearance; the
larger of them are often almost colorless, and, when viewed with the microscope,
an seen to be composed of a transparent colorless jelly, with remarkably large
filaments scattered through it. These filaments are generally without sheaths,
though occasionally a sheath can be faintly traced. The smaller fronds are much
firmer than the larger and are more decidedly colored. Some of them are entirely
opaque, looking simply black when viewed by transmitted light under the micro-
scope. In these the filaments are densely crowded together, often misshapen and

23 FRESH-WATER ALGJ2 OF THE UNITED STATES.

provided with distinct broad brownish sheaths : every gradation exists between
these forms and the first described fronds. The heterocysts are quite uniform in
size, agreeing in diameter with the largest vegetative cells, they are always single.
This species is most nearly allied to N. ichthyoon, RABENH. ; from which it is
separated by the differences in the sheaths, the greater size of the filaments, and
the single heterocysts. It gives me great pleasure to dedicate the species to Mr.
Austin, by whom it was collected near Gloucester, New Jersey, growing amidst
mosses on rocks.

1¥. pruniforme, (ROTH,) Agh.

N. magnum, gregarium, noncohsercns, globosum, magnitudine pisi, pruni majoris et ultra, oliva-
ceum vel saturate serugineuin, estate provecta fusco-nigrescens, baud raro cavum, lajvissimum,
intus aquosum, peridermate coriaceo subachroo ; trichomatibus subtequalibus, hie illic tumidis,
laxe intricatis; articulis globosis, plerumque compressis, ssepe didymis, arete connexis; cel-
lulis perdurantibus articulis duplo majoribus, pleruinque terminalibus, rarius intcrjectis. R.
Species mihi ignota.

Diam.— Artie. 0.00024"— 0.0003" ; cell, perdur. 0.0003—0.00045". (R.)

Syn. — 'N. pruniforme, (Rom,) Ao. RABENHORST, Flora Europ. Algarum, Sect. II. p 1G8.

Hob, — Maine. Leidy.

Large, gregarious, not cohering, globose, varying from the size of a pea to a large plum, or
even beyond this, olivaceous or deep SBrugineous, in old age blackish fuscous, often hollow,
very smooth, within watery, periderm coriaceous, somewhat transparent; filaments subequal,
here and there swollen, laxly intricate ; articles globose, mostly compressed, often twofold,
closely connected ; heterocysts twice the size of the vegetative cells, mostly terminal, rarely
interspersed.

RemarJcs. — I have never found this species ; but some years since some speci-
mens, sent to the Academy of Natural Sciences of Philadelphia from Maine, were
identified by Professor Joseph Leidy as belonging to it.

1¥. rcrriicosiim, (LINN.) VAUCH.

N. magnum, gregarium, bipollicare et ultra, subglobosum, ssepe lobatum, verruculosum, irrora-
tum, initio solidum, postremo cavum, vesiciforme, saturate brunneo-viride ; peridermate mem-
branaceo-coriaceo, olivaceo-fuscescente; trichomatibns varie curvatis, centralibus parcioribus
et laxissime intricatis, periphericis densius intricatis; articnlis oblongis, rare globosis, arete
connexis, crasse granulatis; cellulis perdurantibus interstitialibus vcl terminalibus, sphajricis,
articulorum diametro duplo majoribus.

Diam.— Cell vegetativ. .000166"; cell, perdurant. .000233".

Syn.—N. verrucosum, (LINN.) VAUCH. RABENHORST, Flora Europ. Algarum, Sect. II. p. 176.

Sab.— In fonte, Centre County, Pennsylvania.

Large, subglobose, often lobed, warty; gregarious, two inches in diameter, growing under water,
fixed, in the beginning solid, afterwards hollow, bladder-shaped; periderm membranaceous,
coriaceous, olivaceous-fuscous; filaments variously curved, centrally fewer, and laxly intricate,
towards the outside much more close; articles oblong, rarely globose, closely connected,
coarsely granulate ; heterocysts interstitial or terminal, spherical, twice the size of the other
joints.

RemarJcs.— In the summer of 1869, 1 found a nostoc growing in great abundance
in a very cold, large, limestone spring in Centre County, Pennsylvania, which I

FRKS1I-YY ATKU ALUJi OF THE UNITED STA1 •_>.(

ha\e referred to N. vern«-<«>t>u with some little hesitation. Some of the fronds
were smootliMi, otht TS \i-ry decidedh warty. M\ specimens are old plants,
which h;i\f become hollow by tin- discharge ot" their internal contents. It is pos-
sibly on tliis account 1 have, not been al>lr to \eril\ the minute description giu-n
h\ I'rotevxir Uabenhorst. As tin- latii-r may not be accessible to sonic of those
wlio consult these pages, I append the latter part of it, which differs from that
£\\( -n by myself from the American planK

" Trichoinatihiis hVxtioso-cnrvatK quasi triplici online; ccntralibus pnrcioribus,
•Mine impliratis, apices \risiis plus minus attennatis, articulis oblongis, sub-
(li>taiitilms. periphericis deiisin* sa-pe densissime intricatis, basi haud raro cellulis
biseriatis, articulis glohosis, arete conncxis, extremis (nonnisi in thallo vetusto
oc( urrunt) snbHagelliformibns, articulis oblongis, cylindraceis spha-ricisque sinnil
immixtis, distantibus; cellnlis perdurantibus spho?ricis interjectis terminalibusque,
nonniinqnam pluribns simnl seriatis articulonim diamctro duplo triplove mnjoribus."

According to 1'rofessor Harvey (Nereis Bor. Amer., part iii. p. 114), this species
been collected by Dr. Lyall in pools of fresh water, Isle of Disco, and at
I!. • chey Island, Arctic Regions; also by Mr. Fendler at Sante Fe, New Mexico.

IV. alpinum, KTZ.

V nijirMrc, iinimTsnm ; thallo suborbicularc, erccto, niemfiranaceo, ad ^ = | nnciatn lato, ad
lincaa iluas vel tree craeso, tcnaci, saturate olivaceo-fusco, la.>vi, eapc rugoso-plieato, cum mar-
ginc intcgro et plerumqne incrassato; trichomatibus varic curvatis, laxc vel nonnibil dense
implicatis; articulis fuscis vel dilute rerugineis plerumque globosis, sa-pe subtiliter granulatis,
arete conncxia; cellulis perdnrantibus spheericis plerumque articulorum diamctro paulo nia-
juribus, iniiTiluui subsqualibus, inteijectis vel terminalibus.

Diam.— Artie, vegctativ. .00016"— 00023"; cell. pcrd. .00026.

— " N, alpinum, KTZ. Phycol. General., p. 206, No. 10." RABENDORST, Flora Europ.

Algnrum, TO), ii. p. 174.

"A*. Xutherlandi, DICKIK." HAKVET, Nereis Boreal! Americana, part iii. p. 114.
" N. crixtatum, BAILEY." HARVEY, Nereis Boreali Americana, part iii., 1857, p. 114.
Growing attached by its margin to the- rocks in running water; thallus snborbicnlar, erect,
mcmbranaccous J — j an inch high and 1 — 3 lines thick, very tenacious, deep olive-green,
smooth, often rugosely plicate especially at the base, with the margin entire, rounded, and
mostly thickened; filaments variously curved, laxly or somewhat densely interwoven; arti-
cles fuscous or greenish, mostly globose, often finely granulate, closely connected ; hcterocysts
spherical, generally a little larger than the ordinary cells, sometimes about equal to them,
interspersed and terminal.

Remarks. — This interesting little plant was found in the mountain rivulets
near West Point, New York, by the late Prof. Bailey, and received from him the
ific name crwtatitm, first published in Harvey's work on the North American
Alga>. I have myself seen it growing in very great abundance in rapid mountain
ins in the central portions of this State. It is doubtless, therefore, an inhabi-
tant of the whole Allegheny range. In the low country, east or west of these
mountains and their outlying hills, I do not know of its having been found. I have
very recently received specimens of a nostoc from Sereno Watson, Esq., undoubt-
edly belonging to this species, which were collected by himself, in cold streams in the
Clover Mountains, Nevada, at an altitude of 11,000 feet. Under the name of M.

30 FRESH-WATER ALG^E OP THE UNITED STATES.

Sutlierlandli a nostoc has been described by Mr. Dickie, which was collected in the
neighborhood of Baffin's Bay, and must be referred to this species, although the
description given of it is very imperfect. Again, N. alpinum, KTZ., appears to be in
all respects similar to the North American forms. So that this cosmopolitan little"
plant seems only to ask for a cold shelter, and it nourishes. The Alps, the Alle-
ghanies, the Rocky Mountains, and the cold North are its homes. To those who
believe in a single centre for a species, the suggestion that it has spread across
the globe, through the arctic regions, and followed our mountain chains southward,
will of course present itself.

As I have seen it, the plant is very abundant where it grows, five, six, twelve,
or more of the little fronds adhering to a single pebble. The frond is generally
longer than broad, the margin sometimes sinuous but never, as I have seen it,
lobate or incised. It appears finally to burst and discharge its inner portion,
whilst the outer cortical portion, now a little vesicle containing a globule of air, is
set free and floats down the stream.

I¥. depressum, WOOD, (sp. nov.)

N. euormiter suborbicularc, minutum, gregarium et interdum aggrcgatum mnscos immersos
adhserens, mangitudine seminis sinapcos vcl parvius, durum, clasticum, subnigris; pcridermate
firme, achroo; trichomatibus plerumque laxe intricutis, baud vaginatis; articulis globosis,
plerumque modice arete connexis, rare distantibus; cellulis pcrdurantibus globosis, ccteris
paulo majoribus.

Diam. — Artie, veget. max: .0002"; cell, perdurant. max .00029.
Hob. — In rivulis, New Jersey (Prof. Austin).

Irregularly suborbicular, gregarious and sometimes aggregated, elastic, blackish, about the size
of a mustard-seed, or smaller, adhering to immersed mosses ; periderm firm, translucent ; fila-
ments not vaginate, mostly loosely interwoven ; joints globose, generally rather closely con-
nected, rarely distant ; heterocysts rather larger than the other.

Remarks. — This plant was found by Prof. Austin attached to a brook-moss
(DicJielyma), growing in a rapid rivulet in Northern New Jersey.

The minute fronds sometimes are so thin and spread out as to be almost folia-
ceous. The species I take to be most nearly allied to N. lichenoides of Europe,
from which it is, however, apparently distinct. In the American plant the fila-
ments and heterocysts arc a little larger, and the frequent elliptical cells of the
European plant are wanting. The frond also apparently does not grow so large as
the European, and is further distinguished by its flat, discoid form. In many of the
specimens examined the filaments are very thick, irregular, and contorted, the cells
being fused together. In other instances, a filament will be plainly double, and
every grade between these conditions is present. This is plainly owing to a process
of growth, to the cells enlarging and dividing laterally so as to form new filaments.

W. sphaericnm, (POIRET,) VAUCH.

N. globosum, interdum oblongum vel ovale, gregarium, ssepius aggrcgatum, raro tamen conflu-
ente, durum, elasticum (in state provccta intusmollc ct subaquosum?), olivaceum, niagnitudinc
seminis sinapeos, ad cerasi parvi ; peridermate firmo, pellucido; trichomatibus intricatis, luteo-
lis, aut prasinatis aut dilute cseruleis; articulis plerumque subquadratis, interdum transverse

PUESlI-WATi: K ALG.fc OF T II K f N I I li I) STATK8. 31

subovalilm*, arete connexU; cytioplasmatc granuluto; cellulis pcrdurantibus iiitcrjectii

terminal ilm>i|ii<-, ..plKi-rii-i.*.

Diam. — Vrtie. diaui. long. 10'oB" — .OOOl'J J" ; trangv. n'99" — .00017"; cell. p. rdurmnt.
M'OO"

n. — 3T. tphtericum (I'uiRET ) V.\i <-ii. KAIIKXIKIUCT, Flora Kurop. Algarum, Sect. II.-p. 167.

//,i/,. — In foiitibus, prope Philadelphia.

(Jlolxwe, sometimes oblong or oval, gregarious, l.ut rarely confluent, hard, elastic (in advanced
ago within sort ami watery?), uln.i. ..... i~. varying fruiu the si/.c of a mustard-need to that uf

aKinall eherry; prriderm firm, pellucid ; filament* intricate. yellowish, greenish or bluish;
articles mostly sul>i|uailrate, sometimes tran-vcr-cly suboval, closely connected ; cytioplasm
granular; h I intcr-pcr.-cd ur tiriiiinal, spherical.

/,'• murk*. — The specimens from which the above diagnosis was prepared were
found at Spring Mills, adhering to mosses and twigs in the water. The fronds
were remarkable tor their firmness and elastieity. The color was a dull, rather
greenish, olive ; that of the filaments varied from a decided greenish to a marked
yellowish, or sometimes an almost silvery hlni>h tint. The heterocysts were rather
;n number, and wen- either terminal or interstitial, sometimes they were with-
out, sometimes with evident emlorhromc. The length of the general articulations
varied a good deal, it was, however, mostly less than their breadth, which seems
quite constant. When kept in water in the house, this species softens, and the
periderm as it were peels off, allowing the interior to disj>erse itself as it gradu-
ally heroines more and more diffluent. Most of the fronds afforded ample evidence
of their method of growth by the presence of filaments in every stage of division.
in. pi. •>, represents filaments of this species.

IV. cirruleiim, I.VXOB.

N. minimum, siepc microscopicnm, cnormiter globosum vcl snbglobosnm, nflixmn, grcgaritim,
sejanctum vel aggregatum ; trichomatibuB valde inicqualibus; articulis clongato-cylimlrari-is,
vi -I acute ellipticis, vel pcrfectc cllipticia, vel globosis, vel nubglobosia, vcl sulMjuadranguli^,
et nonnihil distantibus vcl arctc connectis aat confluentibus ; ccllulis perdurantibus
passim interject is terminalibusquc, cctcris duplo vel subduplo majoribus.

Diam— Cell, pcrdurant, .000303; cell, vegetal, plerumquc .00012—000166"; rarius .0001—

.00021.

Syn. — ff. cscrulcnm, LTNOB. RABENnoRsr, Flora Europ. Algarum, Sect. II. p. 1C7.
Hab.— Inter muscos, New Jersey (Prof. Austin).

Vrry small, often microscopic, irregularly globose or subglobose, affixed, gregarinns, Roparnte or
aggregated ; filaments very unequal ; articles elongate-cylindrical, or acutely elliptical or
perfectly so, or subglobose, or globose, or Rubqundrnngnlnr, separate and somewhat distant
or closely connected or confluent ; hcterocysts globose, interspersed or terminal, double or
about double the size of tbo other cells.

/,'• nmrl:*. — I am indebted to Mr. Austin for specimens of this species collected by
him in Northern New Jersey. The fronds grow attached to moss and are very mi~
nute. the largest I have seen being not more than half a line in diameter. The
filaments are remarkable for their inequality, which is often very perceptible in
different parts of the same filament. I have referred my IpecifBeiM to ^V. atruleum —

32 FRESH-WATER ALG^E OF THE UNITED STATES.

the only differences between them and the European plant are that they are not so
large, and do not agree in color, many of them being browner; but these are certainly
insufficient grounds for separating them. Prof, llabenhorst speaks of observing
the contents of heterocysts dividing up so as to form a little colony of cells, which
finally break through the maternal wall. I have only studied mounted specimens,
but have seen very clearly heterocysts in which this process was taking place.

r¥. piiiictnf inn, WOOD, (sp. nov.)

N. terrestre ; thallo expanse orbiculare vel nonnilril irregulare, tenuissimo, ferngineo, parvo
membranaceo, pellucidulo; trichomatibus laxe intricatis, varie curvatis, articulis globosis vel
saepius ellipticis, plerumque medio pellucidulis, laxc conncxis ; ccllulis pcrdurantibus ternu-
nalibus vel interjectls.

Diam.— Cell, vegetat. TI^T" = .000166 ; cell, perdur. T5£5/ = .00033.
Hab. — In terrestre, New Jersey, (Prof. Austin.)

Terrestrial ; thallns expanded, irregular or orbicular, very thin, seruginous, small, membranous,
pellucid; filaments loosely interwoven, variously curved, joints globose or often elliptical,
mostly pellucid in the centre, loosely connected ; heterocysts terminal or interspersed.

Remarks. — Mr. Austin has kindly sent me the only specimens I have seen of this
species; they are labelled "Damp Ground, Sept." The fronds, which are often
aggregated, are very small and exceedingly thin, especially in their central por-
tions, where they are quite translucent; in form they are often circular, some-
times quadrangular, sometimes quite irregular. As to size, most of them are not
more than two lines in diameter, some three, or possibly five lines. The margins
are often reflexed and thickened, especially in the smallest fronds. Two kinds
of filaments are visible ; 1st, those which I take to be in a perfected quiescent
state ; 2d, those which are in active growth. The former are composed of globose,
or more commonly elliptical joints, which are remarkable for the possession of a
central translucent, almost colorless spot, the endochrome apparently being arranged
in a ring around the outer part of the cell. This is, however, occasionally want-
ing. The filaments, which are in active growth, are very irregular in form, often
much broader than the others; their cells very irregular and sometimes fused
together into one mass. The measurements given in the diagnosis were taken
from the filaments of the first kind.

b. Thallus indefinite expansus.

Thallus indefinitely expanded.
1¥. €esatii, BALS.

N. terrestre ; thallo longe latcque expanso, gelatinoso-mcmbranaceo, viridi-flavescente ; tricho-
matibus flexuoso-curvatis, sublaxe iraplicatis, pallide aerugineis ; articulis sphsericis, laxe vel
arctius connexis ; cellulis perdurantibus sphajricis, et interjectis et terminalibus.

Diam.— Artie. .00016— .0002; cell, perdur.— .00033".

Syn. — N.Cesatii, BALS. RABENHORST, Flora Enrop. Sect. II. p. 175.

Nab— In terrestre, Kansas (Prof. Parry) ; Texas (Prof. Ravenel).

Terrestrial; thallus broadly and indefinitely expanded, gelatinous-membranaceons, yellowish-
green ; filaments flexuously curved, rather laxly implicate, pale-greenish ; articles spherical,
laxly or more closely connected ; heterocysts spherical, both interstitial and terminalibus.

FRESH WATER ALOJJ OF THE UNITED STATES. 33

Remarks. — This plant was sent to me by Dr. C. C. Parry, from whose letter the
following is extracted : " I send enclosed specimens of a singular land Alga? which
I met with in this vicinity; lightly attached to hare patches of soil interspersed
with buffalo grass. In the adjoining bluffs are cretaceous shales full of scams and
layers of selenite, from the decomposition of which the bottom soil becomes
strongly impregnated with various saline matters. The present season has been
charactrri/ed by unusual quantities of rain, causing extensive floods over what is
usually a dry, arid district."

The agreement between the mature forms is essentially perfect. There can be
scarcely any doubt as to the identification, although I have not seen the Ameri-
can phut in its young state. The fronds appeared to be 1 — 2 lines in thickness,
with its surface smooth, or sometimes with close subparallel ridges or wrinkles.

According to Rahenhorst, the young European N. oesatii is in the beginning
glol>ose, and pale golden-yellow; soon, however, bursting and spreading out into p.n

indefinitely expanded thallus.

Among the alga; collected by Prof. Ravenel in Texas is a Nostoc, labelled "On
Mud Hats, Cedar Bayou, Harris Co.," which comes so close to N. cesatii, that I
think it must be referred to it. It differs only in being more olivaceous, some-
what firmer and in the size of the heterocysts — the largest of the latter which I
ha\e examined, attaining the size only of .00027". The largest vegetative cells are
.00017 in diameter.

IV. calcicola t Ao.

N. thallo irregulariter expnnso, enormiter sublobato, tenuc, mcrabranaceo, cartilnginco, clastic",
pellucido, aut lactc viride, vcl brunnco, vel dilate viride, irregulariter undulato plicato vcl
l)ii I hit "i i ; pcridcrmate plcrumque subnullo; trichomatibus cum fills leptotbrichoideis rainosia
intt-rniixtis, flexuosis, plcrumqae distantibus, rarissime e cellulis biscriatis compositis ; ccllulis
subglobosis, oblongis, ovalibus, cam ccteris elliptic!* intermixtis, plcrumque laxe conncxis;
cellulis pcrduraiitibug spucricis, intcrjcctis et tcrminalibus.

Worn.— Art. T«V— loW =• .0001"4— .0001"; cell, pcrdur. „§„"— 4BW - .0003"—

.ooor.

Syn. — N. calcicola, Ao. RABIN HORST, Flora Europ., Sect II. p. 174.
JIah. — In rupibus, Georgia. (Prof. Ravenel.)

Thallus irregularly expanded, membranaceous, thin, cartilaginous, elastic, pellucid, bright green,
pale green or brownish, thin, irregularly nndulately plicate or bnllate ; periderm mostly
scarcely distinguishable ; filaments intermixed with branched leptothrix filaments, flexnoun,
mostly distant, very rarely composed of biseriate cells ; colls subglobose, oblong, oval, inter-
mingled with elliptical ones, mostly loosely connected ; heterocysts spherical, interspersed or
terminal.

Remark*. — This species is one of those sent me by Dr. Billings. It was collected
near Catoosa Springs, Georgia, by Prof. H. W. Ravenel. In the dried state it is
of a dirty olive-green, and very much wrinkled and irregular on its surface. The
largest specimens are about an inch long. There is no very distinct periderm,
although in some places the filaments are placed more closely together on the outer
portions of the frond. This plant seems to agree with the descriptions of the

6 March. 1871.

34 FRESH-WATER ALGJE OF THE UNITED STATES.

European S. calcicola, from which it differs somewhat, however, in having its hete'
rocysts both terminal and among the cells, and also somewhat in their size.

IV. calidarium, WOOD.

N. thallo maximo, indefinite expanse, ant membranaceo-coriaceo vel membranaceo-gelatinoso
vel raerabranaceo, aut laete virdi vel sordide olivaceo-viridi vel olivaceo-brunneo, irregulariter
profunde laciniato-sinuato, ultimo eleganter laciniato; trichomatibus inaequalibus, interdum
flexuoso-curvatis, plerumque subrectis et arete conjnnctis, in formis duabus occurrentibus :
forma altera parva, viridi, articulis cylindricis, cum cellulis perdurantibus hie illic interjectis,
vaginis interdum obsoletis, ssepius diffluentibus; forma altera maxima, articulis globosis vel
oblongis, aurantiaco-brunnea, cellulis perdurantibus ab articulis ceteris baud diversis.

Diam. — Formse prirnse articuli maximi j^-yy unc. ; cellulae perdurantis ^Vtf unc- Formae
secundae articuli long. 5^TJ to sinnr unc-' lat- StfVtf to ssW articuli globosi ^ir to ztjW uuc-
Syn. — N. calidarium, WOOD, American Journal of Science and Arts, 1869.
Hab. — "Benton Springs, Owen's Valley, California" (Mrs. Partz).

Thallus very large, indefinitely expanded, either membrano-coriaceous or membrano-gclatinous
or membranaceous, either bright green or dirty olive-green or olive-brown, irregularly pro-
foundly laciniately sinuate, finally elegantly laciniate; filaments unequal, sometimes flexu-
ously curved, but mostly straightish and closely conjoined, occurring in two forms ; the
one small, green, with cylindrical joints, the heterocysts scattered here and there, the sheaths
sometimes absent, often diffluent; the other form very large, with globose or oblong articles,
orange-brown, the heterocysts not different from the other cells.

Remarks. — Numerous specimens of this species were received from Mrs. Partz,
who collected them in Benton's Spring, a thermal water situated in the extreme
northern point of Owen's Valley, California, sixty miles southwest from the town
of Aurora. The following extract from a letter of Mrs. Partz describes the place
and mode of their growth more minutely.

" I send you a few samples of the singular vegetation developed in the hot springs
of our valley. These springs rise from the earth in an area of about eighty square
feet, which forms a basin or pond that pours its hot waters into a narrow creek.
In the basin are produced the first forms, partly at a temperature of 124° — 135°
Fahr. Gradually in the creek and to a distance of 100 yards from the springs are
developed, at a temperature of 110° — 120° Fahr., the Alga?, some growing to a
length of over two feet, and looking like bunches of waving hair of the most beau-
tiful green. Below 100° Fahr., these plants cease to grow, and give way to a slimy
fungus growth, though likewise of a beautiful green, which, finally, as the tempera-
ture of the water decreases, also disappears. They are very difficult to preserve,
being of so soft and pulpy a nature as not to bear the least handling, and must
be carried in their native hot water to the house, very few at a time, and floated
upon paper. After being taken from the water and allowed to cool they become
a black pulpy mass. But more strange than the vegetable are the animal organ-
izations, whose germs, probably through modifications of successive generations,
have finally become indigenous to these strange precincts. Mr. Partz and myself
saw in the clear water of the basin a very sprightly spider-like creature running
nimbly over the ground, where the water was 124° Fahr., and on another occasion
dipped out two tiny red worms."

FKKSII VVATKU Al.li.i: ('I 1I1K I SITED STATKS 3J

In regard t«> the temperatures given, ami the observation as to tin- presence of
animal life in the thermal \\.iter-. Mr. William (iahb, of the State Geological
Sum 'V, states that lie has \isited the locality, knows Mrs. Partz very well, and that
wliati-M-r she says may be relied on as accurate.

The color of the dried specimen \aries from a very elegant bluish-green to dirt\-
greenish and fnscotis-bronn. After somewhat prolonged soaking in hot water, the
specimens regained iipparently their original form and dimensions, and were found
to be in very good condition for microscopical study.

Tlii- plant in its earliest stages appears to consist simply of cylindrical filaments,
which are so -mall that they are resolved with some difficulty into the component
cells by a first-class one-fifth objective. Fronds composed entirely of filaments of
this description were rcceixed. Some of these were marked as "first forms," and
as having i;ro\\ n in water at a temperature of 160° Fahr. Probably these were
collected immediately over the spot where the heated water bubbled up. At this
temperature, if the collection made is to be relied on as the means of judging, the
plant does not perfect itself. To the naked eye these "first forms" were simply
membranous expansions, of a vivid green color and indefinite size and shape,
scarcely as thick as writing-paper, with their edges very deeply cut and running
out into a long, waving, hair-like fringe. Other specimens, which grew at a much
lower temperature, exactly simulated those just described, both in general appear-
ance and microscopical characters. These, I believe, were the immature plant.

The matured fronds, as obtained by the method of soaking above described, were
"gelatinous membranous," of a dirty-greenish or fuscous-brown at their bases, and
bright gn-en at their marginal portions, where they were deeply incised and finally
split up into innumerable hair-like processes. Proximally they were one, or even
two, lines in thickness, distally they were scarcely as thick as tissue paper. Their
bases were especially gelatinous, sometimes somewhat translucent, aud under the
microscope were found to have in them only a few distant filaments.

Two sets of filaments were very readily distinguished in the adult plant. The
most abundant of these, and that especially found in the distal portions of the
fronds, were composed of uniform cylindrical cells, often enclosed in a gelatinous
sheath. The diameter of such filaments varies greatly; in the larger the sheaths
are generally apparent, in the smaller they are frequently indistinguishable.

In certain places these filaments are more or less parallel side by side, and are
glued together in a sort of membrane. It is only in these cylindrical filaments
that I have been able to detect hcterocysts, which are not very different from the
other cells; they are about one-third or one-half broader, and are not vesicular, but
have contents similar to those of the other cells. In one instance only was I able
to detect hairs upon these heterocysts.

The larger filaments are found especially near the base and in the other older
portions of the frond. Their cells are generally irregularly elliptical or globose,
rarely are they cylindrical. They are mostly of an orange-brown color; and there
exists a particular gelatinous coating to each cell rather than a common gelatinous

36 FRESH-WATER ALG^E OF THE UNITED STATES.

sheath to the filament. These larger threads are apparently produced from the
smaller filaments by a process of growth.

Near the base and in the under portions of the fronds, these filaments are scat-
tered in the homogeneous jelly in which they run infinitely diverse courses. In
the upper portions of the frond, and at some little distance from the base, the ad-
joining cells are very close to one another, and pursue more or less parallel courses,
with enough firm jelly between to unite them into a sort of membrane.

This plant certainly belongs to the NostocJiacece, and seems a sort of connecting
link between the genera Hormosiplwn of Kiitzing and Nostoc.

The best algologists now refuse to recognize the former group as generically
distinct; and the characters presented by this plant seem to corroborate that view.

Adherent to, and often more or less imbedded in, the fronds of the Nostoc, were
scattered frustules of several species of diatoms, none of which was I able to iden-
tify. In some of the fronds there were numerous unicellular Algae, all of them
representatives of a single species belonging to the genus Chroococcus, Nageli.
This genus contains the very lowest known organisms — simple cells without nuclei,
multiplying, as far as known, only by cell-division. These cells are found single or
associated in small families ; and in certain species these families are united to form
a sort of indeterminate gelatinous stratum. In these species the families are com-
posed of but very few cells, surrounded by a very large, more or less globular or
elliptical mass of transparent, firm jelly. The species is very closely allied to
Chroococcus turgidua,\aT. thermalis, Rabenh., from which it differs in the outer
jelly not being lamellated.

The technical description of this plant will be found in the proper place.

Fig. 2 a, pi. 2, represents the most mature and largest filament ; Fig. 2 b, a small
filament from the same frond, each magnified 800 diameters. Fig. 2 c, represents
portions of the upper surfaces of fronds.

IV. comminutum, KTZ.

N. thallo indefinite expanse, gelatinoso, natante, modo viride, plerumque sordide ferrugineo;
trichomatibus flexuosis, plerumque subdense intricatis; articulis globosis (ante divisionem
factam subcylindricis), subtiliter granulatis, interdum laete viridibus, plernmque ferrugineis
aut luteo-fuscescentibus aut fuscis; cellulis perdurantibus globosis, articulorum diametro
duplo majoribus, interjectis aut terminalibus.

Diam.— Artie. ^Vr"; cell, perdnr. 3^*"-

Syn—N. comminulum, KTZ. RABENHORST, Flora Europ. Algarum, Sect. II. p. 179.

Hob. — In fossis natante, prope Philadelphia.

Thallns indefinitely expanded, gelatinous, floating, mostly sordidly ferruginous, sometimes
greenish; trichomata flexuous, mostly subdensely intricate; joints globose (before division
subcylindrical), minutely granulate, sometimes bright green, sometimes ferruginous, yellow-
ish-fuscous, or fuscous ; heterocysts globose, about twice as long as ordinary joints, both
interspersed and terminal.

Remarks.— This species is to be found floating on the surface of the ditches
below the city in the latter part of August and September, forming a repulsive,
ferruginous, slimy scum. The periderm is not very apparent, and indeed the sepa-

FRESH- WATER ALG.E OF TOE UNITED STATES. 37

rate fronds are not distinct. Tin- filaments arc very long, mostly closely intricate,
very much cuned; in some places they are more sparse. Their color is mostl\ ;i
Miit of yellowish tcrru^inous-^rcen, sometimes they are, decidedly, almost purely
ferruginous, mure rarely a bright green. This plant agrees pretty well with the
description* of the Kuropean jY<W»*- rt,miniitittn>n, und I Ix-lieve is the same
iesj if. howeNer, .V. laruntre of Kiit/ing i.s distinct from N. cominiiniliiiii, this
is also; lint 1 incline to the opinion that they are all different forms of one plant.
Fig. 3, pi. '.', represents a single filament magnified 800 diameters.

IV. commune, v.\

rn stn , t hallo irrrgularitcr expanse, difformi, undulato-plicato, trcmulo, iotas aqaose gela-
.i. ;cta!<' provecta pliT<iim|uu exeavato, peridurmate gubuoriaceo finno, olivaceo, luti-o-
vcl luteo-fuseo cincto ; trichouiatibus fiexuoso-curvatis, pallidc erugineis, laxe
implicatis, ajqualibus vel saba-qualibus, baud raro a bawl ad medium usque ceilulis bmeriatis
ronipositis; nrtiriilis gphuricis vel e mutua prcssione snbquadrangularibns, laxe conncxis,
passim distantibua, puncto central! turbato prtcditis; ceilulis perdurantibus globosis, articn-
lorum diamctro duplo majoribus, interstialibus terminalibusque.

Diam.— Cell. vegetat .00012"— .00016" ; cell, perdurant .00025"— .00033".

S;in. — y. commune, VAUCH. RABENHORST, Flora Europ. Algarum, Sect. II. p. 175.

Hub. — In terrestre, New Jersey. (Austin.) " Rio BraTO. Schott" Harvey.

Ti-rrrstrial ; thullus irregularly expanded, shapeless, undulate-plicate, tremulous, within of the
consistence of thin jelly, in advanced age mostly hollow; periderm subcoriaceons, firm, oliva-
ceous, yellowish-fuscous ; filaments flexuously carved, pale green, laxly implicate, equal or
siibequal, not rarely composed of a double series of cells from their base to their middle ;
articles spherical or subquadrangular from mutual pressure, loosely connected, here and there
distant, furnished with a central spot ; heterocysU globose, twice as large as the vegetative
articles, interstitial and terminal.

U>-innrk*. — The only specimens I have seen of this species are very old ones,
which have burst and discharged their central portions. I have consequently pre-
ferred to copy the diagnosis of Prof. Rabenhorst. My specimens agree pretty
closely with it. The filaments, and also the single cells, are closer together than
his words would seem to indicate. My measurements of the heterocysts, as given
above, are larger than those of Prof. Rabenhorst. They agree, however, with his
text, which his own measurements do not. I am indebted to Prof. Austin for
specimens of this species, which he collected in Northern New Jersey. According
to Professor Harvey this plant was collected by Dr. Schott along the Rio Bravo,
where it is common on dry flats after rains.

SUBFAMILY SPERMOSIRKE.

Thallas sine peridcrmate, interdum nullus. Tricbomata sporis instructa.

Thallus without any periderm, sometimes absent. Filaments furnished with spores.

Genus ANAB^ENA, BORY.

Trichomata moniliformia, evaginata; uporis spbsericiB, anreis vel aureo-foscis, plcrumque lingalis,
cum eellulis vegctativis vel perdnrantibns conjunctis.

38 FRESH-WATER ALGJ3 OF THE UNITED STATES.

Filaments momliform, without sheaths; spores spherical, yellow or yellowish-fuscous, mostly sin-
gle, variously placed as to the heterocysts aud ordinary cells.

Remarks. The characters which I have given are somewhat different and less

exacting than those of Prof. Kabenhorst, otherwise our American species would
hardly be covered by the diagnosis. Professor Harvey in his Phycologia Britan-
nica states that A. Jussieu had preoccupied the name, Anabawa, by applying it to
a genus of EuphorUacece. The date of Bory's name is, however, 1823, whilst that
of Jussieu is 1824. Hence, it is the latter which must be changed.

A. gelatinosa, WOOD.

A. thallo mucoso gelatiuoso, indefinite expanse, dilutissime brunneo, nonnihil pellucido ; tricho-
matibus haud vaginatis, leviter flexuoso-curvatis, nonnihil distantibus, baud intricatis, aut
dilute aureis aut dilute caeruleo-viridibus ; articulis globosis, homogeneis ; cellulis perdu-
rantibus articulorum diametro fere sequalibus, globosis, vel rare oblongis; sporis terminalibus,
singulis, globosis (fusco-brunneis ?).

Syn. — A. gelatinosa, WOOD, Prodromus, Proc. Amer. Philos. Soc., 1869, 126.

Hab. — Prope Philadelphia.

Thallus gelatinous, mucous, indefinitely expanded, somewhat pellucid, with a brownish tinge ;
filaments not vaginate, somewhat curved, rather distant, not intricate, either a light golden-
yellow or light bluish-green; joints globose, homogeneous; heterocysts about equal to the
filaments in diameter, globose or rarely oblong ; spores terminal, globose.

RemarTcs, — The color of the shapeless mass of jelly of which the frond is com-
posed is a light.brown with, in places, a decided reddish or flesh-colored tint. The
heterocysts are either interstitial or terminal, no hairs were detected on them ;
they are mostly globose and only occasionally are they oblong.

Fig. 4, pi. 2, represents a filament of this species magnified 750 diameters ; the
color of the endochrome of the large spore was possibly due to its being dead.

A. flos aquae, (LYNOB.) KTZ.

A libere natans, submembranacea, seruginea; trichomatibus plus minus curvatis, saepius circi-
natis; articulis sphsericis vel e mutua pressione modo ellipticis modo oblongo-quadratis ; cel-
lulis perdurantibus ellipticis singulis vel geminis; cytioplasmate pallide serugineo granulato
turbato ; sporis exacte globosis aureo-fulvis lucidis, singulis interjectis, articulorum diametro
subduplo majoribus. R. Species mihi ignota.

Diam.— Artie. 0.00011"— 0,00025"; diam. long cell. perd. 0.00048"— 0.00053"; spor.
0.00032"— 0.0004".

Syn. — A. flos aquae, (LYNGB.) KTZ. RABENHORST, Flora Europ. Algarum, Sect. II. p. 182.

Hob.— "Round Pond, West Point, New York." Prof. Bailey. Silliman's Journal, N. S., vol.
iii. 18

Swimming free, snbmembranaceous, seruginons; filaments more or less curved, very often cir-
cinnate ; articles spherical, or, from mutual pressure, elliptical or oblong quadrate ; heterocysts
elliptical, single or geminate ; cytioplasm pale seruginous, granulate ; spores exnctly globular,
golden-fulvous, bright, singly interspersed, nearly twice the diameter of the joints.

A. gigantea, WOOD.

A. thallo nnllo, trichomatibus singulis et numeroso-consociatis, natantibus, rectis, in state
juveni spiraliter convolutis; articulis plerumque subglobosis, arete connexis, granulosis ; eel-

FKESII-WATEIl A L Q .E OF T II K U N I T E D ST A T E 8. 39

lulls pcrdurantibus interjcctis, articulis vcgctativis Bubequalibus, utroqoe polo pnnctifonne
incra.ssutis, subsphiLTicis; uporis aubsphieriris.

Syn. — A. •jfjantra, WOOD, Prodrouiug, Proc. Amcr. .Philos. Soc., 1869, 145.

Hub. — In staguis uatautc, prope l'hiliulfl|>hiu.

Diam. — Artie, vegetal. max. j^,,. lleterocysts „•,„ — .0005. Spor. lat iJJn <- Long.

Thallus wanting ; filaments occurring floating singly on water or in great ntmibera, straight,
but in the young state often spirally con volute ; urtirlf* mostly subglubuse, closely connected,
granulur, lirterix-ysU Rutophcrirul, interstitial, a very little larger than the vegetative cells,
thirkriietl at each end in a punetifunu manner; spore subspherical.

//• mark*. — This plant was found by myself, late in the summer, floating upon a
l>rick-|>nud l>elo\v tin- city, forming a part of a thick, dirty-green, "pea-soup
colored," almost pulverulent scum. The filaments, though occasionally in great
numlx T-, \\ere never, that I saw, joined together by any jelly so as to form a frond.

1 u' •">, pi. 3, represents a short filament of this species magnified 750 diameters.

Genus CYLINDROSPERMUM, KTZ.

Spore ante cellulam tcrminalem ortas.

Spore developing from the next to the terminal cell.

('. minutiira, WOOD.

C. trichomatibus dilute irrugincis, plerumque flexuoso-cnrratis et intricatis, intcrdum subrectis ;
art iriilis ry limit-ids, ad genicula plus minus constrictia, bomogeneis vel grannlatis; cellulis
perdurantibus terminalibus, hireutis, globosis; gporis ellipticis, diametro 2 — 3 plo longioribus,
subtili.ssime granulatis.

Syn. — C. minutum, WOOD, Prodromus, Proc. Araer. Philos. Soc., 1869, 126.
Diam.— Artie. ,aW; 8P°r- long- rAa"; transv. ,^,,".
Hub. — In stagnis prope Philadelphia.

Filaments light ternginous-green, generally curred and intricate, sometimes straightish ; article*
cylindrical, more or less constricted at the joints, homogeneous or granulate ; heterocysts
terminal, hirsute, globose; spores elliptical, 2 — 3 times longer than broad, very minutely
granulate.

Remarks.— This species was found by myself at Spring Garden, New Jersey.
"W ith a number of other alga? it formed a ferruginous-brown gelatinous mass,
growing in a deep, shaded, very stagnant pool. In most instances the filaments
were closely interwoven, and sometimes formed minute greenish balls, just large
enough to be visible to the unassisted eye. In other instances they were mixed
up with various algae in little indefinite masses. There is apparently a stage in
the life of the plant, when it consists of a single filament enclosed in a little cap-
sule, for mixed in with the rest of the gelatinous scum were little microscopic, sub-
globose masses, with a firm outer periderm and a single filament coiled up in the
centre. The color of the filaments was generally a faint bluish-green, sometimes,
however, with a yellowish tint. The spores were decidedly yellowish.

Fig. 6, pi. 2, represents a fragment of a filament with the spore magnified 800
diameters.

40 FRESH-WATER ALGJS OF THE UNITED STATES.

C. flcxiiOMiiiu, (Ao.) RABENH.

C. strato gelatinoso, saturate viride, indefinite expanse ; trichomatibus aequalibns, pallide vel
saturate casruleo-viridibus, plerumque valde flexuosis et intricatis, saepius circinatim vel
fasciatim convolutis, interdum subrectis, et fasciatim contextis ; articulis oblongis, ad geni-
cula plus minus contractis, homogeneis vel granulatis, distinctis ; cellulis perdurantibus
terminalibus, subglobosis, rare hirsutis, nonnunquam in trichomatis utroque fine ; sporis
oblongo-cylindricis, diametro 2 — 3 plo longioribus, distincte granulatis.

Diam.— Spor. T5£5</' = .000416"; cell, veget. vjw" = -000166".

Syn. — C. flexuosum, (Ao.) RABENHORST, Flora Europ. Algarum, Sect. II. p. 188.

Hab. — In locis irroratis, prope Philadelphia.

Stratum gelatinous, deep green, indefinitely expanded ; filaments equal, pale or deep bluish-
green, mostly very flexuous and interwoven, often circinnately or fasciately convolute ; some-
times straightish and in bundles ; articles oblong, more or less contracted at the joints, homo-
geneous or granulate, distinct; heterocysts terminal, subglobose, rarely hirsute, sometimes
at both ends of the filament ; spores oblong-cylindrical, 2 or 3 times longer than broad, dis-
tinctly granulate.

Remarks. — The color of the filaments in young specimens is deeper than in the
older, which, however, grew in a much darker locality. The young spores are a
yellowish-green, afterwards they are of a sort of yellowish reddish-brown. In one
instance two spores were seen closely conjoined together at the end of a filament.
In some filaments one or more heterocysts occur interstitially. Often one or more
filaments will be seen coiled together like a rope. On the banks of the Schuyl-
kill River I have found this species in two localities in the latter part of Sep-
tember. In the one instance it grew along the Reading Railroad, just above the
Flat Rock tunnel, in a dark little grotto, formed by shelving rocks. In the other
case, it was on wet ground by a horse-trough very near the west end of the upper
bridge at Manayunk.

Fig. la, pi. 3, represents a filament, magnified 450 diameters.
Fig. 16, a portion of a filament, magnified 800 diameters.
C. macrosperiuuin, KTZ.

C. trichomatibus curvatis vel subrectis, pallide aerugineis; articulis cylindricis vel subcylin-
dricis (in forma Europrea "globosis vel ellipticis"), ad genicula plus minus constrictis,
passim confluentibus ; cellulis terminalibus plerumque ellipticis vel ovatis, diametro paulo
vel subduplo longioribus; sporis elliptico-oblongis vel oblongo-cylindraceis, viridibus (in
formam Europseam maturam '•> saturate fuscis"), subtiliter granulosis, diametro duplo lon-
gioribus.

Diam— Trich. cell, transv. v^v" = .00003" ; spor. .00046"— .00054".

Syn.—C. macrospermum, KTZ. RABENHORST, Flora Europ. Algarum, Sect. II. p. 186.

Hab.— In rivulis, South Carolina. (Prof. Ravenel.)

Filaments curved or straightish, pale seruginous ; articles cylindrical or subcylindrical (in
European species " globose or elliptical"), more or less constricted at the joints, here and
there confluent; terminal cells mostly elliptical or ovate, a little longer or about twice as
long as broad; spores elliptical-oblong or oblong cylindrical, greenish (in mature European
specimens deep fuscous), finely granular, about twice as long as broad.

Remarks.— I have received this species from Professor Ravenel, who collected
it near Aiken, South Carolina, in the month of September; with it was the follow-

FRES1I-WATEK ALQ.E OF THE LM T I- D STATES. 41

ing note : " In bottom of shallow, slowly running streams, adhering to ground or
fallen lea\es, &e., gelatinous green." The specimens agree well with the descrip-
tion of the European form, except that 1 lia\c n< \< i -<-ni the joints globose or ellip-
tical, but alirui/x c} lindrical, as tliey are said to be «omctimca in the typical speci-
mens. The color of the spores also is not " fuse ou>," but tliat probably depend*
upon their not being fully mature.

Fig. 7, pi. 'J, represents the spore of this species with the neighboring hctero-
cyst, magnified !'>(} diameters.

C. comatiim, W.M.I, (^,. n,>v.)

('. tcrri-stri-, stratum ^elutinosutn Krugincum intonlutn 1>runneo tinctum, formans; trichomati-
l''i- flexuosi.s, iutriciitK haud spiralibus, wqualibuH; articulis breve cvliiiilniccis, diamctro
ttqualibus ad plus duplo lungioribuH, plerumque Hcjunctis, pallide Krugincis, obscure granu-
latis ; ccllulis tcrminalibus hubglobosis ; gporis oblongo-cylindricis, diaroetro fere duplo longi-
oribus, granulatis, lutco-drumici* ; niembruna crassa, distinctc granulata.

iHum.- -Spor. trans?. -nln" — .00048". Long. , AW — -00092". Artie. .0001".
Jlab. — In terra uda; Niagara, Canada.

Growing on the ground, forming a gelatinous stratum of an aeraginous color, sometimes tinged
on edges with brown ; filaments flexuous, equal, intricate, not spiral; joints shortly cylin-
drical, equal to or more than twice as long as the diameter, mostly separated, pale eruginons,
obscurely granulato, terminal cells eubglobose ; spores oblong-cylindrical, about twice as
long as broad, granulate, yellowish-brown ; membrane thick, distinctly granulate.

li»»tn-k*. — I found this Cylindrospermum growing upon the ground in the
marshes which border the Niagara River just above the Canadian Falls. It formed
a bright. Ktuginotis, gelatinous, but firmish, almost membranous, stratum.

The filaments arc often quite long, and arc composed of short, cylindrical cells,
mostly placed rather far apart. The terminal cells are remarkable for being abun-
dantly provided with long, flexible, hair-like processes, upon the ends of which arc
minute lobular bodies (cells?). These appendages are so minute as to make it diffi-
cult to determine their structure, and although I have studied them with a 2'5th
immersion lens, giving a power of nearly 2500 diameters, there are some points
about them still undetermined. I do not know whether they or the little globules
are hollow or not. I do feel pretty certain, however, that the little globules are
distinct bodies, and that they finally drop off, leaving the naked hair behind. Is
it possible that they have any sexual significance I The spore-wall is thick, and
under a high power is seen to be distinctly granulate. The granules are of course
small, but in the perfected spore can plainly be seen with an eighth objective pro-
jecting out from the margin.

Fig. 8, pi. 2, represents the spore-end of a filament, magnified 1375 diameters.

Genus DOLICHOSPERMUM, THWAITES.

Sporir elliptic®, oblonpir vcl crlindraccR, inter cellnlaa vegctativas orttc, saepe in seriebus con-
nexa>, a cellnlis perdurantibns disjuncte.

Spores elliptical, oblong, or cylindrical, occurring amidst the vegeUti?e cells, often connected in
•eries, separated from the hcterocysts,

6 April. 1878.

42 FRESH-WATER ALG.E OF THE UNITED STATES.

Syn. — Sphaerozyga, (AUCTOEES, partim.)

Dolichospermum, THWAITE'S MSS. Mr. J. RALFS on the Nostochinex, Ann. Mag.
Nat. Hist. 1850, p. 335.

Remarks. — This genus differs from Sphcerozyga in that the spores have no rela-
tion, in regard to position, with the heterocysts. Professor Rabenhorst, in his
Flora, does not acknowledge it ; but it is very evident that he has neither seen
the original paper of Mr. Ralfs, nor the species upon which the genus was founded,
for he mentions none of the latter, either as good species or synonyms, and the
memoir itself is not included in his bibliographical list. The generic characters
given by myself are essentially those of the original description, with the excep-
tion that the filaments in the latter are said to be aggregated into a stratum, which
is not true of the American forms herein described.

IK snbrigidum, WOOD.

S. natans; trichomatibus singulis, rectis aut subrectis, minimi's, dilute viridibus; articulis
cylindraceis aut subglobosis, distinctis ; sporis cylindraceis, in medio gradatim nonnibil
constrictis, singulis ant duplicis, sine cellulis perdurantibus inter se ; cellulis perdurantibus
breve cylindraceis, singnlis, distinctis.

Syn. — Sphxroziga subrigidum, WOOD, Prodromns, Proc. Amer. Philos. Soc., 18C9, p. 123.

Diam.— Cell. veg. trans. sAu" = .00016"; spor. transv. ,^5"— ?sW •= -00023"— .00022";

long- T5W = -0°066"; cell. perd. transv. ?5V/ = .00022".
Hab. — In stagnis prope Philadelphia.

S. Floating; filaments single, straight or straightish, very small, light green; articles cylin-
drical or subglobose, distinct; spores single or double, in the middle gradually a little con-
stricted, not having a heterocyst between them ; heterocysts shortly cylindrical, single,
distinct.

Remarks. — I have found this species growing in the scum floating upon the
ditches below the city. The filaments are always, as I have seen them, scattered.
They seem always to be nearly straight, or entirely so, and indeed preserve their
straightness so constantly as to suggest the name given the species. The spores are
very distinct, and all that I have seen were greenish, cylindrical, and constricted in
the middle, so that their sides are concave. Their position does not seem to be
uniform, any further than that they are amongst the ordinary cells. The heterocysts
are large, almost equalling the spores in diameter ; I have never detected hairs on
them. This species appears to be most nearly allied to D. Thwaitesii of Ralfs, from
which it differs in not forming a stratum, and in the great proportionate diameter
of the heterocysts. I have never seen any measurements of D. Thwaitesii.

Fig. 2, pi. 3, is a filament, magnified 975 diameters.

D. polysperma, (KTZ.)

S. trichomatibus plernmque snbsolitariis, sed interdum consociatis et intricatis, dilute cseruleo-

libus, subrectis aut varie cnrvatis et flexuosis ; articulis aut subsptisericis aut breve cylin-

Incis; cellnlis perdurantibus globosis aut latissime ellipticis, articulorum diametro paulo

vel dnplo majoribus; sporis pins minus elongatis, cylindraceis— in setate immatnra, sparse

granulatis, dilute caeruleo-viridibus, et cum mernbranahaud distincta,— in state matura dense

granulatis et cum membrana subcrassa.

FRESII-WATEll ALG.fi OF T II E UNITED STATES. 43

ZHam.— Artie. „"„„" - .00016" ; §por. TJt,"— TIt,," — .00026"— .00033".
Syn. — S. Carmichfln, HARVEY, I'livo.!. Brittaniea, T. cxiii.

> l<.ty*l«rma, (Krz ) KAMkNUoWiT, Flora Eurup. Algmrum, Sect II. p. 192.
Bab. — In stagnis, New .Jersey.

8. filaments mostly subsolitary, lint ~"im time* associated and interwoven together, light bluish-
green, slraighti&h, or variously curred and flexuoug ; articles cither ttubitpberical or shortly
cyliiulrii-ul ; hetrrocysls globose or very broadly elliptic, a little larger to twice aa large in
diameter as the ordinary joints ; i-|M.r. s nmrc or less elongate, cylindrical, in the uncertain
condition sparsely granulate, lijrlii blui.-h-frrem, with the incnibrauc not distinct, in the
mature state densely granulate, and with a tliicLi.ili membrane.

Remarks. — I found this species growing in a brownish jelly, with various other
algo>, in a pool east of Caniden, New .In -. y. The filaments were mostly scattered,
but in some places numbers of them were collected in little masses. In some fila-
ments almost all the cells were developed into spores, so that a single thread con-
tained ten or even more spores. In by far the larger number of such cases there
was bi'twfi-ii each pair of spores a heterocyst; sometimes, however, the latter waa
want in.-,', and the spores would be attached to one another.

My sjM-cinicns differ somewhat from the European form, but are too close to
sc]),iratc from them. They equally resemble, however, S. Carmiduflii. Indeed, I
cannot see any sufficient reason for separating the species. S. Carmidtcelii is, to
be sure, a salt-water plant. I have, however, received specimens collected by Dr.
Lewis, near Stonington, which I believe grew in salt water, and which agree in
: \ ropn-t with my fresh-water specimens.

Fig. 3, pi. 3, represents a portion of a filament, magnified 750 diameters.

FAMILY RIVULARIACK/E.

Thallus gclatinosns, mollis vel induratus, vel crustaceus, interdum calce impletus, subglobosus
vel amorphus. Trichomata ad oscillarium morem articulata, vaginata, Bed interdum state protect*
cum vaginis in gelatinam matricalera confluentibns et baud visibilibns, simplicia vel pseudoramosa,
superne attenuata, sepius in apicem piliformem longe producta, parallel* vel radiatim dispoaita,
cellula basale hyalina globosa et interdum ccllulis interstialibus instruct*. Sporae (manulria, KTZ. ),
eingulc plcruinque inter cellularo perdurantem basilarem et cellulas vcgetativaa positac, sajpe per-
magnae, cylindricte, plernmque pachydermaticae.

Vegetatio terminalis. Propogatio sporis tranqnillis.

Thallus gelatinous, soft, or indurated, or crnstaooons, sometimes filled with lime, subglobose or
amorphous. Trichomata. articulated like an oscillatoria, vaginate, but sometimes, when old, with
the sheaths confluent in the maternal jelly and not visible, simple or pseudoramose, attenuated
above, often with the *pez prolonged into * long hair, parallel or radiately disposed, furnished with
globose hyaline, thick-walled basal cells, and sometimes with interstitial cells. Spores cylindrical,
generally placed between the basal and vegetative cells, often very large, mostly with thick coaU.

Vegetation tranquil. Propagation by means of tranquil spores.

Remarks. — In the Rirulariacfrv the thallus is always small ; but is most gene-
rally in the various species somewhat definite in form and size. Its consistency in
our North American forms varies from that of an exceedingly soft, formless jelly
to that of a gristly mass. The maternal jelly is usually colorless, sometimes brown-
ish or yellowish. There is never any condensation of the outer portion of the

44 FRESH-WATER ALG^E OF THE UNITED STATES.

frond into a periderm. The filaments commonly radiate from the centre to the
circumference ; sometimes, especially in the softer fronds, they are simply parallel
with one another. The sheaths vary in their breadth, firmness, and distinctness.
These little plants grow chiefly in the water ; some species are said to live in
the air in exceedingly damp places, but I have not as yet met with any such.
They appear to prefer cold climates, although I have received specimens from.
South Carolina. With us, I have only found them in the late autumn and winter
months. As to their life-history very little appears to be known; I have not been
able to make any observations myself upon this point, nor to obtain access to the
papers1 by De Bary, almost the only sources of such information, and therefore
pass by the subject.

Genus NOSTOCHOPSIS, WOOD.

Trichomata ramosa cum cellulis perdurantibus aut in lateribus sessilibus aut in ramuloruin brevissi-
inorum apicibus dispositis. Vaginae nullse. Thallus definitus.

Syn. — Nustochopsis, WOOD, Prodromus, Proc. Amer. Philos. Soc., 18G9.

Thallus definite ; filament branched ; heterocysts sessile upon the sides of the filaments, or raised
upon the apices of short branches ; sheaths none.

Remarks. — The curious plant upon which this genus is founded has the habit
of a nostoc. The outer portion of the frond is condensed, so as to give the appear-
ance of a periderm ; but there is, in reality, no true periderm. The consistence
of the thallus is that of a firm, gelatinous mass. The trichomata or filaments
radiate from the inner part of the frond towards the outer surface, but many of
them take their origin in the outer portions of the thallus. In most places they
are distinctly articulated, and, indeed, the joints being swollen and moniliform, in
some parts they almost seem to be composed of globular cells, resembling some-
what the filaments of a nostoc ; on the other hand, in certain portions they are not
at all articulated, and this for long distances. No sheaths are anywhere visible.
The heterocysts are, strangely enough, never placed in the continuity of the fila-
ments. Sometimes they are sessile immediately upon the latter, sometimes they
are raised upon very short branches. They are globose, with rather thick walls.
Possibly, however, I am mistaken in believing these bodies to be heterocysts, for
they may be rather of the nature of spores, as is somewhat indicated by their
thick walls, and often apparently dense contents. Their round shape, and the
absence of anything else representing heterocysts, has induced me, however, so to
consider them. In my Prodromus I placed this plant provisionally amongst the
nostocs ; but the radiation of the filaments from within outwards, and especially
their being branched, on second thought seem to me to indicate a closer relation
with the Rivulariacece. The genus appears to be a sort of connecting link be-
tween the two families.

1 "Flora," 1863.

R ALU.K OK T II K UNITED STATES. 45

IV. lobatiiM, \V<>OD.

N t hullo vivide riride aut luteo-Tiridc, cavo, enormiter lubato, nalaiite, modice raagno, firmo,

•ru-li'MiiutilMi-. |ili-ruiii.|iii- l.iu^i-, ll.-xuoMs, dilute viridibus, plcramque articulatis,
part im iuarticulalis, cvlimlriris uul sub-nioiiiliformilius, .-purse granulalis.

/'mm.— Trirliura. TIiej" - .00000"— yj1,/ — .00013" ; cell perdum. „"„" - .00026".
.Sy/i. — ff. lobatu*, Wixm. I'rmlroimis, 1'n-c. Amcr. 1'hUos. Soc,, 1869.
Ilab. — In Srhuylkill Klumioe, prope I'liiludrlphia.

Thiillus lirijrlii uTi-i'ii or vrllowi.sh-grreii, hollow, irregularly lohod, floating, moderately large,
firm, p-laiinniis ; tilaim-nis mostly lonir, flcxuous, dilute trn-cn, mostly articulate, partly iiiar-
tiruluto, cylindrical or somewhat moniliform, sparsely grauulate.

It- murk*. -I found this plant floating upon the Schuylkill River just above
M;m;i\ link. The hollow from! was buoyed up by a bubble of gas contained within
it. It was an irregular, flattened, somewhat globose mass, of a bright green color
and alxmt half an inrh in diameter. It seems very probable that in its earlier
condition, it was a solid attached frond. The long slender filaments are often very
tortuous, but run a pretty direct general course towards the outer surface.

I ur (> ". pi. 3, represents a section of the frond slightly magnified; a, 6, c, por-
tions of filaments magnified 800 diameters.

Genus GLOIOTRICHIA, J. Ac. (1842.)

Trichomata e planitie orta pseudoramosa, distinctc vaginata; vaginee amplae, Imsi pleramque
•accaUe, transverse undulato-plicate, plus minus constricUe, apice apertae, non laciniatae. Spore
magnw cylindrical.

Kilaments springing from a plane, pseudoramosc, distinctly raginate ; sheath ample, mostly
saccate at the base, transversely undulately plicate, more or less constricted, open at the apex,
nut laciuiate. Spores large, cylindrical

Remarks. — This genus was, I believe, first indicated by Professor Agardh in
his Alijcc Maria Mediterranei et Adriatic*, a work to which I have not access.
< )n account of this, and also because I have not seen any of the typical species
of the genus, I have preferred simply copying the generic characters given
by Professor Rabenhorst. If my understanding of "e planitie orta" is cor-
rect, I do not think it true. Professor Rabenhorst's own figure of Rivularia
shows that the filaments do not all arise on one plane ; although he asserts the
character equally for that genus. In our American species the filaments do not
all arise on one plane, nor can they be spoken of as " peeudoramosa."

<• incrustata, WOOD.

O. globosa rel oubovalis, firma, solida, ad pisi minimi magnitudincm, dilate viridis, crystallo-
phora; trichoraatibus rectis aut leviter curvatis, in pilum productis, riridibus ant flavescen-
tibus, sepe infra loete viridibns sed supra flavescentibns, haad ordinatim articulatis; articulis
inferioribns in trichomatibus maturis breTibns, plerumqne compressis; pilo apicale recto aut
letiter curvato, plerumque indistincte articulato, saepe interrupto; vaginis amplis, achrois,
saccatis, intcrdum valdc constricti." ; spot-is cylindricis, saepe curvatis. diametro ad 9 plo lon-
gioribas ; cellulis pcrdurantibas sphaericia.

46 FRESH-WATER ALG^E OF THE UNITED STATES.

Diam.— Triehoin. cum vag. il^" —T?<>T>" ', sPoris max- TsVs"— TiW; cel1- Pel>d-
gyra. — Cr. incrastata, WOOD, Prodromus, Proc. Aiiier. Philos. Soc., 1869, p. 128.
Hab.— Schtiylkill River, plantas aquaticas adhffireus.

Frond globose or suboval, firm, solid, about the size of a very small pea, light green, crystal
bearing; filaments straight or slightly curved, produced into long hairs, green or yellowish,
sometimes bright green in their proximal portions but yellowish above, not regularly articu-
late; lower articles in the mature filament short, and generally compressed; apical seta
straight or slightly curved, mostly indistinctly articulate, frequently interrupted; sheath
ample, transparent, saccate, sometimes strongly constricted; spores cylindrical, frequently
curved, about 9 times as long as broad.

Remarks. — I found this species growing attached to some little plants, either in
the Schuylkill near Spring Mills, or else in the spring itself, I do not know which.
The roundish fronds varied in size from a mustard-seed to that of a half-grown
pea. They were of a decided green color, but appeared grayish from the amount
of carbonate of lime in and upon them. The larger balls, when cut in two, were
distinctly separable into a central and cortical part. The former was more gela-
tinous and contained fewer of the filaments than the latter. The filaments mostly
arose in sets together, i. e. there were one or more zones or planes in which the
bases of the filaments were placed together. This, however, was not strictly the
case, as there were almost always some scattered trichomata. The matured fila-
ments are very distinct. Their sheaths are very large, and often saccate, with
wavy, loose-looking margins ; sometimes they are suddenly transversely constricted,
once or more in their length ; sometimes they look as if a tight spiral band were
wound around ; sometimes they are entirely free from any constrictions. These
sheaths are open above, appearing as though they had been melted away. The
spore is long and cylindrical, and is highly granular. The endochrome is gene-
rally articulated below, the joints are often so nearly globular in the lower portions
as to give a moniliform appearance ; sometimes the articles are compressed. The
upper portion of the trichoma is frequently interrupted, and if at all articulated
is very irregularly and indistinctly so. The younger filaments have their endo-
chrome variously and irregularly interrupted. The basal cells are globular. I
believe the formation of new filaments and the consequent growth of the frond
take place by distal portions of the projecting endochrome separating from the
parent filament, then forming a basal cell, and lastly a sheath. (See Plate 00.)
The carbonate of lime does not exist as a definite incrustation, but in the form of
semi-crystalline masses scattered through the frond. This species seems to come
closer to 0. boryana than any described species, from the description of which it
differs, in the color of thallus, in the latter being always solid (at least so I have
found it late in the fall, when the spores were fully perfected), in its habit of in-
closing crystals of carbonate of lime, in the curved spores; and, doubtless, a com-
parison of the specimens would show still more important differences.

Fig. 4 a, pi. 3, represents a section of a frond moderately magnified ; fig. 4 6,
the basal end of a filament magnified 460 diameters ; fig. 8 c, filaments magnified
260 diameters.

FRES11-W ATKK A L 0 -E OF T 11 E UNITED STATES. 47

G. mi R ii loin, (KOTH.) J. AOH.

G. globoso-aiigulona, cava, viridi-fuscescens, ad ccrssi magnitndinem ; trichomatibns strictis,
turuln.-is, Huprriic U-viter nYxuosia, pasaim inirrrupii* ; urtu-uli.- inferioribus plus minus
comprvsaia, diametro duplo triplove longioribu* ; vaginia amplia, acbrois bic illic leviter con-
•trictia; spurig plus minus vluiigatis, oblougu-ovatis vet ellipsoiduo-cvlindriciii, diametro 8-6-
10 plo longioribus, icrugineo-fuscescentibus, nonnunquaiu leviier curralis, cytioplasiuate sub-
tiliter granuloso, turbato. (K.) Specie* HII/U i/jnota.

Z>iam.— CelL pcrd. 0.00036"— 0.0005". Spor. max. 0.00059". (R.)

Syn O. anyulosa, (Uom ),.! ADAKDII., KAHKMIURST, Flora Europ. Algarum, Sect. II. p. 201.

Hah. — Hudson Ilivi-r prope West Point. (Bailey.)

Globose anpular, hollow, greenish-fuscous, attaining the size of a cherry; filaments strict, torn-
lose, above somewhat bYxuose, here and there interrupted ; inferior joints more or less com-
pressed, 2-3 times longer than their diameter ; sheath ample, colorless, here and there slightly
conxtrirtrd ; spores more or less elongate, oblong-ovate or ellipsoidal-cylindrical, 3-6-10
times longer than the diameter, Kruginous-fuscous, sometimes slightly carved, cytioplasm
very minutely granulate.

Gonus KIWI. MM \, ( ROTH.) Ann.

Thallus et trichomata cadcra qua Qloiotricha, sed vagina; arctissime, swpe in gelatinam roatri-
calcm confluentca, qua.si nulle.

Thallu8 and filaments similar to those of Gloiotricha, hot the sheaths very close, often confluent
in the gelatinous matrix and apparently wanting.

Rcmnrk*. — The characters given above are those of Professor Rabenhorst.
Flora Europ. Algarum, Sect. II. p. 206

II. cartilaginea, WOOD.

R. subglobosa, parva, cartilaginoa, saturate brunnea vcl sabatra, solitaria in plantis aquaticis : —
trichomatibus maturis-sterilibus, rectis ant subrectis, cylindricis, elongatis, baud articnlatis ;
rytioplasmate sa-pe interrupto; vaginis arctis et distiactis; cellulis pcrdurnntilnis globosis,
diaroetro snboequalibus : — trichomatibus fertilibus — rectis aut Hubrcctis, supra spora cellulis 8-9
inst metis; gporis elongatis, rectis, cylindricis; vaginis nonnihil craseis, arctis : — tricbomatibus
immaturis breve articnlatis ; vaginis subamplis.

Diam.— Trich. cum vag. ,,V»"; «I>or snW'-

Syn. — R carlilayinea, WOOD, Proc. Am. Philos. Soc., 1869, p. 128.

Hab. — ID palade, Northern Michigan.

Frond sobglobose, small, cartilaginous, deep brown or blackish, solitary upon aqnatic plants ;
mature sterile filaments, cylindrical, elongated, not articulated, their cytioplasm frequently
interrupted, their sheaths close and distinct, their heterocysts globose and about equal to
them in diameter; fertile filaments straight or nearly so, above the spores famished with 8 or
9 cells; spores elongate, straight, cylindrical; sheaths rather thick, close; immature filaments
shortly articulate, their sheaths rather large.

Remarks. — The frpnd of this species grows attached to the leaves of water-plants,
and has its under side markedly flattened so that it is somewhat semi-globose. The
filaments which compose the mass of the very firm frond are elongated, cylindrical,
and of nearly or entirely uniform diameter throughout. The sheaths are close,
distinct, rather thin, open above, and, in many instances, almost or even entirely
empty. Scattered atnongst such filaments are the fertile ones. These have at
their base an elongated cell, in which is the long cylindrical spore, which varies

48 FRESH-WATER ALG^E OF THE UNITED STATES.

very greatly in length in the various filaments, but is almost always shorter than
the cell containing it. Just beyond the spore is a series of distinct, variously
shaped cells, about seven in number, which are, as I have seen them, empty. In
the outer portions of the frond occur what I believe to be young filaments. These
are distinguished by their rapidly decreasing in diameter towards their distal end,
by their being distinctly articulated, by their basal cell not being distinctly sepa-
rated as in the older filaments, and by their sheaths being more ample.

These various filaments composing the fronds do not arise from any one place,
but commence at very different distances from the centre, and pursue a more or
less straight course to the circumference of the frond, from which they often project.

Fig. 9, pi. 2, represents a section of the frond moderately magnified ; fig. 9 b, is
a drawing of the basal part of a filament magnified 800 diameters.

Genus ZONOTRICHA.

Thalli pulvinato-hemisphaerici, scepe confluentes, calce praegnantes, plus minus indurati, basi plani
affixa, set ate provecta plerumque excavati, intus zonati; zonis concentricis, variegatis; trichomata
pseudoramosa, gracilia, inaequalia, apice hyalina et plus minus longe cnspidata vel in pihim producta.
Vaginae firmae, homogeneas vel longitudinaliter plicato-fibrillosse, apice Integra vel dilatatae et in
fibrillas solutte. Sporse ignotse.

Thalli pulvinately hemispherical, often confluent, impregnated with lime, and more or less indu-
rated, fixed by the flattened base, in advanced age mostly excavated, zoned within ; zones concentric
variegated ; filaments pseudoramose, slender, unequal, their apices hyaline and more or less cuspid-
ate or prolonged into a hair ; sheaths firm, homogeneous, or longitudinally plicately fibrillose, their
apices entire or dilated and dissolved in fibrillae. Spores unknown.

Z. inollis, WOOD (sp. nov.)

Z. interdum subhsemispherica sed gregaria et in stratum nonnihil mammillosum confluens,
submollis, cinerea vel griseo-carnea, parcezonata ; trichomatibus longissimis, angustis,
flexuosis; vaginis arctis, decoloratis, non fibrosis, firmis ; trichomatibus internis articulatis,
saepe interruptis; articulis disjunctis, diametro a3qualibus ad 4 plo longioribus ; cellulis
perdurantibus singulis globosis.

Diam.— Trich. c. v. T5§TT" = .00017". Sine vag T5J™" = .000084".
Hob. — In saxis irroratis, " Cave of the Winds," Niagara, Wood.

Z. sometimes subsemispherical but gregarious and confluent into a somewhat mammillate, rather
soft stratum, ashy or grayish flesh-colored, sparsely distinctly zoned ; filaments very long,
narrow, flexuous ; sheaths close, colorless, not fibrillose, firm ; internal filament articulated,
often interrupted ; joints separated, equal to 4 times longer than the diameter ; heterocysts
single globose.

Remarks.— Every American tourist is familiar with that most wonderful spot, the
so-called " Cave of the Winds," at Niagara. It is simply a place where it is possible
to go underneath a portion of the great cataract, and then round upon the rocky
debris outside of it. Growing upon these rocks, eternally wet and glistening with
foam and spray, I found this and the following species. The present form was
much the most abundant, making a slippery, grayish, or grayish flesh-colored coat-
ing to many of the rocks, dotted here and there with the rigid, blackish fronds of

K K K> I!-\V ATKH AI 1 Till- I N I T K 1» STAT! - 49

its fellow. This routing \vas not at ;ill uniform, lint was covered with inaminillatod
•MM, and consequently \aried from two to M\ lines in thickness. Internally, it

-triated or radiated, but not so evidently as the following species, and presented
st \< ral distinct variegated /.ones. It was quite soft to tlic touch, as well as readily
broken or crushed, and under the microscope was seen to contain very little lime
salt. When dried it has a pronounced sebaceous appearance. The filaments com-
posing it are remarkable for tlieir great length, often apparently running from the
bottom to the top of the frond. They arc rarely if ever branched, and appear
ne\er to be furni>hed with any heterocysts save at tlieir enlarged base. I have
never seen any distinct hairs terminating them, their ends always appearing broken
and open. They are often quite tle.xuous or even tortuous. The internal filament

markablc for having its articles so distinctly separated. It is often very much
interrupted, and in specimens pn. -em d in carbolic-acid water is of an orange-brown
color.

1- 'ig. :J, pi. 4, represents a single filament magnified 260 diameters.

'A. P.I r< i /oiiata. \\ •"», (sp. nov.)

Z iiiirri>-viri«lis, enormiter semiovalis, ad 6" longa, dura, lubrica, non fragilis, calcc prcgnana,
iiitus a basi distinctc radiata, parce et stepc obsolete zonata; trichomatibus mod ice longis,
subn-ctis; trichomatibus intcrnis cylindricis inarticulatis vcl articulatis, et interdum niouili-
fi>nuil)us ; articulis longis et cylindricis vel brevibua et globosis ; vaginis amplis, fibrillosis;
cfllulis pcrdurantibus basalibus ct iaterjectis, his oblongis Tel cylindricis, illis globosis et
tuepe gcmiiiis.

.i.— Cell. perd. basal. ,,«„"— .00017"; trichom. cum vag. ,B\,0"— ,B:\,0"=.00025" — 00037".
Sine vag. .00006"— .00008".

Hob. — In saxis irroratis. " Cave of the Winds," Niagara.
Far. — Z. cinerca.

Blackish green, irregularly semioval, to 6 lines long, hard, slippery, not fragile, impregnated with
lime, internally distinctly radiate, sparsely and often obsoletcly zoned; filaments moderately
long, straightish ; internal filament cylindrical, not articulated or articulated, sometimes monili-
form ; joints long and cylindrical, or short and subglobose ; sheath ample, fibrillose ; hcterocysts
basal and interposed in the body of the filament ; tbe former globose, often geminate ; the
latter oblong or cylindrical.

Var. — Cineritious in color.

Remarks. — I found this plant growing on rocks as glossy, blackish, very hard and
slippery fronds or masses, which varied in size from that of very small shot to
nearly half an inch in length. The larger ones were not nearly so high as long,
and presented irregular, almost bossellated upper surfaces. The filaments are
often very evidently and frequently pseudoramose. The external surface of the
broad sheath is covered with numerous fibrilla?, which envelop and seem sometimes
to wrap it round and round. The color of the frond internally, when broken, is
mostly a dark chocolate, and the surface presents a radiated appearance, with but
two or three zones at most, and, in the very dark specimens, even these are not
evident. No signs of spores have been found. Certain specimens which I ob-
tained growing with the others, instead of being blackish in color, are grayish, but

7 April, 1878.

50 FRESH-WATER ALGJK OF THE UNITED STATES.

agree in all other respects with their fellows. This gray color depends, I believe,
upon the deposit of an immense quantity of lime salts, which in such specimens
constitute by far the larger portion of the frond.

Fig. 4, pi. 4, represents a section of frond, slightly magnified.

It is either this, or the preceding species, which is referred to by Professor
Bailey in Silliman's Journal, vol. iii, under the name of Rivularia calcarea, Sm.
The present form may possibly be that plant, but not having been able to find any
description sufficiently well made out to make identification possible, I have de-
scribed both species as new.

Z ininntiila, WOOD, (sp. nov.)

Z. minutissima, nigro-viridis, subglobosa, baud distincte zonata, nonnihil mollis, muscicola, calce
non pragnans; trichomatibus internis, breve articulatis, distinctissime fasciculatim pseudora-
mosis; vaginis crassis, arnplis, ssepe dilute aurautiaco-brunneis, apice plerumque coloris
expertibus fissis et apertis; eellulis perdurantibus ovato-globosis.

Diam.— Trich. intern. .00012"— .00021" ; cell. perd. .00025."

Hob. — In lacu, " Clear Pond," muscis affixa, Adirondack Mountains.

Very small, blackish-green, subglobose, not distinctly zoned, rather soft, growing on mosses, not
impregnated with lime ; internal filaments shortly articulate, very distinctly fasciculately pseu-
doramose ; sheaths thick, ample, often pale orange-brown, with their apices mostly colorless,
torn and open ; heterocysts ovately globose.

Remarks. — The locality in which I found this plant is in the heart pf the Adi-
rondack wilderness. The little frond in none of my specimens is larger than a
mustard-seed, and is not distinctly zoned. The plants were collected in the begin-
ning of July, and very possibly are not fully grown, as the season of general growth
opens very late in its parent lake. Very possibly, later in the year, it may be found
larger and distinctly zoned. The general appearance of the plant, the character
of its sheath, and the marked branching habit of the filaments have caused me to

place it in this genus.

-

Genus DASYACTIS, KTZ.

Thallus gelatinosns. mollis, non zonatus. Trichomata matura ssepe hand vaginata. Sporae
nullse.

Thallus gelatinous, soft, homogeneous, not zoned. Mature filaments often not vaginate. Spores
absent.

1» mollis, WOOD.

D. parva, ad magnitudinem pisi minimi, enormiter subglobosa, mollis, gelatinosa, dilute viridis;
trichomatibus plerumque subrectis, partirn distincte, partim indistincte articulatis; vaginis,
in trichomatibus maturis hand visibilibus, in trichomatibus juvenibus supra subamplis; cel-
lulis perdurantibus sub-globosis, globosis, vel ellipticis, diametro duplo majoribus, plerumque
singulis sed interdum bi vel triseriatis.

Diam.— Trich. M'— ^v"; cell. perd. n\rs".

Syn.—D. mollis, WOOD, Prodromus, Proc. Amer. Philos. Soc., 1869, p. 128.

Hob. — In palude plantas aquaticas adhaerens, Northern Michigan.

FRESH WATER ALQJi OF THE UNITED STATES. 51

From! .-mull, ali«mt tin- cirr "f a small pen, irregularly sulijrlolmse, soft, gelatinous, light green;
i!.- >;rin-rull\ -truijchti.sli, (turilv ili.-tiuriU . |>urily indiMiiirily articulate; abeaths in the
tiUim-iit i. ni |» T« |>iil>lc ; in tin- \..uii(f tiluuienU rather large in the upper portion ;
tiuli|(liil>M>r ur u'lobu.sc or dlijilic, iwic-o tut large as the filament, gout-rally siugle
but souii-tiuica bi or tri-acriiitc.

Remarks. — I found this species growing attached to tin- little leaves of various
minute rryptognmic and plMBMngMnk water-plants, in a small bog, near the
mouth of Carp Hiver, in Northern Michigan. Tlie frond is somewhat translucent,
with a slightly greenish tint, and has a soft, gelatinous consistency. The matured
triclmma or filaments are more or less radiating, very long, generally nearly straight
and parallel. Their joints or articles are long, mostly not very distinctly separated,
and often an- entirely wanting. The sheaths are entirely lost, no traces of them
being perceptible. They seem to be altogether melted down into the homoge-
neous jelly, in which the filaments are imbedded. The basal cell is large, mostly
globular, and very prominent. On the edges of the frond may frequently be seen
Miiall, evidently immature filaments, which have no distinct basal cell. Around
the basal portion of these \onng trichoma there is a well-marked close sheath,
which near tlie ape\ is wanting. In their immature filaments the joints arc mostly
very short, rather distinctly separated, almost globular.

Fig. 5, pi. 4.

Genus MASTIGOVEMA, SCHWABE.

Trirhonintaarticulata, sursutn flagclliformia TC! subulata, simplicia vel pseodoramosa (nonnonqnam
fasciculutim ]>s. ud.iramosa), procumbentia vcl erecta, in Uiallo indistincto cespitoso-aggregata ;
vagina arete et homogcnes vel ample et plus minus distincte lamclluse, apice plerumque ujit-rtw,
ititcnlum laciuiaUe.

Filaments articulate, superiorly flagelliform or subulate, simple, or falsely branched, sometimes
fasciculatrlj so, procumbent or erect, cwspitoscly aggregated into a sort of thallus ; sheaths close
and honio^rncDus or ample, and more or less distinctly lamellate, the apex for the most part open,
laciuiate.

HI. fertile, WOOD, (sp. nov.)

M. cespitosnm, cum algis altcris intermiztnm; trichomatibns simplicibnn, elongatis, flexuofto-
•1-urvatis, apice truncatis; trichomatibus internis viridibus, soepe interrupt is, iuterdum dis-
tincte articulatis iuterdum inarticulatis ; articulis diametro 3-5 plo longioribus ; vaginis modico
arctis, firmis, achrois, crassis, coloris expertibus, apice truncatis et apertis ; nporis cylindricis,
Rparsis, in filamcnto nnico stepe plnribuR, in cellnlis inclnsis; cellnlis perdurantibus globosis,
iuterdum comprcssis trichomatis diametro fere eeqnalibus.

^Xam.^-Filam. 5,^" »- -00033" ; spor. ,^" — .000166".

Hob. — In stagnis. Alleghany Mountains, Centre County, Pennsylvania.

Cespitose, intermixed with other algae; filaments simple, elongate, flcxuonsly curved, trim-
rate at the, apex ; internal filament green, often interrupted, sometimes articulated, some-
times not articulate ; joints 2-3 times longer than their diameter ; sheath moderately close,
thick, firm, transparent, and colorless, truncate and open at the apex ; spores cylindrical,
scattered, each contained in a cell, frequently several in a filament ; hetcrocysts globose,
sometimes compressed, about equal in diameter to the filament.

52 FRESH-WATER ALGJ3 OF THE UNITED STATES.

Remarks.— I found this plant in a stagnant pool in " Bear Meadows," forming a
filamentous, felty mass with (Kloyonium eclunatum and other algae. The variously
curved and interlaced flexible filaments are always simple and of uniform, or
nearly uniform, diameter through their whole length ; excepting that in some
instances there are small, local, bulbous enlargements of the sheath. Though the
ends of the filaments in all the specimens I have seen are abruptly truncate, it is
very possible that in the young trichoma the apex is prolonged into a long hair as
in most of the Mastigonema. The inner filament is sometimes very distinctly arti-
culated, often, however, it is not at all so. The sheaths are firm, not at all lamel-
late, and generally project beyond the inner trichoma. The spores are cylindrical,
yellowish, with a pretty distinct, although very close coat. They are always in-
closed in distinct cells, and are mostly several in a filament, placed at intervals in
its length.

This is the first instance, at least that I know of, in which a species of this
genus has been found in fruit, and it is interesting to note the resemblance of the
spores to those of the more commonly fruiting rivularias. At the same time the
peculiar arrangement of the spores is remarkable, and if the other species of Mas-
tigonema should be found to have the more common exclusively basal arrangement
of spores, I think it would afford good ground for considering M. fertile as the type
of a new genus. Moreover, the filaments are not united into a distinct thallus, and
also wantthe apical hair of Mastiyothrix, so that it is very probable that they represent
an undescribed genus-. Until, however, the fructification of the European species
is elucidated, it seems best to forbear multiplying names.

Fig. 1, pi. 4, represents a single filament of this species.

OT. ha I os, WOOD, (sp. nov.)

M. caespitulis ; trichomatibus simplicibus, in setate matura valdc elongatis et cum vaginis trun-
catis et apertis, — in setate imnjatura modice brevibus et in setam modice longam acuroam
productis; trichomatibus internis breve articulatis, subtiliter grauulatis continuis vel varie
interrupts ; vagiuis firmis, modice crassis, saepe distincte lamellosis, coloris expertibus ; cel-
lulis perdurantibus subglobosier

Diam.— Sine vag.= .0003" ; cum vag.= .0005".
Hob. — In ffistuario, Stonington, Conn. (Dr. F. Lewis.)

In little tufts; filaments simple, in mature state greatly elongate, and with the sheath truncate
and open, — in the young condition shorter and often ending in a rather short seta; internal
filament shortly articulate, minutely granular, continuous or variously interrupted ; sheath
firm, rather thick, often distinctly lamellated, colorless ; heterocysts subglobose.

Remarks. — This species is an inhabitant of salt, or at least brackish water, having
been collected in Stonington Inlet by Dr. Frank Lewis. The filaments are very
long and always simple ; forming apparent exceptions to this, I have seen once or
twice a number of young filaments so united as to give the appearance of having
been produced from one old one, and in other cases young filaments growing from
the side of an old one ; but I believe those are always set free so soon as they
attain a certain size. In one instance there were large, globular cells, with very
thick walls, produced, and lying free, in the sheath. Are these spores 1 They are

FK i:> ii \\ATI-: u \i .»;.!: OF TIM: I-.NITKD STATES. 53

well shown in figure '.'/•. pi. .~>. Associated with them \\< iv a number of similar n IN
which hail not obtained a> \et the outer thick wall. The color of the h' laments is
in my *\>< •< -miens of a rich golden l)rnwn ; hut, as they have been ppM mtl in car-
holic at id water, I cannot .speak po>iti\ely a.s to the original tint. The hcteroe\-ts
aie Mih^'luhose, sometimes compressed, sometimes somewhat triangular. They
about equal in diameter the internal tilainent.

•J. pi. ~>, represents a small cluster of youngish filaments of this species.

Jl. -< jllllCllllll. \\ .(.-p. HOT.)

M. ihulln cu-.-pitulo, molle, panwitico ; triclmimitibii<i Minplicilm*. pl.Tiimquc inarticnlatis, ged,
intcnliim l>reve, inicnluiii lunge, artieiiluti.-., continiiis, ruriiis iiitiTni|itis, apice iillennatix,
flavo-iiliwtrcis uut viriililius, sparse granululis ; vaginis |)lcriiiii<|ui! amplJH et dmtinctis, hya-
linis. Mi-pius ralde uniliilulis, apiee plt>rumi|ue vulde amplificutis ft in Gbrillas polutis; cellulis
pcnlurantibus diamutro 8ubtc((Ualibim ; Fporis imllis.

/>in»i._Trii-hom je'uo" — .00016"; cum Tag. ,,'„" — .0005".

•
—In phiiitaruni aquaticarum folii^, Carp Km r, Michigan.

Timlin.-* scunrwhat cwspitose, soft, parasitic; filaments simple, mostly inartirnlatc, but some-
times shortly soinrtimi's long urtii-iilatc, continuous or more rarely interrupted, attenuate at
the npex. yellowish-olire or greenish, sparsely granulate; sheaths mostly ample and distinct
Imilim-, often strongly utululatc, the apex mostly much amplified and dissolved into fibrilke;
lirUT»rysU about equal to the filament in diameter; spores wanting.

It> murk*. — This species was found in tho Carp River bog, growing on the edges
of minute leaves, so as to form little prominences or thickenings of the margin.
The trichomata are quite distinct from one another, and can scarcely be said to be
united into a frond, although they all appear to radiate from the base, where they
are consolidated into a dense mass. The sheaths are generally quite distinct, much
broader than the cytioplasm, and are not sensibly dilated below. In most speci-
mens they are \ery distinctly alternately dilated and contracted, or in other words,
niulnlate-d. This is especially the case when the sheaths are quite wide. Above,
they are rapidly and widely dilated, arc distinctly fibrillose, and appear to gradu-
ally molt away. The cytioplasm is rarely articulated, and, when it is so, the joints
are scarcely longer than broad, and are most generally confined to the distal end of
the filament. The. species appears to be most nearly allied to M. lianertanum,
(iiirx.. from which, however, it is quite distinct.

1 iir. '2 a, pi. 4, represents this species magnified 250 diameters; fig. 2 i, a single
filament magnified 800 diameters.

.H. clongatum, WOOD.

M. initio subglohosum, postea ssepe nonnihil fusinnm, nigro-viride, lubrirum, firme ; triehoma-
tibus erugineis, valde elongatis, flagelliformihns, intcrdnm inarticulatift sod Riepius breve
articnlatis, interdum ad genicula valde constrirtis, apirc interdnm truncatis sod plerumque
in pilum, longum, achroam, flexnosum, prodnctis; vaginis achrois, arctis, ssepe apicc truu-
catin; cellulis perdurantibus globosis Tel subglobosis.

Diam — T/OB" = .00026."

Syn. — M. rlongatum, WOOD, Prodromns, Proc. Araer. Philos. Soc., 18C9, p. 128.

Bab. — In aqnario.

54 FRESH-WATER ALG.E OP THE UNITED STATES.

TLallus at first subglobose, afterwards frequently fusiform, blackish-green, slippery, firm ; fila-
ments seruginous, very elongate, sometimes not articulated, but more generally shortly arti-
culated, sometimes strongly contracted at the joints ; apices sometimes truncate but generally
produced into a long, flexuous, translucent hair ; sheath transparent, close, frequently trun-
cate at the apex ; heterocysts globose or subglobose.

Remarlcs. — This species grew in my aquarium on some brook-moss, which I
obtained from a spring above Manayunk. It forms little nodules of the size of a
pin's head upon the wire-like stems, or sometimes longer fusiform masses, which are
apparently produced by the coalescence of a number of the little globes. The color
of these fronds, which are very firm, is a blackish-green. The filaments radiate from
the base in all directions, and at the apex are tipped with a very long hair-like flexu-
ous. ppint, or they are truncate, apparently from the breaking off of this terminal
.-' :.s0ta. '- The endochrome is not unfrequently interrupted within the sheath. When

it is articulated, the joints are usually about as long as broad, and frequently are
: -distiric'rly separated from one another. The sheath is sometimes quite apparent
and distinctly truncate and open above, but in other instances is with difficulty
perceived anywhere, and above is lost in the long hyaline point. At the points
of attachment of the frond the filaments are so densely crowded as almost to
appear to be coalescent, though I believe they are never really so ; yet it is often
almost impossible to separate them one from another by pressure on the glass cover,
without entirely mashing and distorting the filaments.

Fig. 1 a, pi. 5, represents a section of a frond of this species slightly magnified ;
fig. 1 b, a single filament magnified 460 diameters.

Genus MASTIGOTHRIX, KTZ.

Trichomata siugula, plerumque sparsa, parasitica intra thallurn Chffitophorarum aliarumque
algarum, flagelliformia, in apicem piliformem achroum hyalinum cuspidata, distincte articulata,
arete vaginata, basi cellula perdurante instructa. (&•)

Filament single, mostly scattered, parasitic within the thallus of Chsetophora or other algae,
flagelliform, with tie apex produced in a. hyaline hair, distinctly vaginate, furnished with a basal
heterocyst.

Remarlcs. — I have simply copied the generic description of Prof. Rabenhorst,
although it seems to me more than doubtful whether the place of growth is any
generic character whatever. I have relied more on the long hyaline apical hair,
although our American form docs grow in a gelatinous palmella like jelly.

m. fibrosa, WOOD.

M. dilute vel cseruleo-viridis, vel olivaceo-viridis, vel sub-seruginea, infra baud articulata,
sursum saepe breve articulata, apice in trichomata mntura in setam hyalinam, distincte
articulatam, longam, producta; vaginis achroois — in filamcnto immature, supra distinctis,
latis, hyalinis, infra medico crassis, arctis, — in trichomata matura infra arctis, indistinctis,
supra in fibrillis dissolutis, apice absentibus ; cellulis perdurantibus globosis, interdum
geminis.

Dtam—Trichone ^W; cell, perdur. „&„"—„$„".

Syn.— M. fibrosa, WOOD, Prodromus, Proc. Amer. Philos. Soc., 1869, p. 129.

Hab. — Prope Philadelphia.

i i: i: > n . w A T E ii ALGA: OF THE UNITED STATES. 55

Light bluiHh-grcen, or olivaceous-green, apex in the mature filament prolonged into a long,
distinctly articulated hvulinc .-eta ; sheath trun-|>:tr< m — in the immature filament distallr,
broad, and distinct although hyaline, below rather thick and elo.se ; in the mature filament
In-low close, indistinct, above dissolved in librilhu and wanting at the apex; beterocysU
globose, sometimes geminate.

I '' marks. — This plant was found growing with other low algae in a thick jelly,
whirh clothed some wet, dripping rocks near Manaumk. In tin- young filaments
the sheath is produced above into a broad, thick, gelatinous-looking portion, the
cavity of which is often scarcely apparent. The < ytioplusm in such filaments is
mostly of a li^rht hluish-grecn color, is granular and not very apparent. In older
filaments, the trichoina aho\e is pn. longed into a long, curved hyaline point, and the
sheath ju>t below the base of this is split into a number of fibrilla?. No spores
were perceived. Tlie increase of the species appears to take place in the follow-
ing manner: Near the middle of the filament a tumid swelling forms, in the
centre of which appears after awhile a constriction, and this increases until at last
there are shaped out the liavs of two filaments. Then the heterocysts appear, and
finally the two halves of the original trichoma separate — each a perfect filament.
'•>, pi. ").) Sometimes, instead of a pair of filaments being thus formed, but
a Millie base is shaped out at the place of swelling, and the original filaments split,
as it were, thus gi\ing origin to a second trichoma, which for awhile appears as a
branch of the former, but is soon detached from it. In some specimens there arc
two heterocysts, unless the proximal of these, which is a light orange-clay color,
represents a spore.

:$, pi. •>, represents different forms of this species.

FAMILY SCYTONEMACK/E.

Trichomata nrticulata, sjrpe moniliformia vel Bubmoniliformia, vaginata, pscndoromosa, erllulis

limataneis, ad pseudoramulorum basin, vel interstitialibus, pleromque pacbydermaticis instruetn.

Vagina; e straits pluribus (ctsi non semper distinct!*) formitse, superficic leeves, corrugatse vel

!>eraUe, crustata*, nonnmqaam stratis exterioribus in fibrillas discedcntibus, baud raro passim

intumescentcs vel ocreataj.

•etatio non terminalis; cellalarum TegptatiTarnm divisio ad unam dircctionem, initlo in tricho-
matibus medio, postea in utroque fine sirpe alternans. Cellule litnitanc:e ad utrumque polum loccllo
lueido instrnctte.

Propagatio gonidiis plcrumqnc exnUima gencratione ortis. Oonidia plcrumque nnmerosa seriata
e vagina se exserunt tumquc in singala seccdunt. (R.)

Filaments equal, articulate, often moniliform or snbmoniliform, vaginate, pseudoramose, fnrnif<he<1
with hetcrocysts which are either interstitial or at the base of the branches, and are mostly thick-
walled. Sheaths formed of numerous strata (not always distinct), their surface smooth, corrugate,
or roughened, the exterior stratum sometimes breaking up into fibrille, not rarely intnmescent or
ochreate.

.'elation not terminal ; division of the cells occurring in one direction, in the beginning in the
middle of the trichoma, afterwards often alternately at each end. Heterocysts furnished with a trans-
lucent spot at each end.

Propagation mostly by gonidia arising from the last generation Oonidia mostly numerously
seriate, passing out of the sheaths and then separating one from the other.

56 FRESH-WATER ALGJi OF THE UNITED STATES.

R marks. — The Scytonemacece are simple or branched filamentous plants, which
grow in water, or in the air, upon tree-trunks, rocks, fences, &c., in moist localities.
A number of individuals of one or more species are almost always associated to
form on the ground little mats, or in the water attached or floating masses of vary-
ing color and characters according to the species. The individual filaments are
composed of two distinct parts, the inner the protoplasmic matter, the outer the
cellulose sheath. The former of these is a long cylindrical mass, which is occa-
sionally interrupted by a distinct thick-walled cell, spoken of in this memoir as
the heterocyst, or "cellulis perdurantibus." The inner filament is composed of
colored protoplasm, which is sometimes homogeneous, but in other cases is dis-
tinctly granular. It is most generally articulated after the manner of an oscilla-
toria, but occasionally it is continuous for a great portion of its length, and in one
species, which is here described, although very possibly not belonging in the family,
there are, at regular intervals, partitions running across from one side to the other of
the sheath, so that the inner filament may be said to be made up of a number of cells.

The heterocysts are of various shapes, globular, compressed, cylindrical, oblong,
&c. &c. They are mostly provided with a bright colorless spot at each end. Their
number varies according to the species. Sometimes they are single, in other cases
there are several of them arranged in series. They are placed either at the origin
of the branches, or are scattered apparently without definite arrangement in the
length of the filament. In the one case, they are known as " lasdl" in the other
as " interstitial" In any species, either of these methods, or both of them, may
prevail; but a certain amount of specific value attaches to the situation of the
heterocysts. Their function is totally unknown, although some have imagined
them to have a sexual significance and even to be spermatozoids, but there is
no proof whatever of the truth of such suppositions, and it is, I think, very certain
that these heterocysts are not of the nature of spores.

The sheath of the Scytonema is composed of one or more strata, which are
often very distinct from one another, but are more often, perhaps, not so. It is
opaque or translucent, aud has its outer surface smooth, or tubercular, fibrillate or
roughened in some way.

The specific characters in this family can best be commented upon under two
heads — namely, those which are discoverable with the unaided eye, and those
which the microscope alone can reveal. The points to be observed under the first
of these are as follows : The place of growth of the plant, whether in the air or in
the water, and, if it live in the air, to what it is attached — whether to stones, dead
wood, or living trees, and it is possible that in some cases it may be found that
certain species of Scytonema, inhabit only certain species of trees. If the plant
be in water, it must be noted whether it be attached or floating. Then the habit
of growth must be looked at, including in this the size and thickness of the masses
of filaments, whether they be flocculent, turfy, crustaceous, membranous-gelatinous,
&c., their softness or rigidity, their color, as well as the arrangement in them of
the filaments. To discover the latter, it will generally be necessary to use a low
power of the microscope, and at the same time the mode and profusion of branch-
ing of the individual plant should be studied.

FK i:s ii \\.\r I:K \i.t;.i: «u r n i: i \ i i I:D STATES. 57

second rla^s of ch;ir;ictiTs an- those di-co\c ralilc only with tin- higher powers.
The\ an- divisil.le into t\*o-et«,; thoM- afforded \>\ the inner tilanicnt and those
derhed from tin- sheaths. In the first of these the joints tube noted arc, the
diameter of the filament ; its color, whether it lie or he not articulated, and if it
lx- the length of the joints; whether it is uniform or moniliform ; whether it bo
homogeneous or granulate ; then the heteroc\sts should In- examined as to their
si/e, position, arrangement, shape, numher, and color.

The diameter of the sheath, its honio^encousness, its color, firmness, and the
condition of its outer surface an- to he included in the specific study.

usSCYTOM.M \.

Trii li.'inataca>spitos<wonprognta vel faaciculata, plus minus pgrodornmosa, rellulis interstitialibui
in-iru.-tii ; vigiiite gclatinoso-menibranacea, e strati.-, (interdum obsolctis) pluribus cylindraceis com-

• I'llulis pvriluraiitibiix singulis.

Filaments cwspitoscly-congn-irafr or fasciculate, more or less psendoraraosc ; furnished with in-
irrUtinou.^-uiriiibranaceous, composed of many cylindrical, sometimes ob-
Milrtr. .-.tratu; lii'tcrocysts single.

a. Terrestrc* vel aquatic f.

(i. ']'• >•!•• .-'rial or aq\i"

». «.in:pli« « . \\ ..OB, (sp. nov.)

: si rat o mod ice crasso, subtomcntoso, nipro-viridc ; trichoraatibas valde clongatis, flczaofto-
rurratis, parcissimc pscudoramosis vel sa-pe sine pseudoramulis; pseudoramulis geminis vel
sinfrulis, [ilrniiuque clongatis; trichomatibus internis modo distincte articulatis, modo inar-
tii-uititis. ii|.ii-i- iiitrriluni l>revissime articulatis, granulosis, pallidc viridibus, ad genicula sa^pc
nodosis vel disjunctis, articulia plerumquc diametro a?qualibus ad 7 plo longioribus; vaginis
]ilcnini(|iic supra trnncatis et apertis, pellucidis, etepe colons expcrtibus, interdum dilute
aurou-brunnois; cellulis purclurautibus cylindricis, intcrjectis, diametro 2-5 plo longioribus.

Diam.— Trich. cam vag «W'— uW - -0004" — OOOG6"; sine vag. T^o»"— rA»" — -00013"
— .000-2f,'

H,,h — In lignis irroretis, South Carolina. (Ravcnel.)

S. in a moderately thick, somewhat tomcntose, blackish-green stratum; trichomata very elongate,
flcxuonsly curved, verj- sparsely branched or frequently without branches ; branches geminate
or single, mostly elongate ; internal filament partly distinctly articulate, partly inarticulate,
granular, pale-greenish, in its apex sometimes very shortly articulate, sparsely granular,
often nodose or disjoined at the joints; articles mostly from equal to to 7 times longer than
the diameter; sheaths thick, transparent, often colorless, sometimes pale yellowish-brown,
mostly open and truncate at apex ; heterocysts cylindrical, interspersed, 2-5 times longer
than their diameter.

Remark*.— I am indebted to Professor Ravenel for specimens of this species.
They are preserved in solution of acetate of alumina and accompanied by the fol-
lowing label : " Adhering to the wet sides of a wooden gutter, leading water from
a spring, September 29, 1869: Aiken, South Carolina." The filaments are
remarkable for the fewness of their branches. Generally, indeed, there are no

8 lUy. 1871

58 FRESH- WATER ALGJS OF THE UNITED STATES.

brandies whatever, and I have never seen more than a single pair, or, at most,
three branches to a filament. The mass of filaments is blackish-green, somewhat
tomcntose and quite shiny in appearance. The articles are often very long, and
the internal filament is frequently in such cases enlarged into a sort of globular
node at the joint. Not at all rarely there is a very decided break in the endo-
• chrome at the joints.

This species is very close to S. Austinii, from which, however, I think it suffi-
ciently distinct. The points of difference are in the much firmer, much more
colored and opaque, and rougher sheath of that species; in the swollen ends of
the internal filament of S. Austinii, and its shorter articles, Avith the absence of
nodes or distinct interruption of the endochrome at the joints. The heterocysts
are also quite different in the two forms, whilst the filaments of /S. simplice are
much the longer.

S. Aiislinii, WOOD, (sp. nov.)

S. rupicola, strato tomentoso, caespitoso, crasso, fusco-nigro ; trichomatibus adscendentibus,
curvatis, plerumque simplicibus; trichomatibus internis serugineis vel fuscescentibus, articu-
latis vel inarticulatis, fine ssepe valde incrassatis ; articulis diametro plerumque multo bre-
vioribus, interdura longioribus ; vaginis rubido- vel aureo-fuscescentibus, sscpe sub-opacis,
firmis, indistincte lamellosis, in apice plerumque achrois et coloris fere expertibus, snperficie
subrugosa et hirta; cellulis pedrurantibus breviter cylindricis, vel subquadratis vel subglo-
bosis, interdum valde compressis et diametro multo brevioribus.

Diam. — Fil. cum. vag. .0006"— .0008''; sine vag. .00016" — .0004".
Hob. — ID rupibus, "Little Falls, New Jersey." (Austin.)

S. growing on rocks, stratum tomentose, and somewhat turfy, brownish-black ; tricliomata
ascending, mostly simple, curved ; internal filament seruginous or fuscous, articulate or inar-
ticulate, often very much thickened at the ends; articles much shorter to longer than their
diameter ; sheaths reddish or yellowish-fuscous, at the apex colorless and transparent, firm,
indistinctly lamellate ; surface rough ; heterocysts shortly cylindrical, subquadrate or sub-
globose, sometimes strongly compressed and much shorter than broad.

Remarks. — This plant occurs as a blackish stratum of one or two lines in thick-
ness, forming a sort of miniature turfy cushion upon the rock. When examined
with the hand-glass, this layer is seen to be composed of a great number of ascend-
ing curved filaments whose color, in some specimens, is a reddish-brown ; in
others, apparently younger, yellowish-brown. Under the compound microscope
the sheaths in the older filaments are seen to be much roughened externally and
irregular in outline. The young sheaths are smooth. The filaments are mostly
simple, since I have not seen more than a half dozen having even a single branch.

The heterocysts are scattered at irregular intervals, and are remarkably irregular
in form — sometimes much shorter than broad, sometimes several times as long.
As the ends of the filaments are approached the internal filament suddenly swells
out and increases sometimes to twice the diameter it has in the central part of the
filament. In the filament proper it rarely attains a diameter of more than .0003",
and is commonly about .00025", whereas at the ends it very generally approaches
the maximum .00042".

Fi: i-:> ii • \\.\r 1:1: AI.(,.I: 01 fHi. i MTI:D STATES.

8. Mtllll. I -Illll \\. ".(.. (-p. MOT.)

8. iiiini. I-MIIII i inn ul^'i- uii-r:- ji.t. ruiixiiim i-t pluiituH at|iiutiru* uillm-ri in- ; 1 1 irln>niutiI)U»
vliiiiKulis ; p.-<-inl<.r.ii(iuli* plus minus -ii-tanul-u-, plrrumi|uu )•< uniii*, et e ba»i divi-rgenirr
»-!-«• ii-ii-idii-ii-. brrtilm.1 uui i-l.-njr.iii-; irirliomuiilmn iiiU-rui» la-tc Kfugiueii, intcrtlum dis-
tiiutc uiti< uiuti-. inti niuiu iuurtieul.. ..l.iu.-r r.-tumlato, wrngineo; artii-ulis diaiuetro

subu'<|inililius vd brevioribus ; vu^iui.s amplis, livulinis, colons cxpcrtibun ; ccllulis pordu-
rantiliur; ilJAtinctis, >ii:^rui;-. iuu-rji-i'tia, >ul» -\ limlrii -i.-, diuuii-tru inurduui fi-rc duplo breviuri-
bu.-, iiitcrdum duplo longinribuH.

vag. If8OB" — .000416". Cum tag. T1Je," - .00075".
Hub. — Iii aquis i|uii-ii.-i, Cumberland County, New Jersey.

S. iiiiiiirrscd, intrriiiixcd with other algse and adhering to aquatic plants; filaments elongate ;
l-nujrlirs IK- -.-I I \ griiiiiiuti', more or leas distant, short or elongate; internal filaments bright
a-ruprmuri, HonietinivH ili.-tinrtly articulate, at others not so, apex obtusely rounded wrugiuoun ;
j--:iit.>i ul-out ri|ii:ii i.i tin- tliuiKi-UT »r i-liort<T ; slii-iilli ample hyaline, col<-rl<-» ; lii-UTocyBU
di-tim -t. single, iiiti-rjiTii-d, subcylindrical, souu-tiuies about half aa long an broad, sometimes
nearly twice aa long.

/,'' n«i ,-!.-*. — 1 found this jiliint in September, 1869, in Shepherd's Mill Pond, near
1 nwirh, Ciinilx-rliind County, New Jersey, forming, with other algsr, a floccu-
Icnt, ^n < ni-li-l>la( k, slimy coating to the stems and finely dissected leaves of
A1.//,*///' (//(/.- (HjiiiitiliK. 'Ihr liranches are very few in number in most specimens,
and when they are more plentiful are apt to be short and abortive. Their apices
do not dinvr mat* rially from their other portions.

:. !», pi. '2rt, rejin-M-nts a portion of a filament of this specimen magnified 750
diameters; ti^. '2 b a whole filament magnified 260 diameters.

*. Airjrclii, KTZ. (?)

8. owptoso-floccosnm, bryophilnm, nigro-viride; trichomatibus, plerumqne sparse pseudora-
iii- .>!-, pseudoraniulisque elongatis et intricatis ; trichoinatibns internis brevitcr articulatia, stepc
intrrriiptis. fa-pe uonnihil nioiiiliforinilius, viridibus aut in Ktate provecta brunneia; articulia
saepe sejunctia, diametro pleramque brevioribas, subtilitcr granulatis ; psendoramulis plcrumque
singulis ; vaginis modice arctis, intcrdum subatnplis, baud disliiu-te lamellosis, niodicc crassis,
hyalinis, coloris expertibos aut in sstate proveeta dilute fusco-brunncis; ccllulis |>erdnranti-
IHIS nonnihil reniformibus, plerumqao niilliH, basilaribus.

Diam.— Fil. cam vag. plerumquc TI5off" — max. to'ffo" ; sine vag. TSoro". ''''" P<-r<lurant. lab.
" '

,Si/n. — S.Nseyelii (KTZ.), RABENHORST, Flora Europ. Algarum, Sect. II. p. 252.
Hab. — In fonte, prope Belvidcre, Centre County, Pennsylvania.

Growing in small, blackish-green woolly mats attached to mosses ; filaments mostly sparsely
branched, with the branches elongate and intricate ; internal filament shortly articulate,
often somewhat moniliform, often interrupted, green, or, in mature state, brownish ; joinU
often disjoined, mostly shorter than the diameter, finely granulate; branches mostly single;

• sheaths moderately close, sometimes ample, not distinctly lamellate, rather thick, hyaline,
colorless, or, in old age, light fuscous brown ; heterocysU mostly wanting.

Remark*. — I found this plant in the large spring that supplies Bcllcfonte with
water, growing attached to mosses, so as to form little dark-green mats around

60 FRESH-WATER ALG^E OF THE UNITED STATES.

their stems and branches. These mats never exceeded an inch in length in any
specimens that came under my notice. The filaments themselves are apparently
not much branched and are densely interwoven. The sheaths are close, rather
thick, not lamellate, of uniform diameter, except in that they are occasionally
locally swollen, and are truncate and open at the end. The internal filaments are
frequently much interrupted, and in the younger plants are of a deep green. The
joints are in many instances much separated, and in most cases very distinct.
The filaments, indeed show a remarkable tendency to break up at the joints, so as
to form a series of dish-like gonidia, so that the articles, or endochrome masses,
may be generally described as strongly compressed spheres. In all the specimens
that I have examined, I have seen but a single heterocyst. This was at the base
of a branch, was somewhat reniform, and about three-fifths as long as broad. I
have referred this species, doubtfully, to S. Naegelii, Ktz., the only account of
which that I have met with, or know of, is a brief diagnosis in Rabenhorst's Flora,
in which many of the essential characters are omitted.

Fig. 6, pi. 8, represents a portion of a filament of this species.

S. thermale, KTZ.

S. strato tenne, nigrescente ; trichomatibus flexuoso-curvatis, intricatis, parce pseudoramosis,
internis pallide aerugineis, saepe coloris fere expertibus, passim interruptis, plerumque inar-
ticulatis sed saepe indistincte et interdum distincte articulatis, granulosis ; articulis dianict.ro
brevioribus vel subaequalibus ; pseudoramulis plerumque brevibus, geminis, in diametro tri-
chomatibus aequalibus vel subaequalibus et interdum usque ad medium conjunctis, basi coa-
litis, saepe e basi divergentibus; vaginis crassis, indistincte lamellosis, vel luteo-fuscis vel
fuscis, sed passim fere coloris expertibus, plerumque vix pellucidulis, in ramulorum apice
saepe hyalinis et coloris fere expertibus ; cellulis perdurantibus, subquadratis vel cylindricis,
singulis, interjeetis.

Diam.—Tr. cum vag. jug™"— riW = .00042"— .00058; sine vag. ,^"=.000166"—
«V = - 00025.

Syn. — S thermale, KTZ., RABENHORST, Flora Europ. Algarum, Sect II. p. 250.
Hab. — In terra argillacea, South Carolina. (Ravenel.)

Stratum thin, blackish; filaments flexuously curved, intricate, sparingly branched; internal
filament pale-greenish, often almost colorless, here and there interrupted, mostly inarticulate,
but often indistinctly and sometimes distinctly articulate, granular ; joints shorter or about as
long as broad ; branches geminate, mostly short, equal or snbequal to the filament in diameter,
coalescent at the bases, rarely so even to their middle, mostly divergent from the base ; sheath
thick, indistinctly lamellate, yellowish-fuscous, and scarcely semitransparent, but here and
there nearly colorless and pellucid, generally so in the apices of the branches; heterocysts
subquadrate or cylindrical, single, interspersed.

Remarks. — I am indebted to Professor Ravenel for specimens of this species pro-
served in solution of acetate of alumina. The label reads, "Damp surface of hard
clay, Sept. 25, 1869." The sheaths are quite thick and scarcely translucent, so that
the color of the inner filament seen through them is that of themselves. Curiously
enough, one of these dark sheaths will for a space lose its color and be very trans-
parent, in such places and in the apices of the branches, the inner filament is often
a decided pale-green ; at other times it is almost colorless. The end of the sheaths
are mostly closed, but I have seen them open, with the inner filament project-

FKKS ii-\v.\ TI: i: AI.II.I: OK TIM: r NIT KD STATES. 61

Tin1 branches are nearly alwajs short, and divergent from their united bases.
The h. • tl have frequently one of their ends rounded; and are quite

numerous. This species corresponds too closely to Uabenhorsfs description of
ti-i/tonnna tlfi-iiinli to lie separated, but it is possible a comparison of spccin
illicit show decided differences — the description of the European form is not \< i\
full. The American plants seem to approximate most closely the \'<ir. uitistttni.
1 have seen a single hranch ^iu'ii off only in one instance.

I _:. 1, pi. (!, represents a filament of this species magnified 'JdO diameters; fig.
1 /', the outline of a hcten>c\st magnified 7.">0 diameters.

•

V Myo< liroiiv A..

S. strata triiui, patiMMso-tomcntoao, obtcurc fusco (nonnuiiqtiam subsericeo) ; trichomntibas

vali<li"imi>. CUM-!*, Im-idis, li-niii-r rurvatix, ail-ri-inlrniil.il-. intcrnis :iTiijriin-i-, apicc (articul.
trriu ."•('.) riil» Hi-, ili-tiiictc uriii-iilatis ; |iM'u<loraiiiulis pk-ruuuine gcminis, Bicpc longiKsiraiii
11. i .-, tricliniiiuti' iliiniilici cir.-.ti r trnuuribus ; tric-hoiuatis vaginis crassis, distincto

luini-llosis, liruii.-. puli-lirr iuic.i-i'iiM-i>. gu|H>rficic laeTinaimis, ramulornm semper pallitliuribus
(lull-is, rariiis aclirois), apiro SB-JIC achrois, clauais et olituso-rotundatis; i-cllnlis penlu-
ruutilxis olilongig rel Hubcyliinlricis, achrois, trichomatis intern! diametro gabicqualibus.
i I: i Mr. it.. ..I. -cure nlivacro, tricliomatibus parcc pseudoramnKiii, ad Jf'" crasnis ; pRrudo-
niiiniili.s singulix, vaginis aclirois vel luteolis; Tag. tricb. lutoo-fuacis. (1C) Species mihi

m.— Trichom 0.0011"— 0.0014"; raraulorura ad O.OOOG8". (R.)

.s',/,, — s. M'jochrous, AQARDII ; Var. Contextum, CARMICIIAEL. RABENHOROT, Flora Europ.
Algarum, Sect. II. p. 254.

'.. — " Foot of Crow's-nest, West Point" Bailey. Silliman's Journal, N. S. Tol. iii.

Stnito thin, pannoscly tomentose, obscurely fuscous (sometimes somewhat silky); filaments very
strong, fuscous, bright, slightly curved, ascending; the internal eeruginous, distinctly articu-
late with the apex (terminal 5-6 joints) reddish ; branches mostly geminate, often very l»n?r,
flarcidly erect, about one-half thinner than the filament; sheath of the filament thick, dis-
tinctly lamellate, firm, beautifully yellowish-fuscous, surface very smooth ; sheath of the
branches always paler (luteons or rarely colorless) with the apex colorless, short and obtusely
rounded ; heterocysta about equal in diameter to the internal filament Stratum obscurely
olivaceous, filaments sparsely branched, iilxmt ,'j'" thick ; branches single, with the sheaths
transparent or yellowish ; sheath of the trichoiua lutco-fuscous.

S. calolrirhoideN.

S. cn-spitosum, mucosum, plernmquc cnm algis variis intermixtum; trichomatibus plus minus
cnrratis; pseudoramulis plernmquo geminis, varie curvatis, simplicibus, clongatis; tricho-
matibus internis modo distinctc articulatis, modo inarticnlatis, interdum moniliformibns,
luteo-viridibns rel emgineis, grannlosis ; articnlis plernmque diamctro brevioribus scd in-
terdum permnlto longioribus, baud rare vel snbglobosis vel valde compressis ; cellnlis pcr-
durantibus sinjrulis, subcylindricis; vaginis plernmqne pellucidnlis, distincte lamellosis, in
triclioinntilms plommque rubido-vel luteo brunneis sed interdnm colon's expertibus, in pscu-
doramnlis hyalinis, coloris expertibus vel dilutissime Inteis vel dilute lutco-brunneis.

fliam.— Cnm vag. max. ,Boo"~-00075"» plernmque IB*OB"=. 00045"; sine vog. TiVn' — n'oo"?
pseudoram. ,^Bff" - .0005".

,S'i/n._S. calolrichoides, KTZ. RABENHORST, Flora Europ. Algarum, Sect. II. p. 252.
//,,/,._Soutb Carolina. (Ravcnel.)

.62 FRESH-WATER ALG^E OP THE UNITED STATES.

Csespitose, mucous, mostly intermixed with various algae; filaments more or less curved;
branches mostly in pairs, elongate, simple, variously curved; internal filament partly dis-
tinctly articulate, partly not articulate, sometimes nioniliform, yellowish-green or ajruginous,
granular; joints mostly shorter than the diameter, sometimes muc.h longer, sometimes sub-
globose or strongly compressed; heterocysts single, subcylindrical ; sheaths distinctly lamel-
late, mostly reddish or yellowish-brown, but sometimes colorless, in branches hyaline, color-
less, or with a very faint yellowish tint, or sometimes brownish.

Remarks. — The specimens, from which the above description was drawn up,
were sent me by Professor Ravenel from South Carolina. The extremities of the
sheaths are either closed, or open. The branches are almost always in pairs, and
sometimes three or four are given off together, but this is not common. They
are often nearly or quite colorless; the main filament is generally a sort of
brown — sometimes quite bright from the predominance of the yellow hue.
Although my specimens do not precisely agree with the descriptions of the
European S. calotrichoides, yet the disagreement does not seem sufficient or
sufficiently constant to separate specifically the two forms; the most important of
the differences is in the coloration of the sheaths and heterocysts, which in the
American plant are commonly, but not universally, respectively brownish and
greenish.

The label, which Professor Ravenel has attached to some of the specimens,
reads, " In wet, boggy places, on rotten pine boards, Sept. 25, 1869."

Fig. 2, pi. 6, represents a filament of this plant magnified 250 diameters.

S. cataracta, WOOD.

S. rupicola, caespitosum, fusco-atrum, longe et late expansum; trichomatibus flexuosis, flexili-
bus, fere*0.25" longibns, vage pseudoramosissimis, superficie tevibus; pseudoramis elongatis,
singulis, rarissime getninis, liberis, interdum fuscis, seepius hyalinis, apice plerumque truncatis
et rare nonnihil attenuatis et Sffipe barbais sed haud rubellis ; trichomatibus internis serugi-
neis, tenuissimis, plerumque distincte articulatis ; articulis diametro plerumque brevioribus,
sed interdum longioribus, ssepe sejunctis, stepe subglobosis ; vaginis crassis et firmis; cellulis
perdurantibus et basilaribus et iuterjectis, siiigulis, rarissime geminis.

Diam. — Trich. cum vag. plerumque. 00045"; max. .0011"; sine vag. max. .00013".
Syn. — S. cataracta, WOOD, Prodromus, Proc. Am. Phil. Soc., p. 129, 18G9.
Hab. — In flumine Niagara prope cataractam.

S. forming on rocks an extended turf-like stratum of a brownish-black color ; filaments flexuons,
flexible, almost 0.25" long, irregularly branched, their surface smooth ; branches elongate,
single, rarely in pairs, free, sometimes fuscous, frequently hyaline, their apices generally
truncate, rarely somewhat attenuate, frequently provided with enlargements, never reddish ;
cytioplasm seruginous, very thin, generally distinctly articulate ; articles mostly shorter than
broad, but sometimes longer, frequently disjoined, often subglobose; sheaths thick and firm;
heterocysts both basal and interjected, single, extremely rarely geminate.

Remarks.— This species grows abundantly in the Niagara River, on the rocks
below the great cataract. It is really in little tufts, but these are in many cases
placed so closely as to form a broad turf-like coating to the stones. Often, however,
the tufts are in smaller patches, and are of sufficient length to wave with the
eddies and currents in the water. The branches are almost always given off

i K i:sn-\v A I i: K \i.i;.i: «n riii-: UNITED STATES. 03

v since I have examined some hundreds of specimens, and have only in one
instance detected tin in in pairs. The apices of the branches, and indeed of
the main filament.*, arc In -.uitifully colorless and hyaline, and not nnfrcqncntly a
hranch will have this hyaline sheath for a long distance. The extreme ends are
mostly truncate and open, and, often nrar them, the sheaths will have marked
swelling- ; a condition which, for want of a hetter term, I have spoken of as being
/,.//•/.. 8 'inetimes IK ar the end of the filament the diameter of the sheath will

•:<MenI\ Irssriied. The large celN ale lioth interstitial and placed at the bases
of the branches ; they are more or less oblong or quadrangular, sometimes being

-•h longer than broad, but in other cases several times longer. At their posi-
tion there i> \.ry generally a sort of globular enlargement of the filament. The
sheath is sometimes very obscurely lamellate. The color of the 'older filaments is
a dark, almost cliocolate-hrown. This is apparently the species referred to by
Professor Hailey as being Scytanema ocellatum of Harvey, in Silliman's Journal, vol.
iii. N. S., although that plant, according to Professor Uubenhorst, belongs to the

gelllis Sn-iK.;jJii,ii.

Fig. 1 </, pi. 7, represents a portion of a filament, magnified 280 diameters; fig.
1 I, a whole filament slightly magnified.

S. diihiiim, Wo<>r> (sp. nor.)

S. inniuTsum, in fluccis mucoso-tomcntosis olivaoco-nigris plantns aqaaticas ailliirronit, vcl in
strata raucoso et nonnibil tomcntoso dispositum ; trichomatibua valde clongatis et arete in-
trirutis, vurie curvatis, plerumque sparse pseudoramosis; pseudoramulis plenimquc singulis,
etplus minus distantibns et modice brcvibns, vcl intcrdum brevi&simis et abortivis et nonnihil
confcrtiii; trichomatibus internis sepe in pscndocellalis distinctis contends, intcrdum con-
timiis ct imlistincte articalatis vcl inarticulatis, plerumqne dilute ctcruleo-riridibug sed inter-
iluiii liete nrugineis, snbtilitcr granulatis ; vaginis arctis plerumqne modice rm.-.-is et firmix,
hyalinis, coloris expcrtibus; ccllulis perdnrantibus cylindricis, dianietro 2-C plo longioribus.

Diam.—Cam vag. irl^"— nf »»"- .00025"— .0004".

''. — In aqnis quictis, Cumberland County, New Jersoy.

liiiiiicr-i(l, adhrring to water plants in olive-black tomcntosc flocculent masses, or arranged
in a mncous and somewhat tomcntose stratum ; trichomata very long and closely interwoven,
variously curved, mostly sparsely branched ; branches generally single, more or less distant,
and moderately short, sometimes very short, abortive, and somewhat crowded ; internal fila-
ment often contained in distinct cell-like apartments, sometimes continuous and indistinctly
articulate, or not at all articulate, finely granulate, mostly a pale bluish-green, sometimes a
bright ernginous color; sheath close, mostly rather thick and firm, hyaline colorless; hetcro-
cysts cylindrical, 2-6 times longeV than broad.

*. — 1 found this plant, September, 1869, in Shepherd's Mill Pond, near
1 nwich, Cumberland County, New Jersey. It formed dark, ugly, somewhat
slimy, tomontose flocculi adhering to, and binding together, the finely-dissected
es of Ranunculus aqiiatili*. The filaments are very long, slender, and sparsely
branched. The branches are given off at right angles, or nearly so, but arc fre-
quently sharply bent just above their origin. They are often, but not always.
rather short. The most remarkable character that the plant possesses is that in
many filaments there are very distinct regular partitions stretching across from

64: FRESH-WATER ALG^E OF THE UNITED STATES.

side to side, so that the interior is divided, as it were, into successive cell-like
chambers, in which the colored protoplasm is contained. This character seems
almost to separate the plant from the genus Scylonema, but I have deemed it
insufficient grounds for indicating a new genus. Since writing the preceding
remarks, I have received specimens of this species from Professor Ravenel, who
collected them in South Carolina, near the town of Aiken. They agree in all
respects, except that they form a dark, mucous, somewhat tomentose coating to
pieces of wood.

Fig. 3 a represents the outline of a series of the cells alluded to, magnified 750
diameters, and figs. 3 b and 3 c, portions of filaments magnified 460 diameters.

b. Arboricolse.

b. Growing on trees.

S. cortex, WOOD.

S. minutissiraum, stratum tenue submembranaceum formante ; trichomatibus sparse pseudoramu-
losis, pseudoramulisque repentibus et plus minus concretis, viridibus aut dilute fuse-is, varie
curvatis, baud rigidis; cytioplasmate viride, articulate, rare distincte granuloso; articulis
diametro longioribus aut brevioribus; vaginis arctis, nonnihil tenuibus, plerurnque coloris
expertibus, sed. interdum dilute fuscis; cellulis perdurantibus et singulis et geminis, et basa-
libus et interjectis, globosis vel subglobosis.

Diam.— Trich. cum vag. 7SW— TsW-

Syn. — Scylonema cortex, WOOD, Prodromus, Proc. Am. Philos. Soc., I860, p. 130.

Sab. — South Carolina.

S. very minute, forming a thin, submembranaceous stratum ; filaments sparsely branched, toge-
ther with the branches, creeping and more or less concreted together by their sides, green or
light brown, variously curved, not rigid; cytioplasm (internal filament) articulate, rarely
distinctly granulate; joints longer or shorter than broad; sheaths close, rather thin, trans-
parent, generally colorless but sometimes light brown ; heterocysts globular or subglobular,
single or in pairs, basal or otherwise.

Remarks. — I have specimens of this species collected in South Carolina by Pro-
fessor Ravenel, who found it growing on the bark of Platanus occidentalis. The
thin, almost membranous stratum which it forms, is of a dark olive-black, and has
to the eye a sort of minutely warty appearance. The filaments are so involved
and so adherent, one to the other, that I have not been able to separate any length
of them, nor are the branches distinguishable from the main filaments. The sheaths
are rather thin, and often not very apparent.

Fig. 4, pi. 6, represents this species.

S. Ravciiclii, WOOD.

S. lignicola, breve csespitosum, viride-nigrum ; trichomatibus plerumque repentibus, vel fusco-
olivaceis vel aureo-fuscis, modice pseudoramosis ; ramis ascendentibus, rigidis, flexuosis rare
pseudoramulosis, vel fusco-olivaceis vel aureo-fuscis, rarissime cum apicibus subachrois ; tri-
chomatibus internis coloris expertibus, granulosis, saepe vagina erumpentibus, plerumque
articnlatis ; articnlis diametro longioribus aut brevioribus ; vaginis arctis, crassibus, fusco-
olivaceis vel anreo-fuscis, plerumque supra truncatis et apertis, superficie nonnunquam irregu-
laribus; cellulis perdurantibus subquadratis vel subglobosis singulis aut rare geminis, inter-
jectis ; in stato juvene trichomatibus internis rcrugineis, vaginis tenuibns.

Diam.— Trich. cum vag. TsV— rft/i ram cum vag. 75V— 75V; trich. sine vag.
—2.0005."

FK KSII-U ATI: u Ai.ii.i: <>i TIM. t N i T KD STATES. 65

Syn.—S. /fairnr/ii.Woop. Trodromu-, l'r..i- Am. I'liilog. Sot, 1869, p. 130.
I lab. — In cortice, South Curolina.

> I Tilling little turfy spoU of a grrciiUh color, on bark; filaments mostly creeping, either
brownish-olive <>r ycllowi>li-oro»ii, moderately branched; branches ascending, rigid, flexu-
vi-ry rurrly with secondary bruiichlcts, cither browuitth-olive or yellowish-

bruwn, rarely .-iil>traii>|iareut ut tin' upex ; rytin|ilu>m eolorlemi, granular, often extending out
I'iNond the r.|ii-utli«. i:'-jieral!y articulate; joints longer or shorter than broad; sheath* clone.
thii-k. l.rowni.-h-olive . ij-brown, lor the most part truncate at their ends and open,

their surface sometimes irregular; helerocygUt subquadrate, single, interstitial.

nark*. — I am indebted to Prof. H. ^ ncl for specimens of this very

distinct species. Sonic of these are labelled as having grown on the twigs of a
••(his in South Carolina, other specimens are on the bark of a willow. The branches,
which are mostly .shortish, .simple, and variously curved, are sent up in great
numbers by the creeping stems, and, like the stems themselves, are mostly I
but not unirequeiitly are closely adherent by their edges.

The internal trichoma or cytioplasm, owing to the great thickness of the sheaths,
• : M r\ apparent within these latter, but not unfrequently projects for a dis-
tance beyond them, when it is seen to be colorless, very granular, and mostly, but
not always, distinctly articulated. In the young plant the filaments are bright-
<;rceii, often not more than 5?Vff °^ an *nc^ i° thickness, and have the sheath very
thin, or may be almost imperceptible. It affords me great pleasure to dedicate
this species to Professor llavenel, not as an acknowledgment merely of his aid in
my studies of this hitherto neglected branch of the North American Flora, but
rathe* of the great services he has rendered science in some of its kindred
branch'

1 MI;. 1, pi. 5, represents the end of a filament of this species magnified some 450
diameters.

Genus TOLYPOTHRIX, KTZ.

Trichoma scytonemacca cum ccllulis pcrdurantibus ecriatis.

Filament similar to that of scytoncma, but with the hetcrocysts seriate.

T. di*lorla, (MULLER) Kurz.

T. CRSpitoso-floccosa, Isete et pnlchre viridis ; trichomatibus intcrtpxtis, leete viridibus, modo
distincte articulatis modo inarticulatis ; articulis diametro brcvioribus stcpa aut sub-nullig
aut nullis ; psendoramulis singnlis; vaginis arctis, homogeneis, vitreis; cellulis )>crdurantibuB
basilaribus et interdnm interjectis, pachydermaticis, plerumque in parallclogramma! cnormis
forma, plerumque 4-seriatis, subachrois, interdum sparsissimc granulatis.

Diam — „'„ v" — 3 Jvv".

8yn. — T. distorta, (MuLLER) KTZ. RABKNHORST, Flora Europ., Algarnm, Sect II. p. 275.

Hob. — In aqnario, Philadelphia, Wood. Rhode Island (Olney) Thwaitea. Warden's Pond,
Rhode Island ; Resenroir Pond, West Point ; Fourth Lake, Madison, Wisconsin, Bailey.

Floccnlent cespitose, bright, beautiful green ; filaments intcrwoTcn, bright green, partly dis-
tinctly articulate, partly continuous ; articles shorter than long, often very indistinct, some-
times absent; branches single; sheaths close, homogeneous, glassy; hetcrocysts basilar,
9 M*y. 1878.

66 FRESH-WATER ALG^E OF THE UNITED STATES.

sometimes interspersed, thick-walled, mostly irregularly parallelogrammatic, mostly 4-seriatc,
semitransparent, sometimes very sparsely granulate.

RemarJcs. This species grew spontaneously in the aquarium of my friend Dr.

Fricke, to whom I am indebted for specimens of it, forming little, bright-green
balls adherent to the various aquatic plants. It approaches so very closely the
European T. dlstorta, that I have considered it as a mere variety of it, although it
differs in having the heterocysts mostly arranged in fours, and also apparently in
their shape — they being in our plant mostly parallelogrammatic.

Fig. 1 a, pi. 8, represents a section of heterocysts magnified 800 diameters; fig.
1 b, a portion of filament magnified 800 diameters.

Genus PETALONEMA, BERK. (1833.)

Scytonematis trichomata vaginis crassissimis e stratis numerossissimis brevioribus, infundibuli-
formi dilatatis, imbricatis et plerumque dilutissime coloratis coinpositis. (R.)

Syn. — Arthrosiphon, KTZ. (1845.)

" Filaments stratified, decumbent, free, simple, or branched. Tube or sheath very wide, flat-
tened, longitudinally and transversely striate and crenulate at the edge ; endochrome oliva-
ceous annulated, here and there interrupted by a heterocyst. Branches issuing in pairs,
formed by the division and protrusion of the endochrome of the original filament.

" When placed under the microscope the filaments present the appearance of a cylindrical cen-
tral column, containing annulated, olive-colored endochrome, and a wide wing-like border at
each side of the column. This border or sheath is obliquely striate, the striae running in an
arch from the margin toward the centre, where they become parallel, and are then continued
longitudinally downward along the medullary column, till lost in the density. The margin
of the wing is closely crenulate and in age transversely striate at the crenatures as though
jointed. Such is the apparent structure ; the real structure seems to be, that an annu-
lated central filament is inclosed within a number of compressed, trumpet-mouthed gelatino-
membranaceous tubular sheaths, one arising within the other, and successively developed as
the growth proceeds. These sheaths, thus concentrically arranged, are indicated by arching
longitudinal striae; and the mouths of the younger sheaths, projecting slightly beyond those
of the older, form the crenatures of the margin." HARVEY.

P. alaliim, BERK.

A. pulvinato-crustacens, rupicola, varie coloratus; trichomatibus internis serugineis, cnrvatis,
parce pseudoramosis, modo continuis, modo torulosis, submoniliformibus, apice plerumque
pauluni iucrassatis, saepe roseolis, rotundatis; articulis distinctis, granulosis, diametro sub-
sequalibus vel paulo brevioribus; vaginis stratis internis, aureis vel aureo-fuscentibus,
externis achrois, vitreis; cellulis perdurantibus interjectis et ad psendoramulorum basin,
plerumque solitariis, subglobosis vel oblongis, dilute fuscis. (R.) Species mihi ignota.

Diam.— Trich. intern. 0.00016"— 0.00032" ; vag. 0.003T7". (R.)

Syn.— Arthrosiphon alatus, (GREV.) RABENH. Flora Europ. Algarum, Sect. II. p. 265.

Petalonema alatum, BERKELEY. HARVEY, Nereis Boreis Americana, part iii. p. 99,
Smithsonian Contributions, 1846.

Hob. — " On dripping rocks under Biddle Stairs, Niagara Falls." (Harvey.)

" This forms strata of a dark chestnut-brown color and of indefinite extent on the surface of
rocks or soil exposed to the constant drip of water. The filaments are decumbent, lying
without order in the gelatinous matrix in which they are developed, and which forms the

FKKMI -\\ A I i: K ALGJi OK T II K UNITED STATES. 67

groundwork of the stratum. They appear to be unattached to the soil, and each filament
may be about hull an indi in length; but they are cuiuiuuiily found brukeu offal the inferior
eiitl. <>r tlu- lom-r pan decay* whilst tin- upper continues to grow. They are slightly curved,
in MTpful-liki- iu.-in..n. in \.-r quiii -iruigiit ; ut first they are Biui|>le, but now and then emit
lateral branch- «. which i.-.oue at considerable angle* and generally iu pain. When a filament
is about tu branch, a rupture takes place iu the Hide of the sheath, and the endochrorne issues
iu two portion,, one connected with the upper, the -.ther with the lower half of the filament;
-'• form the nurlri or im-dullary portion of two new branches and become duly invested with
ft meiiibrniiouti sheath, and gradually put on the aspect of the adult Glament. The einlo-
chronir j, granular, dark-brown, and annulated at short intervals, the transverse rings being
placed M ry i -l.i.i- toL'i tlicr in the youngest portionx, and less closely in the older, where they
are distant from i-n.li otluT abont twice tin- diaim-t«-r of the column. This annulated endo-
chrome i~ interni|>tri| at certain fixed places, where an ellipsoidal cell ia formed, separating
the endochroine of the lower from that of the upper portions." HABVKY.

/,'• murk*. — I have ncvi-r scon cither tho genus or species, and therefore am
forced to copy the descriptions of both from Kubcnhorst and Harvey.

FAMILY SmOSIPHONACE^E.

Thallun ramoBos, e cellulia pachydermaticia aut nni Tel pluri seratis ct in vagina ampla inclusis

f.inuaiiis, iiii.-riliini eellulis penlurantibus instructua. Kamificatio rera lit eelliilaruin vegetativarum

i|iiaruniliun divi.jone in axis longitudinalis dircriionem, <|ua ex re cellule due sororie gignuntur;

celluU inferior in trirhomatift continuitate permauct, superior divisioue contiuua rcpctita iu eandeni

• tioiirni .— • ml rainiiin e.xplicat.

I'ropagatio adhuc ignota.

Frond brnncheil, forim-d of thirk-walled cells in an ample sheath, sometimes furnished with liete-
r.iu uni- or mnlti-Rcriate. Branches formed by a longitudinal division of certain
evils, so as to form two sister cells; the inferior of which remains aa part of the trichoma, whilst
the other. l>v repeated divisions, grows into a branch.

l'r-.ji:i'_'.nio:i not known.

Remark*. — The StrmiphonacetB are the most complex in their organization of
:ill tlir J'/ii/rocJiromrqihycece, in so far as the protoplasm within the sheaths is cvery-
wlicrr broken up into a number of distinct cells, each of which is provided with
a thick coat or wall as well as in the circumstance of the frond having more perfect
branching. The so-called pseudo-branches in the other families arc moie truly
comparable to distinct fronds or thalli remaining attached to the parent thallus
than to distinct branches, whilst among the sirosiphons the branches really belong
to the original thallus. The hetcrocysts are much more frequently absent than
present, only one of the known American species being furnished with them.
The sheaths are generally not so distinctly sheaths as among the oscillatoria, &c.,
for. instead of being distinct tubes, they appear rather in most cases as masses of
firm jelly, the outer portion of which is hardened almost into a peridcrm, and in
the inner part of which the cells are imbedded. Their color varies from the
transparent colorlessness of glass to a dark opaque-brown. Their surface is per-
haps most frequently smooth, but at times is tuberculate or otherwise roughened.
I have never seen anything like spores about them.

63 FRESH -WATER ALG.E OF THE UNITED STATES.

These plants grow in the majority of cases in the air, in such situation as on
the face of dripping rocks, on the trunks and branches of trees, on moist ground,
&c. ; but some of the species are found in the water, either attached or floating.
They generally form little mats of indefinite extent, but occasionally the filaments
are united more closely into an almost membranaceous stratum.

The species are, I think, in most instances readily distinguished, the characters
being partly discoverable with the unaided eye and partly microscopic. The
points to be attended to in the first category are the size, color, form, and
consistency of the mats of fronds, and the place of growth. In the second are
included the general shape of the frond and its size and method of branching;
the general shape, color, and size of the cells, the thickness of their walls and the
method of their arrangement, both in the main thallus and the branches, also the
form, &c., of the end cells of the branches ; the heterocysts, their absence, or, if
present, their frequency, size, shape, color, and position; the sheaths, their color
and firmness, and the character of their surface.

Genus SIKOSIPHON, KTZ.

Trichomata torulosa, vaginata, plerumque ramossissima et aureo- vel olivaceo-fusca, e ccllulis
pachydermaticis 1-2-3 vel pluri-seriatis formata et cellulis interstitialibus (sa;pe nullis) subglobosis
vel oblongis coloratis instructa. Vagina plerumque crassissima, firma, pulclire aureo-fusca, lutea
vel olivacea, in apicem obtusum plus minus attenuata.

Filament torulose, sheathed, mostly very much branched, yellowish, or olivaceous-fuscous, formed
of thick-walled 1-2-3 or many seriate cells and furnished with interstitial cells (often wanting)
which are globose or oblong and colored. Sheaths mostly very thick, firm, beautiful golden fus-
cous, clay-colored or olivaceous, more or less attenuate at the obtuse apex.

a. Gellula in trichomatibus plerumque in serie simplice vel duplici ordinata.
a. Cells mostly arranged in a simple or double series in the filament.

S. scytenematoides, WOOD.

S. strato submembranaceo, nigro-viride, ssepe interrupto, cum superficie insequalc ; trichoma-
tibus stepe arete intricatis, flexuosis aut varie curvatis, haud rigidis, plerumque vix ramosis ;
cellulis uniseriatis, interdum interruptis, arctis, irregulare quadrangulis, diamctro subsequa-
libus aut 1-3 plo brevioribus, haud distincte granulatis, cseruleo-viridibus; vaginis ainplis,
haud distincte lamellosis, superficie euormiter corrugatis et hirtis, plerumque coloris experti-
bus sed interdum dilute brunneis.

Diam.— Sine vag. max. 7/5/ = .00066" ; cum vag. max. 7^5" = .0013".

Syn.—S. scytenematoides, WOOD, Prodromus, Proc. Amer. Philos. Soc., 1869, p. 134.

Nab. — South Carolina. (Ravenel.)

S. In a submembranaceous, blackish-green, frequently interrupted stratum, with an uneven
surface ; filaments often closely intricate, flexuons or variously curved, not rigid, mostly
sparsely branched ; cells uni-seriate, sometimes interrupted, close, irregularly quadrangular,
about equal in length to their diameter, or about 1-3 times shorter, not distinctly granulate,
bluish-green; sheaths ample, not distinctly lamellate, their surface rough and corrugate,
transparent, mostly colorless, sometimes light-brown.

Remarks. — This species was collected in South Carolina by Prof. Ravenel, who
found it in the month of February growing on the limbs of Myrica cerifera. The

FKKS II W A T I! II A 1. 1. !! "I mi; UNITED STATES. 69

l>l:i<-kish-i:reen la\tr. which it makes upon tin- hark i- very peculiar, beini: almost
membranaceons, and especially in the dried state, presenting a rough, somewhat
wart\ surface. The trichomata ha\ e tin- sheath inure distinctly in tin* form of a
hollow cylinder, or, in other words, more plainly a sheath, than any other 8j>ocic8
I have seen of the jjenus- ; the cells are also without any apparent walls, and arc
placed \ery closel\ together, so that the whole filament looks very like a acyto-
n> imt.

1, pi. !>, represents a portion of a frond magnified ;?('»() diameters.

M. pHliit idiihiM, WOOD.

S. iuiii)iT>iis ; tricliDiiiatiliiiM ramossisftimis, nolitariii) vcl sulisolitariis ; ramis plorumquo nnila-
teralibus, raiiiul<»is; nunulunim upirilm* late rntundatis, baud attonuntis; ccllulis in scrie-
IMIS -:in|.!i. il.ii- ili-positis, iu trirlniinatiliii* noiiiiihil rutundatis, in rnmulis uepe angularibns,
plrruniqiio comprrssis, diamrtro :r<|iialilius — 4 ]>lo brcviorilnis ; tcnninalibua cylindricig et
obscure articulutis ; i-i-llnlis intcrstitialibus nullis ; Taginis arctis, bjalinis, baud laincllosis ;
cytii<plasiuatc u-rugiiu-u vcl brunneo, minute granulate.

Diam.— Trich. cum v»g. ^f0," = .00106" ; sine rag. — .0008".

Syn. — S. i-elluriilultu, WOOD, Trodromus, Proc. Amer. Philos. Soc., 1869, p. 133.

//,//.. — Iu gtagnis, prope Hibernia, Florida, t \l \V. Canby.)

mi Tscd ; filaments rcry much branched, solitary or eubsolitary ; branches mostly unilateral,
branched; apices of the branches not attenuate, broadly rounded ; cells disposed in a simple
sprigs, in the trk-homa somewhat rounded, in the branches frequently angular, mostly com-

•sed, from equal to 4 times shorter than the diameter; terminal cell cylindrical, obscurely
articulate; interstitial cells none; sheath close, hyaline, not lamellate; cytioplasm a-nigin-
ou.s or brown, minutely granulate.

l;*. — This species was collected by Mr. William Canby in a little marsh
pool near Hihernia, Florida. The branches are given off in abundance, mostly in
a unilateral manner, are often very long, and about equal in diameter to the main
filament, and u'ive origin to numerous branchlets. The sheaths are very trans-
ut and very close. I have never seen them in any way lamellate or fibrous,'
or of any color. The cells do not have very apparent walls. In the main fila-
ment and branches they are globose, or, more commonly, very much compressed,
but in the newer branches, and sometimes in the older, they are very angular.
The few cells near the end of the branches are so shaped as to remind one of the
phalanges of the fingers. The last cell is cylindrical and has a number of cells
indicated in it. The color of the young cells varies from a deep bluish-green
to a ferruginous-brown — that of the older from a light bluish-green to ferruginous-
brown.

Fig. 2 a, and 2 6, pi. 8, represent portions of filaments of this species.

8. compact!!*, (Ao.) KTZ.

S. strato expanse, tomentoso, fnsco-nigro; trichomatibus elongatis ramulisqne adscendentibus,
apice intcrdnm paullum attennatis sed ssepe claratis, obtusis ; trichomatibus internis e cellu-
larnm scrie simpliri format!?, rt plcrumqne monilifortnibus ; cellulis diametro subcequalibus
Tel brevioribns, siiliploliosis vel siibqundratis. sippe compressis ; cytioplasmate dilute ciernleo-
Tiridc, subt ilitrr granulatis ; cellulis apicalilms rylindricis ct oscillariiim modo, Hiepc indistin<-t<>.

70 FRESH-WATER ALGJD OP THE UNITED STATES.

articulatis ; vaginis firmis, aureo- vel rubido-fuscis, in ramulis saepe subluteis, haud distincte
lamellosis; cellulis perdurantibus plerurnque modice uunierosis, singulis, subglobosis, saspe
valde compressis, dilute fuscentibus.

Diam.— Plerumque T5VW'— TsVW' = .0003"— .001" ; max. 3040/ = .0013"; cell, perdurant.

T»W = -00058"-

Syn.—Scytonema compactum, AGARDH. Syst. p. 38, N. 3. HARVEY'S Manual, p. 154.
Hassalia compacta, HASSAL, Fresh-water Algae, p. 232, t. Ixviii. f. 3.
Sirosiphon compactus, (Ao.) KTZ. RABENHORST, Flora Algarum, Sect. II. p. 287.

Hob. — In rupibus ealcareis, New Jersey. (Austin.) Prope Salem, Mass. (Russel.)

Stratum expanded, tomentose, fuscous-black; filaments and brandies ascending, with their
obtuse ends sometimes slightly attenuate but often clavate; internal filaments composed of a
single series of cells, mostly moniliform; cells shorter than or nearly as long as broad,
subglobose or subquadrate, often compressed; apical cell cylindrical and articulate somewhat
like an oscillatoria; cytioplasm light bluish-green, finely granulate; sheath firm, reddish or
yellowish-brown, yellowish in the branches and near the ends ; heterocysts mostly rather
numerous, single, subglobose, brownish.

Remarks. — The specimens from which the above description was drawn up
were received from Messrs. Austin and Russell, and have been considered as
identical with the European S. compactus, although not in absolute agreement
with the descriptions thereof. The most important of the differences are in the
matter of size, the measurements given by Prof. Rabenhorst not equalling those
attained to by the American plant.

The differences, however, do not seem sufficient to separate the forms, and,
in the absence of European specimens, the two have been considered one species.
The sheaths in the older portions of the filaments are nearly opaque, but in the
branches and younger portions they are quite translucent. The heterocysts some-
times are truncate at one end. The internal cells are rarely arranged in a double
series, such arrangement is, however, much more common in the specimens re-
ceived from near Salem, than in those found in Northern New Jersey. Mr. Rus-
sell's specimens are labelled as growing on shaded and moist rocks in patches two
or three inches wide.

Fig. 3 a, pi. 8, represents the end of a filament of this magnified 150 diameters;
3 6, a fragment magnified 250 diameters ; 3 c, a heterocyst magnified 860 dia-
meters.

S. Crameri, BRUGG.

S. csespitibus, tomentosis, spatiose expansis, fusco-nigris ; trichomatibus vage ramosis; ramis
plerumque singulis, saepe elongatis, saepe clavatis ; cellulis internis uniseriatis, diaraetro sub-
Dsqualibus vel brevioribus, interdum subglobosis, ssepe subquadratis, in aetate proTecta saepe
e pressione mutua valde compressis et transverse oblongis, aureo-fulvis vel in setate juvene
interdum aerugineis ; cellulis terminalibus in massam subeylindricam coalesccntibus ; cellulis
perdurantibus nullis; vaginis aureo-fuscis in aetate provecta plus minus subopacis et distincte
lamellosis, in aetate juvene plus minus pellucidis et saepe coloris expertibus.

Diam— Trich. cum vag. max plerumque .002"; interdum .00225"; ram. .0015"— .0025" ; trich.
sine vag. .00083".

Syn.—S. Crameri, BRUGG. RABENHORST, Flora Europ. Algar., Sect. II. p. 288.

I Kl :>II -\VATKK A 1.'. I! OF T1IK U X IT F. I> STATUS. 1 \

—In rupihus irn.ratis inter musois minutis. Mount Tuhawus (vulyo Mount Marcy),1 alt.
6000 feet.

Forming a blackish, widely expanded, t.im.-ntose turfy covering to rocks; filament with scat-
ti red liranclics ; branches innM . fd-u elongate and clavatu ; cells uniscriatc, about

equal, or shorter than long, sometimes subglobotte, often subquadrate ; in advanced age often
strongly compressed and transvi-r-i-ly ol.l.mjr from mutual procure, yellowish, or sometimes,
when ymiiiL'. greenish ; tin- apical cells coalc.-ccnt into nu irregularly cylindrical mass; hete-
r< .cysts wauting ; sheaths yellowish-brown ; at m.iuirity more or less subopaque, and distinctly
lauic'llate; in ynitli tnuro »r less transparent, and sometimes colorless.

x. — Near tin- top of Mount Tahawus, in the Adirondack Mountains,
tin re is, at an altitude of about live thousand feet, a strep slope of bnro rock,
the bed of an old landslide, over portions of which water is continually drip-
ping. In such places the plant under consideration flourishes, forming with
some \ery minute mosses a hlacki-h, turfy coating to the rock of many feet,
or e\en yards, in extent. The specimens agree well with the descriptions of the
Kuropeaii plant, which also grows at about the same altitude as the American.
They ha\e. ho\ve\er, one peculiarity not noted in description of the European
form, namely, that oftentimes the sheath of a branch widens out until it is actually
much larger than the main lilament. Tin; color of the cells in the European form
.id to he a-rn^inous ; but I conceive this depends somewhat upon the age of
the specimens and is scarcely of primary value. The only other difference worth
noticini,' is that my measurements exceed somewhat those given of the European
plant. I do not think, however, there is any good ground for separating the forms
as distinct spec .

The finding of an Alpine plant growing on a mountain half way across the world
from its first discovered home, at practically the same altitude, is a matter worth
noting as a fact in Botanical Geography.

8. neglectuM, WOOD.

S. imm«T«us; trichomatibus subsolitariis, lonpis usque ad lincas qnatuor, cylindricis, ramosMs-
simis; ramulis singulis; cytioplasmatc interdum erngineo, plerumque aureo-brunm-n; cellulis
nntseriatis rarissime bmeriatis, sabglobosis, interdum scjunctis sed plerumque arete connectis
et monilifonnibus, mode conflucntibns, baud distinctc pachydermaticia ; ccllnlis trrmiimlibus
elongato-cylindricis, R«cpc nonnihil oscilatorinm modo srticulatis; cellulis interstitialibus nulli.- ;
taginis interdum brunncis, plerumque coloris czpertibns.

Diam. — Trichom. cum vag. t}B" — .0017" ; sine vag. T,'ffir" — -001".

Syn. — S. negleciu*, WOOD, Prodromus, Proc. Amer. Philos. Soc., 1869, p. 133.

llab. — In stagnis, New Jersey.

S. immersed, subsolitary. attaining a length of 4 lines, cylindrical, very much branched ; branches
single ; cytioplasm Kruginons, mostly yellowish-brown ; cells uniseriate, very rarely biscriatc,
subglobose, sometimes separate but more frequently closely united and moniliform ; terminal
cell an elongated cylinder, often articulate somewhat like an oscillatoria ; interstitial cells
wanting ; sheaths transparent, sometimes brown, mostly colorless.

1 " Tahawvs," cloud splitter. The Indian names of the American mountains ought to be retained,
in s|>ite of the fact that some vulgar land surveyor haa defiled the Adirondacka with the names of
politicians, through whose influence he hoped for patronage.

72 FRESH-WATER ALG^ OF THE UNITED STATES.

Remarks. — This plant was found in a very stagnant pool, forming, with various
other species of alga?, a gelatinous, seruginous-brown stratum, through which the
single plants were thickly scattered, without anywhere forming the major portion
of the mass. The plants themselves are large enough to be distinguished by the
unaided eye. Under the microscope the sheaths are seen to be exceedingly trans-
parent and colorless, except in the older part of the filament, where they are often
dark brown and opaque ; but even in such case, -the edges are translucent and
lighter colored.

The internal cells or globose masses rarely have distinct coats, and even when
such were apparent, as in the older portions of the plants, there appeared to be a
communication between the cells. The original main stem is rather short, shorter
often than numerous branches into which it breaks up. Very often the apices of
the branches are colorless and entirely empty, consisting simply of sheath ; often,
however, they are occupied by a cylinder of protoplasm, which is sometimes arti-
culated more or les.s distinctly like an oscillatoria.

Fig. 4, pi. 8, represents a fragment of a filament with a small branch.

S. lignicola, WOOD.

S. strato expanse, tomentoso, atro ; trichomatibus ramossissimis, arete intertextis ; ramulis ab-
breviatis vel elongatis, subrectis aut varie curvatis, apicibus obtuse rotundatis vcl subacumi-
natis ; trichomatum et ramulorum cellulis uni-vel biseriatis, rare in trichomatibus matnris mul-
tiseriatis, plerumque pachydermaticis, dilute vel saturate a?rugineis, enormibus, plerumque
homogcneis ; cellulis terminalibus in trichomatibus immaturis elongatis, cylindricis, saspius
nonnihil oscillatorium rnodo articulatis, granulosis; vaginis sat amplis, haud achrois, vcl
luteo-brunneis vel fuscentibus vel ferrugineis.

Diam. — Trich. cum vag. max. r5Vs" = -OOOC6".

Syn. — S. lignicola, WOOD, Prodromus, Proc. Amcr. Philos. Soc., 18C9, p. 133.

nab. — South Carolina. (Ravenel.)

Occurring in an expanded, tomentose, black stratum ; filaments very much branched, closely
interwoven, branches abbreviate or elongate, nearly straight or variously curved, their apices
obtusely rounded or subacuminate ; cells 1-2 seriate, mostly thick-walled, light or deep
seruginous, irregular, mostly homogeneous ; terminal cells elongate, cylindrical, frequently
articulate somewhat like an oscillatoria, granulate ; sheaths somewhat ample, not transparent,
light bright, fuscous or ferruginous.

Remarks. — I have seen dried specimens only of this plant, which were collected
by Prof. H. W. Ravenel, in South Carolina. It is said to grow on old boards,
and appears to be a very distinct species. There are frequently two or three
very short, stubby branches arising together. The apices of the filaments and
branches are in some cases filled with endochrome to the end, and are broadly
rounded at the apex. In other cases the sheath of the filament extends a distance
beyond the endochrome, and is finally rapidly diminished to a point. The cells
within the filaments are of various shapes, sometimes globular, sometimes quad-
rangular, more often irregular. The original specimens from which this descrip-
tion was written were collected in April. I do not know whether they grew
immersed, or merely on boards exposed to the weather. I have since received

FKI:>H \v A i I:R ALU, EOF THE UNITED STATE s. 73

flpecimons collected in the month of Aumi-t, which grew on boards over which
spring water was constantly miming. These .specimens agree perfectly with the
otln T-. ezi '-pt that the filaments are larger und the elongated apical cell is wanting;
differences which 1 helieve to he due to the specimens collected in August being
older than those tir>t recei\ed.

Fig. 2 a and '2 /', pi. '.', \\ere taken from the t\pes, whilst fig. 2 c, pi. 9, from the

st >pe( illiclis.

o. Cfllulx ]>lfrumi]tie in terie duplici vcl multijilici.
a. Ci'lU generally in double tenet, or multiple tenet.

8. arffillaceus, WOOD, (sp. nor.)

;i\-> tfimi. rxpanso, subnigro, submembranaceo ; trichomatibas brevihun, dense intricatig
et snpe noimiliil coiirrrtis, ramosia, irregularibus; ptteudoramulis brevibns, varie curvatix,
nuiiiiiliil rijriili-i, plrruin<|iii! awviulrulibua, apice nonnihil attrnuatis; cellulis subglobosis,
stepo compre88J8, plcrumqne in serie simplici >«•<! interdum in eerie duplici, vel rare multiplici ;
(•••Hulls ii|iicalilius valde elongatix, cyliinlricis, ftcjtouemn trichomatibus internis Bimiliban;
Taginis craesi.-, linnis. in trichomatilius maturis saturate rubido-brunneis, in rainulis sepe luteo-
lirunueis ct in apice hvulinis vt fere colons ezpcrtibus; cellulis pcrdurantibus nullis.

Diam.— if,," - .000833".

Hub. — In palude argillacea, Sonth Carolina. (Ravenel.)

••mi thin, expanded, blackish, submembranaceons; filamentfl short, densely intricate, and
i"ivi|iii-nily somewhat concreted, giving origin to nnmcroas branches, irregular; branchefl short,
variously curved, somewhat rigid, mostly ascending, apex somewhat attenuate; cells sub-
globose, often compressed, mostly in simple series, sometimes in double, rarely even in multi-
ple ; apical cells elongate, cylindrical, resembling the inner filament of a scytonema ; sheath
thic k, linn, in the mature filament deep reddish-brown, in the branches yellowish-brown, at the
apices of the branches nearly colorless and transparent ; heterocysts absent

Remark*. — I am indebted to Prof. Ravenel for this plant, which was found by
him on a moist clay bank near Aiken, South Carolina, August, 1869. It forms a
thin, somewhat membranous, dark stratum, the filaments of which are so closely
united that it is almost impossible to tease them apart with needles. Neighboring
filaments are often united at the edges so as to form distinct bundles, and even
the branches are sometimes concreted, although, generally, as seen under the
microscope, they project from the mass in all directions. The surface of the fila-
ments is mostly rough and ragged with fibrillac and membranous projections. In
the older filaments the cells are often entirely absent. They are mostly single,
but sometimes multiple in the filaments ; in the branches they are often partially
double. The ends of the older branches are often broken and empty, whilst those
of the younger are rounded. The color of the cells, as I have seen it, does not
strikingly differ from that of the sheaths.

Fig. 3 a, pi. 9, represents a portion of an old frond magnified 460 diameters,
and fig. 3 i, the end of a younger branch. No. 79. Collection of Ravenel, Aug.
1869.

8. jnittiiln, WOOD.

S. in maculis snbnigris, parvis, tennibns, plernmque rotnndatis, interdnm enormibns, dispositae;
trirhomatibns arete intertextis. ramossissimis, rigidis, intequalibng, snbcylindricis, nonnihil

10 M»y. 1871.

74 FRESH-WATER ALGJB OF THE UNITED STATES.

contortis; ramulis abbreviatis vel nonnihil elongatis, apice obtuse rotundatis; ramulorum et
trichomatum cellulis tri-multiseriatis, plerumquo pachydermaticis, ferrugineo-fuscis, enormiter
globosis, homogeneis ; cellulis apicalibus interdum breve cylindrieis, baud articulatis ; vagiuis
sat amplis, luteo-brunneis vel dilute ferrugineo-brunneis.

Diam. — Max. trich. cum vag. 7^" = .0013".

Syn. — S. guttula, WOOD, Prodromus, Proc. Amer. Philos. Soc., 1869, p. 132.

Hob. — South Carolina, in Taxodium distichum. (Prof. Ravenel.)

Arranged in small, thin, black spots, which are generally round, but sometimes irregular : fila-
ments closely interwoven, very much branched, rigid, unequal, subcylindrical, somewhat con-
torted ; branches abbreviate or somewhat elongate, apex obtusely rounded ; cells of the
trichoma and branches 3 to many seriate, mostly with thick coats, ferruginous-fuscous, irregu-
larly globose, homogeneous ; apical cells sometimes shortly cylindrical, not articulate, sheaths
ample, yellowish-brown.

Remarks. — This species was found growing on the bark of Taxodium distichum,
by Prof. H. W. Ravenel, in South Carolina, and by him given to Dr. Billings,
U. S. A., to whom I am indebted for specimens. It forms on the bark minute
roundish, blackish, dot-like spots of about a line in diameter, or sometimes, appa-
rently, by the coalescence of two or more of these spots, larger irregular patches.
The habit of the plant is a rigid one. The main stem is often irregular in size,
variously bent and rebent, and mostly gives off a number of branches, which fre-
quently nearly equal the main filament in size, and like it are bent in various
directions. They also frequently give origin to numerous short branches. In
some instances, there is a distinct apical cell, which is cylindrical, but only two or
three times longer than broad; in many cases, however, this cylinder being want-
ing, the ordinary cells extend to the extreme apex.

Fig. 4 a, pi. 8, represents a filament, and fig. 4 J, the end of a branch magnified
460 diameters.

S. acervatns, WOOD.

S. in guttulis minutissimis, subcrnstaceis, nigris, in strato subcontinuo saspe aggregatis; tricho-
matibus parvis et brevibus, rigidis, admodum inaequalibus, prostratis, tuberculis, arete et dense
ramossissimis, viridibus aut anreis aut brunneis ; ramulis brevibus, plerumque haud ramulosis,
erectis aut ascendentibus, sa?pe abbreviatis et papilliformibus, obtusis, sfepe lateraliter connatis ;
cellularura serie in trichomatibus multiplici in ramulis plerumque simplici ; cellulis subglobosis
vel subangularibus, viridibus, haud distincte granulosis, in ramulorum apice ssepe breve cylin-
drieis et interdum obsolete articulatis ; vaginis anreis, nonnihil hyalinis.
.— Trich. max. 7Hfo" ; ram.

Syn.—S. acervatus, WOOD, Prodromus, Proc. Amer. Philos. Soc., 1869, p. 132.
Hob.— South Carolina, in corttce (Ilex opaca). (Prof. H. W. Ravenel.)

Arranged in drops, which are very minute, subcrustaceous, black, and frequently aggregate into
a subcontinuous stratum ; filaments small and short, prostrate, rigid, somewhat unequal, tuber-
culate, densely and closely branched, green or golden or brown ; branches short, for the most
part not branched, erect or ascending, frequently abbreviate, and papilliform, obtuse; series of
cell multiple in trichoma, mostly simple in the branches; cells subglobose or subangnlar,
green, not distinctly granulate, in the apices of the branches frequently shortly cylindrical and
sometimes obsoletely articulate ; sheaths golden, somewhat hyaline.

FUKsii-WA TI: K A i. (..I: 01 TIIK r.\iTi:n STATES. 75

k*. —This sprri. - u u found in winter by 1'rof. II. \\'. Kavcnel in South
Carolina, growing upon the lurk of /<• i <•_ • <••», forming minute, firm, crustaccous,
roundish dot> or m.i^.--., much smaller than a mustard-seed, but in gome cases so
cloM'ly ai^regated as almost to make a continuous stratum. "When one of these
dots is placed under the microscope, the branches are seen presenting their ends
upon all siile>, reminding one of some varieties of coral, and between these are
blackish matters, which prevent the whole dot from being seen. These branches
are frequently placed very close to one another, and cohere by their < dges so as to
make a sort of membrane or a solid mass. The filaments themselves ure mostly
obscured in the dense mass of branches which clothe them. This species seems
to be closely allied to X. i M /•<(//<,/(/,. --, and I am not certain whether it is distinct or
not. It is certainly MTV much smaller.

V |Mlll Ill.tllls.

S. piilvinatu-. liiiiin-i-;;itiif», saturate olivaceo-nigcr, ad tres lincae crassus; trichomatibng crassis-
Kiinis, nimossissiiiiis, fuscescentibns, cuormitrr curratis; rumiilis pulymorphis pro state cras-
sitie UgDitndineque variis, apicc plerunH|uc obtuse rotundatis; trichorantum rcllnlarnm eerie
imiltipliri. raiiiiiloruiii :! I pliri ; \ iiirinis crassis, lutco-fuscis ad satnrate-fuscix, vel pcllucidi*
vrl non pflliicitlis, intcrdura rugoao-tuberculis.

im. — Trich. cum. vag. max. .0042".

.s',/,1. — .S'. I'lilri'nttlii*, (lliifin ) ItAi-.KMionsr, Flora Europ. Algar., Sect. II. p. 290.
//,;/,. — in rupibus propc Philadelphia. Wood.

In innist, dcfp olive-black cushion-like masses of two or three lines thick ; filaments very thick,
much liruiicln-d, limwiii.-h, irregularly curved ; branches polymorphous, varying in thickness
and M/r, mostly with their apices obtuse; cells of the filament many seriate, of the branches
tw<> to four seriate; sheaths thick, yellowish-fuscous to deep fuscous, pellucid or opaque,
sometimes rugose-tuberculate.

-k*. — I have received specimens of this species found by Mr. Austin in
•hern New Jersey, growing on the exposed face of rocks.

The si/.e attained to exceeds that given by Mr. Rabenhorst for the European
form. The color of the cytioplasm varies from an almost verdigris-green to

fllscOUS.

l'ie>ides these specimens, Dr. I. Gibbons Hunt has given me fresh ones of a
-if/ton which he found growing on the face of dripping rocks along the
\\ -ahickon Creek, near this city. These are much smaller in every way than
their more northern brethren, and differ in other respects, I think, sufficiently for
a distinct variety. The filaments and branches are much flatter than in Mr.
Austin's specimens. I append a description.

( Far. p.i r vii*.

S. trichomatibus in respite saturate olivaceo-nigro arete intertextis; trichomatibns crassissimis,
cnonniter ramosissirais, luteo-fuscescentibns, Tarie cnrvatis; nunulis polymorphis, apice
plerumqne obtuse rotnndatis; trichomatnm cellnlarnm serie multiplici, ramnlonim 1-4 plici ;
cytioplasmate grannlato, plerumquc saturate fuscesccnte, intcrdura licte viride ; vaginis crassis,
dilute luteo fnsccscentibus, interdum achrois.

Diam. — Trichora. cnm. vag. max. SJS" •• .03"

76 FRESH -WATER ALG^E OF T1IE UNITED STATES.

Filaments closely interwoven into a deep olive-black turfy mass, very thick, irregularly and fre-
quently branched, yellowish-fuscous, variously curved ; branches polymorphous, their apices
mostly obtusely rounded ; series of cell in filament multifold, in branches 1-4 fold ; cytio-
plasm granulate, mostly deep brown, sometimes bright green ; sheaths thick, light yellowish-
brown, sometimes transparent.

Remarks. — The fronds are very irregular in form and size, much branched, and
so closely interwoven that they mostly cannot be separated without breaking.
The branches are sometimes short and stumpy, sometimes they are very long.
The color of the cells approaches somewhat to a chocolate, at times with a little
red in it so as to give something of a mahogany tint. The walls of the cells are
mostly very thick, but they are often lost in the general mass of the frond. In the
branches, the cells are often so closely crowded as to almost obliterate their walls.
In a few specimens I have found the cells to be of a bright green color, instead
of that just mentioned. The exact meaning of this I do not know ; it would
scarcely seem to indicate immaturity, for I have found it in the oldest portion of
large fronds, whose other parts were of the normal color.

Fig. 1, pi. 10 represents a filament of this variety magnified 160 diameters.

I have received from Prof. Ravenel certain dried alga?, labelled Stigonema
Ravenelli, BERKELEY, which appear to me to belong to this genus. In what place
Berkeley described them, if ever, I do not know, nor why he placed them in the
genus Stigonema. The following is a description of the species : —

S. strato sub-nigro; trichomatibus arete intertextis, ramossissimis, enormibus, varie curvatis'
ramulis brevibus et sublongis, varie curvatis, latis, apiee nonuihil attenuatis et obtusis ; tri-
chomatum et ramulorum cellulis arctis, enormibus, in serie duo-multiplici enormiter dispositis;
cytio-plasmate bomogeneo, laete viride ; vaginis aureis, lucidis.

Diam. — Max. trich. cum vag. 7^a".

When dried blackish ; filaments closely interwoven, very-much branched, irregular, and variously
curved ; branches short or largish, variously curved, broad, their apices somewhat attenuated
and obtuse ; cells of the filament and its branches very close, irregular, Irregularly arranged
in a twofold or multiple series ; endochrome homogeneous, bright green ; sheath yellow,
semitranslucent.

Remarks. — This plant was collected by Prof. Ravenel on the now famous Look-
out Mountain. It is of a thick, bushy habit, and appears to form turf-like mats
of a line or two in thickness and of a blackish color. The filaments throw off in
all directions very numerous branches, some of which are short and stumpy, others
quite long, and are themselves the parents of numerous secondary branches. The
longer branches often rival the main filament in size, and like it vary continually,
in being irregularly expanded and contracted. There is never a long, articulated
cell, not even in the apices of the branches. The apices are often somewhat
attenuated, and are always more or less obtuse. The cells are -of a bright green
color, are very irregular in form, and are often very irregularly arranged in rows
of from two to five, both on the main filament and branches. The base of the
filament often gives origin to several small, cylindrical, root-like processes.

FRESH-W A TKK A L li .K OF T II K f N I T K I> STATES. 77

Fig. 4 a, pi. 9, represents a frond of this plant magnified 125 diameters; fig. 4 6,
a fragment magnitinl Jiiil diameters.

Profe>sor Hailey, in Ameriran Journal of Scienees, vol. iii., new series, states
that he has found two species of the genus Stii/<>n< nm, namely, St. atrorirens, A.G.
and St. iintiiunilli^inn, Ac. ; tlie former growing on wet rocks at Indian Falls,
Putnam Comity, New York ; the latter at Round Pond, near West Point. I have
no personal knowledge of the genus, but, according to authorities, it belongs to
tin- lirhens rather than the alga?, apothecia having been detected in various
ies.

CLASS CIILOKOPIIYLLACEJE.1

I*liiiitiiln> a<|iiatira> vd aercie, uni-, bi-, vel multicellulares, aut singulae
uut eonsoeiatu1, fainilias foniuintcs.

\':/tfiitin tenniiialis \d non tenninalis.

l;<unijir<it!n aut nulla aut vera, sed ccllularum non divisione, potius
prolificatione.

Ci/innl, nun non siliccum, combustibilc, saepius e stratis successivis
«-iiiii|M.>i(iiin, Mili-tantiaiu irrlatinosam pleruinque liquidam exsudans.

( 'i/tin/Jii^ma chlorophyllosum, chlorophylli loco nonnunquam erythrino
\el sul»taiitia (ilciisa coccinea, carnea aut rufescente coloratura, nuclco
(centiali vel lateral!) plerumque prseditum, granulis amylaceis rarissirae
evens.

ijih'i-iiti'n fit cellularum divisione vegetativa. Foecundatio ple-
scxiialis.

iu lit aut oosporis vel zygosporis aut gonidiis tranquillis vel
agilibus.

Aquatic or aerial uni-, bi-, or multicellular plants occurring singly, or
consociated in families.

Vegetation terminal or not so.

/•'randies either wanting, or if present, true branches, although formed
rather by a process of proliferation than division of the cells.

< 'i/tntlerm not siliceous, combustible, often composed of successive
strata.

Cytioplasm chlorophyllous, sometimes colored by an oily crimson, flesh-
colored or yellowish-red substance, in the place of the chlorophyl, gene-
rally furnished with a nucleus (either lateral or central), very rarely
without starch granules. Growth occurring by the division of the cells.
Fecundation generally sexual.

/'/ •<>/i<t</>iiion taking place by oospores or zygospores, or by tranquil or
motile gonidias.

1 The description of this Class and Order is that of Prof. Rubcnhorst.

78 FRESH-WATER A L G yE OF THE UNITED STATES.

ORDER CoCCOphycCSC.

Alga: unicellulares. Cellulae ant singulse (plerumque perfecte scgregatae) aut plures in familias
consociatas, tegumentis involutae vel nudse, aut ramificatione aut vegetatioue terminal! destitute;.
Propagatio fit aut cellularum divisione aut zoogonidiis.

TJnicellular algse. Cells either single (mostly entirely segregate), or mostly consociated in fami-
lies, walled or clothed with teguments, destitute of branches or terminal vegetation. Propagation
by means of zoospores, or by the division of the cells.

FAMILY PALMELLACE.E.

Algae unicellulares sensu latiori. Cellulse aut singulse aut numerosae, familias constituentes, in
muco matricali plus minus firmo, stratum gelatinosum amorphum, saepius figuratum, tubulosum
(Hormospora) varie divisum et perforatum (Tetraspora), quasi ramificatum (Hydrurus) formante
nidulantes, vel nullo (Rhaphidium, Dactylococcus). Cytioderma plerumque tenue, saepius tegumento
gelatinoso aut homogeneo aut lamelloso praeditum. Cytioplasma homogeneum, aetate provecta ple-
rnmque distincte granulosum, viride, aut rubescens aut fuscescens, vesicula chlorophyllosa semper
instructnm (excepto Rhaphidio).

Multiplicatio fit cellularum divisione vegetativa, propagatio gonidiis ex ultima ccllularum gene-
ratione transitoria cytioplasmatis divisione varia ortis. Gonidia tegumentis liberata, polo autico ciliis
vulgo binis plerumque instructa et alacriter circumvagantia. (R.)

Algae unicellular in a broad sense. Cells either single or numerous, constituting families, imbedded
in a jelly to form a gelatinous stratum which is amorphous or shaped, as tubular (Hormospora),
variously divided and perforate (Tetraspora), falsely branched (Hydrurus), or sometimes is wanting
(Rhaphidium, Dactylococcus). Cytioderm mostly thin, often furnished with a gelatinous or homo-
geneous or lamellate tegument. Cytioplasm homogeneous, mostly at maturity distinctly granular,
green-reddish or fuscous, always furnished with a chlorophyllous vesicle (except Rhaphidium).

Multiplication taking place by a vegetative division of the cells, propagation by transitory gonidia
arising by various divisions of the protoplasm from the last vegetative generation. Gonidia with-
out integument, mostly furnished with two cilia at the anterior end, and moving about actively.

Genus PLEUEOCOCCUS, MENGH. (RABENH.)

Cellulae globosse vel e mutua pressionc angulosae, plerumque nucleo instructae, turn singialae turn
in familias consociatae. Cytioderma firnium, ssepe crassum, laeve, hyalinum ; cytioplasma homoge-
neum viride vel oleosnm rubrum. Multiplicatio cellularum vegetativarum divisione in directiouem
ad omnes dimensiones altcrnantem. Propagatio fit gonidiis intra sporangia ortis.

Cells globose or angular from mutual pressure, mostly furnished with a nucleus, sometimes single,
sometimes aggregated into families. Cytioderm firm, often thick, smooth, hyaline ; cytioplasm
homogeneous-green or oleaginous-red. Multiplication occurring by a vegetative division of the
cells alternately in three directions. Propagation by means of gonidia, formed within sporangia.

P. serial us, WOOD, (sp. nov.)

P. corticolus, strata pulverula, rubido-brunnea, nonnihil Crustacea formans ; cellulis enormiter
subglobosis, vel ovalibus, laete aurantiacis, interdum viride tinctis, hand distincte nucleatis, in
seriebus singulis rectis vel curvatis conjunctis ; tegumentis crassis, baud lamellosis, coloris
expertibus.

Diam._7EV'— TSV = .00053"— .0012".
Eab. — In palude. New Jersey. (Austin.)

Growing on bark, forming a reddish-brown, somewhat crustaceous powdery mass; cells irregu-
larly subglobose, or oval, bright orange, sometimes tinged with green, not evidently nucleated,
conjoined in single straight or curved series; tegument thick, lamellate, or not so, colorless.

FIIESH-V ATI-: K ALG.fi OF Till: PK1TBD > I ATI-: 8. 79

Remark*. — I am indebted to Mr. Austin for sprrini<-ns of this little plant, which
he found growing in a swamp near Closer, Northern New Jersey, on a young
pin oak. It forms a sort of crustaceous powder, with little aggregations here and
there, of a dull reddish-brown color. "When these little masses are broken up,
they are found to be composed of little series of very closely joined cells, generally
a half dozen to :i do/en in the row. I belie\e that ;it certain states of their growth
tin se cells are green, as many of them have a very decided green tint on their
iiid 1 have seen one or two of them quite green.

Fig. ',', pi. 10, represents this species magnified 460 diameters.

P. piilvrrrii*. W , <.<p. nov.)

P. cellulia iiiiiiiinis, orruleo-Tiridibos, enormiter pubplobosis, vel aogulosts, in familias nurae-
rosas coDBociafls ; fmniliis e o-llulis iininerossissiinis et dense confertis com posit is, irregu-
laribus, intrnluin conflucntibua, plcrumquc pseudotcgumculia byalinis involutis, in strato
pulvi-iYo hi'U- viridi aggrcgatia.

Diam.— nl<sv"—nlm" - .00004"— .00013".

lliil i. — In fmitc. " Boiling Springs," prope Bellcfontc, Pennsylvania.

Cells very small, bluish-green, irregularly snbglobose, oral, or angular, associated in numerous
families ; families composed of very numerous and densely crowded cells, irregular, sometimes
cuiilliimt, mostly surrounded by a false hyaline tegument, aggregated into a bright green
pulverulent stratum.

/, n<<irk«.—In. Centre County, Pennsylvania, two miles from Bcllefonte, there is
a very lari;e and beautiful limestone spring, which is a favorite roadside watering
place, and is laid down on the maps as "Boiling Springs." Forming a stratum
DM r mn>t of the bottom of this spring is the little plant here described. The
nin is in places nearly an inch in thickness, and when lifted by the hand is
fonrtd to t>e dry and crumbly, instead of mucous and tenacious. Under the micro-
scope it is seen to be composed of vast numbers of irregular masses or families of
imbedded in a firm jelly, which projects so as to form a sort of transparent
to the whole mass; this cast I have spoken of in the description as a false
inent. The cells themselves are exceedingly small and furnished with an
t-ntric point, which is probably a nucleus.

Genus PALMELLA.

Cellule globose vel ovalos rel oblongae, tegumentis plus minus crassis in nincnm gclatinosum,
MBpios mox conflucntibus involute, thulium diffbrme efficientcs. Cellularum dirisio dircctione in
omneg dimensioned alternunte.

!« globose, oval, or oblong, nnrroonded with a more or less thick integument generally very
soon confluent into a firm or soft jelly. Thallus shapeless. Division of the culls alternately in all
directions.

P. Jesenii, WOOD.

P. t hallo indefinite expanse, initio dilute aut laete viride, molle, pellncidnlo; etate prorecta
firmo, tnbcrculoso, saturate olivaceo-viride; cellulis globosis vel ellipticis, — in thalli state
immatnro, plcrnmque singulis ant geminis, siepe distantibus, — in state provecta etepc in fami-
liaa connexis, plcrumque confertis ; tegumentis in thalli setate immaturo plerumque difflucuti-
boi, state provecta plcrumque dUtincli*.

80 FRESH- WATER ALG.E OF THE UNITED STATES.

Zttoro.— Cell, glob. max. ^v" = .00028"; cell, oblong, long. max. 35Vs" = .0004".

Syn. P. Jesenii, WOOD, Prodromus, Proc. Am. Philos. Soe., 1869, p. 134.

Hub. — In rupibus irroratis, prope Philadelphia.

Thallus indefinitely expanded, in the beginning soft and pellucid, afterwards firm, tubercular,
deep olive-green ; cells globose or elliptical ; in the immature thallus, single or geminate, fre-
quently scattered ; in the mature thallus often closely conjoined into families, mostly crowded ;
in the young thallus the teguments of the cells are mostly diffluent, afterwards distinct.

Remarks. — This little plant was found along the banks of the Schuylkill River,
just above Flat Rock tunnel, near Manayunk, forming in the early winter a gela-
tinous mass of two to three lines in thickness, irregularly and. interruptedly spread
over the face of wet, dripping rocks. In what appeared to be the younger por-
tions, the jelly was often quite soft and almost colorless, and had the cells scat-
tered rather sparsely and distantly through it. The cells were but partially filled
with chlorophyl, the vacuole left containing often numerous granules, and had
distinct walls, being, as it were, merely immersed in the general maternal jelly.
In the older fronds the texture is more firm, the color a deep green, and the bright
green cells are mostly surrounded by a thick, very distinct tegument. They are
also largely arranged in little families of two, four, or even eight cells, surrounded
by a common integument. The oldest fronds are of a deep olive, almost blackish
color, markedly tuberculate upon their upper surface and very firm in texture.
They are surrounded by very distinct, firm, dark brown coats (a simple coat often
involving two or more cells), and arranged in groups or families. As shown by
the microscope in the superficial portion of such fronds, the jelly is of a yellowish-
fuscous color, and the cells are themselves of a dark brown tint. The number of
cells in the individual families varies from two to a dozen or more. Even in these
old, firm fronds, the interior portions are frequently composed of greenish cells,
without any distinct teguments or coat. In such cases the cells are mostly oblong
or elliptical, and very much crowded together. This species appears to come
closest to P. BrSbissonii, KTZ., from which it differs, however, in its habit of
growth and the size of its cells.

Fig. 3 a, pi. 10, represents a fragment of the upper surface of an old frond
magnified 750 diameters; fig. 3 b, when taken from the inner jelly of similar
fronds.

P. dura, WOOD, (sp. nov.)

P. thallo enormiter subgloboso, enormiter minute lobato vel verrncoso, caeruleo-nigro, nonnihil
crustaceo, minuto ; cellnlis arctissime coufertis, plerumque enormiter oblongis, ssepe in serie-
bus irregulare dispositis, cseruleo-viridibus vel luteo-brunneis ; tegumentis baud distinctis ;
sporis globosis vel ovalibus.

Diem.— Cell. nW'-.OOOOS"—^"- .00016"; spor. T5^5" = .00058"— 75<W' = . 0008"
Hob. — In fonte prope Philadelphia.

Thallus irregularly snbglobose, irregularly minutely lobate or warty, bluish-black, somewhat
crustaceous, minute ; cells densely crowded, mostly irregularly oblong, often arranged irre-
gularly in series, bluish-green or yellowish-brown ; coats not apparent; spores globose or
oval.

FKESI1 \VATKK A L O M OF T II K LMTi:i> .- T A IKS. gl

Remark*. — I found this plant growing in the large spring at Spring Mills in
Man-h or April. Tin- fromN \\. -re in tin- form of little bluckish balls attached to
the stems of mosses in the water. They varied in size from the minutest speck,
scarceK visible to the naked eye, up to ten lines in diameter; they are globose,
firm and hard, and the larger look almost as if they were aggregations of
smaller ones. They are gregarious. The spores are mostly borne on the edges
of the frond, sometimes they appear to be imbedded in its substance. At first
they are of an inten>e bluish-green, but afterwards they appear to be yellowish-
browii. None of the cells, as I have seen them, have their contents granulate.

Fig. o n, pi. 10, represents a section of a frond magnified 460 diameters; fig.
;"> /'. a section of the edge of an old frond, developing spores.

P. hyaliiin, I.YNOB.

" Fronds from a quarter of an inch to an inch in diameter, somewhat globose, bat at length fre-
<jii> nth- more or less elongated into an orate or even cylindrical form. Substance gelatinous
and very tender, of a pellucid, watery appearance. Grannies numerous, globose, green.
The fronds are produced at first on rocks and stones at the bottom of streams, and afterward!
become disengaged aud float on the surface."

It-murk*. — Professor Bailey states that he has found this species from Rhode
Island to Wisconsin. Whether it is identical with the P.hyalitia of Brebisson, or

not, 1 cannot say.

/
Genus PAGEROGALA,1 WOOD.

Tliallus solidus, gclatinosns, indefinitus, exalbidus, nonnihil pcllucidulns, nodulis dense aggregatis
nlliii ntibus formatus. Cellulte globoste, conferte, in familias consociaUe. Familie tegu-
ment is tenuilms et membranaceis inroluUe, in nodulorum centro posiUe.

Tliallus solid, indefinite, gelatinoas, whitish, somewhat pellucid, composed of closely aggregated
iKMluU-s whirli arc often indistinct. Cells globose, crowded in families. Families surrounded by a
thin mcmbranaceous coat and placed in the centre* of the gelatinoas nodale.

/,'• murk*. — This curious plant was found by myself floating as indefinite masses
of milk-white jelly on a mountain spring near Bear Meadow, Centre County, Penn-
s)l\ania. Thelargestof these gelatinous masses was six inches long. On taking
them out of the water they were seen to be composed of somewhat irregular
nodules, which in some portions of the mass were very distinct one from the other,
but in other parts were confluent into an almost uniform jelly. When the nodules
were separated it was discovered that each contained a membranous very delicate
sack of a pale green color, which the- microscope showed to be really a cell family.
Their interior was hollow, or at least only partially filled with a transparent fluid,
and they contained all round their exterior portion a layer of round, closely placed
cells. In some instances the outer membrane was ruptured, and the sac only con-
tained a few cells, which could often be seen to be moving freely in the inner
liquid. The sac membrane, is thin and delicate, colorless, and marked with curious,
regular wrinkles or folds. In those portions of the common gelatinous mass, where
the nodules were lost, I could not find any of these sacs.

, frozen ; y«oa, milk.

82 FRESH-WATER A L G M OF THE UNITED STATES.

No opportunity was afforded to study the development of this plant ; but there
can be but little doubt that the globular, thickish-walled cells are finally dis-
charged by a rupture of the membrane and escape from the softening jelly into the
water, each to be a possible starting point for a new frond.

I have given this curious plant the name of Pagerogala, from its milky white-
ness. Floating in the water it offered so close a resemblance to the spawn of frogs,
though more opaque, that my companion, a most excellent naturalist, insisted,
until its true nature was absolutely demonstrated, that I was simply wasting my
time collecting the spawn of an amphibian.

P. stellio, (sp. nov.)

Diam.— Frond £ inch ; cells ifa"— WOT/'-

Genus TETRASPORA, LINK.

Thallus gelatinosus, membranaceus vel submembranaceus, initio saccato-clausus, setate provectiori
vel postea explanatus. Cellulse globosee (vel anguloso-rotuudatse) plus minus distantes sed in familias
magnas unistratas consociatae ; tegumentis erassis in mucum homogenenm cito diffluentibus. Cel-
lularum divisio in planitiei duas directiones alternans.

Propagatio fit gonidiis mobilibus.

Thallus gelatinous, membranous or submembranous, in the beginning a short sack, afterward
expanded. Cells globose, or angularly so, more or less distant but consociated in a single stratum
into large families. Tegument thick, very rapidly diffluent into a homogeneous mucus. Division
occurring in two directions in the one plane.

Propagation by means of zoospores.

T. Inbrica ? (ROTH) AG.

T. thallogelatinoso-membranaceo, lubrico,dilutissime viride, tubuloso sed seepe postea explanato,
simplice vel ramoso, undulato-sinuoso, siepe lacunis munerosis perforate ; cellulis globosis
vel ellipticis, laete viridibus, interdum singulis sed plerumque quaternis vel geminis, locello
achroo hyalino parietal! saepe prseditis ; cytiodermate tenuissimo, haud distincte visibile.

Diam.— Cell, ^i^"—^/ = 0.00025"— 0.0005".

Syn. — T perforata, HAEVET. BAILEY, Silliman's Journal, N. S. vol. iii.

T. lubrica, (ROTH) AG. RABENHOBST, Flora Europ. Algarum, Sect III. p. 41.

Hob. — Northern Atlantic States.

Thallus gelatinoso-membranaceons, slippery, very dilute green, tubular, but often finally ex-
panded, simple or branched, undulately-sinuate, often perforated with numerous holes ; cells
globose or elliptical, bright green, sometimes single but mostly in pairs or fours, furnished
with a parietal transparent hyaline space; cytioderm very thin, not distinctly visible.

Remarks. — This little plant is very common around this city, growing usually
in limpid, quiet water, such as springs, little rushy pools, and clean ditches. The
frond is a translucent, light green or scarcely greenish, very slippery jelly, with
the edges often very markedly undulate. It is very rarely simple, but on the con-
trary is often very much and very irregularly branched, frequently indeed consist-
ing of several broad portions united by narrow necks. It is an irregular sack,
generally profusely perforate, and often with large imperfect portions. I think it
finally in many instances becomes expanded and open. It is sometimes found
lying on the bottom, but more frequently floats on the surface of the water. The
breadth of the frond varies from two or three lines to an inch. The length often
reaches several inches. The cells are mostly globular; but, immediately after

FKKSH-W A 1 Hi: ALli.K UK T 11 K I .\ 1 I I' I) STATES. 83

division, they arc elliptical. Thry arc of n bright green color and almost always
have a conspii -nous rounded granule within tlirni ; sometimes, but not commonly, at
one end then- is a hj aline space or vesicle, similar to that seen in zoospores. I
lia\c watched tlic prodm tion of /oosp.,res in a plant gathered late in November.
The cinter wall of the cell is always so thin as to be scarcely perceptible, and when
the /oosporc is beginning to move, it looks as though the \\hole cell were rocking,
the thin outer coating beini; lost to eight. After a considerable period of vain
rrl'ort the /oospore c-i ap< - from the thick gelatinous mass which surrounds it. It
is hiciliated, roundish, and furnished with a hyaline space at the end.

I have observed a '!'< /r<i"j>ora growing in rapidly running water, which some
would no doubt consider distinct, but which seems to me rather a variety. The
itc frond was of a very vivid green, erect, buoyed up by an air-bubble con-
tained in its upper end. Its shape was that of a long sack widened very much
above, and below constricted into a fine point, by which it was firmly attached.
In some instances it attained a length of seven or eight inches. In all other
rcsprrts these plants agreed with the others found in quiet water.

The species of this genus are to me not at all well-defined in any work which I
ha\c had access to. The plant now under consideration abounds everywhere in
tins neighborhood, and is without doubt the one identified by Prof. Bailey as T.
ijtliitintuta (Vauch), of which, however, he afterwards states that Prof. Harvey, to
whom he had sent specimens, writes that it is a distinct species, and proposes to
call it jxrforala. In my Prodromus I referred the plant to T. lubrica (Roth).
My reasons for doing this were that the size of the cells corresponds very closely
with the measurements of that species as given by Prof. Rabenhorst, and the
absence of anything that seemed to me definite in the descriptions of the two
:es. Moreover, if the possession of a parietal hyaline spot be not simply an
accident of growth, it would indicate that the plant belongs to P. lubrica. I do
not think, however, that any importance is to be attached to this, as the vacuole
is often absent, and, although Prof. Rabenhorst makes no mention of it, is, in all
ability, present in certain states or stages of T. gclatinosa. My own convic-
tion is, at present, that T. gdatinosa and T. htbrica are very probably synonyms.
If they be distinct, the plant from which the above description was taken is refer-
riblc to T. perforata (Harvey), which, if not new, is a form of T. lubrica rather
than T. gelatinosa. If T. lubrica and T. gelatinosa be united, no grounds are left
for sustaining the separateness of T. perforata.

Whilst botanizing in a primeval glade and forest, known as Bear Meadows, in
this State, I came across a spring, covered with a Tetraspora, which appears to
represent the T. gelatinoea type. It formed great masses half an inch in thickness,
at first attached, afterwards floating and covering the surface of the pool for several
feet each way. When young these masses were elongated and were formed of
numerous lobes attached often by very slender pedicles, and having their margins
thickened and undulated so as to give a beautiful waved appearance to the light
green mass. Under the microscope the structure was similar to that of the other
form, except that the cells varied more and attained a greater size. Their diame-
ters ranged from JT>yj* = 0.00027" to T3J5/ = 000066*.

84 FRESH-WATER ALG.E OF THE UNITED STATES.

I have also received from Prof. Ravenel specimens of a Tetraspora, which may
be the young of a variety of this species, but which is very possibly distinct. If
the specimens are adult, it certainly is. They consist of numerous little fronds not
more than a third of an inch in length, often composed of several subcylindrical
arms, as it were, radiating from a central portion, and attaining a length of a third
of an inch or so. These fronds are irregularly perforate, and are composed of
cells agreeing perfectly in form, size, and arrangement with the more ordinary
forms of T. lubrica.

T. foiillosa, (ROTH) Aa.

T. thallo membranaceo-saccato, obovato, sinuoso-bulloso, unciam usque palmam longo, postea
explanato, dilacerato, saturate viridi, plus minus verrucoso; cellulis subsphericis (post divi-
sionem factam hemisphaericis vel angulosis) geminis vel quateruis, confertis, granulosis.
(R.) Species mihi ignota.

Diam.— Cell, ante divis. 0.00032"— 0.00049" ; post divis. 0.00022"— 0.00029". (R.)
Syn. — T. bttllosa, (ROTH) Aa. RABENHORST, Flora Europ. Algarura, Sect. III. p. 39.

Hub. — " Salem, North Carolina. Schweinitz, Newburgh, New York." Bailey, Silliman's
Journal, New Series, vol. iii.

Thallns membranaceons saccate, obovate, sinuosely-bullose, from one to six inches in length,
afterwards expanded, torn, deep green, more or less verrucose ; cells subspherical (after divi-
sion hemispherical or angular) in twos or fours, crowded, granular.

Genus DICTYOSPH^EEIUM, N.EG.

Thallus gelatinosus plus minus liquidns, libere natans, saepe quasi nullus. Cellulse vesicula chlo-
rophyllosa unica et locello achroo parietali praeditse, tegumentis crassis in gelatinam homogeneam
confluentibus involutae, filis propriis subtilibus dichotome diyisis, e familiarum centro ad peripheriam
radiantibus connexae. Cellularum divisio ad omnes directiones.

Propagatio fit gonidiis mobilibus

Thallus gelatinous, more or less liquid, swimming free, often almost wanting. Cells furnished
with a single chlorophyllous vesicle and a lateral transparent spot, surrounded with thick coats,
which are confluent into a homogeneous jelly and united by very fine filaments, which are dichoto-
mously divided and radiate from the centre to the peripheral families. Division of the cells occur-
ring in all directions.

Propagation by motile gonidia.

D. pulchelluin, WOOD, (sp. nov.)

D. thallo subgloboso vel subovale, interdum subnullo, interdum indistincte lobato ; cellulis
globosis plerumque sparsis sed interdum nonnihil confertis.

Diam.— Cell. ^v" = 0.00025" ; thalle plerumque 3£/ = 0.0033" ; interdum T£s" = 0.0054."
Hob. — In stagnis prope Philadelphia.

Thallus subglobose or suboval, sometimes indistinctly lobate, sometimes almost wanting; cells
globose, mostly scattered, but sometimes rather crowded.

Remarks.— I found this little plant, one August day, floating, in company with
Closterium acerosum, in a brick-pond below the city. The little fronds are mostly
roundish, or longer than broad, with a distinct outline, sometimes, however, the con-
stituent jelly seems to fade into the surrounding water. There is never a distinct

FRESH-WATER ALO.E OF THE UNITED STATES. sj

outer coat. The lateral transparent spot in the cells is mostly very evident, some-
times it is wanting, however. Occasionally then- is a very distinct blackish "eye
spot." The threads which join the cells arc very delicate, and I have never been
alile to absolutely demonstrate their meeting in the centre of the frond, although
I believe they do so. In mounted specimens, even when preserved in carbolic
acid water, they disappear after a time. I have never seen zoospores or any other
reproductive bodies.

Genus RHAPHIDIUM, KTZ.

.ulir fu.-iformes vel cylindracete, utrinquo (plernmque) sensim srnsitnquc cuspidate vel acumi-
nate, rarius uliiu.-ata*, rectw vel vnrie curvate, singule, gemine Tel fasciculatim aggregate, medio

-utiiii vd radiatira conjunct*, rarius bine sub polls lateraliter conncxe, cetcrura liber*.

• lermu tcnue, hfvo. ('yti"i>la.sina viridc, subtiliter granulosum, locello pallidiori vel acbroo,
ceutrali, rarius lateral!, preditum. Cellularutu divisio ad uiiam directionem. (R.)

Cells fusiform or cylindrical, generally very gradually cuspidate or acuminate at the ends, rarely
obtuse, straight or variously curved, single, geminate, or fasciculately aggregate, decussate in the
centre or radiately conjoined, rarely two laterally united at the end, other cells free. Cytioderm
thin, smooth. Cytioplasm green, very finely granular, furnished with a central or rarely lateral
transparent vacnole. Division of the cells occurring only in one direction.

R. polyiiiorphiini, FRESIM.

K. crllulis rectis vel varie curvatis, singulis, vel 2-4-8-16 fasciculatim collocatis, gracilibns,
sepe gracillimis, nonnunquam medio paullum tnrgidia, subvcntricosis, nonnunquam panllum
constrictis, apices versis, seu.sim attenuatis, acutissimis.

,,,._T /„,"=. 00013".

Sy,i. — Jt. polymorphism, FRKSKN., RABENOORST, Flora Europ. Algarum, Sect. III. p. 44.
Hub. — Prope Philadelphia, Wood-
Cells straight or variously curved, single or 2-4—8-16 faacicnlately joined together, slender,

often exceedingly so ; sometimes slightly turgid in the centre, Bubventricosc, sometimes

slightly constricted ; the apices gradually attenuate, very acute.

Var. fhlcntuiii.

< Yllnlis fusif'irniibiis. gracillibus, utroque fine acutissirao cnspidatia, curvatis vel scmilnnaribug,
4—16 fasciculatim congregatis.

Syn. — Ankisirodesmus falcatus. (CoRDA.) RABENHOROT, Flora Enrop. Algarum, Sect. III.

p. 45.
Hob. — South Carolina, Georgia, Florida, Rhode Island. (Bailey.)

Cells fusiform, slender, at each end very acutely cuspidate, curved or semilunar, 4-16 fascicn-
lately congregate

Remark, — Fig. 3, pi. 7, represents different forms of R. pdymorphum.

FAMILY PROTOCOCCACELE.

Algic unicellnlares scnsu strictissimo, chlorophyllosa, et vegetatione terminal! et ramificatione
vera carentes, sine cellularum generatione vegetativa. Vivnnt aut singulee, segregatae aut in farai-
lia« conaociate. Harum familiarnm cellule nnraero ant indefinite semper se angentes (turn sensu
vero familiie nomen fcrnnt), aut definite, se non augcnUs (qne coenobium dicuntur).

86 FRESH-WATER ALG.E OP THE UNITED STATES.

Propagatio fit gonidiis, q\nB intra cellulam matricalem cytiogenesi libera oriuntur et dnplicis iudolia
snnt; altera majora, quae macrogonidia, altera miiiora quse microgonidia dicuntur ; ilia oblonga, polo
antico plerumque rostelliformi-producta, pallidiora, ciliis vibratoriis praedita, polo postico truucato-
rotundata, obscure viridia, individuum propagant ; haec forma similii, itidem mobilia, brevi postea
in statum quiescentem transeunt, druique in sporas perdurantes (Hypnosporas, BEAUN) transinu-
tantur. (R.)

Unicellular algae, in the strictest sense of the word, chlorophyllous, without terminal growth or
true branching, without a vegetative generation of cells. They live either single, segregate, or con-
sociated into families. The cells of these families, either indefinitely increasing in number (then
families in the true sense of the term), or of definite number (then forming a ccenobium).

Propagation by means of gonidia arising within the mother-cell by free cell-formation ; gonidia of
two kinds ; the one larger, macrogonidia — the other smaller, microgonidia ; the former oblong,
mostly produced into a pale bicilate beak anteriorly, rounded and greenish at their hinder end,
developing into the individual plant ; the microgonidia similar to these and also motile, but passing
after a short time into a quiescent state, and at last into resting spores or hypnospores.

Genus PROTOCOCCUS, AG. 1824.

Cellulae sphseroideae, segregates, cytiodermate tenui, hyalino, absqne tegumentis, libere natantes
vel extra aquam in stratum tenue pulvereum cumulatuu. Cytioplasma initio hornogencuni, deuique
granulosura, viride vel rubellum.

Spheroidal cells, segregate, cytioderm thin, hyaline, without integument, swimming free or col-
lected out of water into a thin pulverulent stratum. Cytioplasm in the beginning homogeneous,
finally granular, green, or reddish.

Remarks. — I have introduced this genus as given by Professor Rabenhorst in
his Flora Europaea Algarum for the purpose of describing a little plant, upon which
I have made some observations. As the notes were originally drawn up as a de-
scription of a species, I leave them in that form. I believe it has never before
been described.

Protococcus, (sp. nov. ?)

P. aqnaticus ; cellulis globosis vel angulis, viridibus in stratum pulvereum cumulatis vel in fami-
lias arete conjunctis; cytiodermate plerumque distincto; sporis rotundatis, tegumentis duobus
vel tribus protectis ; tegumentis externis, crassibus ; zoogouidiis ovalibus, vel subrotundatis,
vel subellipticis, ciliis duobus instructis.

Diam.— Max. spor. perdurant. jfa" = .00093" ; microg. TS%/ = .00053".

Aquatic ; cells green, globose or angular, accumulated in a green pulverulent stratum, often
closely united into families; cytioderm mostly not distinct; resting spores round with two or
three thick coats ; zoospores oval or roundish, or somewhat elliptical, furnished with two
cilia.

Remarks. — I found this species growing in a spring near Hestonville, West
Philadelphia, in the month of March. The large winter spores are round, with
thick coats. Except in one instance, in which the color was a decided reddish-
brown, all that I have seen have been green. How they are produced I do not
know. The history of their development into the plant appears to be as follows :
The first change is the rupture of their outer thick coat (fig. 4 6, pi. 7) from which
the spore finally escapes still clothed with a coat of moderate thickness. The
green contents next divide into a number of oval bodies (fig. 6 b, pi. 7) which

FKKS11- WATER ALGJi OF THE UMTK1' STATES. 87

grow, and, at the same time, separate from one another. Whilst these changes
II.IM In i ii taking place the spore coat has been hi'comini; gelatinous and enlarging,
M> that it continues to enclose its progeny. In this way a family of oval cells is
furmril (fig. 4/>, pi. 7). So fur, 1 think, is positive. The next step I have never
actually s»-cn, but believe to be the escape of these oval bodies as zoospores (fig.
4 r, pi. 1) which are of very various sizes and are elliptical, globose, or oval. They
a tolerably well-marked bright vacuole at their beak, and after swimming
about actively for a time finally settle down, lose their cilia, and undergo division.
They seem often to cluster together before thus becoming quiescent, so as to make
little colonies (fig. 5, pi. 7).

Genus CHLOROCOCCUM, FRIES.

ula- sphirroiileir, aut singnlir, liberto, vesicula chloropbyllosa ct locello lateral! pallidiori cavo?
ihstrurta-. limbo livuliuo ct teguuientis uepe smplissimis cincUe, aut plures in stratum vel acervulos
cuinuUtte.

I'ropagatio fit zoogonidiis cytioplasmatis divisione ortis, e cytiodermatis abaviae (intclligc tegu-
nirntiiiu extremum) rupturis cxcvdcntibua

< b spheroidal, either single, free, furnished with a chlorophyllous vesicle and a paler lateral
(hollow .'i spot, with a hyaline nimbus and surrounded by a wide coat ; mostly accumulated together
into strata or little heaps. Propagation by means of zoospores, which are formed by a division of
cytioplasui and escape from their general tegument (the cytioderm of the original cell).

/,' murk*. — But a few weeks after the commencement of my study of fresb-
u.it, r :ilir:r, a friend, a young microscopist, asked me to look at his aquarium, as
the water of it had become stagnant, opaque, and green. On examining a little
of the water with the microscope it was found to be full of what I now know to
ha\e been either one of the forms already described under this genus, or else one
umleseriheil, but still embraced within its limits. There were two sets of bodies,
the one motile the other at rest. The motile forms (Fig. 5, pi. 3) were globular or
pyriform. and generally contained a large, roundish, green, distinct mass. They were
i>f course provided with cilia, although at that time I was not able to demonstrate
their presence. These bodies, even when moving, appeared to have a distinct
wall. After a time they settled down and assumed the quiescent state. The
outer coat now rapidly enlarged so as to leave a considerable space between it and
the green endochrome, which rapidly underwent division, forming two or more
cells which were still surrounded by the enlarged maternal coat. The num-
ber of daughter-cells enclosed in the parent cell varied. A considerable quantity
of the water was allowed to stand in a glass jar, exposed to the light. In a very
few days all the motile forms had disappeared. The contents of the vessel were
allowed slowly to evaporate. The jar being tall and narrow it was some weeks now
before this process was completed, before which consummation hcematococcua forms
were abundantly developed.

Instead of being green, and surrounded by a distant, almost sac-like wall, the cells
had acquired a dark brownish-red color, were very opaque, and were protected by
a thick wall, whose surface was quite rough. Unfortunately, I did not measure
either the active gonidia or their progeny, the quiet cells, but I found the general

88 FRESH-WATER ALG^E OF THE UNITED STATES.

diameter of these hamate-coccus cells to be one twelve-hundredth of an inch

(.00083").

MM. Famnitzin and Boranetzky, in a recent paper (" Zur Entwickelungsgeschichte
der Gouidien und Zoosporenbildung der Flechten," Mem. de L' Academic Imperiale
des Sciences de St. Petersbourg, 1868, Annals and Mag. Nat. History, Feb. 1869),
state as the result of direct observation that this genus of algee, so called, is really
a stage in the life history of the gonidia of lichens. These gentlemen took thin
slices of lichen thalli containing gonidia, and placed them upon pieces of fir and
linden bark, which had been previously boiled to kill any plants that might be
growing on them. These were then put in a glass jar inserted over a vessel con-
taining water, in such way that they would be constantly exposed to a very damp
atmosphere, and at the same time communication with the external air would be
impossible. In another set of experiments, pieces of the lichens were allowed to
lie for a long time in water, until the component filaments were decomposed into
a gelatinous mass, in which the still green vigorous gonidia were imbedded. These
pap-like (breiige) masses were then washed with pure water and smeared upon
pieces of linden bark. The results obtained were identical in the two cases. The
gonidia were at first provided each with a distinct nucleus and a well-marked
lateral vacuole, and resembled closely the first form of cystococcus. The next
change was a division of their contents into a large number of roundish masses,
with the disappearance both of the vacuole and of the central nucleus. The cell-
membranes were next ruptured, and the endochrome, protruding through the open-
ing, formed a little ball sitting upon the parent cell. In doing this it doubled
in size, so that the part without was as large as the part within, although the latter
still filled the cell. The contents finally escaped, but were yet surrounded by a
very thin membrane, which soon, however, ruptured, and freed the biciliated
zoospores into which the endochrome had in the mean time resolved itself. These
zoospores remained a long time in the motile state, but finally settled down, drop,
ping their cilia, and became little round cells, which grew to three or four times
their original size. Further development was not made out.

Certain of the gonidia, belonging to a lichen of the genus Physeia, failed to
produce zoospores, but their endochrome, divided so as to form a number of
quiescent cells, which either ruptured very early the original cell-membrane and
became free in the water, or else remained bound together by it into a family for a
longer period. In these researches MM. Famnitzin and Boranetzky employed
lichens of three genera, namely Physcia, Cladonia, and Evennia, and claim, as
above stated, that their investigations prove that they developed the algee genus
Cystococcus of Naegeli (Chlorococcum, Fries), from the gonidia.

Genus POLYEDRIUM, NJSGELI, (1849.)

Cellnlae singulse, segregate, libere natantes, compressee, 3-4-8 angulares, angulis plus minus pro-
ductse, nonnunquara radiatim elongatse, aut Integra aut bifidse, plernmqne armate, a latere oblongo-
ellipticee, ntroque polo rotundatse vel snbtruncatse. Cytioderma tenue, Iseve. Massa chlorophyl-
lacea plerumqne granulosa, per cellules lumen uequaliter distributa, nonnunquam guttnlis oleosis
rubris 1-4 mixta.

Propagatio adhuc ignota. (R.) Genus mihi ignolum.

i i: i: s ii -\v ATI: u AI.<; i: .11 TIM: i \ ri K D STATES. v.»

:* single, segregate, swimming free, compressed, 3-4-8-anglcd, more or lew produced as to tln-ir
an^lc*, sometimes rudiuttly elongate, i-itlu-r entire or bifid; mostly armed, oblong-elliptical when
viewed laterally, at each end rounded ur subtrancutc. Cytiodrrm thin, smooth; chloropliyl mo.-ily
granular, «M|iiully distributed through the n-11, sometimes mixed with reddixh oil-drop*.
Propagation unknown.

Remark*. — This genus was described 1>% Nirgeli in his "Gattungcn Einzelliger
Aluen," and, although 1 ha\e never seen any specimen of it, it claims a place- h
because one species ha> lieeii found iu this country by Prof. Builcy.

P. eiiornir, ( HALTS) DB BABY.

•ni.-dii.-iiiii. angulis productia achroia profunde bilobis, nonnunquam rcpctito-bilobis, lobis

mucroimtiv ( II )

l>iam.— 0.0011"— 0.001C". (R.)

— P. enonin; ( KAI.FS) DK BART. RABENRORST, Flora Europ. Algarum, Sect III. p. 62.
Mnura*tru»i enorme, KALFS, British Desmidieae.

Hub.— Florida. Bailey.

" Frond irrrirular or quadrate, spinotis; end view three or four-lobed ; lobes broad, more or
!• -- • iiKirjrinatc or bifid, and terminated by ppincs, which are either simple or branched.
Sometimes the front view differs but little from the end one, usually, however, there is a
slight constriction or sinus at the junction of the segments, but I have never observed any
difference in the endochrome at that part. The spines, which arc almost confined to the
anglc.s, are irregular, some simple and some branched. The end view has three or four broad
and very irregular lobes ; these are spinous and more or less emarginate, and frequently one
lobe is much broader and more spinous than the others. The spines on such lobe form two
groups, separated by the notch; they vary much in size and are either simple and subulate,
or else forked; sometimes the forked spines are again divided at the apex." — 7.'u//V Jlriit.-k
Desmidiete, p. 141.

Genus SCENEDESMUS, METEN.

Cellulir polymorphic, utroque polo tcquales vel intequales, tuepe in cornu spiniforme product®, in
Ktatc pcrfccto 2-16 aut in svriem simplicem aut parencliyrnatice arete conjunct a- et co3nobinm con-
.-ti'in i.i. - ; cytioplasmate initio homogcneo, postea granuloso, vesicula chlorophyllosa central! vel
MibliitiTuli «'t siepe loci-llo achroo lateral! instructo.

1'ropagatio fit cytioplasmatis divisione snccedanea, unde gonidia oriuntur, quac inlr.i ccllulnm
inatricalem jam in coenobium planum sese conjungunt et membrane matricalis ruptura vel dissolu-
prodeunt.

In polymorphous, equal or unequal at the ends, often produced into a spine-like horn, in tlic
t state 2-16 closely conjoined, cither as a simple series or in a parenchyma-like manner so as to
f'.rm. a cepnobinm. Cytioplasm in the beginning homogeneous, afterwards granular, furnished with
a central or sublateral chlorophyllous vesicle, and often with a lateral transparent spot

Propagation occurring as a succedanenm to the division in the cells, whence arise gonidia, which,
already within the mother-cell, join themselves into a ceenobiuin, and are finally set free by the rupture
and dissolution of the maternal cell-wall.

Remarks. — According to Unger, in the genus Scenerksmtts the cells never exist
singly, but always in families.

Two of the species here described as representatives of the genus certainly do
not conform to this, for 1 have frequently seen them both separate and in coenobia

13 M«y. 1879.

90 FRESH-WATER ALG.E OF THE UNITED STATES.

or families. The latter were exactly like those of the European forms, at least
in one of the two species, and I do not therefore think it justifiable to indicate a
new genus. Moreover, I have certainly seen single cells, belonging to a species
which agrees precisely in its characters with a European form, save only in the
occasional existence of these single cells.

I have never studied the method of propagation, but it is said to occur by the
division of the cytioplasm of a large cell into a minute ccenobium composed of
two or more cells, which remains for some time within the walls of the mother-
cell, but is finally set free by the solution of the latter.

The cells are mostly much longer than broad, cylindrical, elliptical, or oval, but
in one species herein described they are habitually globular.

a. Cellulae inermes.

a. Cells unarmed.

S. obtnsns, MEYEN.

S. cellulis oblongis vel ovatis, utroqne polo obtusis, 4-6-8 modo arete modo laxe irTseriem
simplicem aut rectam aut duplicem obliquam conjunctis, diametro 3-5 plo longioribus. (R.)

Diam.— Transv. max. 0.00023"— 0.00028". (R.)

Syn. — S. obtusus, MEYEN. RABENHORST, Flora Europ., Algarum, Sect. III. p. 63.

Hab. — Georgia: Rhode Island, Bailey.

Cells oblong or ovate, obtuse at each end, 4-6-8, partly closely partly laxly conjoined into a
simple series either straight or oblique and double, 3-5 times longer than broad.

Remark. — I have never met with this species.

S. acntn§, MEYEN.

S. cellulis fusiformibus, vel ovato-fusiformibus vel ovatis, utrinque acutis sed inermibns, inter-
dum singulis sed pleruraque in seriem aut simplicem rectam aut duplicem inordinate alter-
nantem dispositis, arete concretis, diametro 2-4 (6 ?) -plo longioribus.

Diam. — Trans, vag. max. ? .00016".

Syn. — S. acutus, MEYEN. RABENHORST, Flora Europ. Algarum, Sect. III. p. 64.

Hab. — Prope Philadelphia, Wood. Rhode Island, Bailey.

Cells fusiform, or ovate-fusiform or ovate, acute at each end but unarmed ; sometimes single
but mostly conjoined into a single straight series or into an irregularly alternate double series,
2-4 times longer than broad.

RemarJcs. — This species is common around Philadelphia. Our specimens agree
very well with the descriptions and figures of the European, excepting that occa-
sionally a cell is single, and that none which I have measured have attained the
size given by Prof. Kabenhorst as the maximum, namely, 0.00023". According
to Rabenhorst, S. oUiquus, Ktz., is only a variety of S. acutus, Meyen. It has
been found by Prof. Bailey in South Carolina, Georgia, and Rhode Island.

b. Cellules armatse.
b. Cells armed.

FKESH-W ATEU ALU.K OF Till. I .\IIKD STATES. <J1

8. polymorphic, WOOD.

S. cfllulis fusiforniibu.s, aut ovalilms aut rllipticis aut globotus, singulis aut 2-8 conjunct is,
plfruiuijuv uirmjur j»ulu aculfu uniro, inii-nluiu aculris duolius, iii.-iruclis : apicibus obtusJB,
acutix, Tul acutisaiuii.i ; aculvis gracillimiii, rtctis, uuxlicu clongatis, iucliuutis.

Syn.—S. polymorjJiu*. WOOD. Prodroiuus. Proc. Am. Pbiloft. Soc., 1869, p. 135.
Hob. — In aquis quietis propo Caradcn, New Jersey.

8. cells fusiform, or oval, or elliptic, or globose, single or 2-7 conjoined, furnished in moat
cues with a single spine, simiciiiiu'K 2, at each end ; ends obtuse, acute, or very acute; spines
exceedingly slender and acute, straight, moderately lung, inclined.

/;*. — Tli is plant was found in a quiet pool, filling the water in such num-
as to make it opaque and very green. The color of the cells, as first obtained,
under the niic -roM-npr, was a vivid green, but, the water containing them having
been plan-d iii a di>h, during the slow desiccation which followed the color of the
crlN changed to a golden yellow.

Fig. 1 , pi. 1 1 , represents different forms of this species magnified 450 diameters.

8. quadricatida, i.Ti WIN) Bate.

• llulis oblongo-oyliudricis, utroquc polo obtuse rotundatis, 2-4-8 arctissime conjunctis,
ordini- aut -iiiipliri recto aut duplicc alternante, omnibus rectis, medianis inermibug vel bis
illisve apice uno allerove aculeo eurvato instruct!*, extimis utroque apice sepius item dorso
armatis.

'i —0.00035"— 0.00039"; long. 0.00091".
Syn. — ,S. quadrirauda, (TuRPiN) BR&B. RABEnnoarr, Flora Europ. Algar., Sect. III. p. 85.

//«/(. — Illinilf I-land, Bailey. Pennsylvania, Wood.

(YIU oblong-cylindrical, obtusely rounded at each end, 2-4—8 very closely conjoined either in a
single straight series or a double alternating one, all straight, the median unarmed or some of
tin-in with the apex furnished with a curved spine, the external with both apices and some-
times the dorsum thus armed.

Remark. — Fig. 2, pi. 11, represents this species magnified 750 diameters.

8. rolundatiiM, WOOD, (sp. nor.)

8. cellulig globosis rel rabgloboain, spinnlis longtasimis, rectis, gracillimis, acntissimw, 3-6
armatit, aut tingulis aut genii n is aut 3-4 arete duplicc conjunct is.

Diam.—,^" to iJn".

Hab. — In aqnis quietis prope Philadelphia. (Dr. Chapman.)

Cells globose or snbglobose, armed with three to five very long, slender, acute, straight spines,
single or in pair*, or three to four closely conjoined in a twofold rank.

Remark*. — The cells of this species are globular, and, when more than two,
they are arranged in two rows placed at right angles one to the other. The con-
tents of the cells are markedly granular, and the endochrome a bluish-green, and
trmn the surface of the walls project outwards, very long and fine, rigid hair-like
spines.

It seems scarcely correct to place this plant in the genus Soenesdcsmu*, but I do

92 FRESH- WATER ALG^E OF THE UNITED STATES.

not know any other genus to which it is more closely allied, and do not feel dis-
posed to indicate a new one for it.

Fig. 3, pi. 11, represents a cell-family magnified 250 diameters.

Genus HYDKODICTYON, ROTH. (1800.)

Cellulae oblongo-cylindricae, in coenobium reticulato-saccatum connexse, oranes fertiles; alise
procreant macrogonidia, quae jam intra cellulam matricalem in coenobiura filiale se connectunt ; aliae
microgonidia, quae multo ruinora, cellulae matricalis membranam perrumpunt, polo antico ciliis vibra-
toriis binis et puncto rubro laterali praedita sunt, brevi postea in globules protococcoideos tranquillos
transformata sporas perdurantes efficiunt.

Cells oblong-cylindrical, joined into a reticulated saccate coenobium, all fertile; some producing
macrogonidia, which join themselves into a coenobium within the parent cell; the others producing
microgonidia, which are furnished with two vibratile cilia and a lateral red spot, and which, escaping
from the parent cell, are, after a brief period of motile life, transformed into protococcoid thick-walled
spores.

Remarks. — The genus Hydrodictyon comprises, as far as known, but a single
species, which is common to North America and Europe. It grows in great
abundance in the neighborhood of Philadelphia, especially in the ditches and
stagnant brick-ponds in the low grounds below the city known as the " Neck."
There it very frequently forms floating masses several inches in thickness and
many feet in extent, so that with the aid of a rake it could be gathered by the
bushel. When thus in mass the color is very generally dingy and yellowish,
although the fronds, when in active vegetative life, are mostly of a bright, beauti-
ful green. The plant is in greatest profusion in June and July, after which time
it gradually disappears, until in the autumn it is scarcely to be found, but early
in the spring it reappears. The very young fronds are minute, oval, cylindrical,
filmy-looking, closed nets, with the meshes not appreciable to the eye ; when growth
takes place, the fronds enlarge until finally they form beautiful cylindrical nets
two to six inches in length, with their meshes very distinct and their ends closed.
In the bright sunlight they, of course, by virtue of the life-functions of their chlo-
rophyl, liberate oxygen, which being set free in the interior of the net, and its
exit barred by the fine meshes, collects as a bubble in one end of the cylinder and
buoys it up, so that, the heavier end sinking, the net is suspended, as it were, ver-
tically in the water. I know of few things of the kind more beautiful than a jar
of limpid water with masses of these little nets hanging from the surface like cur-
tains of sheen in the bright sunlight. A few cells collected in the fall or early
spring, if put into a preserving-jar and the water occasionally changed, will multi-
ply, and in a little while become a source of frequent pleasure to the watcher.

As the fronds increase in size they are always in some way or other broken up,
so that, instead of being closed cylinders, they appear as simple open networks of
less or greater extent. The extreme length to which the frond attains is, I think,
very rarely over twelve inches, with meshes of about a third of an inch in length.
The construction of the frond is always the same. It is composed of cylindrical
cells united end to end in such a way as to form polygonal, and mostly pentagonal

FRKSII-W A TKK A LG.E OF THE UNITED STATES. 93

meshes, the size of which varies with the age of the plant. These cells,
which are closely conjoined but have no passage-ways between them, are capable
of independent lift1, so that tin- hydrodictyon may be looked upon as an elaborate
typo of a cell-family, one in which cells are conjoined in accordance with a defi-
nite plan, so as to make a body of definite shape and size, yet in which each cell
is an independent being, drawing nothing from its neighbors. The cells them-
sdvrs are cylindrical, with a thickish cellulose wall, and have no nuclei. Their
chlnrophyllous protoplasm is granular, and is placed in the exterior portion of the
cell, forming thus, within the outer wall, a hollow cylinder, in which are imbedded
starch granules, and whose interior is occupied with watery contents. The hydro-
die t yon cell, when once formed, is capable of growth, but not of going through the
usual process of cell multiplication by division, so that the adult frond is com-
posed of just as many and indeed the same cells, as it had in its earliest infancy.

No true sexual reproduction has as yet been discovered in the water-nets. There
have been described, however, two forms or methods in which the species multi-
plies, both of them occurring by means of motile zoosporoid bodies. In the one
case these develop immediately into the new plant, whilst in the other before
doing so they pass through a resting stage. Of the life-history of the latter, the
micro jo/i ii/ la, I have no personal knowledge.

The investigation of the production and development of the macrogonidia, how-
ever, has occupied considerable of the time devoted by myself to the microscope,
and I have seen large numbers of specimens in almost all the stages of develop-
ment. I have never been able to detect, however, any decided motion in the
iiincrogonidia.

They are formed in the protoplasmic stratum, already alluded to as occupying
the outer portion of the interior of the hydrodictyon cell. The first alteration in
this, presaging their formation, is a disappearance of the starch granules, and a
loss of the beautiful, transparent green color. Shortly after this, even before all
traces of the starch-grain are gone, there appear in the protoplasm numerous
bright spots placed at regular intervals; these are the centres of development
around which the new bodies are to form. As the process goes on, the chlorophyl
granules draw more and more closely around these points, and at the same time
the mass becomes more and more opaque, dull, and yellowish-brown in color. This
condensation continues until at last the little masses are resolved into dark hexa-
gonal or polygonal plates, distinctly separated by light, sharply defined lines. In
some, the original bright central spot is still perceptible, but in others it is entirely
obscured by the dark crowded chlorophyl. The separation of these plates now
becomes more and more positive, and they begin to become convex, then lenticular,
and are at last converted into free, oval, or globular bodies. When these are fully
formed, they are said to exhibit a peculiar trembling motion, mutually crowding
and pushing one another, compared by M. Braun to the restless, uneasy movement
seen in a dense crowd of people in which no one is able to leave his place. "Whilst
the process just described has been going on, the outer cellulose wall of the hydro-
dictyon cell has been undergoing changes, becoming thicker and softer and more

94 FRESH -WATER ALG^E OF THE UNITED STATES.

and more capable of solution, and by the time the gonidia are formed it is enlarged
and cracked, so that room is afforded them to separate a little distance from one
another within the parent cell. Now the movements are said to become more
active — a trembling jerking which has been compared to the ebullition of boiling
water. There is, however, with this a very slight change of space, and in a very
short time the gonidia arrange themselves so as to form a little net within the
parent cell, a miniature in all important particulars of the adult hydrodictyon.
The primary cell-wall now becomes more and more gelatinous, and soon undergoes
complete solution, so that the new frond is set free in its native element. As pre-
viously stated, in my investigations I have never seen the peculiar motion above
described, the newly formed gonidia simply separating and arranging themselves
without my being able to perceive any motion, or exactly how they fell into posi-
tion.

It is evident that when the species is multiplied in the way just described, the
birth of the new frond is consentaneous with the death of the old cell. But when
the hydrodictyon disappear in the fall, it is months before they reappear in the
spring. It is, therefore, evident there must be some other method of reproduction.
This slow development of new fronds takes place, according to Pringsheim, by
means of little motile bodies which he calls " Dauerschwcirmer," which has been
translated into English chronispores (stalospores, Hicks). M. Braun stated already
some years since that sometimes, instead of the hydrodictyon producing the ordi-
nary reproductive bodies (macrogonidia), there are formed in the cells much smaller
and more active bodies, the microgonidia. The changes which occur in the pro-
duction of these are very similar to those already described as happening when
the macrogonidia are formed. When the chronispores are once formed, however,
they, instead of uniting together escape in a free distinct condition into the water.
They are now small ovate bodies, with a large anterior transparent space, to which
are attached a pair of cilia, and their life and history, according to Pringsheim, is
as follows : For a few hours they move about very actively in the water, and then,
dropping their cilia, and acquiring an outer cellulose wall, pass into a quiescent
stage, in which they closely resemble protococcus granules. They are capable of
living in this state for a long time, if kept in water. They can also endure desic-
cation if the light be excluded during the process, but, if it be present, they wither
and die, and cannot be revivified.

After a longer or shorter period, but never shorter than three months, according
to Pringsheim, they recommence their life, provided they be in water. For four
or five months after this the chief change consists simply in an increase in size.
The dark-green protoplasm is arranged around the exterior of the cell, within are
the more fluid colorless contents, the whole body still looking like a protococcus
cell. After a size of about ^ mm. is attained, the endochrome divides succes-
sively into several portions. The external layers of the surrounding wall now
give way in some spot and allow the inner layers to protrude and form a sort of
hernial sac, into which the several endochrome masses soon pass, at the same time
assuming the well-known characters of true zoospores. From two to five of these

FRESH-WATER ALQ& OF THE UNITED STATES. 95

bodies arc thus produced out of each original microgonidium. They are large,
ovutc, biciliate, and, generally, soon escaping from the hernia! sac, move about
actively in the water for a few minutes. Sometimes, however, they settle down
within the generative utricle. In either case, after a little time, they become
motionless, lose their cilia, and develop into polyhedral cells, which are structurally
remarkable for having their angles prolonged into long horn-like appendages. Under
favorable circumstances, at the end of a few days, the bright green endochrome of
these undergoes similar changes to those described as presaging the production of
tin microgonidia, and is finally formed into zoospores, which, in from twenty to forty
minutes, unite, within the polyhedron or large cell, into a Hydrodictyon, which is
finally set free by a solution of the cellulose coat of the polyhedron. The network
thus formed differs in no essential way from that which arises in the better known
way, except that it is composed of much fewer cells. It is generally a closed
sac ; but when the polyhedron, out of which it is developed, is small, it is some-
times merely an open network. Its after-history appears to be identical with that
of the ordinary hydrodictyon frond.

II. utriculatiim, ROTH.

Species nnica.

Syn. — II. utriculatum, ROTH. RABENHOBST, Flora Europ. Algarnm, Sect III. p. 66.

Hal, In aquis quietis. West Point, Bailey. Weehawken, (Mr. Walters.) "Waterholes

between Van Hum's Mills and Mueote on the Mexican boundary, Dr. Bigelow. Pennsyl-
vania, Wood.

Genus PEDIASTRUM, MEYEN, (1829.)

Ccenobinm plannm, disciforme, libere natans, e cellaarnm strato nnico, rarius centre entro duplicate,
continue vel perforate formatum. Cellnlas polygoniw, periphericB saepe bilobas, lobis cuneatis et
gimplicibas et bidentatis, nonnunqnam in cornna prodactis.

Casnobium plain, discoid, swimming free, formed of cells in a single, rarely in the centre double
stratum, which is continuous or perforate ; cells polygonal, the peripheral often bilobed, the lobes
cuneate, either simple or bidentate, sometimes produced into a horn.

Remarks. — The coenobium or cell-family, or colony, in the genus Pediastrum is
always discoid, and has generally a more or less truly circular outline. The cells
are mostly in a single stratum, but in some species there are two, more or less,
complete strata superimposed one upon the other. The arrangement of the cells
in this stratum, or these strata, varies greatly, as does also their number. They
arr mostly more or less polyhedral, and often have their margins scooped out or
their angles prolonged. This may occur in such a way that the projecting point
of one cell fits into the hollow in its neighbor, and the ccenobium be rendered
entire, or, no such relation existing between the parts of adjacent cells, the cceno-
bium mjiy be perforated with regular or irregular openings. The outer or mar-
ginal cells are often deeply notched externally, and frequently are prolonged into
acute or obtuse lobe-like processes. The walls of the cells are, in adult specimens,
quite thick. The contents consist of chlorophyl, protoplasm, starch granules, &c.

96 FRESH-WATER ALG^E OF THE UNITED STATES.

There are generally one or more hyaline spaces, besides a distinct chlorophyl
vesicle, but no distinct nuclei.

At certain periods of their existence the Pediastrums produce both macrogonidia
and microgonidia. The life-history of the former is very similar to that of the
same bodies in the water-nets. The ultimate fate of the microgonidia has not as
yet been determined, but in all probability they go through cycles of change
similar to those seen in the lives of the corresponding bodies in the Hydrodictyon
utriculatum. I have not had an opportunity of watching the development of
either of these reproductive forms, but, according to MM. Braun, Pringsheim, &c.,
their life-history, as far as known, is as follows: In most cases, all the cells of a
pediastrum produce their macrogonidia simultaneously, or within a very short
period of time, so that the ccenobium will be left emptied of its contents as a mere
shell, the outer skeleton of its former self. When a cell is about to give birth to
these reproductive bodies, the endochrome divides into two parts ; each of which
then undergoes a similar binary division. This is repeated once, twice, thrice, or
oftener, until the endochrome is divided into 8-16-32-64 gonidial masses, the
number of which, generally, but not always, corresponds to the number of cells in
the colony, to which the parent-cell belongs. After the division of the endochrome
is completed, a slit occurs in the outer strata of the wall of the mother-cell through
which a hernial protrusion of the inmost stratum occurs. The protruded part
now rapidly enlarges until at last there is formed a sort of hourglass-shaped sac,
one portion of which is within, the other part without, the old parent-cell.
Whilst this has been going on a portion of the gonidia have escaped from the
parent-cell into the outer free portion of the sac, and each end of tho hourglass,
therefore, contains some of them. The sac with its contents now gradually
withdraws itself more and more from the parent-cell until at last it lies a free
globose vesicle in the water. The gonidia occupy the centre, and M. Braun states,
that, although he has never been able to demonstrate any cilia upon them, yet
they have an active swarming motion. At first, they are irregularly heaped toge-
ther in the nearly filled sac ; but the latter rapidly enlarges and elongates, and the
gonidia in a little while arrange themselves in a flat, tabular group within it, and
cease to move. Then the several individuals of this group begin to develop,
becoming emarginate and assuming the form of the parent-cell, until, finally, they
have all grown into the shape which is peculiar to the adult cells of the species,
and after a few hours have closely cohered to form a young cccnobium.

The microgonidia are formed in a very similar way by the dividing of the endo-
chrome, the cracking of the outer membrane, and the protrusion and final escape
of the inner. They are, however, much smaller and more numerous than the
macrogonidia. When the parent vesicle first escapes into the water, they are
crowded in its centre, and are nearly globose. As it enlarges, however, they elon-
gate more and more, and finally become distinctly bi- or, more rarely, uni-ciliate.
The cilia are much longer than the body, and are attached to the smaller end,
which is prolonged into a pointed, transparent beak, about equal to the green por-
tion in length. The microgonidia now become more and more restless, they, moving
about very actively, and after awhile bursting the parent sac, escape into the water.

FHKS II WATER A L 0 & OF T II K U N I T E D STATES 97

"What becomes of them after this, as h is been stated, is a mere matter of conjec-
ture. M. braun1 ami others have described unicellular forms of several of the
imilticelhilar species of 1',- /i<t*intin, and I'ringsheitn suggests that these are really
polyhedrons developed out of these microgonidia, as is seen in the water-nets.
This, of course, may or may not be the case.
P. Ilorvaiiuiii. (Ti KI-IM MKN..H.

P. coenobio orbicular!, oblongo vel elliptico, magnitudino vario, continue, Isete viridi, c cellulis
4-8-16-82-64 (rarissirue 128) composite (ci-llulunim strato Bimplici, nonnunquam medio
duplicate); cellulis periphericis plus minus profunde emarginatis vel bilobis, lobis cornutis,
cornibus achrois hyalinis, abbreviatis Tel elongatis, teretibus, obtusis vel subobtusis, interdum
capiu-lluto-iiicrassatis, centralibus nrctissime concretis, polygonis (4-6 angularibus), in antica
parti- modo angulo prominnlo raodo plane truncatis, modo leviter repandis, omnium mem-
brana dcciiRsatim punctata. (R.)
£>tom.— Transv. cell 0.000795"; rarius 0.00088"— 0.00094". (R.)

Syn. — P. Boryanum, (TuRpiN,) MENOHINI. RABENHORST, Flora Europ. Algarum, Sect III.

P. 74.
Hub. — Georgia, Florida, Rhode Island, Bailey ; Pennsylvania, Wood.

(Ylls arranged in one or more circles round one or two central cells; the inner variable, generally

concave at one side, the outer tapering into two long subulate points, the notch narrow.
L. 1-2083" to 1-1633"; B. 1-2733" to 1-2222". (Archer.)

P.Selenwa, KTZ.

1'. KI nol.io orbicular!, integro, e cellolis 8-16 (rarius 31 = 1 -f- 5 + 10 + 15, KTZ.) fonnato;
ccllulis periphericis angustia, lunatis, acute lobatis, disci cellnlis leviter excisis, central! unica
5-angulari, omnium membrana firma, snbcrassa, aetate provecta rubesccnte. (R.)

Diam.— Ccenobii 0.00124"— 0.0035"; cell, (distant!* interlobos) 0.00026"— 0.00069". (R.)

a.—P.Selensea, KTZ. RABENUORST, Flora Enrop. Algarnm, Sect. III. p. 73.
llnb. — Rhode Island, Bailey.

Cells crescent-shaped, arranged in one or more circles round one or two central ones, connecting
medium colored. (A.)'

P. pcrtiiMiim, KTZ.

P. coenobio orbicular!, lacunis pcrtuso, magnitndine vario, e cellnlis plernmqne 1 + 5+10 + 15
(in fortnis quibusdam ad 64) composite ; cellnlis periphericis basi tantum laxe connexis, ad
medium usque bilobis, lobis rectis, in cornna hyalina modo subacuta modo obtusa vel trnn-
cata plus minus productis, centralibus plus minus exacto quadrangularibns, et in antica parte
et ntrinque umaginatis, omnibus Uevibus, locellis pallioribus finis instructis. (R.)

Diam. — Transv. cell, perfect® evolnt circiter 0.00065" — 0.00089". (R.)
Syn. — P. pertusum, KTZ. RABENHOBST, Flora Europ. Algarnm, Sect. III. p. 75.
Cells arranged in circles round one or two central ones; inner cells quadrangular, sides concave
and leaving angular vacant intervals; the outer cells with square bases, externally triangu-
larly notched, the subdivisions tapering to an acute point L. 1-2266" ; B. 1-3268". (A.)

P. constrictum, HASSAL.

P. coenobio orbicular! vel suborbicnlari, Isete viridi, continno, Itevi ?, e cellulis 16 (ad 1 + 5 +
10) vel 32 (ad 1+6 + 10 + 15) formato; cellnlis periphericis irregulariter bilobis, sinu

1 The best exposition of this genus is to be found in Braun's Unicellular Algse.
' The letter A used here signifies that the description is copied from Mr. Archer in Prichard's Infu-
soria.

13 June. 1872.

98 FRESH-WATER A L G M OF THE UNITED STATES.

nngusto, lobis inaequalibns, basi plerumque constrictis, in cornua subcrassa obtusa productis,
centralibus polygonis, in autica parte repandis. (R.)

Syn. — P. ellipticum, HASSAL. RABENHORST, Flora Europ. Algarum, Sect. Ill, p. 77.
Hab. — South Carolina, Georgia, Rhode Island, Bailey.

Cells varying in number and arrangement; outer cells suddenly contracted into two short,

cylindrical, obtuse processes. L. 1-1754" to 1-906"; B. 1-1515" to 1-1020".
3, Processes of the lobes truncately emarginate. (A.)

P. Ehrenbergii, (COBDA) BRAUN.

P. cosnobio et orbicular! et oblongo, perfecte clause, e cellulis 8 vel 16 composite et quadrato,
e cellulis 4, late cuneatis, profuude lobatis, exacte cruciatim dispositis formato ; cellulis peri-
phericis cuneatis a basi truncata ad apicena usque concretis, profunde bilobis sinu angusto,
lobis saepe oblique truncatis, plus minus sinuato-excisis, angulis interioribus ad duplum lon-
gioribus, omnibus acutis vel breviter appendiculatis; cellnlis centralibus aut singulis aut
pluribus (2-5-6 v. 8), omnibus flavo-viridibus, polygonis, uno latere repandis vel profunde
incisis. (R.)

Syn. — P. Ehrenbergii, (CORDA,) BEAUN. RABENHORST, Flora Europ. Algarum, Sect. III. p. 77.
Hab. — South Carolina, Georgia, Florida, Rhode Island, Bailey.

Frond minute ; cells eight (seven disposed in a single series round a central one), bilobed,
angular. L. 1-2900" ; B. 1-2500". (A.)

P. simplex, MEYEN.

P. cellulis peripheries ovato-cuspidatis, 8-10-16 basi tantum concretis, circulum simplicem
coustituentibus, centralibus ssepe nullis. (R.)

Syn. — P. simplex, MEYEN. RABENHOKST, Flora Europ. Algarum, Sect. III. p. 71.

Monactinus octonarius, BAILEY, Smithsonian Contributions.
Hab. — South Carolina, Rhode Island, Bailey.
Var. — duodenarius.

Coenobio clathrato, cellulis periphericis 12, centralibns 4, regulariter cruciatum dispositis. (R.)
Syn. — Monactinus duodenarius, BAILEY.

Inner cells four, somewhat triangular, enclosing a central, quadrate vacant interval, and four
broadly lanceolate vacant intervals between them and the outer series, to which they are
united by their terminal angles, outer cells twelve, subovate, truncate below, much attenuated,
acuminate. (A.)

FAMILY VOLVOCINE^E.

Crenobia mobilia, globosa, subglobosa vel quadrangulo-tabulata, e cellulis viridibus cilia bina
agilia gerentibus, intus vesica duplici contractibili prseditis composita, membrana (tegumento,
chlamyde) communi achroa hyalina plus minus ampliata involuta.

Propagatio aut sexualis, monoica vel dioica (adhuc in paucis tantnm generibus probata) ; cellulis
coanobii ant omnibus aut qnibusdam genus masculinura vel feminnm exhibentibus, illis in fasciculus
spermatozoideorum (autheridia), has in oosporas episporio inclnsas, non mobiles comrnutatis, aut
non sexualis, gonidiis agilibus, (et macrogonidiis et microgonidiis— etiam zpogonidia vocantur).
Macro- et microgonidia (cellulas primordiales) cytioplasmatis divisione simultanea et multiplici orta;
priora numero definita (2-4-8-16, &c.), majora oblonga vel rotnndata, polo antico plus minus rostri-
formi producta, ciliis binis per vesicse membranam exsertis, puncto (ocello Ehrberg. stigma) sanguineo
central! vel parietali et locellis (vacuolis) saepe binis contractibilibus instructa; ultima numero indefi-
nita, multo m.nora, pallide vel sordide viridia vel luteola, apice ciliis instructa, plerumque jam intra

lulam matricalem vmde vacillantia, postea membranse ruptura libere erumpeutia, examinantia. (R )

!

F UK S II -WAT KH A !.(;.!•: OK T 11 K U X I T E D ST A TES. 99

Cccnobium mobile, pl.ilxisc, subglobose or in square tables, composed of green cells which hare
two motile cilia ami a double cuiiiraciile vesicle. The common tegument surrounding the coeuobium
hyaline, ami more or loss amplified.

Propagation either s« \ual or non-sexual. The sexual moneciou* or diecioas; either all or some
of the cells of the coenohiuin exhibiting male and female characters. The male cells containing
tipcrmutozoids, the female finally converted into a quiet oospore. Non-sexual propagation taking
plan- by means of inutile gonidia (both tnacrogonidia and microgonidia, by some called zoogonidia).
Macro- and micro-gonidia arising by the simultaneous and repeated division of the cytioplasm ; the
Dr>t definite in number (2-4-8- 1C, Ac ), the larger, oblong or rounded, with the anterior end more
or le.-s ro.-tellatc, with two cilia exserted through the membrane of the reside, furnished with a cen-
tral or parietal red spot, and often with two contractile vaeuoles; the microgonidia indefinite in
number, much the smaller, pule or dirty green or luteolous, furnished at the apex with cilia, mostly
even within the mother-cell, moving rapidly, and finally escaping on the rupture of the membrane.

Genus CHLAMYDOCOCCUS, A, BBAUN.

f YllulfB globose, Tel subglobosae (4—8 in coenobium fugacissimnra conjunct®), cytiodermate sub-
cra->o firnio, cvtioplasmate granuloso, fusco-rubro vel puniceo (in erolutionis gradibus quibusdam
in colon-Hi viridem mutato). Macrogonidia 2-4-8, rotundata, polo antico rostriformi producta, duo
cilia longissima gerentia, nucleo central! rubro, glubulis amylaceis 4-6, non semper visibilibus
in.-!ruei:i. te'.'uineiito aniplissirao byalino plerumque ovoideo vestita. Microgonidia miilto minora,
numerosa, lutcola rcl 8ordide viridia,- apice rubella, ciliis binis instructa, iutru tcgumentuui matri-
cali alaeriter vacillantia, denique meiubrunffi ruptura t-lubentia. (R.)

Cells globose, or subglobose (4-8 conjoined in a very fugitive coenobium), cytioderm thicki.-h,
firm, eytioplasm granular, brownish-red or puniceus, in certain stages of evolution changed into
trreen. Macrogonidia 2-4-8, rounded, the frond end bearing very long cilia, furnished with a
••••lit ml reddish nuclei and with four to six, not always perceptible, starch granules, clothed with a
very ample, hyaline, mostly ovoidal tegument. Microgonidia much the smaller, numerous, luteolous
•r sordid LTren. the apex reddish, furnished with two cilia, moving actively within the maternal
'.egument, and at last escaping by the rupture of the membrane.

4 h. nit ali* (BAUER, Ao.). A. BRAUN.
Ch. globulis, 0.004"— 0.00135". (R.)
Ilab. — In nive tetcrna, Greenland. Rocky Mountains.

ti'/ n. — Ch. niralig (liAi it, Aa.). A. BaAUN. RABENHORST, Flora Enrop. Algaram, Sect III.
p. 97.

Globules, 0.004"— 0.00135" in diameter.

Remarks. — I have never seen any good specimens of this plant, merely some
n-lls mounted in Canada balsam, and therefore ruined for scientific study, which
had been collected by Dr. Kane in one of his Arctic voyages. I have also had
some indications of plants in a little parcel sent me by Mr. Sereno Watson, who
informs me he has seen the red snow very abundant in the higher peaks of the
Rocky Mountains. It is a matter of presumption rather than determination, there-
fore, that the soecies is identical with the European.

Genus VOLVOX, EHBB.

Coenobium exacte sphtericnm, continno rotatum et agitatum, globum cavnm quasi fingcns, e cel-
lulis nnmerossissimis equal! distantia peripheries dispositis, gelatina matricali connexiM, puncto
rnbro lateral!, locellig (vacuolis) binis contractibilibus necnon ciliis binis longe exsertis instructis,
vt-sica commutii hyalina circumcinctia compositum.

100 FRESH-WATER ALG^E OP THE UNITED STATES.

Propagatio duplex ist, aut non sexualis aut sexualis; ilia fit cellulis quibusdara certa distantia
intumescentibs, multipartitis, in coenobia filialia intra cosnobiuin matricale evolutis, postea libere
erumpentibus; haec cellulis masculis multipartitis in fascicules spermatozoideorum mobilium, con-
tractilium, pyriformium, ciliis binis instructorum, postea liberorum evolutis; cellulis femineis intu-
mescentibus, non divisis, sed post feecundationem in oosporas immobiles episporio duplici tircum-
datas postremo rubras evolutis. (R.)

Coenobium exactly spherical, continually rotating and agitated, looking like a hollow globe,
composed of very numerous cells, which are arranged on the periphery at equal distances, and are
connected by the maternal jelly, and surrounded by a common hyaline bladder; they are also fur-
nished with a lateral red point, with two contractile vacuolcs, as well as two long exserted cilia.

The propagation is both sexual and non-sexual. In the latter, certain distant cells enlarge greatly,
divide into numerous parts, and evolve within the parent ccenobiuru daughter-cceuobia, which are
finally set free. In the sexual propagation certain molecular cells undergo a multipartite division
into fasciculi of spennatozoids, which are motile, contractile, pyriform, and furnished with two
cilia; the feminine cells are enlarged, and do not undergo division, but after fecundation develop into
immovable oospores, which are finally red, and are surrounded by a double episporium or coat.

V. globator, (LINN.) EHRB.

V. cffinobiis majoribus ad £"', cellulis numerossissimis (ad 12,000); ccenobiis filialibus semper
octo intra matricale fructificatione non sexuali evolutis; fructificatione dioica; coenobiis
masculis fascicules spermatozoideorum numerosos rubescentes foventibus (= Sjrfiasrosira
volvox, Ehrb.); ccenobiis femineis cellulas sexuales (oogonia) 20-40 post fecundatiouem in
totidem oosporas globosas rubras episporio hyalino stellato circumdatas foventibus (= Vol-
vox stellatus, Ehrb.). (R.)

Syn. — V. globator, (LiNNE,) EHRB. RABENHORST, Flora Europ. Algarum, Sect. III. p. 97.
Hab. — In stagnis. United States.

Larger ccenobium, about £" in diameter, composed of very numerous (about 12,000) daughter-
ccenobia, always 8 within the maternal one, evolved without sexuality ; fructification dioe-
cious ; male coenobium giving origin to numerous reddish spermatozoids (= Sphaerosplisera
Volvox, Ehrb.) ; female ccenobium, giving origin to from 20-40 sexual cells, which, after
fecundation, develop into the same number of globose red oospores surrounded by a stellate
hyaline episporium.

Remarks. — Some of my friends tell me they have found this species abundantly
around Philadelphia. I have not been so fortunate, and have seen but a few
scattered specimens, which have afforded no opportunity of studying their deve-
lopment and life-history.

OEDER Zygophyceae.

Algae aut uni- aut psendomulti-cellulares, sine vegetatrone terminal! et ramificatione vera. Cellulaa
singulae aut geminatae aut seriatim conjunctae. Multiplicatio fit cellularum divisione in unain direc-
tionem.

Propagatio fit zygosporis conjugatione cellularum similium binarum ortis.

Algae either uni- or pseudomulti-cellular, without terminal growth or true branches. Cells segre-
gate or geminate, or arranged in a single row. Multiplication taking place by a division of the
cells in one direction.

Propagation by zygospores, formed by the conjugation of two similar cells.

FAMILY DESMIDIACE^l.

Algae unicellulares, sine ramificatione vel vegetatione terminal!. Cellula? forma admodum varia,
plerumque in medio plus minus profunde constrict® et in duas semicellulas symmetrieas <I:vism.

1 ULSll-VVATEK ALUJi OF THE UMTKD STATK8. 101

libene vel in fascia* filifrrnies nut tseniiformps arete conjunrtie aut in mnco matrirali nidulantcs et
in latnilius iudcliuitus coii.MH-iaiu.-. Cvtimleriua non silici-um, plus minus fmauiii, lieve ant varie
a.<|»'iuiuin (striutum, costatum, ai-uleuiiiin, \c.). Mausa cbloropuyllacea iu lauiiuulfs axiles vel
parictulcs, .-a'pe e crutro railiantc.-, di>tribulu.

1'rupugatio nun sexuulis JUT divisioue tranaverea in eaudcm directionem rcpetiu ; sexualis per
cygosporati, qua; per ccllularum binaruiu conjugaliouem uriuutar.

I'nicellular alga-, without branches or terminal growth. Cells of very various forms, mostly more
or less profoundly constricted in the middle and divided into two symmetrical semicells, free or con-
joined in filiform or tttiiiforiu fascia, or involved in the maternal jelly so as to form indefinite fami-
lies. Cytiixli-rm not silii -eous, more or less firm, smooth, or variously roughened (striatc, costate,
aculeate, <kc.) Chlurophyl iua*ses in axillary or parietal lamina, which often radiate from the
centre.

Non-sexual propagation by repented transverse division in one direction; sexual by zygosprires
which are formed \>y the coiijugalioii of two cells.

Remark*. — Of all the fresh-water alga?, with the exception of the diatoms, this
family has attracted most attention, owing, not only to the beauty and variety of
its forms, but also to their universal presence and abundance, and the ease with
which their most wonderful life-histories are observed. They are exclusively, as
fur as known, denizens of fresh-water, and preferably that which is pure and limpid.
Although Mr. Rail's states that they never grow in stagnant water, I have often
found them in great abundance in such, yet never in that which was actually putrid.
The same authority is also too sweeping, at least as far as this country is concerned,
in stating they are never found in woods, although they are really most abundant
in the open country. My experience has taught me to look for them in brick-
]><>n<ls, small mountain lakes, springy fens, ditches, and, in the fall, growing among
mosses and in the thick jelly composed of unicellular algae on the face of drip-
ping rocks, or, to sum up in a word, they dwell in quiet, shallow waters, for I have
never found them in rapidly moving or very deep water.

The single cell, of which a desmid is composed, is mostly divided into two very
marked similar portions, the exact counterparts one of the other, which by some
have been asserted to be distinct cells. Their close union and connection, and their
inherent oneness are, however, so apparent that it is needless here to spend time
in demonstrating that they really are halves of one individual cell. They contain
together all the parts found in the typical vegetable cell ; an outer cellulose wall,
chlorophyllous protoplasm, a nucleus, starch granules and semiliquid contents.
The cell-wall, or cytioderm, as it is called in this memoir, varies in thickness
and firmness. During life it is mostly, if not always, colorless ; but in certain
species in the dead empty frond is of a reddish-yellow. The markings upon it are
various, and arc not infrequently altogether absent ; they are such as fine or coarse
pnnrtations, granulations of various size, striae, furrows or elevated ribs, tuber-
cles, obtuse or sharp simple or forked spines, hair-like processes, umbonations, &c.
&c. These markings are within narrow limits constant in each species^ and
more or less peculiar, so that they afford valuable characters to the systematist.
The cytioderm itself is mostly composed of cellulose free from appreciable inor-
ganic matters, but in certain species contains a large amount of silex. Thus,

102 FRESH-WATER ALGJK OF THE UNITED STATES.

according to De Barry, if Closterinm lunula be carefully burnt upon a slide, a per-
fect hyaline silex cast of the cells is left.

The chlorophyl is variously placed in the cell, sometimes it is arranged in
lamina, sometimes in spirals, sometimes in the form of radii from a central mass.
These different methods afford good generic characters, and will be dwelt upon
more in detail under the various genera. The color of the chlorophyl during
active life is a vivid green, which, as the vital forces lessen, changes to a faded
yellowish tint.

Na?geli and others affirm that there is always a central nucleus in the desmid,

-. ':\ and probably do so with truth, although in many instances I have found it impos-

. sib'le to demonstrate its presence from the size and opaqueness of the frond,

;; „.*.•" 'Crowded with endochrome, &c. In a large number of cases, however, it is very
•

apparent.

As ordinarily viewed under the microscope the two most striking peculiarities
presented by these little plants are the motion of the whole desmid in the water
and the various movements exhibited within the fronds. The general movement
is most apparent in the larger species, which exist free and distinct in the water,
especially in the boat-shape closteria. It mostly consists of a steady, stately,
slow onward movement, with sometimes backward oscillations. By virtue of it,
desmids in a bottle will often congregate in such positions as are most exposed to
light. There have been various theories advanced as to the cause of this motion.
Ehrenberg believed that he had found foot-like processes protruding from the end
of the frond and giving the motile power. Others, such as Rev. Mr. Osborne and
Mr. Jabez Hogg, have attributed the movements to the presence of cilia, but I
think have failed so entirely to establish this that their views are more than pro-
blematical. That the motion is due to vital actions, taking place especially under
the action of light, is as much as can be at present affirmed with any certainty, though
it is probable that the immediate agents are endosmotic currents of gas or water.

The movements of the contents within the cells are chiefly of two kinds. Tak-
ing Closterium lunula as an illustrative example, there will be found on ex-
amination with an |th objective, a narrow, very transparent, and therefore
often not very apparent layer or zone lying immediately within the cell-
wall, between it and the endochrome, and dipping inward in the middle of the
frond so as to communicate with the nucleus. In this zone are protoplasm,
watery fluid, and scattered granules. In the ends of the fronds the different por-
tions of this zone, meeting and widening, fill up the whole of the cavity, and within
the space thus occupied by them, there is a globular, sharply defined, still more
transparent vacuole. This, some have thought to be a closed sac, with a distinct
wall, but it seems really to be a vacuole lying in the midst of the inner protoplasm,
which with a few granules occupies more or less completely the transparent zone
already described. Sometimes the chlorophyl encroaches upon this zone at the
ends so as to more or less completely surround the vacuole, within which are always
found watery fluid and granules. In the protoplasmic zone and its vacuole active
movements are probably always present during active life. Streams of protoplasm
appear to be constantly passing to and fro between the nucleus and the ends of

FUKSII-W A Ti: K A LG^E OF THE UNITED STATES. 103

the cell along the outer zone, and granulos can be always seen passing backwards
and forwards witli an unsteady motion.

When the streams of protoplasm are setting very actively from the centre to-
wards one end, there will often be an accumulation of the protoplasm there, and a
consequent decided (evening in the size of the vacuole, which will again expand
as the return currents arouse themselves. Within the vacuoles are seen more
or less numerous smaller or larger granules in active busy motion, swarming over
and about one another with an unsteady hurrying to and fro.

A form of motion, similar in appearance to this, but probably of different signi-
ficance, is seen in most desmids when in an unhealthy feeble condition. I
have seen it most marked in Cosmarium margnritaceum. In such fronds the ciulo-
chroine has lost its deep green color, and become shrunken, and lying within it is
a great space containing myriads of minute blackish particles swarming about
actively. This peculiar state and appearance is by no means confined to the
de-mids, for I have seen it very highly developed both in species of Sjrirogyra and
(l'.ili><j»nniin. It appears to be connected with decay. Is it possible that these
minute particles are foreign to the plant, vibrionic in nature?

In regard to the nature of the movements seen within a healthy desmid, some
have viewed them as exceedingly mysterious, the result of the presence of
cilia, &c. ; but these views have been so thoroughly exploded that it is scarcely
necessary even to mention them here. The movements arc, in truth, precisely
parallel to the so-called cyclosis of the higher plants. Protoplasmic germinal mat-
\\hen-ver it exists, be it in animal or vegetable, has as one of its distinguish-
ing characters the power of active, spontaneous, apparently causeless movements,
and it is simply the carrying out of this power or attribute which has attracted so
much attention in the desmids, because it is in them so readily seen.

There arc, in this family, two distinct methods in which the species are multiplied
one with, the other without, the intervention of anything like sexuality. The
non-sexual method of increase is really a modification of an ordinary vegetative
process, a peculiar cell multiplication by division. In such fronds as those of the
genus Cosmarium, which are composed of two evident halves connected by a
longer or shorter isthmus, the first step in the process is an elongation of this neck.
In u very short time there appears around the centre of this a constriction, and I
believe an actual rupture of the outer coat. By this time a new wall has formed
inside each half of the isthmus, and stretches also across its cavity, forming with
its fellow a double partition wall, separating the two halves of the old frond.
Rapid growth of the newly formed parts now takes place, the central ends become
more and more bulging as they enlarge, and in a little time two miniature lobules
have shaped themselves at the position of the old isthmus. These are at first
small, colorless, and destitute of all markings, looking, as Mr. Ralfs says, like con-
densed gelatine. They, however, rapidly increase in size and firmness, their con-
tents assuming a green color and their walls taking on the peculiar markings of
the species. At last, the parts thus formed having assumed the shape and appear-
ance of the original lobules, the two fronds, which have been developed out of one,
separate, mostly before the new semicells have acquired their full size.

104 FRESH- WATER ALG^E OF THE UNITED STATES.

What part the nucleus has in the process just described I have never actually
demonstrated, but have little doubt but that it undergoes a division in the very
commencement, so that the new nucleus of each secondary frond is formed out of
one-half of the old one.

In proportion as the form of the desmid becomes simpler, so do the peculiarities
of its cell multiplication become less. In those species which are simple cylindri-
cal cells, there appears to be nothing peculiar in the method of dividing, which,
however, always takes place through the centre of the cell, and subsequent growth
occurs, generally, only in the newly formed part.

True sexual reproduction apparently does not take place as freely in this family
as the former process, for whilst I have seen hundreds of cells undergoing the
latter, it has not been my good fortune to meet with conjugating specimens on
more than two or three occasions.

The process has, however, been studied very closely by De Bary, Braun, Hof-
meister, and others, and appears to consist generally in a rupture of the outer wall
of two cells and the protrusion of delicate processes from an inner, often newly
formed coat, with subsequent union of these, and consequently of the two cells,
and afterwards a condensation of the contents in the enlarged connecting passage.
The connecting passage between the fronds is really a sporangium in which the
spore is perfected, the contents of the cells finally condensing it into a firm globe
and secreting around themselves a thick coat.

The after-history of this spore has been very successfully studied by M. Ilof-
meister, whose observations were made upon Cosmarium tetraophthalmum, which
he watched conjugating and forming a sort of resting spore which was perfected
early in the month of July. This was composed of a thick outer coat and green
endochrome lying within as a distinct ball, nowhere in contact with the invest-
ing membranes. In three weeks' time this chlorophyllous protoplasm had divided
into ellipsoidal masses, or primordial cells, which soon surrounded themselves with
cellulose walls and became distinct free cells in the granular fluid which filled the
cavity of the original spore. In August, each of these masses was divided into two
and in the month of September the process was repeated, so that out of the original
endochrome eight strongly flattened primordial cells were produced. Division in
some specimens ceased here, and in others took place once more, so that by the fol-
lowing spring all of the living Sporangia contained eight or sixteen green daughter-
cells, each of them discoid in outline with a strongly marked central notch.
These daughter-cells were finally set free by the solution of the spore wall, as Cos-
maria of minute size, but agreeing in all other characters with the specific form to
which they belonged.

According to Braun, in the larger, more or less lunate Closteria, conjugation
occurs in the following method : Two fronds approach one another in such a way
that they lie back to back. In the middle of each of them, there then appears an
annular line or trench reaching through the cell wall, and accompanied by a dis-
tinct separation of the endochrome into two halves. Whilst these changes have
been progressing there has also formed a new double wall at the position of the
trench, so that out of the two Closteria two pairs of separate equal cells have been

FRESH- WATER A L G .E O F THE UNITED STATES. 105

formed. Near to the larger or central end of each of these now appears a pouting
transparent nipple-like process. The corresponding opposing processes enlarging
and meeting coalesce, so that the upper half of one closterium, in the form of a
daughter-cell, is finally united with the upper half of the other closterium, and the
two lower halves are also joined together. Thus from a single pair of fronds arise
two conjugating pairs of cells, and finally two sporangia, in each of which a spore
is perfected.

This process does not seem, however, to be universal amidst the Cloeieria, for
in many, if not all, of the smaller species, a pair of fronds produces a single spo-
rangium.

In the genus Palmogloea, in which I have had an opportunity to study the devel-
opment of the spores, the process closely simulates that seen in certain of the
A)/// •(«////•<». The contents of the cells first became broken up and confused, and
almost simultaneously the nucleus disappeared (fig. 4, pi. 11) the cells became
swollen at one side and slightly bent backward so as to form jutting processes,
which meeting grew together, became confluent and developed into a sporangium
ninch larger than either of the parent cells. Into this sporangium the contents of
the latter passed and soon became converted into a thick-walled spore (fig. 00, pi.
00) often completely tilling the cavity, and apparently with its wall adherent to that
of the latter.

Genus PALMOGIXEA, KTZ. (1843).

Cellulte oblongffi, ellipticse vel cylindrical, ntroque polo rotundattc, medio non constrict®, plerumque
in muco gelatinoso nidulantes, liberse, singular vcl in fumilias consociatee, lamina chlorophyllacea
axili vel excentrica, state provecta medio constricta, denique divisa prseditse. (R.)

,s'y>i. — Jleaotxnium, X^EUELI.

(VII oblong, elliptical or cylindrical, rounded at each end, not constricted in the middle, mostly
swimming in a gelatinous mucus, free, single or associated in families, chlorophyl lamina axillary
or cxcentric, in the early state constricted, and at length divided in the middle

Remarks.— The above diagnosis of the genus is that given by Prof. Rabcnhorst,
and agrees essentially with that of De Bary, Nacgeli, &c. In the species herein
described however, the axillary lamina of chlorophyl were not so pronounced, for
the green coloring matter seemed often to surround the cavity of the cell, and in
other specimens was broken up and diffused through it.

P. clepsydra, WOOD.

P. saxicola et bryophila, In gelatina achroa interdnm dilute viride nidulans; cellulis cylindricis,
cum polls obtuse truncato-rotundatis, diametro 2-3 plo longioribus ; lamina chloropbyllacea
axili, plernmque indistincte, s«epe nulla; plasmate dilute viride; nncleo plerumque distincto;
zygosporis snbfuscis aut subglobosis aut enormitcr in clepsydra forma; membraua externa
enormiter excavata et sulcata.

Syn. — P. clepsydra, WOOD, Prodromns, Proc. Amer. Philosophical Soc.
Hob.— In rupibus et in muscis irroratis ad Chelten Hills, prope Philadelphia.

14 June, 1879.

106 FRESH-WATER A L G JE OF TUE UNITED STATES.

P. living on rocks and mosses, swimming in a transparent, sometimes light-green jelly; cells
obtusely truncated, rounded at the ends, 2-3 times longer than broad; chlorophyl lamina
axillary, mostly indistinct, often wanting; endocbrome light-green; nucleus generally distinct;
zygospore subfuscous, either globose or of an irregular form, somewhat resembling that of au
hour-glass ; external coat irregularly excavated and sulcate.

Remarks. — This species was found along the North Pennsylvania Railroad, near
Chelten Hills, growing amid mosses on the rocky juttings over which the water
was dripping. It occurs as a rather firm, transparent jelly, mostly of a light
greenish tint, in which the cells are often placed quite thickly. They are .cylin-
drical, mostly straight, but sometimes slightly curved, and often completely filled
with a light greenish endochrome. The central lamina is irregular, and mostly
not at all pronounced. In some cells the endochrome is much broken up, so that
the interior is filled witli little green masses with light spaces between them. In
these cells the nucleus is generally not perceptible, whilst in the others it is very
well marked. The zygospore is often globular, sometimes it is irregularly elliptical,
with a constriction in the centre, so as to give it somewhat of an hour-glass shape.
The outer coat mostly fits pretty closely on the inner contents, and is very often
distinctly marked with little pits, some round, some irregular in shape; in other
cases, instead of being thus pitted, the spores seem to be marked with deep curved
furrows.

Fig. 4, pi. 11, represents this plant in different stages of growth. (See Expla-
nation of Plates.)

Genus PENIUM, BREB. (1848.)

Cellulse cylindrical vel fusiformes, rectse, utroque polo rotundatas vel truncato-rotundatae (nee eniar-
ginatas nee excisai), medio saspius constrictas. Lamina chloropbyllacea axilis, ex transverse conspecta
radiatim-divergens, radii saspe furcati, granula amylacea plerumque longitudinaliter seriata includcns.
Individua in aqua libere natantia, singula, sparsa vel in massa gelatinosa consociata. Cellular nii'in-
brana laevis vel granulata, achroa vel fuscescens vel rubicunda, saBpius lougitudiualiter striata. (R.)

Syn. — Netrium, N^EGELI.

Cylindrocystis, MENGH.
Closterium, partim, EIIRENBERG.

Cells cylindrical or fusiform, straight, rounded at each end, or trnncately rounded (not emarginate
or excised), medianly often constricted. Chlorophyl lamina axillary, when seen transversely radi-
ately divergent, arms often forked, and containing starch granules, mostly longitudinally striate.
Individuals swimming free in the water, scattered and single, or associated in gelatinous masses.
Cell membranes smooth or granulate, transparent or fuscous or reddish, often longitudinally striate.

a. Lamina chlorophyllacea peripherice lobata vel radiatim expansa.
a. Chlorophyl lamina, lobale on the periphery or radiately expanded.

P.Digifus, (EHRB.) BREB.

P. cellulis ovato-cylindricis, diametro 3-5 plo longioribus, utroque polo parum attenuatis, sub-

truncato-rotundatis ; laminis chlorophyllaceis peripherice lobatis, medio interruptis.
Diam.—^" = .00173"— Tf jfo" = .0029".
Syn.—P.Digitus, (EHRB.) BREB. RABENHORST, Flora Enrop. Algar., Sect. III. p. 118.

Cells ovately cylindrical, 3-5 times as long as broad, at each end slightly attenuate, subtrun-
cately rounded; chlorophyl lamina lobate on the periphery, interrupted in the middle.

FUKSII-WATKU ALd.fi OF T I! I! C M T I! H STATES. 107

/,'• //id /•/.•.-•. - This species is probably widely diffused through the temperate por-
tions of North America. I lia\e found it abundantly near Philadelphia, as well as
among the Alleghanics, and ha\e received specimens from Dr. Lewis, collected in
5 o Lake, Northern New York ; Prof. Bailey also notes it as occurring in Georgia.
There is one form of it which resembles somewhat in outline the modern coffin,
one end In-ing much broader and much more rapidly narrowed than the other.
There is no distinct vucuolc at the end, at least in any specimen I remember to
have seen, although frequently large numbers of moving granules can be detected
in that portion of the frond.

i'ig. (i, pi. 'JO, represents the outline of a frond of this species.

P. lamrlloMiiiii, r.ui.ii.

1'. cflluli* oblongo- vcl fusiformi-cylindricis, diamutro 6-6 plo longioribus, medio ssepe levitcr
con.-tririis, utruque polo magis atteuuatis, obtuso rotuudatis. (It.)

Uium.—O 0023"— 0.0029". (R.)

v • — /'. lamellosum, BBEB. RABENHOKST, Flora Europ. Algarum, Sect. III. p. 118.

//,i/,._Rhode Island (Olney) Thwaites.

Cells oblong or fusiform cylindrical, 5-6 times longer than broad, often slightly constricted in
the centre, more attenuate at the ends, obtusely rounded.

Remark*. — I have never recognized this species, but it is one of those sent over
l'\ Mr. Olney, and identified by Prof. Thwaites.

6. Lamina chlorojihyllcu-ea integerrima.
b. Chlorophyl lamina entire.

* Cellulte in media jrfus minus constrictte.

* Cells more or less constricted in the middle.

P. mar^aritacenm, EIIRB.

I*. r|cni!;iitii cylindricum, diametro 8-9 plo longios, medio plernmquo leviter constrirtuni, utroqne
polo rotundato-truncutum ; cellule mcmbrana nodulis seriatis quasi margariUtcca ; locellus
in medio (circiter) atriasque craris corpusculis mobilibus in more Closteriorum replctus. (R.)

Diam.— 0.00098"— 0.0011". (R.)

Hub. — Rhode Island. (Olney) Thwaites ; Bailey. Florida. Bailey.

Elongate cylindrical, 8-9 times longer than broad, in the centre generally slightly constricted,
at each end roundly truncate ; membrane of the cells somewhat pearly with seriate granules;
vacnole about in the centre of each eras, filled with moving grannies, as in closterinm.

Remarks. — I have not seen this desmid, but it is in Prof. Bailey's list; it was
also among those sent by Mr. Olney to Prof. Thwaites.

P. iiiiiiuf mil. CLEVK.

1'. cylindricum, gracile, diametro 5-7 plo longins, laeve, ad polos obtusissimos (latissime rotnn-
datos) parum attenuatum, medio leviter constrictum. (R.) Species mihi ignota.

Diam.— 0.00044"— 0.00063". (R.)

8yn. — Docidium minutum, HALF'S British Desmid.

P. minutum, CLKVE. RABKNHOROT, Flora Enrop. Algarum, Sect. III. p. 122.

108 FRESH-WATER A L G M OF THE UNITED STATES.

Hob. — South Carolina; Florida. Bailey. Rhode Island. (S. T. Oluey) Thwaites.

Frond slender, suture not prominent; segments four to six times longer than broad, somewhat
tapering, inflation obsolete, sides straight, ends entire; e. f. without puncture. L. 5^2' >
B. T5W- (Archer.)

6. Cellulse in medio non constrictae.

b. Cells not constricted in the middle.

P. interrnptam, BREB.

"P. cellulis late lineari-cylindricis, diametro 5-6 plo longioribus, utroque polo subito cuneato-
acutatis, apicibus obtuso-rotundatis ; laminis chlorophyllaceis longitudiualibus saturate viridi-
bus, astate provecta fasciis transversis tribus pallidis interruptis." (R.) Species mihi ignota.

Diam.-O.QOUr— 0.00177". (R.)

Syn. — P. interruptum, BREB. RABENHOEST, Flora Europ. Algarum, Sect. III. p. 119.

Hob. — In fossis, South Carolina, prope Grahamsville. Prof. Bailey.

Cells broadly linearly cylindrical, 5-6 times longer than broad, at each end suddenly cuneately
sharpened, the apex obtusely rounded ; longitudinal chlorophyl lamina deep green, in ad-
vanced age interrupted by three transverse pale fascia.

P. Jenneri, RALFS.

P. ab P. Brebissonii vix discernendam, cellulis cylindricis, utroque polo rotundatis, lasvibus, dia-
metro 2^-5 plo longioribns ; zygosporis plerumque globosis, membrana fuscescente subgranu-
lata. (R.) Species mihi ignota.

Diam.— 0.00057"— 0.0006". (R.)

Syn. — P. Jenneri, RALFS. RABENHOKST, Flora Europ. Algarum, Sect. III. p. 120.

Hab. — In fossis, Florida. Prof. Bailey.

Scarcely distinguishable from P. Brebissonii, cells cylindrical, rounded at each end, smooth,
2^-5 times longer than broad; zygospores mostly globose, membrane somewhat fuscous, sub-
granulate.

P. Brebissonii, (MENGH.) RALFS.

P. in massa mucosa indefinite expansa saepe cum algis alteris intermixtis; cellulis perfecte
cylindricis, interdum nonnihil curvatis sed plerumque rectis, diametro 2^-4 plo longioribus,
ntroque polo late rotundatis, in medio non constrictis ; " zygosporis angularibus vel rotuiidatis,
membrana fuscente, subtiliter granulata."

.— 7iV = .00066".

Syn. — P. Brebissonii, (MENGH.) RALFS. RABENHORST, Flora Europ. Algarum, Sect. III. p.
120.

Hab. — In fossis, South Carolina. (Prof. Ravenel.)

In an indefinitely expanded mucous mass, intermixed with other algae; cells perfectly cylindri-
cal, sometimes slightly curved, but generally straight, at each end broadly rounded, not con-
stricted in the middle ; " zygospores angular or rounded, membrane fuscous, finely granu-
late."

Remarks. — Among the numerous desmids which I have received from Prof.
llavenel are some which, I think, must be referred to P. Brebissonii, although they
do not nearly equal the size of the European form, nor even the diameter given
above, which is almost the lowest limit of the mature foreign plant. I believe,
however, Prof. Ravenel's specimens are immature.

f
FRKSH-WATKK A L G M OF THK UN T KID STATES. 109

Mr. Kulfs' description of tlie conjugation is as follows: The process of the con-
jugation in tliis specie* (litters frnin that in the rest of this genus; for, as in Hi/or
lutItx-,1 ,/<W<» /«.-•, tin- conjugation cells enter into the formation of the containing
cell and are permanently attached to the sporangium, instead of being detached,
as commonly happens, in tin- l)e.>mids. The sporangium is at first cruciform, then
quadrate, and finally orbicular.

P. closterioides, lUtra

P. rrllulis anguste lanccolatis, diametro innximn 5-6 plo longioribuR, a mcdioin apices subtrun-
cat<>-roMimlat.is scn.-iin aticiiuutis ; laininis chlorophyll, saturate viridibus, mcdio fascia trans-
viTsa pullidu inti-rruptis. (K.) Species mihi ignota.

Diam— 0.00159"— 0.00175". (R.)

Syn. — P. closterioides, U.M.I-.-. RABENHORST, Flora Enrop. Algarnm, Sect. III. p. 121.

Hab. — Propc Grahamsville, Sooth Carolina. Prof. Bailey.

Cells narrowly lanceolate, 5-6 times longer than the greatest diameter, sensibly attenuate from
tin- initlillc into the subtruucate apices; chlorophyl lamina deep green, interrupted by a median
pale baud.

Genus CLOSTERIUM, KITSCH.

(Ylluhr intcrdum cylindricse sed siepius fusiformes ct utroque polo attenuate, plus minus lunula-
tim ciirvatie, in medio hand constrictae sed stria transversa unica vel 2-5 impressse. Cytioderma
UMIMC, -ni tirmura, leave vel plus minus distincte striatum et interdura longitudinaliter costatum.
r\!i"], hi-ina chlorophyllosa plerumqne in laminis longitudinalibas disposita, et sub cellulae polis
Im-rllo achroo, plcrumque globoso et corpusculis plus minus numerosis se vivide morentibus impleto
instructa.

Cells sometimes cylindrical, but more often fusiform and attenuate at each end, more or less
Innately curved, in the centre not constricted but marked with from 1-5 transverse striae. Cytioderm
tliin, moderately firm, smooth or more or less distinctly striate, and sometimes longitudinally costate.
Cblorophyllous cytioplasm mostly arranged in longitudinal lamina, and furnished at each end with a
clear space, which is mostly globose, and contains more or less numerous actively moving corpuscles.

a. Zygosporas globoste, rarinsime angulares ; cellulx crura attt non aid minus producta.
a. Zygospores globose, very rarely angular ; crura of the cells not at all, or only slightly, pro-
duced.

1. Cellulte cylindrical, ad utrumque polum vix vel paullum attenuatx, recta vel leviter curvatee,
apicibus rotundalis vel truncatis.

1. Cells cylindrical, not at all or but slightly attenuated at the ends, straight or slightly
curved, the apex rounded or truncate.

C. -Iriolalum, EHRB.

C. anguste lanceolato-fuBiforme, leviter arcnntnm, 8-12 plo fere longius qnam latnm, utroque
polo paulum sensimque attenuatum, apicibus truncatis saepe fnscoscontibus ; membrana dis-
tinctissime striata, vacnata fuscescente; vesicnlis chlorophyllaceis 5-7 (in qnoque crure);
locello apices versus sito, submagno, corpuscula 12-20 includente. (R.)

Diam.— ^,"_^"= 0.00152"— 0.00187". (R.)

Syn. — C. striolalum, EHRB. RABENHORST, Flora Europ. Algarum, Sect III. p. 125.

Ilab. — In aqnis quietis, Centre County, Pennsylvania. Wood. Saco Pond, New Hampshire.
(Lewis)

Narrowly lanceolately-fusiform, slightly bent, 8-12 times longer than broad, sensibly attenuated

110 FRESH-WATER A L G JR OF THE UNITED STATES.

•

at the ends, which are truncate and often somewhat fuscous ; membrane very distinctly striate,
when empty somewhat fuscous; chlorophyl globulos 5-7 (in each limb); vacuole placed in
the bent apex, moderately large, including 12-20 corpuscles.

Remarks. — The measurements given are those of Prof, llabcnhorst. Our Ame-
rican forms agree well with them.

C. angnstatuiii, K '' A

C. gracile, sublineare, diametro 16-18 plo longius, ad polos levissime attenuatum, apicibus late
truncatis; costis longitudinalibus paullulum prominulis 4-5, interstitiis circiter f JT'" latis;
vesiculis chlorophyllaceis in quoque cruro 6-7 ; locello ab apice subremoto mediocri, corpus-
culis 12-20 impleto. (R.)

Diam.—^-["—Ji"<= 0.00081"— 0.0010". (R.)

Syn. — C. angustatum, KTZ. RABENHORST, Flora Europ. Algarum, Sect. III. p. 126.

Hab. — In aquis quietis, prope Philadelphia, Pennsylvania. Wood. Rhode Island. Bailey.
New Hampshire. (Lewis)

C. slender, sublinear, 16-18 times longer than broad, very slightly attenuate at the ends, which
are broadly truncate ; with from 4-5 somewhat prominent longitudinal ribs, the interstices
about 5^5"' broad ; chlorophyl globules in each limb 6-7 ; vesicle subremote from the apex,
moderate, containing from 12-20 corpuscles.

C. jillicidilin, RALFS.

C. elongatum, anguste lineare, diametro 20-35 plo longins, leviter arcuatum, utroque polo vix
atteuuatum; apicibus truncatis; cytiodermate luteolo, interdum longitudiualiter striato.

Diam.—^Tns" = -0004".

Syn. — C.juncidum, RALFS. RABENHORST, Flora Europ. Algarum, Sect. III. p. 127.

Hab. — In fossis, South Carolina. (Ravenel) In lacu Saco, New Hampshire. (Lewis)

Elongate, narrowly linear, 20-35 longer than broad, slightly bent, scarcely narrowed at the
ends ; apices truncate ; cytioderm yellowish-brown, sometimes longitudinally striate.

Remarks. — I am indebted to Prof. Ravenel for specimens of this species, by
whom they were found on the slimy surface of a half dried-up ditch, associated
with numerous other desmids. The specimens are all smaller than the measure-
ments of Rabenhorst, but much larger than those given by Mr. Ralfs. None of
the plants have any chlorophyl granules — a circumstance probably simply depen-
dent upon the stage of their development. The longitudinal striae are in none of
the specimens very distinct, and in many cannot be demonstrated.

Since writing the above I have seen specimens collected by Dr. Lewis in " Saco
Pond," near the Crawford House, New Hampshire.

Mr. Archer (Pritchard's In/us., p. 749) lays stress upon the fronds being straight
in the middle, with the ends curved downwards ; but I have seen numerous speci-
mens in which the curve was through the whole length.

Fig. 2o, pi. 12, represents one of the specimens collected by Prof. Ravenel in
South Carolina.

2. Cellulae cylindricae, dorso plus minus convexae, venire subplanse, nunquam ventricoso
— inflates.

FRKSII-\VA TKll AL(i.i: Of Till.' IMTED STATES. Ill

a. Cell* cijtintlrii-itt, irttJi t/ie Jur*um more or less convex, the belly utraightinh, never ventri-
cutely injlut, •/.

€. Luniiln, (MILLER) EIIRB.

C. pcrniagimm, sublmve ^strise subtilissimoj vel indistinct*), semilnnare, dorso alto convexum,
vi'iitrr Mili|il:iiiuin. u]>icil>us attriuiatis rotundatis ; vcsiculis chlorophyllaceis numcrosis spar-
sis; lurrlln ili>iincto sulmpicali corpuscula uumerosa iucludeutc. (II.)

Diam.—jj"— ,'„" — 0.00032"— 0.0045". (II.)

&>//i. — C.Lunula, (MiiLi.ER,) EURB. RABENHORST, Flora Europ. Algarum, Sect. III. p. 127.

llnli. — South Carolina, Georgia, Florida. Prof. Bailey. Pennsylvania. Wood.

V<-ry large, smoothish (stria very fine or indistinct), srmilunar, dorstim strongly convex, belly
Mraitrliti>li, the ends attennate and rounded; chlorophyl globules numerous, scattered; vesi-
cle distinct, subapicul, including numerous corpuscles.

C. accroMiiii, (SCURANK) EIIRB.
( I'm: not: maximum.

C. lineare-fusiforme, sub-rectum ant leve curvatnm, ntroque fine sensim et panllulum atteu-
uatuui, diamctro 15-24 plo lougiore; apicibus augustissimc truncatis, achrois; nicmbrana
hand striata; vesiculis chlorophyllaccis 11-14 in quoquc crure, in serie axilli siniplici collo-
catis; locello apical! parvo, corpuscula numerosa iucludente; zygosporis globosis.

Diam.— Transv. max. TtS0" = .0017" ; zygosp. Tf J," =.0027".

Sijn. — C. acerosum, (Scu&ANK) EIIUB. RABENUORST, Flora Europ. Algarutn, Sect. III. p.
128.

Hab. — Pennsylvania; Wood. South Carolina, Georgia, Florida; Bailey.

Linear, fusiform, straightish, or slightly curved, at each end sensibly little by little attenuate,
15-24 times longer than broad ; apices narrowly truncate, transparent; membrane not striate;
chlorophyl globules 11-14 in each limb placed in a simple axillary series ; apical vesicle
small, containing numerous corpuscles ; zygospores globose.

/,'• nun-la. — The dcsmid, described above, was found in New Jersey, near Cam-
elm. It differs from the typical form of C. acerosum in its size, proportionate
length to breadth, and in not being striate. The European "formd major"
(ItAiiENH.) appears, however, to exceed it in transverse diameter, and, according
.'ine authors, certain fronds of the species are not striate, and all authorities
jijjrcc that at times the striae are exceedingly delicate. For these reasons, I think,
our American form must be regarded simply as a variety. As far as can be judged
from the rude figure, it is this species which Prof. Bailey identifies as C. tetiue,
KTZ., in Silliman's Journal for 1841.

Fi<j. 5, and 5 a, pi. 11, represent this species magnified 250 diameters; 56
represents the sporangium with portions of the dead fertile fronds still attached.

C. areolatiun, WOOD, (sp. nov.)

C. fusiforme, subrectum vel noifnihil cnrvatnm, lateris ventralis medio saepe paullulum concavnm,
diametro 9-10 plo longius, utrinque modice attcnuatum; apicibns truncato-rotnndatis; mem-
brana crassa, et firma, rubido-brunnea, profunde distantc striata, et minutissime Bed distincte
grannlata vel areolata; suturis medianis distinctissimis 4-10.

Diam.— 0 0024".

Hob. — In aquis puris qnietis ; Northumberland Co., Pennsylvania.

112 FEES II -WATER ALG^E OF THE UNITED STATES

Fusiform, straightish, or very slightly curved, the ventral side often a little concave in the
middle, 9-10 times longer than broad, moderately attenuated at each end; the apices trun-
cately rounded ; cell-membrane reddish-brown, thick and firm, distantly profoundly striate,
and v«ry minutely but distinctly granulate or areolate; median sutures very distinct,
4-10 in number.

Remarks. — I found this species growing in a quiet pool of pure water, in a wild,
deeply wooded ravine, near Danville, Central Pennsylvania. It was in great
abundance, forming a translucent greenish jelly, one or two gills of which might
have been readily gathered. Unfortunately, I had no microscope with me and
cannot, therefore, determine at all as to the arrangement of the endochrome, the
carbolic acid, used as preservative, having entirely disarranged this by the time I
got the fronds upon a slide. The empty frond is of a reddish-brown color. The
membrane is quite thick and firm, and is marked with very prominent broad striae
or grooves. In a number of cases I have counted these and always found nine
present upon one face of the frond. There are also upon the surface numerous
minute markings not fairly visible with a lower power than a ^th objective.
Under this glass they appear as minute punctations. An eighth resolves them
into granules mostly of an oblong shape, arranged more or less regularly in longi-
tudinal rows. Very generally, each side of the stria or groove has a close row of
larger and more distinct granules forming a sort of border to it. In truth, the
surface of the frond is covered with broad longitudinal bands of these granules,
and the narrow smooth spaces between them constitute the stria spoken of. This
species is very closely allied to C. turgidum, EHRB., agreeing pretty well with it in
general outline and size.' I think, however, the peculiar markings upon the
membrane are sufficient to separate it, and do not doubt that if fresh specimens
were at hand, differences would be found to exist also in the arrangement of the
cell-contents. The turning up of the ends, generally so marked in C. turgidum,
is mostly entirely absent in this species, rarely there is some tendency to it.

Fig. 6, pi. 11, represents in outline a frond magnified 160 diameters; Fig. 6 a,
the end of an empty cell, magnified 1375 diameters ; the color of this is, perhaps,
a little too dark.

C. I in cat u in, EHRB.

C. valde elongatum, gracile, quater vicies-tricies longius qnam latum, distincte striatum, e
medio recto cylindrico utrinque valde attenuatum, apices versus leviter incurvum, obtuso-
truncatum; vesiculis chlorophyllaceis in quoque crure 20-21, in sericm unicam axilem dis-
tributis; locello parvo, ab apice remote, corpusculis 10-12 impleto. (R.)

Diam.— WW' = .0015".

Syn.— G. Uneatum, EHRB. RABENHORST, Flora Europ. Algarum, Sect. III. p. 130.

Ilab. — Pennsylvania, Wood.

Very much elongate, slender, distinctly striate, from the centre straight and cylindrical, at each
end very greatly attenuate, apex bent, slightly incurved, obtusely truncate; clilorophyl glo-
bules 20-21 in each limb, placed in a simple axillary series; vacuole small, remote from the
apex, containing from 10-12 corpuscles.

Remarks. — The American forms agree well with the above description ; some

1 K i:s ll-WATER ALG-E OF T II K UNITED STATES. 113

of them, however, are a little more curved in the central portion than it would
imply.

l-'ig. 1, pi. 1:3, is a drawing of an American plant, magnified 160 diameters.

4 '.Cur ii mi*, KIIKH.

C. oblougum, turgidura, levitcr cnrvum, laeve, diametro 4-7 plo longius, apicibas obtusis. (R.)

Syn. — C. Curttmia, KIIUKNBEUU, Verbreit b. 28, IV. F. 28. RABENUOKST, Flora Europ. Alga-
rum, Sect. III. p. 138.

Hab. — New York ; Ehreubcrg.

Oblong, turgid, slightly curved, smooth, 4-7 times longer than broad, the apex obtuse.

/,'< •>/!« /•/.•.-• . — I have no knowledge of this species other than that in the above
short description, which has been copied from Itabeuhorst's works.

3. Cellulx gemilunares, plerumque mayis curvatte quam in Seel. 1 et 2, venire semper tumidr,
ventricoso-injlalee.

3. Cells semilunar, mostly more curved lhan in Sect. 1 and 2, wilh the belly always tumid,
venlricosely injlaled.

C. Ehrenbergii, MENOII.

C. fusoidco-scniilunare, ventre inflate, ceterum nt in C. Lunula. (R.)

Diam.— Lat. jjjfo" - .0029". Long. ,JJ5" = .0042."

Syn. — C. Ehrenbcrgii, MENCJII. RABENHOBST, Flora Europ. Sect. III. p. 131.

Hab. — Prope Philadelphia.

" Frond large, stout, about five or six times as long as broad, Innately curved, extremities taper-
ing ; upper margin very convex, lower concave with a conspicuous central inflation ; ends
broadly rounded; large granules, numerous, scattered ; fillets several; e. f. colorless, without
stria;, central suture not evident. Sporangia orbicular, smooth, placed between the but-
slightly-connccted empty conjugated fronds, the cndochrome during the process of conjuga-
tion emerging from the opened apex of a short conical extension from each under side of each
younger segment (or shorter cone) of each pair of recently divided fronds, the conjugating
fronds being produced immediately previously by the self-division of a pair of old fronds — two
sporangia being thus the ultimate produce of the two original fronds. L. SV; B. ^Jo"-
Archer." Pritchard's Infusoria, p. 748.

Remark. — Fig. 2, pi. 12, represents a plant of this species magnified 160 dia-
meters.

C. moniliferiim, (BOBT) Kuan.

C. semilunare, plus minus curvatum, diametro maximo 6-9 plo longius, ventre inflato, ntroquc
polo Bonsim attenuatnm, apicibus achrois obtnsis, vesiculis cblorophyllaceis in scric unica
longitudinal! axili dispositis, in quoque crure 7-10; locello apical! submagno, corpnscula
nnmerosa includente (corpusculum in quoque locello unicum mobile ellipsoidcum, magnitudine
linese partem millesimam eequans, cetera mobilia per totum corporis distributa observavit cl.
Perty.) (R.) Species mihi ignota.

Diam.— 0.0019"— 0.0022". (R.)

Syn. — C. moniliferum, RABENFIORST, Flora Europ. Algarum, Sect III. p. 131.

Bab. — Georgia ; Rhode Island ; Bailey.
15 June, 1878.

114 FRESH-WATER ALG^E OF TUB UNITED STATES.

" Frond smaller than C. Ehrenbcrgii, stout, five or six times as long as broad, Innately curved,
extremities tapering, upper margin convex, lower concave, with a central inflation, ends
rounded; large granules, conspicuous, in a single longitudinal series; e. f. colorless, without
stri«, suture not evident. L. 7y — SV'- B- sis" — lie"- Archer." Pritchard's Infusoria,
p. 748.

€. Leibleinii, KTZ.

C. priore minus, semilunare, magis incurvum, ventre inflate, ad utrumque polum largius attenu-
atum, apicibus achrois acutis; vesiculis chlorophyll, in quoque crure 5-6, in serie simplici
axillari dispositis; locello niagno, apices versus sito, corpuscula numerosa includente. (R.)

Diam. — 7^".

Syn. G. Leibleinii, KTJTZING. RABENHOEST, Flora Europ. Algarnm, Sect. III. p. 132.

Hab. — Georgia; Rhode Island ; Bailey. Pennsylvania; Wood.

" Frond somewhat stout, distance between the extremities six or eight times the breadth,
crescent-shaped, much curved, rapidly attenuated, upper margin very convex, lower very con-
cave, often with a slight central inflation; ends subacute ; large granules, in a single series;
fillets few or indistinct; e. f. somewhat straw-colored, without striae; suture evident. Spo-
rangium orbicular." Archer.

Remark. — Fig. 6, pi. 12, represents this plant, magnified 260 diameters.

4. Cellulx maxime curvalse, ventre non tumidae.
4. Cells most curved, the belly not tumid.

C. Dianae, EHRB.

C. anguste fusiforme, semilunare, utroque polo valde attenuatum, apicibus subacutis ; cytioder.
mate achroo (vel dilutissime nmbrino), striis subtilissimis medio interruptis praedito, in media
parte striis transversalibus 3-5 ; vesiculis in quoque crure 6-7, in serie unica axili dispositis ;
laminis chlorophyllaceis pluribus, sa?pe flexuosis; locello indistincto, corpusculis pluribus
vivide mobilibus. (R.)

Diam.— Lat. 75V' =.00053". Long. Tf §/ = .00082".

Syn. — C. Dianae, EHRENBERG. RABENHORST, Flora Europ. Algarum, Sect. III. p. 133.

Hab. — Georgia ; Florida ; Rhode Island ; Bailey. Pennsylvania ; Wood.

Frond crescent-shaped, six or eight times as long as broad, much curved, rapidly attenuated;
upper margin very convex, lower very concave without a central inflation ; ends subacute
with a very slight emargination at the upper outer extremity ; large granules in a single
series ; empty frond, somewhat straw-colored, or faintly reddish, without striae, suture evident.
(A.)

Remarks. — Mr. Archer marks G. Venus, KTZ., as a doubtful synonym of this
species ; not having Prof. Kiitzing's work at hand, I do not know whether C.
Venus, KTZ. is really the following species or not. The two forms here known as C.
Dianas, EHRB. and C. Venus, KTZ. are, however, I think sufficiently distinguished.

Fig. 4, pi. 12, represents this species of desmid.

C. Venus, KTZ.

C. parvum, plus minus gracile, semicircnlare, octies-duodecies longius quam latnm, in apices
subacutos sequaliter sensimque attenuatum ; cytiodermate tenui, Ireve ; laminis chlorophylla-
ceis obliteratis ; vesiculis in quoque crure 3-4 ; locello distincto corpusculis 4-6 repleto. (R.)

Diam.— .0004".

FRES II -WATER ALG^E OF THE UNITED STATE 8. 115

Syn. — C. I'enus, KtrziNU. RABENUOHST, Flora Europ. Algarum, Sect III. p. 134.
llab. — South Carolina. (Raveacl.)

Small, more or less slender, semicircular, eight to twelve times longer than broad, equally and
very |>erre|>iil>ly ultenuate ut both apices; cytiodenn tliin, smooth; chlorophyllou8 lamina
obliterated ; vesicles in each crus 3-4; vacuole distinct, containing 4-C corpuscles.

Remark. — Fig. 7, pi. 1 1 , represents iii outline a frond magnified 450 diameters.

< . parvuluni,

C. parvnin. scmieirculare, medio non tumidnm, grncile, anguste lanceolatum, sexics-octies lon-
jrius (jiiaiu latuin, apicibus acutis; cytimlcrmatc trnui, lu-vissimo, vacua! o nonnunquam luteolo-
fu.tcesccnte et subliliter striato ; vesiculis uniseriatis, in quoque crure 2-4, varius 1-7 ; lumiiiia
chlorophyllaceis 4-5. (R.)

Diam.— Max. O.OdUi'G"— .00062" (R.) (.0008" W.)

Syn. — C. parvulum, N.-KiiKi.i. RABENHORST, Flora Europ. Algarum, Sect. III. p. 134.

Hub. — Prope Philadelphia, Wood.

Small, semicircular, not swollen in the middle, slender, narrowly lanceolate, six to eight times
longer than broad, with the apices acute; cytioderm thin, very smooth, when empty some-
what yellowish-fuscous and finely striate ; vesicles uniseriate, in each crus 2-4, rarely 1-7;
chloroplivllous lamina 4-5. .

/,'• marks. — I have referred to this species a desmid which I have found about
Philadelphia, and which agrees in all respects with the description of Prof, llaben-
horst except in attaining a larger size.

Fig. 5, pi. 12, represents this plant magnified 450 diameters.

€. Jennerii, RALFS.

C. cylindraceo-fusiforme, Bemilunare, Iseve, ntrinque modice attennatnm, seiies-octies longiua
quam latum, apicibus obtuse rotundatis; vesiculis in quoque crure 5-7, in serie unica axili
disposals; lamiuis chlorophyllaceis 2-3; locello subaequali magno, corpuscnlis numerosis
inipleto. (R.)

Diam.— 0.00057". (R.)

Syn. — C. Jennerii, RALFB. RABENHOROT, Flora Enrop. Algarum, Sect. III. p. 134.

Sab.— Rhode Island, Bailey.

Frond small, distance between the extremities six or seven times the breadth, crescent-shaped,
much curved, gradually tapering (sometimes with an obscure central constriction) ; upper
margin very convex, lower very concave without a central inflation ; ends obtuse, rounded;
large granules in a single series; e. f. colorless without striae. L. ,JT". B. TT"JO". Archer.
Pritchard's Infusoria.

b. Zygosporu plerumque quadrangulares, cellularum crura longe vel longissime producla,

strpe eetiformia.
b. Zygoepores mostly quadrangular, crura of the cells greatly produced, often setiform.

C. rofttratiim. EHRB.

C. eorpore lanceolato-fusiformi, utrinqne valde et longe attenuate, leviter cnrvato, striato ; cor-
nibus setaceis singulis corpus vix teqnantibus, stepius longe brevioribus; cytiodermate dilute
un>brino vel luteolo, dense striato : vesiculis nniseriatia, in quoque crure 5-6; locello oblongo,
sepias indistincto, corpusculis 12-15 vivide se moventibus. (R.)

116 FRESH-WATER ALG^E OF THE UNITED STATES.

Diam.— 0.0008". (0.0009"-0.0016." R.)

Syn. — C. rostratum, EHRENBERG. RABENHORST, Flora Europ. Algarum, Sect. III. p. 135.

Hob __ In fossis, prope Philadelphia; Wood.

Body lanceolate-fusiform, at each end greatly and for a long distance attenuated, slightly curved,
striate ; crura setaceous and scarcely as long as the body and sometimes much shorter; cytio-
derm light or luteolous, densely striate, vesicles uniseriate, 5-6 in each eras ; vacuoles oblong,
often indistinct, containing from 12-15 actively moving granules.

Remark. — Fig. 3, pi. 12, is a drawing of this species, magnified 260 diameters.
€. setaceum, EHRB.

C. corpore anguste lanceolate, recto vel subrecto, distincte striato, utrinque in rostrum setaceum,
levissime incurvum, obtusum, longissirae porrecto; singulo rostro corpore 3-4 plo longiore;
et vesicnlis et locello indistinctis. (R.)

Diam.— Max. (plerumque) 0.0004"— 0.00044." (R.)

Syn. — C. setaceum, EHRENBERG, Flora Europ. Algarum, Sect. III. p. 136.

Hob. — Stonington. (Lewis) Pennsylvania ; Wood. Georgia ; Florida ; Providence, Rhode
Island ; Bailey.

Frond very slender, from twenty to twenty-five times as long as broad, narrow-lanceolate;
upper and lower margins nearly equally and but slightly convex ; each extremity tapering-
into a very long and slender setaceous colorless beak, longer than the body, ultimately curved
downwards, ends obtuse; e. f. colorless, strise close, faint, central suture solitary. Sporangium
cruciform. L. TTS"- B. ^T"- Archer. Pritchard's Infusoria.

C. Amlil.voiiciiin, EHRB.

C. filiforme, cylindricum, laeve, utroque fine parum attcnuatum, apice rotundum. (R.)
Syn. — G. lineatum, EHRB. BATLEY, American Journal of Science and Arts, 1841, p. 303.

G. Amblyonema, EHRB. Verbreit. p. 123. RABENHORST, Flora Europ. Algarum, Sect.
III. p. 138.

Hob. — West Point, New York ; Providence, Rhode Island, Bailey.

Filiform, cylindrical, smooth, gradually attenuated at each end ; the apex rounded.

Remarks. — I have never recognized a specimen of this species, nor have I had
access to the original description of Ehrenberg.

Genus TETMEMORUS.

Cellnlee cylindricae vel fusiformes, rectae, medio distincte constrictse, utroqne polo anguste incisae
cytioderma sat firmum, plerumque granulatum vel punctatum.

Cells cylindrical or fusiform, straight, distinctly constricted in the middle, narrowly incised at
each end. Cytioderm firm, mostly punctate or granulate.

T. Brebissonii, (MENGH.) RALFS.

T. diametro 4-6 plo longior ; a fronte cylindricus, utroqne polo non attenuates sed rotundato-
truncatus ; a latere fusiformis et a medio in apices rotundatos sensim attenuatus ; cytiodermate
striato-punctato.

Diam.— 7^ff" = .0016".

Syn.— T. Brebissonii, MENGHEINI, RABENHORST, Flora Europ. Algarum, Sect. III. p. 139.

FUESII-W A TICK A I. (;.K OF T11K INITKD STATES. 11T

Hob. — In fos.sis, Atlantic Static.

Four to six times lonjrer tliati broad; from the front cylindrical, not attenuate at the truncately
rounded ends; viewed laterally fusiform, attenuated from tin- middle to the rounded ends;
cytiodenn striatrly pnnc-tutc.

Remark*. — The central constriction is more apparent in the lateral than front
vir\v. When the frond is full of endochrome the punctae on the outer wall are
not apparent, but when it is empty they are seen to be small, and closely arranged
in -nia-like rows. This species extends through all the Atlantic sea-board States.
Prut". Bailey has found it in South Carolina and Florida, as well as in Rhode Island.
1 have collected it hi Centre County, of this State.

Fi«j. 3, pi. 21, represents an empty half frond of this species; 3 a the outline of
tlu1 frond.

T. gran Hiatus, (Bufcn.) HALTS.

T. habitu Tetm. Brcbissonii, sed major et cytiodermato irrcgularitor grannlato-piinctato. (R.)

Diam TJ," = .0013". (.00155". R.)

Syn. — 7'. granulalus, (BufcuissoN.) RALFS. RABENUORST, Flora Europ. Algarum, Sect. III.
]>. 140.

y/ufr.—I'rope Philadelphia; Wood Rhode Island; (S. T. Olney.) Thwaites. South Caro-
lina ; Bailey.

Frond somewhat longer than T. Brebissonii, about fire or six times longer than broad ; in both
f. T. and s. T. fusiform, the constriction a very shallow groove, ends with a hyaline lip-like
projection extending beyond the notch ; endochrome with a longitudinal series of large
granules; e. f. punctate, the puncta scattered, except near the constriction; where they are
disposed in two transverse rows. Sporangium orbicular, smooth, margin finely striated, placed
between the deciduous empty fronds. L. -rJu". B. -g\y". Archer. Pritchard's Infusoria.

Remark. — Fig. 8, pi. 12, represents this species magnified 450 diameters.

T. giganteus, WOOD.

T. maxitnus, oblongus, diametro 3 plo longior ; apicibns hand attenuatis, late rotundatis ; suturis
profundis, linearibua; cytiodennate irregulariter granulato-pnnctato.

Diam rjfo" = .0031".

Syn.— T. giganteus, WOOD. Proc. Acad. Nat. Sci., 1869.
Hob. — In stagnis, Centre County, Pennsylvania.

Very large, oblong. 3 times longer than broad ; with the ends not attenuate but broadly rounded ;
suture profound, linear ; cytioderm irregularly granulately punctate.

Remarks. — I found this beautiful desmid in a stagnant pool in Bear Meadows,
Centre County, in the month of August. It is very different in its outline from
its nearest ally, T. gramdaius. The diameter is preserved uniform until near the
end, where there is an alteration in the line of the margin, so as to cause
some contraction, which is, however, wanting in some specimens. The ends are
therefore broad and obtuse. The size is also double that of T. granulatiu.

Fig. 7, pi. 12, represents a frond of this species magnified 260 diameters.

118 FRESH-WATER ALG^E OF T II E UNITED STATES.

T. leTis, (KUTZ.) RALFS.

T. Brebissonii formis similis sed parvior, 3-4 plo longior quam latus ; cytiodermate plerumque

levissimo, interdum indistinctissime paiictato.
Diam.—f^,v" = . 00066".

Syn. _ T. levis, KUTZINO. RALFS. RABENHORST, Flora Europ. Algarura, Sect. III. p. 140.
Hob __ In aquis quietis, prope Philadelphia.

Similar in form to T. Brtbissonii, but smaller, 3-4 times longer than broad ; cytioderm mostly
very smooth, sometimes indistinctly punctate.

Remarks. — Prof. Rabenhorst states that the cytioderm of this species is very
smooth, and Mr. Ralfs says that he has failed to detect any punctations, but also
states that " Mr. Jenner and Mr. Ross assure me that they (punctse) are scattered
as in T. granulatus." I have no doubt of their existence in certain individuals,
whilst in other cases they appear to be absent.

Genus PLEUROTJENIUM, NJEGEU (1849).

Cellulae singulse in aqua natantes, rectae vel snbrect®, cylindrical vel fusiformes, valde elongatae,
utroque polo • rotundatae vel truncatae, medio leviter constricts, ex transverso circulares. Cytio-
plasma chlorophyllaceum in laminis longitudinalibus pluribus dispositum, et sub'utroque polo locello
rotundato corpusculis se vivide moventibus impleto instructum.

Cells single, swimming in water, straight or nearly so, cylindrical or fusiform, very much elongate,
rounded or truncate at each end, in the end view with a circular outline. Chlorophyllous protoplasm
arranged in longitudinal laminae and furnished at each end with a round vacuole containing actively
moving corpuscles.

Remarlcs. — This genus appears to include the main portion of the species, which
have been described under the name of Docidium ; the remainder being represen-
tatives of a number of genera. I have not had access to the original description
of Docidium, and do not know in what year it was published ; but, according to
De Bary, Docidium is much the older name ("Ueber de Conjugat.," p. 75). M.
De Bary states, however, that he prefers the name of Na?geli, because that autho-
rity first defined the genus and his name expresses very clearly the character
of it, as well as from the circumstance that the name Docidium having been
made to cover a heterogeneous mass of species, its retention might cause confu-
sion. I confess to thinking that this action of De Bary is not in accordance witli
the recognized laws of priority, but, in the absence of the original description,
have thought best to follow it.
P. trabecula, (EHRB.) N^GELI.

P. saepe valde elongatum, octies vicies-longius quam latum, cylindraceum, utroqne fine laevissiino

attenuatum aut incrassatum, juxta medium constrictum ssepius bigibbum (quasi biundatum),

apicibus late truncatum ; cytiodermate tenui laevi, achroo. (R.)

Diam.—

Syn. — " Docidium Ehreribergii. RALFS." BAILEY, Microscopical Observations. Smithsonian
Contributions.

Pleurotamium trabecula, (EHR.) NJEGELI. RABENHORST, Flora Europ. Algarum, Se^t.
III. p. 141.

Hob. — South Carolina, Georgia, Florida ; Bailey. Pennsylvania ; Wood.

FRESH-W ATKK AI.C.K O F T II E U N I T E D 8 T A TE 8. H9

(DofiiJinm Khr?it>H'r,jii. RALFS.) Frond slender, linear,- suture forming a rcrj sharply
delim-d rim ; segments 8-12 times longer than broad, basal inflation having another smaller
one above it, siiU-s otherwise straight, parallel; ends crenate, owing to a number of cmargi na-
tions on the edge of the truncate extremities, from three to five of the crenations being
usually visible ; e. f. punctate or rough with minute granules. Sporangium suborbiculur or
elliptic, or slightly angular, smooth, placed between the deciduous empty fronds. Ciliated
/.""spores formed by segmentation of the cell contents, and their emission effected through
the opened apex of each one, two or three, especially, formed lateral tubes arising from be-
neath the Imse of one of the segments. Archer.

*. — This species is quite common around Philadelphia; but I do not
n 'member ever to have seen one with the cell-wall granulate. The smaller of the
two umlxmations near the centre is often wanting or exceedingly small, and the
crenulaticms in the ends are very often obsolete.

Fig. 9, pi. 12, represents a cell of this species magnified 160 diameters.

1>. lint ilium, (Hutu.) DE BART.

P. priori simile, sed gracilius, angnstius et plerumque longius, mcdio tantnm semcl constrict um ;

rytiodermate laevi. (K.) Species mihi iynola.
Diam.— 0.00054"— 0.0009". (K.)

.Vy/i. — P.Baculum, (Bafefl) DuBA&Y. RABENHORST, Flora Europ. Algarnm, Sect. III. p. 141
Hub. — Oeorgia ; Bailey.

Frond slender, suture not prominent; segments very many times longer than broad, basal in-
flation very conspicuous, solitary, sides otherwise straight, very nearly parallel, large gran-
ules of the endochrome in a single series ; ends entire; e. f. without puucta. L. , J ," B
1*7".
P. breve, WOOD.

P. robustuin, diametro 4—8 plo longins, in mcdio distincte constrictum sed hand undulatum,
utroque polo nonnihil attenuatum ; apicibus truncatis et nonnihil rotundatis ; cytiodermate
crassissimo, dense granulato-puuctato; marginibus vel rectis, vel breve undulatis.

Diam. — . 0038"—. 000 95".

Syn. — P. breve, WOOD. Proc. Acad. Nat. Sciences, 1869.

Hab. — District of Columbia. (Billings.)

Robust, 4-8 times longer than broad, distinctly constricted but not undulated in the middle,
slightly attenuated towards the ends; apex truncate and somewhat rounded ; cytioderm very
thick, densely minutely granulate; margins either straight or shortly undulate.

/,'< marks. — This species was sent to me by Dr. Billings, who obtained it near
^ -liington, D. C. The margins are sometimes straightish, but in other fronds there
are three or more distinct short undulations, or rounded projections in each half
margin. The cell-wall is excessively thick, especially at the end — in many cases
much thicker than the drawing.

Fig. 2, pi. 21, represents an empty frond of this plant magnified 750 diameters.

P. crcnulatum, (EHRB.) RABENHORST.

P. robustum, cylindraceo-subclavatnm, octies-duodecies longins qnam latum, medio nndnlato-
nodulosntn, strictune mediae margine tumido, apicibns late Iruncatis, altero stepe creuulato ;
cytiodermate granulato-punctato. (R.) Species mihi ignota.

Diam.— 0.0023". (R.)

Syn. — P. crenulatum, (EiiRB.) RABENHORST, Flora Enrop. Algarum, Sect III. p. 142.

120 FRESH-WATER ALG^E OF THE UNITED STATES.

Docidium nodulosum, BREB. RALFS. British Desmidife, p. 155.
Closlerium trabecula, BAILEY. American Journal of Science, 1841.

Hob. In aquis quietis, South Carolina ; Georgia ; Florida ; Rhode Island ; Bailey. Pennsyl-
vania ; New Jersey ; Wood.

(Docidium. nodulosum.') Frond very stout, the thickened sutures forming a projecting rim ;
segments four to six times as long as broad, scarcely attenuated, regularly inflated at intervals
so as to form an undulated margin, the basal inflation the most prominent, the others, as they
approach the ends, less so, where they are indistinct or wanting ; ends entire ; e. f. coarsely
punctate. L. g1^ ". B. 55-5". Archer. Pritchard's Infusoria.

Remarks. — I have found this species in " Shepherd's Mill Pond," near Greenwich,
Cumberland County, New Jersey, and also in a Spring in the Philadelphia Park,
near Columbia bridge.

Fig. 1, pi. 21, represents the outline of a frond of this species magnified 160
diameters.

P. Clavatnin, (Kiz.) DE BARY.

P. subcylindraceum, multoties (16-24) longius quam latum, ad utrumque polum sensim incras-
satum, subclavatum, apicibus late truncatis ; cytiodermate firmo achroo, dense et irregulariter
granulato-punctato. (R.) Species mihi ignola.

Diam.—M&x. 0.00165"— 0.00147" ; min. = 0.0010"— 0.00092". (R.)

Syn. — P. clavalum, (Kiz.) DE BARY. RABENHORST, Flora Europ. Algarum, Sect. III. p. 141.
Docidium clavatum, KUTZING. RALFS, British Desmidise. ARCHER. Pritchard's Infusoria.
Hob. — South Carolina ; Georgia ; Bailey.

Frond slender, suture scarcely prominent, segments eight to ten times as long as broad, slightly
clavate near the ends, and ultimately somewhat attenuated, basal inflation sometimes solitary,
sometimes having another slight one above it; ends entire; e. f. punctate. L. ffy. B. ^iV'-

P. undulatnm, (BAILEY.)

D. laeve, gracile cylindricum, undulatum, latitudine 18-20plolongins, medio modice constrictum ;

cruribus et basi et apice truncatis et crenatis. (R.) Species mihi ignota.
Syn. — Docidium undulatum, BAILEY. Micros. Observ. p. 36.
Hob.— Florida, Bailey.
" Segments eight to ten times longer than broad, constricted six to eight times at regular intervals

throughout their entire length, with the base and ends crenate, smaller than D. nodulosum,

BREB., with more frequent and deeper constrictions. The same characters distinguish it from

D. nodosum and D. constrictum."

P. nodosum, (BAILEY.)

D. validissimum, undulatum, spinulis eparsis hirsutum, medio valde constrictum, diametro 8-10
plo longius ; cruribus e basi dilatata leviter attenuatis 4-undatis, apicibus quasi productis,
latissime truncatis; locello apicali ratione parvo, rotundo, corpusculis paucis (ut videtur)
repleto. (R.) (Species mihi ignota.)

Syn.— Docidium nodosum, BAILEY. Micr. Observ., pi. 1, fig. 4. RALFS, British Desmids,
p 218.

Hab. — United States ; Bailey.

"Frond stout; segments with four prominent nodes separated by constrictions; end view
crenate. An end view shows that each node is not a simple swelling, but really formed by
whorls of tubercles. 'This species is easily recognized by the deep indentations in its out-
line, corresponding to the constrictions which separate the transverse rows of knob-like pro-
jections. It is one of the largest species in the genus,' Bailey." Ralfa.

FKKSH- WATER ALGJS OF TUB UNITED STATES. 121

P. conwtrirtiim, (BAILEY)

D. subvalidum, lasve, latitudinc 10-12 plo longius, medio valdc constrictura, stricture margine
noil proiniuente ; cruribus a basi tutuida hi apictnu lute truucatuiu uon atlenuatis, 4 umlu-
liitis. (H.) (.S/xvifi mtfii iynuta.)

Syn. — Docidium constrictum, BAILEY. RAITS, British Desmids, p. 218.
llab.— Rhode Island, Bailey.

" Frond stoat, segments with moderately deep constrictions, which separate four equal, gently
curving prominences ; end view entire. ' This species is at once distinguished from /'. nodosum
by tin- iTn.-s suction of the nodes bciug a simple circle instead of an indented one,' Bailey."
Half*.
P. TrrrucoMum, (BAILEY)

I> vulidum, granulosc-vcrrucosnm, latitudine 10-12 plo longiui, undulatum, apicibus integria
truucatis. (II.) (Species mihiiynota.)

Syn Cosmarium verrucosum, HAILKY, Araer. Journ. Sci. and Arts, 1846.

Docidium verrucosum, RALFS, Brit. Desm. p. 218. BAILEY, Micr. Observ. p. 28.

Hub.— Rhode Island ; Bailey.

"Segments, with numerous whorls of small prominences, which give the margins an undulated
appearance, all the undulations are equal. ' This is a very pretty species with a waved out-
lii.e, caused by the slight projections, which are arranged in numerous transverse rings,'
Bailey." Haifa.

P. Itir-ntiim, (BAILEY)

It. spinuloso-hirsutum, medio valde constrictura, diametro 10-12 plo longins; crnribns ct basi
et apice subdilatatis, truucatis. (R.) (Species mihi ignota.)

Syn. — Docidium hirsulum, BAILEY, Micr. Observ. p. 36.
Bab. — Florida; Bailey.

"Segments many times longer than broad, slightly inflated at the base, surface hirsute. A
small species resembling 1>. Ehrenbergii in its form, but strongly hirsute on its outer sur-
face." Bailey.

Genus TRIPLOCERAS, BAILEY.

Cellule singulte, rectse, Talde elongate, processus magnorum scriebus transvereis armatse, utroqne
polo trilobatie, lobis acute bidentatis.

Syn — Triploceras, BAILEY, Microscopical Observations, p. 37, Smithsonian Contributions, I860.

Cells single, straight, very much elongate, armed with transverse series of large processes, trilo-
bate at each end, lobes acutely bidentate.

T. verticillatum, BAILEY.

T. cellulis snbcylindricis, sed ntroqne fine leviter angustatis et nonnihil fusiformibus, modice
robustis, diametro 12-20 plo longioribus; processibus lateralibus robnstis, magnis, apice
emarginatis.
Diam.— Cum process. 7Jfo" = .00146"; sine process. T^,W' =-00113".

Syn. — T. verticillatum, BAILEY. Microscopic Observations. Smithsonian Contributions, 1850.
Docidium verticillatum, RALFS, British Desmids, p. 218.
Pleurotienium verlicillatum, RABENHORST, Flora Enrop. Algar, Sect. III. p. 148.

Hob.— Rhode Island, New Jersey, Georgia, Florida ; Bailey. Saco Lake, (Dr. Lewis) Wood.

Snbcylindrical, but slightly narrowed at each end, and therefore somewhat fusiform, moderately
robust, 12-20 times longer than broad; lateral processes large, robust, with their apices
emarginate.
16 June, 1871.

122 FRESH-WATER A L G JK OF T II E UNITED STATES.

T. gracille, BAILEY.

T. cellulis subcj'lindricis, utroque fine vix angustatis, gracillimis, diametro 25-30 plo longi-
oribus ; processibus lateralibus brevibus, conicis.

Diam.— Cum process. TS8SW" = .008"; sine proc. T5f^" = .0006".

Syn — T. gracille, BAILEY, Smithsonian Contributions.

Docidium pristidse, HOBSON, Magazine Natural History, v. p. 168.
Pleurolsenium yracile, RABENUOKST, Flora Europ. Algar., Sect. III. p. 144.

Hab. — In iisdem cum antecedente locis.

Subcylindrical, scarcely narrowed at the ends, 25-30 times longer than broad ; lateral processes,
short, conical.

Genus SPIROT^NIA, BREB.

Cellulae rectae, cylindrical vel subfusiformes, saepe in muco gelatinoso aggregates, medio haud con-
strictss, utroque polo rotundatse vel acuminatae. Cytioplasma chlorophyllaceum in laruinis spiralibus
dispositum.

Cells straight, cylindrical or subfusiform, often aggregated in a gelatinous mucus, not constricted
in the middle, rounded or acuminate at each end. Chlorophyllous cytioplasm arranged in spiral
lamina.

Sp. bryophila, (BREB.) RABENHORST.

Sp. mimina, bryophila ; cellulis in gclatina matricali consociatis, oblongo-cylindricis, rectis vel
subcurvatis, bis vel ter longioribus quarn latis, utroque polo rotundatis ; lamina chlorophyl-
lacca singnla anfractu l-2£.

Z>tam.— 3^7" = • °0033" (0.00024"— .00029". R.)

Syn. — Spirotsenia bryophila, (BREB.) RABENUORST, Flora Europ. Algarum, Sect. III. p. 146.

Hab. — Prope Philadelphia ; Wood.

" (S. muscicola (De Bary)) Frond cylindrical two to four times as long as broad, ends rounded;
endochrome a single, broad, smoothly defined, widely wound spiral baud, its revolutions very
few (one or two}." (A.)

Remarks. — I found this beautiful little desmid on the North Pennsylvania Rail-
road, near Chelten Hills, growing amongst some mosses which were kept con-
stantly wet by overhanging dripping rocks. It formed little transparent masses of
almost colorless jelly looking much like drops of dew. It agrees well with the
descriptions of the European form, except that there were generally from 2-2|
turns of the spiral, and the cells exceed somewhat the measurements of Prof.
Rabenhorst. The cells are closely placed in the jelly.

Fig. 10, pi. 12, represents some plants of this species.

Sp. condensata, (BREB ) RABENHORST.

Sp. cellulis cylindraceis, rectis (vel leviter curvatis) octies vel decies longioribus quam latis,
utroque polo rotundatis; lamiuis chlorophyll, singulis, anfractibus subarctis (plerumque 8-12).

Diam.— 0.00075".

Syn. — Sp. condensata, (BREB.) RABENHORST, Flora Europ. Algarum, Sect. III. p. 146.

Hab. — Florida ; Rhode Island ; Bailey. Pennsylvania ; Wood.

Frond cylindrical, two to four times as long as broad, ends rounded ; endochrome a single,
broad, closely wound spiral band, its revolutions numerous. L. ?&*"• Br. -HTIB"- Archer.
Pritchard's Infusoria.

FRBSH-W A TK K A !,<;.!: Of fHl I'MTKD STATUS. 123

/.'- ;/»<i/7.-x. — The only specimens that I have seen of this species were found in a
spring in the Philadelphia Cit\ Park, near Colmnbiii bridge.
Fig. 11, pi. 1'2, was drawn from one of these specimens.

(u nns Sl'ILl-KO/OS.MA, CoBDA.

('(•Hulas coniproMi-, meilio transvi-rsitn profundc incisse, itnquc bilobattc, in quoque lobo massa
clili)r(>|ihyllosa quadriradiata iiiicleuni amylaoeum inTolvente pried i to;, in filum planum Ueniiformem
i.-tlimis i-oiijuiirtii'. Xvgosporas globosse ?el ovales, glabra. (II.)

n. — Jat/i iHoxira, Krz.

• Odontellx, «;«•<•., KHRB.
Ifthmitf, Kj)ec., MKNKO.
Spondylogium, Hufcu.

Cells compressed, transversely very deeply incised in the centre and therefore bilobate, furnished
in each lube with a quadriradiatc mass of chlorophyl surrounding a starch grain, conjoined laterally
l.v istlniiuses in a tteuiform fascia.

1,'nnarfa. — I have never found any species of this genus in America. Professor
Bailey lias, however, detected the following: —

Kpli. r\< avalniii, RALFS.

Sph. plcniinqne nudura (sine tubo mucoso) sph. vertebratnm multo minns ; cellulis diametro
duplo-longioribus, medio excavato-constrictis, a latere ellipticis utroque polo rotundatis; lobis
bn-vibus truncato-rotundatis, laevibus vel granulato-dcnticulatis ; isthmis biuis parvis rerru-
ciforniibua ; zygosporis pleruraque ovatis. (R )

Lalil. filor. 0.00047"— 0 00032". (R.)

Syn. — Sph. excavatum, RALFS, British Dcsmids, p. 67.

Hab. — Florida; Georgia; South Carolina; Rhode Island ; Bailey.

"Joints longer than broad, having a deep sinns on both sides and two sessile glands at each
margin at their junction, veryminnte, seldom more than twenty-five joints in the filament,
\\liich is fragile, and finally separates into single joints ; at their junction, in the front view
are two minute glands or processes, situated one near each angle, and nearly invisible before
tli<> escape of the endochrome. The joints are nearly twice as long as broad and much con-
stricted in the middle ; the constriction is like an excavation or broad sinus on each Bide, so
that the margins of the filaments appear sinuated. The endochrome is pule bluish-green
with minute scattered granules. The transverse view is oblong with four sessile glands, two
on each side and situated near the ends." — Ralfs' Brit. Desm., p 67.

Sph. pulchriim, BAILKT.

Sph. cellulis oblongo-quadrangnlaribas, diametro dnplo-brevioribns, acute incisis, arete con-
nexis; lobis oblongis rectis, apice rotundatis; isthmis nullis, vagina mucosa ampla dis-
ncta. (R.)

Syn. — S. pulchrum, BAILEY. RALTS, British Desmid., p. 209 (Cum icone).
Sab. — West Point, New York ; Princeton, New Jersey ; BAILEY.

" Joints twice as broad as long, deeply incised on each side ; junction margins straight, con-
nected by short bands."

Remark. — " Prof. Bailey informs me that this species is twice as large as Sph.
i-t >•/- Iratum" RALFS.

1-24 FRESH -WATER ALG^E OF THE UNITED STATES.

Sph. serratum, BAILEY.

Sph. cellulis diametro duplo brevioribus, profunde et acute excisis, arete conjunctis ; lobis
utrinque cuspidatis, paulum conniventibus ; isthmis nullis ; vagina crassa. (R.)

gyn Sph. serratum, BAILEY, Micros. Observation. Smithsonian Contributions, 1850. Cum

icone.
Hob. — South Carolina ; Georgia ; Florida ; Bailey.

"Joints broader than long, deeply notched or divided into two transverse portions with acute
projecting ends, which give a serrated outline to the chain." Bailey.

Genus HYALOTHECA.

Cellulee brevse, cylindricae, medio non profunde constrictae, a latere disciformes, in fila confervacea
sine isthmis arete conjunctae et vagina mucosa ampla achroa inclusse. Massa chlorophyllosa in
quaque semicellula 4-8, 5-10 radiata.

Cells short, cylindrical, not profoundly constricted in the middle, disciform in the end view,
closely united without intervening isthmuses into a confervoid filament, which is inclosed in an
ample mucous sheath. Chlorophyl masses in each cell 4-8, 5-10 radiates.

H. disilliens, (SMITH) BREB.

H. fasciis praelongis ; cellulis oblongo-quadrangularibus, diametro sub-duplo brevioribus, inter-
dum ante divisionem subaequalibus, angulis nounihil rotundatis, plerumque medio obsolete
constrictis, saepe baud constrictis.

Diam — 0.00089"— 0.00098". (R.)

Syn. — H. disilliens, (SMITH) BREB. RABENHORST, Flora Europ. Algarum, Sect. III. p. 152.

Hob. — South Carolina ; Florida ; Rhode Island ; BAILEY. Rhode Island (S. T. Olney),
Thwaites. Pennsylvania ; Wood.

Filament very long, cells oblong, quadrangular, about one-half as long as broad, sometimes before
division as long as broad, angles somewhat rounded, mostly obsoletely constricted in the
middle, often not constricted.

Hemarks. — The specimens which I have identified as H. disilliens, agree with
the various figures and descriptions of the European form, in every thing except
that in many cases there is no constriction whatever in the centre of the cell, and
when the constriction does exist, it is never so pronounced, as some of the descrip-
tions indicated. The plant is very common about Philadelphia, growing in springs
and ditches.

Fig. 12, pi. 12, represents this part of a filament of this species.

H. mucosa, (MERT.) EHRB.

H. fasciis confervaceis, minus fragilibus ; cellulis quadrangularibus, diametro aequalibus vel
subaequalibus, medio non constrictis, ad utrumque finem (annuliformi-bicarinatis) bidentatis.
(R.) Species mihi ignota.

Diam.— 0.00073"— 0.0008". (R.)

Syn. — Gloeoprium mucosum, HASSAL, Fresh Water Algae, p. 346.

H. mucosa, (MERT.) EHRB. RABENHORST, Flora Europ. Algarum, Sect. III. p. 132.

Hob.— Rhode Island ; (S. T. Olney) Thwaites.

Filament scarcely fragile, mucous sheath very broad ; joints about as broad as long, not con-
stricted, but having at one of the ends a minute bidentate projection on each margin, the

FRESH-WATER ALG.E OF THE UNITED STATES. 125

adjoining ends of the next joint being similar, these projections being produced by an annular
grooved rim. L. „"**"— GOO", li. TiW'— rWi"- (Archer)

Genus BAMBUS1NA.

Cellule oblongo-orculiformes, in filamonta articulata nodosa dense conjunct®, medio vittu trans-
VIT-:I nirinis duiilws annulifnriniluis liniitiita instructs, itaque superue et infcrue bideutaUe, fronte
circulurt'.s, supra et infru (lento union proiuiuente. (R.)

Cells oblong-orculiforiu, densely united into an articulate nodoso filament, surrounded by two
median bonds.

II. IIr« l>i«.-oiiii, KTZ.

li. lilumriitis njjdoso-articulatis ; cellulis diametro duplo long! ori bus. (R.)

Diam.— 0.00077"— 0.00092". (R.)

Syn. — B. Brtbissanii, KUTZINO. RABENHOBBT, Flora Europ., Algarnm, Sect III. p. 152.

Uab. — South Carolina. (Ravenel) Wood. South Carolina; Georgia ; Florida ; Rhode Island.
Bailey.

(Didymopriura Borreri, (Ralfs)) Joints inflated, barrel-shaped, longer than broad, without a
thiokened border at their junction; angles bicrenate, crenatures rounded; transverse view
circular; sporangium elliptic, formed within the (for some time) persistent extensions from
the conjugating joints, which do not previously break np into single joints, but couple, still
united in the filament, in a confused or zigzag manner, some of the joints remaining unchanged.
L. j4ff". B. T^".

Remarks. — The specimens which I have seen agree well with the descriptions,
:»t in regard to size; some of the cells which I measured were more than
T^Vff °f an iuck in diameter.

Genus DIDYMOPRIUM.

Cellnlte oblongo-ellipticse, modice compressse, ancipitcs, angulis porrcctis inciso-bidentatis, in fila-
menta articulata biconvexa et torts sine istluuo arete conjunctsc, et in vagina murosa indusie.
' plasma cbloropbyllosa cellulse a fronte cruciatim disposita, cujus crura e lamiuis duabus paric-
talibus divergentibns granum amylaceum uuicum involventibus formantur.

Cells oblong-elliptical, moderately compressed, two-edged, with the produced angles inciscly-biden-
tate, closely united into a biconvex and twisted filament, which is inclosed in a mucoid sheath, cytio-
plasm so placed as to be cruciate when viewed from the front (end), each crus composed of two
parietal divergent lamina, each of which contains a single starch granule.

D. Grevillii, KTZ.

D. cellulis oblongis diametro duplo brevioribus, saturate viridibus. (R.)
Dwm.0.0024"— 0.0031." (R.)

Syn. — D. Orevillii, KVTZIXO. RABKNHORST, Flora Europ. Algarnm, Sect. III. p. 153.
Sab. — Georgia, South Carolina ; Bailey. Pennsylvania ; Wood.

Sheath distinct ; joints broader than long, with a thickened border at their junction ; angles
bidentate ; teeth angular; transverse view broadly elliptic. Sporangium orbicular, formed
within one of the two conjugating joints, the endochrome passing over from one by a narrow
connecting tube produced between the otherwise, but little altered, broken-up single joints. (A.)

Remark. — Fig. 13, pi. 12, represents the end view of a broken filament of this
species.

126 FRESH-WATER ALG^E OF THE UNITED STATES.

Genus DESMIDIUM.

Cellulae oblongo-tabulares, medio inciso-bilobae, lobis integris vel irregulariter dentatis, a fronte
tri- vel quadrangulares, angulis obtuse rotundatis, in fila angulosa, praglonga, torta, fragiles arete
connex*. Massa ehloropbyllosa (a cellulse fronte visa) 3-4 radiata ; quisque radius e lamiuis
duabus lateralibus divergentibus compositus. Zygosporae globosa? vel oblongae, glabrje.

Cells oblong-tabular, medianly incisely bilobate, with the lobes entire or irregularly dentate, as
seen from the front tri- or quadrangular, and having the angles obtusely rounded, closely conjoined
into an angular, fragile, twisted filament. Chlorophyl (as seen from the front) 3-4 radiate ; each
radius composed of two lateral divergent lamina ; zygospores globose or oblong, smooth.

I>. Swartzii, Ao.

D. cellulis a fronte triangularibus, diametro 2-3 plo brevioribus. (R.)

Diam.— 0.00096"— 0.00189". (R.)

Syn. — D. Sivartzii, AGARDH. RABENHORST, Flora Europ. Algarum, Sect. III. p. 154.

Eab. — In aquis quietis, Atlantic States. Florida; Georgia; South Carolina ; Rhode Island ;
Bailey. New York; Edwards. Pennsylvania ; Wood.

Filament triangular, equal, with a single longitudinal waved, dark line, formed by the third
angle; joints in front view somewhat quadrangular, broader than long, with two slightly
angular crenatures on each lateral margin, united at the whole of their end margins by a
thickened border, end view triangular; endochrome three-rayed. Archer. Pritchard's Infu-
soria.

D. quadrangnlatum, KTZ.

D. quadrangulare, cellulis oblongo-quadrangularibus, diametro 2-3 plo brevioribus, lobis denti-
formibus obtusis, a fronte sinuato-quadrangularibus, angulis late rotundatis, lateralibus exca-
vatis. (R.) Species mihi ignota.

Diam.— 0.0021"— 0.0029".

Syn. — D. quadrangulatum, KUTZINQ. RABENHORST, Flora Europ. Algarnm, Sect. Ill, p. 155.

Filament quadrangular, varying in breadth from its twisting, having two longitudinal waved
lines ; joints in f. v. broader than long, with two somewhat rounded crenatures on each lateral
margin, united by the whole of their end margins ; e. v. quadrangular ; endochrome four
rayed. L. T5»4?". B. ri»"-*h" (Archer)

D. aptogo ilium, BREB.

D. fasciis plerumque subbrevibns, nudis, perforatis; cellulis quadrangularibns, inciso-bilobis,
lateralibus concavis, lobis crenatis, a fronte triangularibus (nonnunquam biangularibus), ceutro
concavo, angulis rotundatis protensis isthmum brevissimum triplicem efficientibus. (R.)
Species mihi ignota.

Diam.— 0.00089"— 0.00147". (R.)

Syn. — Aptogonium desmidiwm, RALPS, British Desmids.

D. aptogonium, BREBISSON. RABENHORST, Flora Europ. Algarum, Sect. III. p. 155.

Hob. — Georgia; South Carolina; Bailey.

Joints in f. v. quadrangular, broader than long, with two rounded crenatures on each lateral
margin, united at the outer portion only of each end margin by mutual projections, thus pro-
ducing intervening central oval foramina. Archer.

Genus APTOGONIUM, RALFS.

Cellulse 3-4 angnlares vel compressse, non constrictee ; margine lateral! plants vel crenatse, io
fascias peiforato-articulatas, angulares conjunctae. (R.)

FKKSII-\V AT i: II ALO.« OF T II K U X I T K I> SI ATI: S. 127

Cells 3-4 angular or com pressed, not constricted, their lateral margins plain or crenatc, conjoined

into angular jterforutrly articulate fascia.

A. liailfvi, KALFB.

" Filament not crcnated ; joints aboat equal in length and breadth.

Syn. — Odontellaf tridentata, BAILEY. In lit. cum icone (1846).

Hob.— Worden's Pond, Rhode Island; near Princeton, New Jersey, with sporangia," Bailey.

" Filament triangular; joints excavated at their junction like those of Aptogonum desinidium-
Tin- joints an; not bicrcnate, hence the margins of the filament are entire, a character which
distinguishes it from that species. The cud view is triangular, with rounded angles." HALTS,
lirtiish. Dcsmidicse, p. 208.

Genus COSMARIUM, (CoBDA)

Cellulffi oblonge, oblongo-cylindricae, cllipticie, vcl orbicolarcs, medio transverse plus minus con-
strict, utroque polo obtusie vel rotundatffi et Integra, a vertice elliptic®. Zygosporac muricaUe vel
Terrucosse.

Culls oblong cylindrical, elliptical or orbicular, more or less transversely constricted in the middle,
olitu.se or rounded, and entire at each cud, viewed from the end elliptical. Zygospore warty or
muricate.

1. Cellulee sejunctse.

1. Cells separate.

a. Cellulte ellipticae, vel subelliplicse ; semiccllulse medio nonventricosa.

a. Cells elliptical or subelliplical ; semicells medianly not ventricose.

* Cytiodermate granuloso vel verruculoso.

* Cytioderm granular or warty.

C. iiinrsarilifcriini, (TUBP.) MENOR.

C. paulo longius quam latum, profunde constrictnm ; sinn amplo, vel modice angusto, intcrdiim
intra cxcarato; semiccllnlis semiorbicularibus, rcl rcniformibus vel nonuihil quadrangulis
dorso plcrumque late rotundatis ; cytiodennate verruculoso.

Diam.— Max. , -fa" = .0006" (0.00073"— 0.0012". R.)

Sijn. — Euastrum margaritiferum, EHRB. BAILEY, Silliraan's Journal, 1841.

Cosmarium margaritiferum (TuBPix), MENEGIIINI. KABENHORST, Flora Europ. Algar.,
Sect III. p. 157.

Hab. — In aqnis quietis, South Carolina ; Florida ; Mexico ; Bailey. Pennsylvania, Wood.

A little longer than broad, profoundly constricted ; sinus ample or moderately narrow, some-
times widened on the inside; semicells seniiorbicular, reniform or somewhat quadrangular ;
dorsum mostly broadly rounded ; cytioderm warty.

Remarks. — I have found a form of this species growing in the vicinity of this
rity, which I at first was disposed to look upon as distinct, but which, in truth,
grades into the typical form. In it the cells are almost quadrangular, often with
their basal angles acute. The margin of the frond in C. margaritiferum, as it
occurs with us, is sometimes distinctly serrate or, more correctly, crenulate from
the presence of the granulations. The granules are larger than in C. botrytis, but
smaller than in C. tetrophthalmum. When viewed laterally the semi-cells are
roundish, or nearly so (according to Ralfs' elliptical), and closely connected by

128 FRESH-WATER ALG^E OF THE UNITED STATES.

a very broad neck. I have never seen the sporangia, but, according to Mr. Ralfs,
they are orbicular and inclosed in a granulated cell.

Fig. 8, pi. 21 , represents half of an empty frond of this species magnified 750
diameters; and fig. 21, pi. xii., a frond densely filled with living endochrome

C. Botrytis, (BORY) MENGH.

C. late ovale, profunde constrictum, diametro plerumque l£ — 2 plo longius ; sinu angusto,
lineare ; semicellulis nonnihil triangularibus, apice iiiterdum truncatis, interdimi late rotun-
datis ; cytiodermate minute granulate.

Diam.— 5^ff" = 0.0019" (0.0014"— 0.0023"). (R.)

Syn. — C. Botrytis, (BORY) MENEGHENI. RABENHORST, Flora Europ. Algarum, Sect. III. p.
158.

ITab. — Pennsylvania, Wood.

C. broadly oval, profoundly constricted, l£-2 times longer than broad; sinus narrow, linear;
semicells somewhat triangular, with the apex sometimes truncate, sometimes broadly rounded ;
cytioderm minutely granulate.

Remarks. — In this species the semicells, as viewed transversely, are broadly
elliptic in outline. The end view presents a longer narrower ellipse. Their out-
line, when seen from the front, varies remarkably from that of a very broad semi-
oval to distinctly triangular with a truncate apex. The granules are small and
arranged regularly, sometimes they are very obscure. I have often seen the endo-
chrome so arranged as to leave a large pyriform central vacuole in each cell, com-
municating with the narrow margin between it and the cell-wall. This vacuole
was apparently filled with a transparent fluid, in which were minute granules in
immense numbers, in constant active motion circling among one another and pass-
ing out, into and along the marginal connecting space. According to Ralfs, the
sporangia of this species are large (jj^")> with branched spines.

Fig. 5, pi. 21, represents an empty frond of this species; 5 a, outlines of semi-
cells to show the variations, and fig. 14, pi. 12, represents a frond crowded with
endochrome, magnified 460 diameters.

C. ovale, RALFS.

C. magnum, ovale, compressum, profunde constrictum, diametro subduplo longius, ambitu inte-
gerrimum vel crenatum, a vertice late ellipticum ; semicellulis basi paulo latioribus quam
longis, triangulo-rotundatis, disco punctatis, margiue verrucis margaritaceis achrois hyalinis
in series 4 ordinatis. (R.)

Diam.— Long. 0.0053"— 0.0067". Lat. plerumque 0.0041". (R.)

Syn. — C. ovale, RALFS, British Desmidiese, p. 98.

Bab. — South Carolina ; Rhode Island ; Bailey. Cobble Mountain, Pa. (Lewis) Wood.

Frond very large, elliptic, nearly twice as long as broad, constriction very deep, linear; seg-
ments somewhat broader than long, somewhat triangular, rounded at ends, rough near the
margin, with a band of large pearly granules, producing a dentate appearance, the disc punc-
tate; e. v. elliptic. (A.)

C. Br6bissonii, MENEOH.

C. paulo longius quam latum ; semicellulis semicircularibus, diametro paulo longioribus, angulis
inferioribus obtusis approximatis, ventre modice concavis subplanis, dorso latissime rotun-
datis; cytiodermate muricato, muricibus conicis in ordinibus regularibus collocatis. (R.)

I K KS1I-U ATKK A I. «;.!•: OF THE UNITED STATES. 129

l, 0.0019"— 0.00-Ji' <i: )

ii. — ('. Hr-i.i.-fiitii, MKNUIIIIKM. KAHKNIIORST, Flora Europ. Algarum, Sect. III. p. 158.
7/,//,._Whit,. Mountain-, V n llaui|>.-hiiv, (I»r. F. W. Lewis) Wood.

From! somewhat longer than broad, constriction deep, linear; segments scmiorbicular, rough
all over, with Mmirwhut elongate conical scattered pearly granules; c. v. elliptic. (A )

A'///-?//.. — 1 •'!:,'. (i, pi. 21, represents an empty frond of this species, magnified
1.~>l) diainrti T-.

<'. Hiiborbiculare, u ••• .•

C. parviiiM, suliorlu'culare, paalo longius quam latnm, cum margine enorraiter crenato vel
rrt-nato-undulato; semiccllulis a latcro orbicularibus, a vertice elliptici»; sinu extrorsum
august issimt) sod introrsum nonnihil excavato ; cytioderraate crasso, sparse verruculoso;
^ranulis in semicellulis singulis subdistantibus et in scriebus clongatig, duabus (interduni
unica) externis curvatis, et in scriebus duabus internid brcvibus et rcctis.

/>iam._Lat. T,'0V' - .0012" ; lat. T1'0V - -0013".
,syi. — C. orbiculare, WOOD, Proceed. Acad. Nat Sc. 1870.
//,//>. — In lacn " Saco," New Hampshire, (Lewis.)

Small, suborbicular, a very little longer than broad, with the margin irregularly crenate, or
n-1-nate undulate ; semicells from the side orbicular, from the vertex elliptical ; sinus very
narrow, but within somewhat excavated ; cytioderm thick, sparsely coarsely granulated ;
irnmiili's subdistant, in each cell arranged in one or two curved marginal scries and in a cen-
tral group of two or three short rows.

/,'- ,<//•/•-. — The arrangement of the granules in this desmid is peculiar, one, of

soinrtimi •> two rows of large obtuse pearly granules are placed at rather wide in-

N aloiii; the whole outer margin, and then in the centre of each semicell is a

irnmp of two or three, or even more short straight rows of three or four similar

nit rather smaller granules. The isthmus is rather broad and short; sometimes it

on it one or two granules.

1 -'ig. 9, pi. 21, represents an empty frond of this species, magnified 750 diame-
ters ; 9 a, the outline of the end view of the same.

4 . trtroplitlinlituim, (KT/ ) P.KEB

C. tortiam partcm circa longins quam latum, profunde constrictnm ; sinu angnsto, plerumque
sublineare ; ambitu obtuse crenato; semicellulis nonnihil scmicircularibus, venire subplanip,
dorso rotundatis; cytiodermato verruculoso; verruculis tnagnis, obtusis, subordinatim dispo-
sitis.

Syn.— C. tetrophthalmum, (KtTZiNo), BB£BISSON. RABENHORST, Flora Enrop. Algarum, Sect.
III. p. 159.

Hab.— New Jersey ; Wood.

About one-third longer than broad, deeply constricted ; sinus narrow, mostly snblinear ; margin
obtusely crcnated ; seraicells somewhat semicircular, belly nearly even, dorsnm rounded ;
cytioderm warty ; prominences large, obtuse, arranged somewhat regularly.

Remarks. — The only specimens I have seen, and I believe the only ones hitherto

17 July. 1871

130 FRESH- WATER ALGJi OF THE UNITED STATES.

found on the continent, were collected by myself in " Shepherd's Mill Pond," near
Bridgeton, Cumberland County, New Jersey.

Fig. 7 a, pi. 21, represents the outline of a frond magnified 460 diameters.

C. amcennm, BREB.

C. mediocre, oblongum cylindricum, levitcr compressum, diametro duplo fere triplove longius,
utroque polo rotundatum, medio profunde constrietum, sinu angusto, linear!, nmbitu granulis
margaritaceis achrois obsessum, a vertice ellipticum; seraioellulis oblongo-rotundatis, dor.so
alte convexis, lateribus vero rectis parallelis, angulis inferioribus rectis et subacutis ; cytio-
dermate granuloso-vcrrucoso, verrucis hyaliuis in series regulares dispositis. (11.) Species
mihi ignota.

Long. 0.0017"— 0.101G"; lat. O.OOOSt". (R.)

Syn — C. amoenum, BREBISSON. RABENIIORST, Flora Enrop. Algar., Sect. III. p. 159.

Hab.— Florida ; Bailey. Rhode Island (S. T. Olney); Thwaites.

Frond twice as long as broad, sides parallel, ends rounded, constriction deep, linear ; segments
rough with crowded obtuse papilla-like pearly granules ; s. v. much compressed, about thrice
as long as broad ; e. v. elliptic. (A.)

** Cytiodermate glabro.
** Cytioderm smooth.

C. Cucumis, CORDA.

C. ovale ellipticum, utroque polo late rotundatum, tertiam partem vel duplo longius quam latum,
profunde constrietum ; siuu linear! ; semicellulis angulis inferioribus rotundatis, cytioderinate
glabro, hand punctato.

Diam.— Max. long. ^5" = 0.0026" ; lat. 7' g5" = .0019".

Syn. — C. Cucumis, CORDA. RABENHORST, Flora Europ. Algarum, Sect. III. p. 161.

Hab. — South Carolina ; Georgia; Florida; Bailey. Pennsylvania; Wood. Saco Lake, (Lewis.)

Oval or elliptic, at each end broadly rounded, one-third to twice as long as broad, profoundly
constricted; sinus linear; semicells with their inferior angles rounded ; cytiodurm smooth,
not punctate.

Remarlcs. — This species is very abundant around Philadelphia. The semicells
generally each contain two large globular masses placed near the median line,
which are sometimes hidden by the crowded endochrome.

Figs. 15, 15 a, pi. 12, represent this species with their endochrome in different
conditions; 15 b, represents a monstrous frond, which had attempted to divide, but
had not succeeded in so doing.

C. depressum, BAILEY.

" Elliptical, binate, division in the plane of the longest axis. Segments entire, nearly twice as

long as broad, rounded above, very much flattened at base.
Hab. — Lakes in Florida.

This species resembles G. bioculatum, BREB. ; but the segments are much closer together, and
are angular, not rounded at the basal extremities." BAILEY. Microscopical Observations.
Smithsonian Contributions.

C. pyramidatiim, BREB.

C. mediocre, ovale vel subovale, utroque polo truncatum, medio profunde constrietum, duplo

FKKSH-WATi: K A Mi.K OK T1IK I' N 1 T V. 1> STATi

fere lon^ius i|ii:iin lutuin ; M'liiicrllulis lireviter pyriiinidiitis, angiiliH inferiiirilnis rotumlatis,
apiee (dur-uj iinulo triincatis modo rolumlali.-, a \criico laic clliplicis ; cytiodcriimtc punc-
tilio vel siibtilis.-iiiic jrraniilato. ( I! )

I _- MMl"— 4MS7". I.at. iimx. 0.0026".

,S'y/i. — C. pyramidal urn, HKEIIISSH.N. KAIIKMIORST, Flora Europ. Algarum, Sect. III. p. 1C2.

Huh. — (Jeor^ia ; Florida; Bailey. Pennsylvania ; Wood.

Frniid searccly twice as loutf as broad, subnval ; constriction deep, linear; segments pyramidal,
rounded at basal anirles, somewhat truncate at llie ends, punctate ; e. v. broadly elliptic. (A.)

Remark. — Fig. 14, pi. 13, is a drawing of this species.

C. I»io< ulaliiiii. I'.IIKII.

C. parviicr, eirciirr lam Inngum qnnm laiuni vel paulo Inngiun, profundc conslrictum, sinu ex-
trorsuia ainpliato ; scraiccllulis diainetro duplo latiorilms, elliptieo-prope lie.\a<r<niis angulis
obtuse rotundatis, integerriaiis aut Icvissimo crcnulutis ; cytiodermate laevi vel sublilissime
punclato. (11.) Species mihi ignola.

Long. 0.00069". Lat O.OOOC6". (II.)

Syn. — C. bioculatum, BREBISSON. RAIIENIIORST, Flora Europ. Algarum, Sect. III. p. 1C3.

7/(;/;._Rhodc Island, (S. T. Olney) Thwaites.

Frond minute, about as long as broad, constriction deep, producing a gnping notch at each
siile ; segments about twice as broad as long, elliptic, smooth; s. v. compressed s. v. elliptic.
Sporangium orbicular with conical spines L. -H'JB" ; B. TT'TC"- (A-)

C. ITIenr^liriiii, HKEB.

C. parvum, tain longum quam latum, modo paulo-longius, modo paulo-brcvius, profunde eon-
striclum, sinu linear!, cxtrorsum non amplialo ; sciniccllulis subqnadratis, Icvitcr sinuato-
hexagonis ; angulis rotundatis, cytiodermate lev! vel subtillissimc punctato. (11.)

Long. ,V"~fV"= 0.00103"— 0.0013"; lat. jJ/'-^J,'" - 0.00081"— 0.00089". (R.)
,s'y,i. — C. Meneghenii, BREBISSON. RABENUURST, Flora Europ. Algar., Sect. III. p. 163.
Hab. — Pennsylvania ; Wood.

Frmid very minute, rather longer than broad, constriction linear; segments subqnadratc, bicre-
ua te at the sides and ends, smooth ; e. v. elliptic. (A.)

HI mark. — Fig. 18, pi. 12, represents a frond of this species, magnified 750
diameters.

C. crenatum, RALPS.

C. oblongum, tertian) partem circa longins quara latum, profunde constrictum, sinu linear! an-
gusto ; semicellnlis e basi lata subsemicircularibns, dorso plus minus depressis ycl truncatis,
anibitu crenatis vel regulariter undulato crenatis, crenis 10-14; cytiodermate punctato. (R.)
Species mihi ignota.

Long. 0.0021"— 0.0023"; lat. 0.0015". (R.)

Syn. — C. crenatum, RAI.FS, British Desmidiea:, p. 96.

Hob— Rhode Island ; (S. T. Olney) Thwaites.

Frond slightly longer than broad, constriction linear ; segments semiorbicular, ends and sides
broadly rounded, crenate or minutely undulate at margin ; c. v. elliptic. Sporangium orbi-
cular, spiuoas ; spines elongate, slender, swollen at the base and divided at the apes. L. 4 1 »" ;

132 FRESH-WATER A L G .E OF THE UNITED STATES.

C. undulatuin, CORDA.

C. submediocre, oblongum, diametro subduplo longius, utroque polo late rotundatum, ambitu
leviter sinuato-undulatum, profunde constrictum, sinu linear! extrorsum paullum ampliato ;
semicellulis semiorbicularibus, et dorso et lateribus late rotundatis, margine undulato-crenatis,
crenis 9, sublatis ; cytiodermate leevi ; zygosporis sphsericis spinis elongatis, apice bi-tri-fldis
obsitis. (R.) Species mihi ignota.

Long. 0.0024". Lat. 0.0017". (R.)

Syn. — C. undulatum, CORDA. RABENHORST, Flora Europ. Algaram, Sect. III. p. 165.

Hob. — South Carolina ; Rhode Island ; Bailey.

Frond rather larger than that of C. crenatum, slightly longer than broad, constrictions linear;
segments semiorbicular, ends and sides broadly rounded, crenate or minutely undulate at the
margin ; e. v. elliptic. Sporangium orbicular, spinous ; spines elongate, slender, swollen at
the base and divided at the apex. (A.)

b. Semicellulee medio-ventricoso inflatse.

b. Semicells medianly ventricose.

* Cytiodermate Ixwi.

* Cytioderm smooth.

C. sublobatum, (BREB.) ARCHER.

C. parvum, oblongo subquadratum, diametro subdaplo longius, sinu angusto linear! ; semicel-
lulis subquadratis, e basi dilatata ad verticem sensim angustatis, angiilis et inferioribus et
superioribus rotundatis, dorso late truncatis lateribusque leviter sinuatis ; cytiodermate
Iffivissimo. (R.)

Long. 0.001t9"— 0.00196". Lat. max. 0.0015"— 0.00157". (R.)

Syn. — C. sublobatum, (BREBISSON) ARCHER. Pritchard's Infusoria, p. 731.

Nab. — Georgia; Florida; Rhode Island ; Bailey.

Frond scarcely twice as long as broad, oblong ; constriction linear, segments subquadrate,
somewhat wider at the base, lateral and end margins slightly concave, smooth and trans-
verse vein cruciform. (A.)

* * Cytiodermale granulato.

* * Cytioderm granulate.

C. ornatum, RALFS.

C. parvum, plerumque tarn longnm quam latum ; semicellulis reniformibus, diametro duplo
longioribus, angulis inferioribus una cum lateribus rotundatis; dorso sub-proclucto late trun-
catis; cytiodermate granulato-verruculoso ; zygosporis longe spinosis, spiuis elongatis apicc
furcatis. (R.) Species mihi ignota.

Long. 0.0016"— 0.0015". Lat. 0.0016". (R.)

Syn. — C. ornatum, RALFS, British Desmidiese, p. 104.

Hob.— Rhode Island; (S. T. Olney) Thwaites.

Frond in f. v. about as long as broad, constriction deep, linear ; segments semiorbicnlar or
subreniform, with a central truncate projection at the ends produced by the continuation of a
central inflation, rough towards the margin and on the inflation with pearly granules ; e. v.
with a rounded lobe on each side. Sporangium orbicular, spinous ; spines elongated, dilated
at the base and slightly divided at the extremity, ^3". (Archer.)

€. commissiirale, (BREB.)

C. minutum, fere dimidio latins quam longum, profundissime constrictum, sinu amplo basi ex-
cavato ; semicellulis anguste reniformibus, diametro paene triplo longioribus, leviter incurvis,

FHKS1I-U ATKK ALG^I OF THE UNITED STATES. 133

rotundutis, dorso triiiu-ato-rntundaiis, margine crenulato-dentatis, a dorso oblongis,
mediu ventrifo.-U, uinMjuc polo plus miim* tuiuidis ; cyliuderuiate grauulato margaritifuro.
(B

Long. 0.0010"— 0.0012." Lat. 0.0013"— 0.0015". (R.)

,Syn. — C. comniitsiiiiriili-, l!iu;iii.ssu.\. RAUK.NHORBT, Flora Europ. Algarura, Sect. III. p. 170.

Hab — In lacu. While Mountains, New Hampshire ; (Dr. F. W. Lewis)

Frond small, in f. v. one-third broader than long; constriction very deep, rounded; segments
iiarrow-reiiifortn, with a central, somewhat truncate projection, produced by the continuation
of the cent nil inflation, rough on the inflation and on the extremities, with somewhat large
pearly granules, e. v. three times longer than broad, constricted between the central inflation
and the rounded extremities. Sporangium as in C. ornalum. (A.)

Remark*. — I have seen but a single specimen of this species which differed from
the typical form, in having the sinus very narrow in its outer portion, and in being
shorter.

Fig. 1(5, pi. 13, represents the frond of this specimen, magnified 750 diameters.

C. < ;rlalimi. RALFS.

C. suborbicularc, profande constrictum ; sinu angustissimo linear! ; semicellnlis inciso-crenatis,
angnlis rotundatis, a vertice medio nonuihil inflatis; cytiodenuate granulato, granulis in
series regulariter circulares positis.

Diam.— Long. T8VW = -0017". Lat. ^^ = -0014".

Syn. — C. culalum, RALFS, British Desmidieaa, p. 103.

llab. — In Btagnis prope Aiken, South Carolina. (Ravenel.)

Suborbicular, profoundly constricted ; sinus very narrow, linear ; semicells inciso-crenate,
angles rounded, when seen from the end somewhat inflated in the middle ; cytioderm granu-
late, granules placed in circular series.

Remarks. — This species was collected by Prof. Ravenel in a quiet ditch near
Aiken, South Carolina, sparsely scattered amidst innumerable diatoms and desmids.
The number of the crcnations appears to vary. In the few individuals I have seen
there were six end ones besides the two very broad basal ones, if the latter can be
called crcnaturrs. Ralfs gives six as the total number, and yet every one of his
figures has many more. So I think the number a character of but little import-
ance. The circular arrangement of the granules is not so positive and regular in
the specimens I have seen, as is represented in the figure of Ralfs, otherwise the
agreement is perfect.

C. Broomei, TIIWAITES.

C. subparvum, plcrumque tarn lonpum quam latum, nonnnnqnam paulo longins, obtuse qnad-
rangnlare, profnndc constrictum, sinu angustissimo linear! ; gcmicellulis oblongo-quadrangulis,
diametro duplo longioribns, angnlis et inferioribns et snperioribus obtuse rotundatis, venire
snbplanis, dorso latissime trnncatis et saepius leniter retusis vel plane convexis; cytioder-
mate granulato-margaritaceo, granulis in seriebus snbrectis collocatis. (R.)

Long. 0.00194"— 0.0022". Lat max. .002", thick .0015".

Syn. — C. Eroomei, THWAITM. RALFS, British Desmidieoe, p. 103.

Hab. — Georgia ; Bailey. Prope Philadelphia ; Wood.

134 FRESH-WATER ALG^E OF THE UNITED STATES.

Frond in f. v. about as long as broad, constriction deep, linear; segments quadrilateral, ends
straight, angles rounded, rough all over with minute granules; e. v. twice as long as broad,
slightly inflated at the middle and rounded at the ends. Sporangium orbicular, smooth. (A.)

Remarks. — The only specimens which I have seen were found in a brick-pond
below the city in the month of June. They agree well with the descriptions, ex-
cepting in that I should describe their central inflation as pronounced. The sinuses
also are ampliate or hollowed out within. The granulations are quite large, and
are arranged somewhat irregularly in rows.

Fig. 15, pi. 13, is a view of the front of the frond magnified 460 diameters;
fig. 10, pi. 21, the outline of the lateral view.

c. Cellulae fusiformes, cylindricae vel ovules, in medio leviter conslriclse.

c. Cells fusiform, cylindrical, or oval, lightly constricted in the middle.

C. Thwaitesii, RALFS.

C. mediocre, diametro bi-triplo longius, fusiformi-cylindraceum, medio leviter constrictum, am-
bitu integerrimum, utroque polo rotundatum ; semicellulis e cylindraceo subconicis, e mcdio
in apicem sensim sensimque (sed modice) atteuuatum; cytiodermate Isevi vel indistincte punc-
tato. (R.) Species mihi ignota.

Long. 0.00267"— 0.00287". Lat. max. 0.0012". (R.)
Syn. — 0. Thwaitesii, RALFS, British Desmidieae, p. 109.
Hob. — Florida ; Bailey.

Frond in f. v. two or three times longer than broad ; constriction a very shallow groove ; seg-
ments subcylindrical, with rounded ends ; endochrome scattered ; e v. circular, or very slightly
compressed ; e. f. not punctate, or puncta very indistinct. (A.)

C. connatum, BR£B.

C. validum, subrnagnum, leviter compressum, diametro dnplo circa longius, snbpanduriforme,
plus minus constrictum, utroque polo late rotundatum, a vertice lato ellipticum; semicellulis
subhemisphsericis, ambitu sequabiliter rotundatis, integerriniis ; cytiodermate punctato. (R.)
Species mihi ignota.

Long. 0.0035". Lat. max. 0.00165"— 0.0019". (R.)

Syn. — C. connatum, BE£BISSON. RALFS, British Desmidiese, p. 108.
Ilab. — Flqrida ; Bailey.

Frond large, in f. v. about one-half longer than broad ; constriction shallow ; segments about
two-thirds of a circle, coarsely punctate, and with a distinct, sometimes striated, border; e. v.
circular. (A )

d. Cellulse in familias connexse.
d. Cells united into families.

C. Quimbyii, WOOD. (sp. nov.)

C. cellulis parvis, sub-ellipticis, medio profunde constrictis, in familias copulis hyalinis con-
nexis ; semicellulis a fronte ellipticis et diametro subduplo longioribus, a vertice ellipticis, a
latere rotundatis ; sinu lato ; marsis chloro-phyllaceis in quaque semicellula singulis; cytio-
dermate tenue, glabro.

Diam.— Long. TTrV' = 0.001". Lat. a fronte ,&/ = 0.00075" ; a latere 15§^" = 0.00042".
Hab. — In aquis puris, New Jersey.

FRESH-WATER ALO^E OF THE UNITED STATES. 135

Cells small, nuMliptiral, profoundly constricted in the middle, joined by tranalnceDt bands into
families; Ki'inirells si-en from tlio front elliptical, and nearly twice aa long aa broad, from the
Tvrtcx elliptical, from the side roundish; sinus broad; chlorophyl masses single in each cell;
It-nil thin, smooth.

Remarks. — This plant was found by my friend Mr. Quimby growing in a beau-
tiful spring above Canulcn, upon whose bottom it formed a gelatinous, trans-
lucent, grrrnUh mass. The cells resemble in shape those of C. cucitmu, although
much siiKillcr. They arc joined by bands into little families, in which the original
parent-cell is iri 'in Tally very distinct, it, or rather the two cells into which it first
divides, remaining in the centre of the group. The bands are so hyaline that their
edges can alone be distinctly seen, and hence the latter often look as though they
were threads — there appearing to be two parallel threads, or two threads crossing
one another, or a single thread, according as the band is flat, twisted, or on edge.

It gives me great pleasure to dedicate the species to my friend Mr. Quimby, by
whom it was collected.

Fig. !), pi. 1, represents one of the family groups of this plant.

Genus EUASTRUM, EHRB.

Celluhe vel oblonga vel elliptic®, medio profunde incisae, symmetrice sinuatae, rel lobatae, tumori-
bu> inlliitid circularibus (rare obsoletis) instruct*, utroque polo sinaato-emarginatte vel inciso-bilo-
baUe, a vertice elliptic*.

(Vila either oblong or elliptic, profoundly incised in the middle, symmetrically sinuate or lobed,
proviilnl with circular inflated protuberances (which are rarely absent), at each end sinaately emar-
ginute or iucisely-bilobate, from the vertex elliptic.

A. Lobo polares in apict late sinualo-excisi.

A. Polar lobe with Us apex broadly sinuately excised.

I!, mult iloha In in, WOOD.

E. magnum, fere dnplo longias qnam latum, medio profunde constrictnra, et cum sinn modice
amplo; a latere medio ventricosum et duplo biumbonatnm, ad verticem dilatatum et emar-
ginatum ; semicellulis a fronte trilobatis, lobis sinus amplissimia inter se scjunctia ; lobi basal e
distinctc late emarginato, lobo cent rule obtuso, lobo polare late leviter sinnato-emarginato;
semieellulis a vertice quinque lobulatis; cytiodermate laevi.

Diom.— Long. rffn" = .00475". Lat. rffa" = .0025".
Syn—E- mtiUilobaium, WOOD, Proc. A. N. S., 1869.
Sab — In lacu "Ssco;" New Hampshire; (Lewis.)

E. large, about twice as long as broad, in the centre profoundly constricted, with the sinus
moderately large ; from the lateral view somewhat enlarged and doubly biumbonate in the
middle ; gemicclls from the front trilobate, the lobes separated by very wide sinuses, the basal
lobe broadly emarginate, the central lobe obtuse, the end lobe broadly and shallowly sinuately
emarginate; semicells from the vertex 6ve-lobed; cytioderm smooth.

.— The basal lobes of this beautiful desmid are distinctly five lobulate,
the lateral lobules being longer and broader than the others, which, instead of
bring emarginate, are obtuse. The sinuses, separating lobes and lobules, are very
broad, with very obtuse angles. When the desmid is viewed from two-thirds
round, so as to show the anterior and posterior lobules especially, it presents an

136 FRESH-WATER ALGJS OF THE UNITED STATES.

outline in which all the sinuses are of similar form, and the central and basal lobes
are about equal size; whereas, when viewed from the front, the basal lobe is much
the broader. When the desmid is viewed from the side it is seen to be enlarged
in the centre, and provided with two distinct umbonations each side of the com-
paratively narrow central sinus.

Fig. 10, pi. 12, represents the front view of a frond of this plant; fig. 5, pi. 20,
the outline of a two-thirds view, and fig. 5 a, the outline of a lateral view, all mag-
nified 450 diameters.

E. Yerrucosuni, EHRB.

E. magnum, late ovatura, vix longius quam latum, medio profunde constrictum, sinu extrorsum
dilatato; semicellulis trilobatis, lobis triangularibus, divergcntibus, apice late et profunde
sinuatis ; a latere ovato-oblongum, sinuato-lobatura, lobis octo in apice rotundatis, polaribus
singulis porrectis, lateralibus terms ; cytiodermate granulato-verrucoso. (R.) Species mihi
ignota.

Long. 0.0036"— 0039". (R.)

Syn. — E. verrucosum, EHRENBERQ. RABENHORST, Flora Europ. Algarum, Sect. III. p. 179.

Hob. — South Carolina ; Georgia ; Florida ; Rhode Island ; Bailey.

Frond somewhat longer than broad, rough all over with conic granules ; segments 3-Iobed,
sqme what .divergent, all the lobes broad, cuneate, with a, very broad, shallow, or external
sinus. Empty frond ; f. v. segments with one large circular basal inflation on surface, one
smaller on each side, and two others on the end lobe ; s. v. segments inflated at the base,
narrowed into a short neck, end dilated with a central sinus ; e. v. oblong, with three infla-
tions at each side, one at each end, end lobe having 4 divergent lobelets. (A.)

E. geiumatiim, BREB.

E. mediocre, diametro duplo longius, profunde constrictum, sinu angusto linear!, a vertice ovato-
oblongum, arabitu sinuato-lobatum, lobis 8 couformibus, rotundatis ; semicellulis trilobatis,
basi tumoribus 3 in seriem dispositis, lobis in apice profunde emarginatis, lobnlis rotundatis,
lobo polari dilatato et paulum producto ; cytiodermate in tumoribus et lobulis granulato-
punctato, cseterum Isevi. (R.) Species mihi ignota.

Long. 0.00224"— 0.0029". Lat. 0.00157''— 0.0011". (R.)

Syn. — E. gemmatum, BREBISSON. RABENHORST, Flora Europ. Algar., Sect. III. p. 180.

Hab. — Rhode Island ; Bailey.

Frond scarcely twice as long as broad; segments 3-lobed, lateral lobes horizontal, deeply emar-
ginate, the pro.tuberances minutely granulate; end lobe dilated, its dilatations inclined
upwards, and minutely granulate ; ends with a deep rounded emargination. Empty frond
slightly punctate ; f. v. segments with three granulate inflations near the base ; tr. v. broadly
elliptic, with three granulate inflations at each side and one at each end ; e. v. end lobe cruci-
form, lobelets rounded, granulate. (A.)

E. ohloii £iim, (GREV.) RALFS.

E. magnum, diametro duplo triplove longius, oblongum, profunde constrictum, sinu angusto,
a latere oblongo-lanceolatum, utroque polo truncato- leniter retusum, ambitu undulato-
sinuatum ; semicellulis (fronte) sinuato-quinquelobis, basi et in quoque lobo tumore instructis,
lobis lateralibus in apice dilatato sinuato-retusis, inferioribus latioribus quam superior., lobo
polari late cuneato in apice profunde inciso, angulis omnibus rotundatis, cytiodermate Isevi ;
zygosporis globosis verrucosis, verrncis obtuse conicis achrois hyalinis. (R.) Species mihi
ignota.

1 UE8JI- WATER A L G X OF THE UNITED STATES. 131

Long. 00057" — 0.0066". Lat. max. 0.00346".

Syn.— i: i-iiliHtyum, (OaiviLLE) KALFS' British Desmidiea, p. 80.

lla.l>. — Klimle Island ; Bailey.

Frond rather mure than twice as long as broad, smooth, oblong; segments 5-lobed ; lobes nearly
rqiml, cuiiftitf ; lateral loUrs, or the basal only, with a broad, shallow, marginal concavity,
all their angle.-* ruiiinleil, terminal notch linear.

limply frond; f. T. seg. punctate, with three large inflations, on surface near the bnsc, t\v>
others above and two on terminal lobe ; tr. T. three times as long as broad, with three sul>-
distant marginal inflations at each side, and one at each end, in ft, broader in proportion,
more elliptic, and inflations close; e. T. end lobe notched at opposite external margin*.
Sporangium orbicular, beset with numerous conical tubercles. (A.)

/.'. Lvbi polares entknter discreti et in apice anguste incisi.

11. End lobes evidently seftaraied and narrowly incised in the centre.

E. cra-Mim, (Unto.) KTZ.

E. oblongum, diametro subtriplo longius, profunde constrictom, sinn an gusto linoari, e vcrtice
subquadrungularc, utroque polo profunde excisura, angulis rotundatis; semicellulis (front*)
trilubis, basi et in quoque angulo tumore instructis, lobis lateralibus latissirais unisinuatis,
lobo polar! paullum prominente, in apice bifido, segmentis late rotundatis; cytiodcrmate dis-
tiucte puuctato, punctis in series transvcrsas ordinatis. (R.)

Long. 0.0051"— 0 0073". Lat. max. 0.0041". (R.)

$,j,,. — E. crassum, (BRtBissoN) KUTZING RAMNHOBOT, Flora Europ. Algarum, Sect. III.

p. 181.
Hab.— United States.

Frond about twice as long as broad, snbquadrilateral, smooth ; segments 3-lobed ; basal lobes
very broad, with a very broad, shallow marginal sinus, in which there is sometimes a slight
intermediate rounded projection; end lobe creneate, rounded, terminal notch linear.

Empty frond; f. v. punctate, segments with three inflations below and two above; tr. T. two or
three times longer than broad, with three lobes or inflations at each side and one at each end;
e. v. end lobe sinuate at opposite external margins. (A.)

E. omnium. WOOD.

•longum, diametro duplo longius, profunde constrictum, sinu angnsto lincari ; scmicellulis
a froute trilobatis; lobis basalibus latwsirais, nonnihil sinuato-emargiuatis, angulis plus minus
productis et rotundatis; lobo polar! medio profunde lineare inciso, segmcntis late rotundatis ;
semicellulis a latere bilobatis, lobis basalibus profunde emarginatis et cum angulis plus minus
acutis; cytiodcrmate distincte ordinatim punctato.

Diam.— TsYoo" = -00029".

Syn. — E. ornatum, WOOD, Proc. A. N. S., 1869.

Hob. — SacoLakc; New Hampshire. Lewis.

E. oblong, twice as long as broad, profoundly constricted ; semicells from the front trilobate ;
basal lobe very broad, slightly sinnately-emarginate, angles more or less produced and
rounded ; polar lobe medianly profoundly linearly incised, segments broadly rounded ; semi-
cells bilobate at the sides, basal lobes profoundly emarginate and with the angles more or
less acute ; cytioderm distinctly regularly punctate.

Remarks. — This species is close to E. crassum, from which it differs in the pro-
portionate length, being only twice instead of three times as long as hroad ; in the
M/« l.cing only three-fourths as large; and especially in the peculiar lateral split-
ting, as it were, of the basal lobes.

18 July, 187i

138 FRESH-WATER ALGJ3 OF THE UNITED STATES.

Fig. 12, pi. 21, represents the front view of an empty half frond of this species,
magnified 450 diameters; fig. 12 a, the side view of an empty frond.

E. afflne, RALFS.

E. E. humerosum affine, paulo minus ; semieellulae quinquelobae ; lobi basales quales in E. hume-
rosum sed tumores quatuor in seriem transversam siraplicem dispositi, lobi interruedii valde
abbreviati eorumque basi tumoribus duobus instruct!, lobus polaris magis porrectus ct in
apice minus dilatatus; cytioderma subtilissime punctatuin sublaeve. (R.)

Long. 0.0038"— 0.0041". (R.)

Syn. — E. affine, RALFS, British Desmidese, p. 82.

Hab. — South Carolina ; Georgia ; Bailey.

Frond about twice as long as broad ; segments 3-lobed ; basal lobes slightly emarginate,
having intermediate between them and the end lobe on each side a tubercle representing
middle lobes, the upper margin of which is horizontal ; end lobe exserted, dilated, its notch
linear.

Empty frond ; f. v. minutely punctate ; the segments with four basal inflations, two above and
two on end lobe ; tr. v. elliptic, with four inflations on each side and one at each end ; e. v.
end lobe emarginate at opposite ; e. v. end lobe emarginate at opposite external margins,
producing four shallow lobulets. (A.)

E.Didelta, (TURPIN) RALFS.

E. robustum, diametro duplo longius etiam supra, in sectione transversa ellipticum, ambitu un-
dulato-crenatum, in utroque latere crenis quaternis ; semicellulis pyramidalibus, quinquelobis,
tumoribus 9 in series tres alternantibus ordinatis, lobis inferioribus oblique truncato-rotundatis
nonnunquam leniter retusis, intermediis subadscendentibus, rotundatis, lodo polari minus
dilatato, bifido, segmentis rotundato-truncatis, conniventibus, in apicc tumidis ; cytiodermate
distincte punctate, punctis modo irregulariter sparsis modo in seriebus rectis collocatis. (II.)

Long. 0.0055". Lat. 0.002Y9".

Syn. — E.Didelta, (TURPIN) RALFS, British Desmidese, p. 84.

Hab. — South Carolina; Georgia; Rhode Island; Bailey. Pennsylvania; "Wbod.

Frond rather more than twice as long as broad ; segments pyramidal, inflated at the base and

again at the middle, end scarcely dilated, rounded, its notch linear.
Empty frond punctate ; f. v. segments with several inflations in lines and two at the end ; tr. v.

elliptic with four inflations at each side and one at each end ; e. v. end lobe entire at margin.

Sporangium orbicular, with subulate spines. (A.)

Remark. — Fig. 13, pi. 21, represents this species.

E. ampullaceum, RALFS.

E. diametro dnplo longius ; semicellulis trilobis, ad basin tumidis, e basi latissima subito in lobi
polaris collum attenuatis, lobis basalibus maximis integris, loco loborum intermediorurn pro-
cessu deutiformi, lobo polari cuneato, in apice bifido, segmentis late truncato-rotundatis;
cytiodermate subtiliter punctate. (R.)

Long. 0.0035"— 0.0038". Lat. max. .0026" ; lat. in colli (lobi polar.) 0.00085". (R.)
Syn. — E. ampullaceum, RALFS, British Desmideae, p. 83.
Hab. — South Carolina ; Florida ; Bailey.

Frond rather more than one-half longer than broad ; segments obscurely 3-lobed, short, with
broad inflated base ; basal lobes not emarginate, having on each upper side a small inter-
mediate tubercle between each and the end lobe ; end lobe exserted and dilated, its notch

FRKS II- WATER ALG^E O F T II E U N I T E D ST A T E 8. 139

liiH-ar. Empty frond minutely punctate; f. v. narrow elliptic, with several inflated protubo-
ranct •-, • -IK!.-, -c.u,. _\ diluted, rounded; tr. v. with Tour iuflutiuns at sides and one at each
i-ii.l. (A.)

circularr, H VSSAL.

E. mediocre, dianu>tro duplo longins; semiccllnlia trilobis (at non semper distigcte), ad basin
versus tuinoribus quinm aut pluribus in scries duas v. tres alternantcs aut Bingulo ccntruli,
quatcrnis scmicircularitcr onlinatis instrurtis, lobifl basalibus sinuato-emargiiiuti*), subito in
lubum polurem upicc puulluui dilutatiim attetiuatitt ; cytioilermate Kubtilitcr ]>unrtuto. (K.)

,S'y;i. — A1, rirciiltirr, IlASSAL, Froli- Water Algae, p. 383.

Hub. — Providence, Rhode Island ; Builej.

" Frond about twice as long as broad, tapering upwards into a neck, end not dilated, iU notch
an acute incision. Fmpty frond, segments with five basal inflations, four in a half circle
around the fifth and two others at the extremity." Archer.

(Far. It. 1 1 Is 1 1

Scniicclliila tumoribus minirais 11 in scries tres alternantcs ordinal is.
Hub.— Saco Lake, New Hampshire ; (F. W. Lewis) Wood.

K. Jenneri, nobis. Frond scarcely twice as long as broad ; segments 3-lobed, basal portions
8ulx|iiadrate, cmarginate at the sides; end lobe, its notch linear. Empty frond punctate,
segments with several inflations arranged in alternate lines. (Archer.)

E. iitftigne, HASSALL.

F. sulijrrnrili-. dia metro dnplo-triplove longius, a vcrtice fere qnadratum, lateribus concavis,
angulis rotundutis; semicellulis basi inflatis, integris, e basi subreniformi in collum clongatuin
chins attcmiutis, lobo polar! dilatato bifido truucato ; cytiodermatc subtiliter puuctato. (U.)

Long. 0.0039"— 0.0043". Lat. max. 0.0023C'', (R.)
,S'y;i. — E. insigne, HASSALL, Fresh- Water Algae, p. 21.
y/,,6._Florida ; Rhode Island ; Bailey.

Frond rather more than twice as long as broad ; segments inflated at base, sides entire, without
lateral tubercles, and tapering into a long slender neck; end lobe dilated, its notch linear.
Kinpty frond minutely punctate ; f. T. segments with two inflations at the base ; f. v. narrower,
gradually tapering to the end, which is considerably dilated ; projections rounded, with a
sinus between ; tr. T. subquadratc, slightly concave at sides, with a rounded lobe at the
centre of each end ; e. v. end lobe with a sinus at opposite external margins, angles thus
protruded into four divergent rounded lobelets. (A )

!•:. RalfNii, RABENH.

K. mediocre, leviter comprcs.snm, mcdio inflatum, diametro duplo circitcr longius; semicellulis
pyramidalibus, c basi ventricosa in lobum polarem rectum truncatum sinuato-attenuatis ;
cytiodermate subtiliter punctato, punctis in lincos rectos ordinatis. (R.)

Syn. — E. ansatum, EHR. etanctores. RABENHOBST, Flora Europ. Algarum, Sect III. p. 184.
E. Ralfaii, RABENIIOBST, Flora Europ. Algarum, Sect. III. p. 184.

Hab. — South Carolina ; Rhode Island ; Bailey. White Mountains, New Hampshire (F. W.
Lewis).

"K. anttnliim, Ehrb. Frond about twice as long aa broad; segments inflated at the base, taper-
ing upwards without siuuations into a neck, end not dilated, rounded, its notch linear. Empty

140 E RES II -WATER ALG^E OF THE UNITED STATES.

frond punctate; f. v. segments turgid on the surface, at the middle without circular inflations ;
tr. v. elliptic, with a single large inflation at each side ; e. v. cud lobe entire at the margin,
its divisions circular. (A.)

v

Remarlcs. — I have seen only a very few specimens in a gathering made in Saco
Lake, New Hampshire, by Dr. Lewis, which differ considerably from the typical
form in the proportion of the breadth and length. There are also certainly four,
if not more, umbonations on the face of each half-cell. These are nowhere dis-
tinctly spoken of as existing, and Mr. Archer states there are none visible in the
front view of E. ansatum. They are, however, represented in the side view of the
original figure, and are said to be very noticeable by Mr. Archer himself, when
the desmid is so looked at. In the Saco Lake specimens they are always seen in
the front view with great difficulty, and in some cases I failed entirely to demon-
strate them, so that they do not afford a good character for the indication of a nev?
species.

Fig. 1, pi. 13, represents a front view of a Saco specimen, magnified 450 dia-
meters.

C. Lobi polares non-evidenter discreti.
G. End lobes not evidently distinct.
E. elegans, (BREB.) KTZ.

E. minus, oblongum, diametro duplo longius, utroque polo bifhlum, segmentis introrsum rotun-
datis; semicellulis sursum modice attenuatis, utroque margine laterali bi- vel tri- sinuatis,
sinu superior! vel intermedio profundiori, sub polo utrinque dente acuto prominentc ; cytio-
dermate subtiliter punctate, punctis irregulariter sparsis ; zygosporis globosis aculeatis,
aculeis elongato-subulatis. (R.)

Long. 0.0012" 0.002". Lat. max. circiter 0.0011". (R.)

Syn. — E. elegans, (BREBISSON,) KUTZINO. RABENHORST, Flora Europ. Algarum, Sect. III. p.
185.

Eab. — South Carolina ; Georgia ; Florida ; Rhode Island ; Bailey. White Mountains, (F. W.
Lewis).

Frond minute, scarcely twice as long as broad, oblong; segments with their basal portion emar-
ginate at the sides, connected by a broad neck with the terminal portion ; ends protuberant,
rounded, acutely emarginate at the centre, pouting ; s. v. with an inflation at the base of the
segments, sides concave, ends rounded. Sporangium orbicular, spinous. (A.)

Remarks. — According to Prof. Rabenhorst E. rostratum, Ralfs, which is noted
as an American species by Bailey, is a variety of E. elegans. Its peculiarities, ac-
cording to Rabenhorst, are as follows : " Forma magis evoluta, profundior sinuata,
segmentis polaribus latioribus, angulis acutis, dente panlo longiore."

Fig. 14, pi. 21, represents the outline of the frond as viewed laterally; fig. 2,
pi. 13, a front view of the frond, magnified 750 diameters.

E. binale, (TURPIN) RALFS.

E. minimum, diametro paulo vel snbduplo longius, in sect, transversa oblongo-cylindricnm,
medio tumidum, utroque polo rotundatum ; semicellulis indistincte trilobis, lobis basalibus

FRKSH-W ATKK ALQ.E OF TUB UNITED STATES. 141

latis, rotundatis vel sinuato-l.i- trit-renatis ; lobo polari abbrcviato lute truncate, levitcr cmar-
giuuto, anguli.-. ueutis laterulitcr plus minus ponvctis; cytiodvrmate subtilissimc puuctato.

Syn. — E. binalf, (TriUMN) UAI.FS, British Dcsmidee, p. 90.

Jl,i!>.— Florida; Bailey. Rhode Island, (S. T. Olncy,) Thwaites. Pennsylvania ; Wood.

Kri'iid rcry minute, scarcely twice as long as broad, oblong ; segments with their basal portion
cither entire. or liierenate ut thu sides, slightly contracted beneath the ends ; ends dilated, not
protuberant beyond the angles, its central notch acute, broad; tr. v. with two lateral infla-

tions, encl-4 truncate, angles rounded. (A.)

ik. — Fig. 3, pi. 13, represents the front view of a frond, magnified 750

diameters.

Genus MICRASTERIAS, Ac. (1827).

ihi- compresssp, |irofonde constrict®, a fronto orbiculares vel late ellipticffi, a vcrtice fusiformcs
cum utroi|iie polo acuto, semicellulse tri- vel quinquc-lobe ; lobi basalcs aut intcgri aut pluripliciter
iiiciMi-lohuluti ; lobus polaris aut integer aut sinuatus ant emarginatus, et interdum angulis produc-
tus ct bitidiis. Cytioplasma chlorophyllacca in cellulae lumen subeequalitcr ili.-trilnitii, granula
ainylacea sparsa involvena. Cytioderma plerumque la-ve, nonuuuquam punctatum, granulatum vel
muiTonatum.

-porse globosa, aetate provecta aculeis simplicibus, apice bi- multi- fldis, nonnanqnam repetito-
multilii'lis armato;.

M compressed, profoundly constricted, viewed from the front orbicular or broadly elliptic, from
the \ertex fusiform with acute ends. Semicells 3- or 5-lobed ; basal lobes either entire or many
times incisely-lobulate ; end lobe either entire or sinuate or eraarginate, and sometimes with its angles
.'•ed and bifid. Chlorophyllona cytioplasm distributed nearly uniformly in the cavity of the
cell, surrounding scattered starch granules. Cytioderm mostly smooth; sometimes punctate;
granulate or mucronate.

• -pores globose, at maturity armed with simple spines, whose ends bifid or multifid, and somc-
repeatedly multi lid.

A. SemiccUula trilobx. Lobi batalea horizontales ; lobus polaris valde dilalalus, dorxo plane
convexus, Iruncatua vel leoiter retusug, a lobin bagalibus ginu amplixximo dixcretus.

A. Semicells trilobate. Ba»al lobe» horizontal ; end lobe strongly dilated, with the back con-
vex, truncate, or slightly refuse.

JI. nrcnaln. BAILET.

M. mediocris, quadrangularis, paulo latior qnam longa, profunde pinnatifida; lobis basalibns
angustis elongatis, arcuatis, in apiccra acutum attcnuatis, divergentibus; lobis polaribus
angustusirais, atrinque graciliter productis, in apicera acutum attenuatis, in medio dorso
modice rctusis. (R.)

Sijn. _ M. arcuata, BAILEY, M-icroscopical Obserrations : Smithsonian Contributions, vol. ii.

Bab. — In stagnis. Florida; Bailey.

" Quadrangular, segments three-lobod, the basal lobes long and arcuate, subtended by the trans-
verse projections from the ends of the slightly notched terminal lobes." (Bailey.)

HI. eipanM, BAILEY.

M. mediocris, tain longa qnam lata, lobis stellatim expansis; lobis basalibns angustis in apicem

acutnm attcnuatis, divergentibus, rectis; lobis polaribus e basi angusta sensim dilatatis, in

mcdio dorso late sinuatis, angulis acutis (sed muticis). (R.)

Syn. — 3r. expansa, BAILEY, Microscopical Observations : Smithsonian Contributions, vol. ii.
Ilab. — In stagnis, Florida; Bailey.

142 FRESH-WATER ALG^E OF THE UNITED STATES.

Segments three-lobed, basal lobes long, subconical, acute ; termina. lobes slender, forked at the
end, with the divisions much shorter than the basal lobus. (Bailey.)

M. quadrata, BAILEY.

M. arcuatse siruilis, sed duplo major, semicellularum lobi basales minus arcuati, basi iuflati,
apice bidentati et cytiodenna irregulariter grauulatuui. (R.)

Diam.— 0.0043"— 0.0049".

Syn. — M. quadrata, BAILEY, Microscopical Observations : Smithsonian Contributions, vol. ii.
Large quadrangular, three-lobed, basal lobes elongated, slightly curved, bidentate ; terminal
lobes with two slender transverse bidentate projections. Bailey.

1H. disptitata, WOOD.

M. magna, fere tarn longaquam lata, subpinnatisecta, sinuacuto, lobis sequalibus; semicellulispro-
funde trilobis, lobis basalibus in apicem acute bidcntatuin yalde atteuuatis; lobo polari valde
dilatato, dorso rotundato, angulis latcralibus acutissimis.
Long. Tf fo" =.005". Lat. 7f fa" = .004".

Syn. — Micrasterias incisa, KTZ. BAILEY, Microscopical Observations : Smithsonian Contribu-
tions, 1850.

Haud Micrasteria incisa, KUTZING, Spec. Algarum, p. 171.
Tetrachastrum Americanum, ARCHER, PRITCHAHD'S Infusoria, 1800, p. 725.
Hab. South Carolina; Georgia; Florida; Rhode Island ; Bailey. Pennsylvania; Wood.

M. large, about as long as broad, subpinnatisected ; sinuses acute ; semicells profoundly trilo-
bate ; basal lobes strongly attenuate into the acutely bidentate apex ; distal lobes strongly-
dilated, rounded, with their lateral angles bidentate ; end lobe broadly dilated, lateral angles
very acute.

EemarJcs. — This desmid was first figured by the late Prof. Bailey in his Micro-
scopical Observations (Smithsonian Contributions), as M. incisa of Ktz., and Ra-
benhorst, in his Flora Europaea Algarum, confirms this identification. He has
probably, however, never seen the plant itself, but merely accepts the opinion of
Professor Bailey. Mr. Archer (Pritchard's Infusoria), thinks the American plant
is certainly distinct from the European, and this seems to me correct. The points
of difference are — the American form is nearly twice the size of the European, the
sinuses are much more widened outwardly, and the lobes are reduced rapidly in
breadth to a mere point at the end, the dorsum of the distal lobes is also, I believe,
more rounded. In his description of T. Americanum, as he calls it, Mr. Archer
states the end lobe has its angles bidentate. In the only specimen I have seen,
the angles end in a very sharp, almost spine-like point. Dr. Leidy found the spe-
cies abundantly at Newport, Rhode Island, and his figure agrees with mine in this
respect. In regard to the name, as there is already an M. Americanum, the specific
name of Archer cannot be adopted, and for a similar reason it would not do to call
it M. Ea'deyi. I have then been forced to give it a new title.

Fig. 4, pi. 13, was drawn by myself from the single specimen I have seen; fig.
4 a was drawn by Dr. Leidy from a Newport specimen.

M. oscitans, RALFS.

M. magna, paene tarn longa quam lata, subpinnatisecta, a vertice elliptico fusiformis, utroque
polo bifida; lobis basalibus horizontalibus conico-productis, apice bifidis; labo polari a lobis
basalibus sinu amplo ac rotundato discrete, plus minus convexo, haud raro truncate, rarius
leviter retuso, utrinque producto acuminato, plerumque bidentato. (R.)

1 UKSII-WATER ALGJ-l OF TUB UNITED STATES. 143

Diam.— 0.0047". Long. 0.0039". (R.)

;i. — M. oxctianK, HALTS, British Dcsmidicte, p. 76. RABENHORST, Flora Europ. Algarum,

Sect. III. p. 119.
M. pinnatijida KTZ. RABENUORST, Flora Europ. Algarum, Sect III. p. 119.

Hub. — Florida ; Rhode Island ; Bailey.

Frond about aa broad as long, pinnatifid; lateral lobes separated from the terminal by a rounded
sinus, horizontal, conical, their extremities bidentate ; end lobe short, broad, its lateral pro-
jections short, conical, usually bidentatc, narrower and shorter than the lateral lobes; ends
uves at the centre; tr. v. fusiform, e. f. punctate. (A.)

/,'- niarktt. — According to Prof. Rubenhorst M. pinnatifida, Ktz., is a variety of M.
otcilans, different from the typical form only in being smaller, and in having the
lobes narrower. •

Ji. SemieeUulte 3-vel b-lobae, plerumque rodiotim inciso-lobulotte. Lobi boaales assurgentes
out non out minus a lobo polari remoli.

B. SemicelU 3, or b-lobate, mostly radiately innsely tabulate. Basal lobes assurgent, either
close to, or but slightly remote from the end lobes.

* Semicellula: trilobte.

* Semicells trilobate.

n. Americana, (EHRB.) KTZ.

M. nmgna, oblonga, snbpinnatiseeta, lobis polaribns paulam remotis, psene duplo longior qimm
luta ; cytiodermate spinuloso unde laborum rnargines dentato-serrati conspiciuntur ; cellula
e latere conspecta oblonga, in medio leviter constricta. utroque polo bicornuta ; semicellulee
liasi tumore plus minus distincto instructs, fere quinquelobae, lobis basales latitssimi iisderaque
profunde bilobati, lobulis late excisis, segment is dentato-serratis ; lobis polaribus plus minus
productis, in medio late excisis, scgmentis profunde bifidis. (R.)

/>/«m.— 0.0041". Long, circa 0.0051". (R.)

n. — M. Americana, KUTZIXO. RABENHORST, Flora Europ. Algarum, Sect. III. p. 189.
h. — In stagnis, South Carolina; Florida; Bailey.

Frond angular elliptic, more or less punctate ; segments 3-lobed ; lateral lobes broad, cuneate,
ilicir margins concave, ineiso-serrate ; and lobe broad, cuneate, end exserted, bipartite at the
angles, the subdivisions narrow, and minutely dentate at the extremities; end concave. (A.)

Remark. — Fig. 17, pi. 12, represents a plate of this species.

M. Baileyi, RALFS.

M. ]>:irvn, oblonga, granulata; semiocllulia trilobis, lobis basalibns a lobo polari sinn amplo
discretis, excisnra acute triangular! in duas lacinias partitis, laciniis e basi latiori in apicem
truncatum bidentatum attenuatis; lobo polari e basi angnsta longe porrecto, snrsum valde
dilatato, in rertice leviter et late sinnato, angulis truncate, bidentato. (R.)

•S'yn. — M. Baileyi, HAI.FS. British Desmidieae, p. 211.

ffab. — New York; Rhode Island ; South Carolina; Florida; Bailey.

Frond granulated ; segments three-lobed ; lobes bipartite, end one much exserted. (Ralfs.)

!H. rin^ens, BAILET.

M. inediocris, oblonga, margine grannlata; semicellnlis trilobis; lobis lateralibns bipartitia,
laciniis divaricatis, apjce obtnsis, trnncatis yel bidentatis; lobo polari e basi angusta sursum
valde dilatato, exserto, in vcrtice leniter sinuato, angulis truncate. (R.)

144: FRESH-WATER ALGJE OF THE UNITED STATES.

Syn. — M. ringens, BAILEY, Microscopical Observations, pi. 1, fig. 11: Smithsonian Contri-
butions, vol. ii.
Hob Florida; Bailey.

Oblong, segments three-lobed, coarsely granulated near the edge ; basal lobes subdivided by a
deep notch into two rather broad and obtuse or slightly bidentate projections ; terminal lobes
exserted, emarginate ; extremities bidentate or obtuse.

* * Semicellulee quinque-lobatae.

* * Semicells 5-lobed.

M. truncata, (CORDA) BEEB.

M. magna, orbicularis, aut Isevis aut snbtiliter punctata ; scmicellulis quinquelobis, lobis inter
se sinu obtusangulo subangusto discretis, basalibus et interuiediis inciso-lobulatis, segmentis
• acute bidentatis; lobo polari late cuneato, in dorso truncate, m'odo leviter convexo, modo
leviter retuso, angulis aut bidentatis aut integris. (R.)

Diam.— 0.003" Long. .0036".

Syn. — M. truncata, (CoRDA,) BREBISSON. RABENHORST, Flora Europ. Algarum, Sect. III. p.
191.

Hab. — Georgia ; Florida ; Rhode Island ; Bailey. Pennsylvania ; Wood. Rhode Island
(S. T. Olney) ; Thwaites.

Frond orbicular, smooth ; segments 5-lobed ; basal and middle lobes obscurely bipartite, ex-
tremities bidentate ; end lobe very broadly cuneate, bidentate at the angles, and with a slightly
central concavity. (A.)

Remarks. — The dimensions given above were taken from the largest specimens
I have seen, but do not at all equal those given by Prof. Rabenhorst, his breadth
is .OOil". According to the same authority, M. crenata, Breb., is merely a variety
of this species.

Fig. 15, pi. 21, represents the outline of a frond of this plant.

M. furcata, Aa.

M. permagna paulo longior quam lata, levis ; semicellulis quinque lobis (paene 7-lobis) ; lobis
omnibus rectis ; lobis basalibus angustioribus, bilobulatis, lobulis bifidis, sinu obtusangulo
vel acutangulo, segraentis linearibus bidentatis (denticulis ssepe inrequilongis) ; lobis inter-
mediis duplo latioribus, inciso-bilobis, lobulis iisdem ac loborum basalium ; lobo polari non-
nihil anguste cuneato, prominulo, in apice plus minus profunde sinuato-vel undulato iuciso,
angulis bidentatis.

Diam.— 7|g/ = -008".

Syn. — M. rotaia, RALFS, British Desmidiese, p. Tl.

M. furcata, AGARDU. RABENHORST, Flora Europ. Algarum, Sect. III. p. 191.

Hab. — South Carolina ; Georgia ; Florida ; Rhode Island ; Bailey. New Jersey ; Wood.

M. very large, a little longer than broad, smooth ; semicells 5-lobed (scarcely 7-lobed) ; lobes
all straight ; basal lobe narrower than the intermediate, bilobulate, lobules bifid, their sinuses
acute or obtuse, segments linear, bidentate ; teeth often long and unequal ; intermediate lobes
twice as wide as the basal, bilobate, their lobules of the same form as the basal lobe ; end
lobes narrowly cuneate, prominent, more or less profoundly sinuately or undulately cut at
the apex, angles bidentate.

Remarks. — According to Rabenhorst and others, there is a European form of
this species in which the marginal teeth are wanting. This may exist in this

FRESH-WATER ALG.tt OF THE UNITED STATES. 145

country, but 1 have never met with it. All the specimens which have come under
my notice \M ic obtained in "Shepherd's Dam," near Greenwich, Cumberland
County, New Jersey. None of them were as large as the maximum of the European
measurements of which llabenliorst gives 0.0109" as the diameter.

Fig. o, pi. l;3, represents a frond of this species, magnified 260 diameters.

.71. denticulata, BHEB. ?

M (.cniiniritu, paulo longior quain lata, Itrvis; semicellulig quinquclobis (ptene 9 lobis) ; lobis
intrrmediis et basalibus simillimis, bilobatis, lobulis item in lobulis bifidis duobus divisis ;
lobo polare angusto, cuncato, in apice plus minus inciso ; margine minute denticulato.

IHam.—LtA. .0092". Long. .011."

>'i/;i. — M. <!f»tt,-ttlala, .BREBissoN. RALFS, British Desmidicse, p. 70, et AKCIIER, FRIT-CHARE'S

Infusoria.
M. denticulata, BREBissox. ? RABENHOR8T, Flora Europ. Algarum, Sect III. p. 192.

Ilab. — Pennsylvania; Wood. Florida; Bailey.

Vi-ry large, a little longer than broad, smooth; semicells with five lobes (scarcely 9); basal
and intermediate lobes alike bilobate, lobules also divided into two bifid lobules; end lobe
narrow, wedge-shaped, more or less incised at its apex ; margin minutely denticulate.

L'> marks. — Prof. Rabenhorst gives M, denticulata, BREB. as merely a variety of
M. r'/irriiin, Ac., stating that it only differs from the latter in the marginal incisions
and teeth. Not having access to the original description of Brebisson I cannot
express an opinion as to whether Prof. R. is correct or not, but the specimen from
which the above description was drawn up (and which is figured on plate 13) cer-
tainly differs from M. furcata very essentially in the arrangement of its lobes, and
is, I feel confident, M. denticulata, BREB. of RALFS and ARCHER.

Fig. 6, pi. 13, is a drawing of this plant, as seen by myself, magnified 260
diameters.

ffl. radio*.-!, Ao.

M. maxima, orbicularis, Isevis, antecedent! simillima, diflcrt in prim is segmentis ultimis turoidis
in apicem bi- tri- fidum attenuatis, lobo polari vix prominulo, apicc sinuate, ad ntrumque
angulum bi- tri- dentato. (R.) Species mihi ignota.

Diam.— 0.0076". (R.)

Syn. — M. radiosa, AoARDn. RABENHORST, Flora Enrop. Algarum, Sect III. p. 192.

Hob. — Florida; Bailey.

Frond orbicular, smooth ; segments 5-lobed ; basal lobes twice, middle lobes generally thrice
dichotomous, ultimate subdivisions inflated, attenuate towards the end, bidentate; end lobes
emarginate, its angles dentate. (A.)

in. fimbriata, RALPS.

M. magna, orbicularis, laevis (nonnunqnam superficie aculeis singulis sparsis); semicellulis
quinquelobis, lobis omnibus confertis, basalibus angustioribus, repetito bilobulatis, lobis inter-
mediis duplo latioribus, repetito-bilobulatis, lacinnlis extremis levitcr emarginatis, in angulis
apinis elongatis armatis; lobo polari prominnlo, in apice obtuse sinuato-vel-undulato-emar-
ginato, angalis lateralibns rotnndatis, ad marginem superiorem spiuis singulis vcl geminis
obsito (rarius nndo). (R.) Sjtecies mihi ignota.

19 August. 1873.

146 FRESH-WATER ALGJS OF THE UNITED STATES.

Diam.— 0051"— .0078". (R.)

Syn. — M. fimbriata, RALFS, British Desniidiese, p. 71, et RABENUORST, Flora Europ. Algarum,
Sect. III. p. 193.

Hob. — South Carolina ; Florida ; Bailey.

Frond orbicular, smooth ; segments 5-lobcd, basal lobes twice, middle lobes thrice dichotomous ;
ultimate subdivisions acutely bidentate; end lobe very slightly exserted, its angles very
slightly produced, bidentate, ends emarginate. In transverse view is seen an inflated pro-
tuberance just over the central isthmus, which may possibly exist in other species of Hicras-
terias. (A.)

HI. papillifera, BREB.

M. orbicularis, superficie lajvis, margine extremo dcntato papillifera; sernicellulis quinquelobis;
lobis basalibus et interniediis ffiquilatis, bilobatis ; lobulis biiidis, laciniis linearibus bidentatis,
dentibus papilliferis ; lobo polari vix promiuulo, in apice siuuato, angulis et margiue dentato-
mucronatis. (R.) Species mihi ignota.

Diam.— 0.0045". (R.)

Syn. — M., papillifera, BREBISSON. RALFS, British Desmidiete, p. 72, et RABENUORST, Flora
Europ. Algarum, Sect. III. p. 194.

Hob. — Florida ; Rhode Island ; Bailey.

Frond orbicular, having the principal sinuses bordered by a row of minute granules, otherwise
smooth ; segments 5-lobed ; basal and middle lobes twice dichotomous, their ultimate shal-
low subdivisions terminated by two, sometimes three, gland-like teeth ; end lobe emarginate,

its angles dentate. Sporangium as in M. denticulata, but considerably smaller. (A.)

•

Ifl. granulata, WOOD (sp. nov.)

M. magna, suborbicularis, arete granulata ; semicellulis quinquelobis, lobis inter se sinu angusto
discretis, basalibus et interniediis plerumque integris, lobo polari supra valde dilatato, in
dorso medio leviter retuso ; marginibus valde crenatis.

Diam.— Long, ^h" = -0043". Lat. T545V' = -0036".
Hob. — South Carolina, (Ravenel)

Large, suborbicular, closely granulate; semicells Wobed, lobes separated by narrow sinuses;
basal and intermediate lobes mostly entire; end lobe distally broadly dilated, broadly and
very shallowly emarginate ; margin of frond strongly crenate.

Remarks. — The only specimens of this species that I have seen were collected by
Prof, ftavenel in a shallow ditch near Aiken, South Carolina, where they formed a
greenish, gelatinous mass, with numerous desmids and diatoms. It is most closely
allied to M. truncata, from which it is separated by its entire lateral lobes, by its
granulated surface, and its crenated margins. It also does not apparently attain
as large a size as that species. The granules are very small in the central portion
of the frond, but become larger as they approach the margin.

Fig. 16, pi. 21, represents an empty frond of this species, magnified 460 diam-
eters.

M. Jenneri, RALFS.

M. magna, oblonga, plerumqne snbtiliter granulata; semicellulis quinquelobis; lobis basalibufl
et intermediis sequilatis, confertis, cuneatis, bilobulatis ; lobo polari late truncate vel late
rotundato, in medio interdum leviter et obtuse emarginato, interdum nonnihil profunde emar-
ginato.

Diam.— Lat. Tf gj '—rffvt* = .006"— .0062". Long. 7f »5"_ T,y^" = . 0062"—. 0087".

FUKSH-W ATKK A L 0 ^E OF TUB UNITED STATES. H7

Syn. — J/. Jrnnen. K.M.r.-. J'.ritish PeMiiidiea', p. 16.

Hah. — prope Philadelphia; Wood, Suitli Carolina; (IlaTcnel)

Large, oblong, Tor the must part finely granulate ; semicells 5-lobod ; lobes wedge-shaped ; banal
and inti-rinvdiatc, about equally broad ; end lobe broadly truncate or broadly rounded, iu the
middle Minn-times slightly aud obtusely eniarginate, sometimes rather deeply emargiiiate.

/,'. mark*. — I have found this species near Philadelphia, and also received it from
Prof. Kavenel, 1>\ whom it was collected in South Carolina. The American plant
ditl'ers from the typical form in not having the ultimate lobules emarginate, they
bring merely a little hollowed out in the centre, and sometimes scarcely this. The
angles in >oine specimens are also more acute. Mr. Archer, however, speaks of a
variety occurring in England, in which these lobules are not emarginate, and I do
not think characters can be found separating the American from the European
forms. The median suture is in all the specimens very narrow and deep, a were
line, as it were, -extending nearly to the centre.

;. 7, pi. 13, represents a frond of this species.

M. Torreyi, BAII.ET.

M. pcrmagna, oblongo-orbicularis, laevis, proftindissimc lobata; semicellnlis quinqnelobis, lobU
basalilms profunde bifidis, laciniis inferioribns apicc bidentatis, superioribns integris, lobis in-
termediis profunde trifidis, laciniis supcrioribns bidentatis, inferioribus integris, lac. omnibus
lanceolatis acuminatis, inferioribus paulum incnrvis, superioribus rccurvia ; lobo polar! non
prominente, e basi angusta seusiiu dilatato, in vertice acute siuuato, ougulis iutegris acumin-
atis. (R.) Species mihi ignota.

fyn. — M. Torrryi, BAILEY. KAI.KS, Brit. Desmidieae, p. 210.

J/ufi. — Prope Princetown, New Jersey; Bailey.

Frond smooth ; segments 5-lohed ; basal lobes bifid, middle lobes trifld, the subdivisions nearest
the opposite segments and those nearest the terminal lobe bidentate at the apex ; the inter-
mediate three terminating in acute points; all somewhat inflated and tapering ; terminal
lobe narrow, not exsertcd, spreading at the angles into divergent tapering points, ends
slightly cmarginate. (A.)

HI. foliacea, BAILET.

M. parva, subquadrata, Isevis; semicellnlis trilobis, lobis lateral ibus profunde bifidis (undc rec-
tior semicell. quinqnelobse), lobulis inaequaliter inciso-dentutis, loldilis inferioribua rectis,
superioribus recurvis; lobo polar! plus minus prominente, anguate cuneato, in vertice plus
minusve emarginato, angulis aut acutis iutegris aut productis, bidentatis. U. Species mihi
ignota.

Syn. — M.foliacea, BAILEY. RALFS, British Pcsmidieae, p. 210.

//„/,._" AVorden's Pond, Rhode Island; Bailey."

Frond subquadratc, smooth ; segments 3-lobcd ; lateral lobca deeply bipartite, inciso-dcntate,
their margins concave, inciso-serrate; end lobe brond, cuneate, and exserted, bipartite at the
angles, the subdivisions narrow, and minutely dentate at the extremities ; end concave. (A.)

Genus STAURASTRUM, METEN.

Cellulse libere natantes, in medio plus minns profunde constricts? ; seraiccllula! a vertiee 3-6 angn-
larcs vel radiate. Cytioderma aut leeve aut puuctatum aut verrucosum out aculoatum, nonnunqnam
ciliis vel pilis obsessnm.

Cells swimming free, more or lees profoundly constricted in the middle; semieells when seen
from the vertex 3 to 6 angular or radiate. Cytioderm either smooth or punctate, or vcrruoosu or
aculeate, sometimes covered with baira or cilia.

148 FRESH-WATER ALG^E OF THE UNITED STATES.

A. CYTIODERMA LJEVE VEL RARISSIME SUBTILITER PUNCTATUM.
CYTIODERM SMOOTH OR VERY RARELY VERY FINELY PUNCTATE.

1. Semicellularum anguli rotundati.
Angles of the semicells rounded.

St. iiiiiliciiiii, BREB.

St. a fronte orbiculare, Iseve, profunde constrictum, nudum, vel muco plus minusve firmo invo-
lutum ; semicellulis ellipticis, a vertice conspectis 3-4 angularibus (rarius quinquangularibus)
angulis rotundatis, lateribus leviter sinuato-retusis ; zygosporis aculeatis, aculeis elongatis,
subulatis, fureatim fissis. (R.) Species mihi ignota.

JHam— 0.0013"— 0.000147". (R.)

Syn. — S. muticum, BREBISSON. RABENHORST, Flora Europ. Algar., Sect. III. p. 200.

Hob. — South Carolina ; Rhode Island ; Bailey.

Segments in f. v. elliptic, smooth, without spines ; e. v. with three or four broadly rounded
angles, sides concave. Sporangium beset with numerous elongate somewhat stout spines,
forked at the apex. (A.)

St. orbiculare, (EHRB.) RALFS.

St. suborbiculare, leeve, saepius muco matricali involutum ; semicellulis divergentibtis, semi,
orbicularibus, dorso nonnunquam elevatis, angulis plus minus late rotundatis, lateribus plus
minus sinuato-retusis ; zygosporarum aculeis elongatis, subulatis, integris. (R.)

Diam. — .002".

Syn. — St. orbiculare, (EHRB.) RALFS, British Desmidieae, p. 125. RABENHORST, Flora Europ.
Algarum, Sect. III. p. 200.

Hob. — Rhode Island ; Bailey. Pennsylvania ; Wood. Rhode Island ; (S. T. Olney) Thwaites.

Segments in f. v. semiorbicular, smooth, without spines ; e. v. with three broadly rounded angles,
sides slightly concave. (A.)

Remarks. — Fig. 17, pi. 21, represents the outline of the end view of a frond of
this species. Fig. 8, pi. 1 3, is a drawing of the front view of a living frond.

2. Semicellularum anguli mucronati vel aristati.
Angles of Che semicells mucronate or bristly.

St. longispinum, (BAILEY) ARCHER.

St. magnum triangulare, laeve, angulis in aculeos geminos validos subulatos longe productum,
lateribus subplanum. (R.) Species mihi ignota.

Syn. — Didymocladon longispinum, BAILEY, Microscopical Observations.

Hob. — Florida; Bailey.

"Large, smooth, triangular, with two long spines at each angle." Bailey.

St. dejectum, BREBISSON.

St. Ia3ve, parvum, sinu amplo, obtusangulo (vel acutangulo) ; semicellulis ellipticis (vel snbtri-
angularibus), dorso nonnihil convexo, utroque fine in aculeum achroum rectum vel varie cur-
vatis productis; a vertice triangularibus (vel quadrangularibus), angulis ssepe rotundatis
aculeo interdum obsolete imposito.

IWam.— Lat. TSSo*— nVW' = 0008"-.001". Long. T5'5°,/— T5VV = .0008"— .0001".

Syn. — Staurastrum dejectum, BREBISSON. RABENHORST, Flora Europ. Algarum, Sect. III.
p. 203.

FRESH-WAT i: K ALG^E OF THE UNITED STATES. 149

Hab.— South Carolina ; (Ravenel) Wood.

Smooth, small; sinus ample, obtuse angled (sometimes acute angled?); serairells elliptic (or
subtriangular ?), with the dorsum slightly convex, at the angles with a straight or curved
transparent spine ; frura tbe vertex triangular (or quadrangular ''.), angles often rounded,
wiili u suiuetiuies obsolete spine superimposed.

•

It-nun-];*. — This species was collected near Aiken, South Carolina, by Prof.
Ravenel, who found it forming with various diatoms and desmids a slimy mass in
•A feebly rumiiiii; ditch. It agrees very well with the European form, except that
it is not so largo (at least the largest I ever measured did not come up to the
si/.e of their transatlantic brethren), neither does it appear to vary quite so much.
In the description, I have placed in brackets those characters in which the European
form varies, and the specimens I have seen do not.

Fig. 18, pi. 21, represents outline of end of a scmicell, magnified 7;>0 diameters.
9, pi. 13, a front view, and 9 a the end view, of the living frond, magnified
diameters.

St. nrittifVriim, i: AI.KS.

St. Iteve, St. cuspidatum quodammodo simile, et eadem mnpiitudine sed isthmo destitntnm ;
semiccllulis tumidis, in media partc subrotundatis, latcraliter in lobum, basi constrictum,
a]>i(>e aristatum productis, lobis divergentibus, a verticc tri-quadrilobo-radiatis, radiis strictis
:niui(li.-iuniilms cruciatim dispositis, iuterstitiis profuude excisis. (11.) Species mihi ignoia.

/>iVim.— Incl. arist. 0.0014". (R )

Xyn. — St.aristiferum, RALFS, British Desmidieae, p. 123. KABKNHORST, Flora Europ. Algarum,
Sect. III. p. 204.

Hab. — Georgia ; Rhode Island ; Bailey.

Segments smooth, in f. v. prolonged at each lateral extremity intoamamillatc projection, which
is terminated by a subulate, acute straight awn, the awns divergent, e. v. with three or four
angles ; angles inflated muiaillate, terminated by au awn, sides deeply concave in the centre.
(A.)

St. Lew isii, WOOD.

St. Iteve ; Binn amplissimo, spinulo parvo armato et cum angnlo obtnso ; isthmo nullo ; semi-
cellulis a fronte late triangularibus, a vertice triangularibus et cum augulis nonnihil tumidis,
et rotundatis ; angulis spino maximo, robnsto, acuto armatis.

Diam. — Long. cum. spin. ,JO" = .0025"; lat. cum. spin. y^oVn" — .00225". Sine spin. : long.
*£," = .001666" ; lat. rf&g" .001666". Spin. : long. TSW' = -000666"

Syn—St. Levnsii, WOOD, Proc. Acad. N. S. 1870.
Hob. — In lacu Saco; (Lewis) Wood.

Smooth, with a very ample sinus, which is armed with a small spine and has a very obtuse
angle ; isthmus absent ; semicells from the front broadly triangular, from the vertex trian-
gular, with the angles somewhat tumid and rounded ; angles armed with a very large acute
robust spine.

Remarks. — This desmid is most closely allied to St. arwtifertim, Ralfs, but differs
from it in outline as seen from the front, there being no mamellation of the ends.
The spines in the sinuses are always wanting in the European species.

Fig. 19, pi. 21, represents the outline of the end of a semicell, magnified 750
diameters. Fig. 11, pi. 13, represents the perfectly formed frond, magnified 750
diameters.

150 FRESH-WATER ALG^E OF THE UNITED STATES.

B. CYTIODERMA GEANULATUM VEL VERRUCOSUM.

CYTIODEKM GRANULATE OR WARTY.
1. Sem.icellu.lse a vertice 3-7 angulares ; anguli plus minus radiatim elongati.

Semicells seen from the vertex 3-7 angled; angles more or less radiate! >/ produced.

St. margaritacewm, Emm.

St. mediocre, granulatum ; semicellulis convergentibus, subfusiformibus, in medio turaidis,
utrinque productis, truncatis, a vertice orbicularibus, 5-7 radiatis, radiis obtuse truncatis
achrois, hyalinis, granulato-margaritaceis. (R.) Species mihi ignola.

Diam.— 0.00135"— 0.0017". (R.)

Syn. — St. margaritaceum, (EHRB^MENEGHENI. RABENHOHST, Flora Europ. Algaruin, Sect.
III. p. 206.

Hob. — South Carolina ; Georgia ; Florida ; Rhode Island ; Bailey.

Segments in f. v. gradually widening upwards, rough with pearly granules, outer margin con-
vex, produced at each side into a colorless, more or less attenuate, short process, having the
granules in transverse lines, blunt and entire at the apex, e. v. circular, bordered by from five
to seven short, narrow, obtuse, colorless, granulate marginal rays. (Archer. J

St. dilatatuni, EHRB.

St. parvum, granulatum ; semicellulis rectis, cylindrico-fusiformibus, non tumidis, utroque fine
obtusis vel subtruncatis, a vertice 3-4-5 radiatis, radiis latioribus, truncatis vel rotundatis,
achrois, hyalinis, granulato-margaritaceis. (R.) Species mihi ignota.

Diam.— 0.0008"— 0.0011". (R )

Far. alternans.

Semicellulis ellipticis rectis, utroque fine rotundatis, a vertice triradiatis, radiis obtusis, alter-
nantibus cum semicellulse inferioris. (R.)

Far. tricorne.

Semicellulis fusiformibus, nonnunqnam in medio snbtumidis, haud raro isthmo distincto con-
junctis, a vertice 3-4 angularibus, angulis truncatis vel obtusis, plus minus radiatim pro-
ductis. (R.)

Hob. — Georgia ; Florida ; Rhode Island ; Bailey.

Syn. — S. alternanSj BREBISSON. Far. alternans et tricorne. RABENHORST, Flora Europ.
Algarum, Sect. III. p. 207.

Remarks. — Prof. Rabcnhorst considers St. alfernans and tricorne, as simple varie-
ties of St. dilatatum, whilst both Archer and Ralfs describe them as distinct. I
have not seen either of them, and am not therefore entitled to offer an opinion.
Mr. Archer describes the two species as follows : —

St. alternans, BREB.

Segments in front view elliptic or oblong, two or three times as broad as long, separated by a
wide sinus, twisted, unequal; rough with very minute pearly granules; e. v. with three
obtuse and rounded angles, forming short, not colorless rays, alternating with those of the
other segments, sides concave. L. ^37". Br.

St. tricorne, BREB.

Segments in f. v. somewhat fusiform, often twisted, rough with minute puncta-like grannies,
tapering at each side into a short, usually colorless process, blunt or divided at the apex ;

FRKSH-WATER ALGJi OF TUB UNITED STATE 8. 151

e. T. tri-or quadriradiutc, processes short, usually colorless, sides somewhat concave. Spo-
rangium orbicular, beset with sjiincs ultimately brauched at the apex. L. tJVt" — »)«"•
B. ,1,".

2. Semtcellula- triangular es ; anyuli non producti, obtnsi vel rotundati.

,'nicelln trianyular ; the angles not produced, obtuse or rounded,

M. piim tiilntum, Hutu.

St parvum, pnnctulato-granulosum; semrcellnlis enormiter cllipticis, doreo lato rotuudatis, a
vertice triangular! bus ; angulis nun productis, obtuso rotuudatis ; latcribus uiudicu retusia.

Diam.— Lat. T^ff," — .001^".

.S'yn. — S. punriiildtum, ISutiiissoN. RALFS, British Dcsmidicse. RABENHOBST, Flora Europ.
Algarum, Sect. 111. p. 208.

Hab. — Pennsylvania ; Wood.

Small, pnnctulatc-granulate ; semicells irregularly elliptic, with the dorsum broadly rounded
from the vertex triangular ; angles not produced, obtusely rounded ; sides somewhat rctuse.

/.'' mark*. — This desmid is exceedingly common around Philadelphia, growing
in the greatest abundance upon the face of wet dripping rocks. It is represented,
fig. 10, pi. 13.

M. rrenatum, BAILZY.

St. duplo circitcr longins qnara latum, in medio utrinqnc exsectione profunda rotundata;
semicellnlis e basi cuneata flabclliforniibus, margiue superiore crenatis, a vertice triangular! bus,
angulis rotund ato-truncatis, crenatis, lateribus sinuatis glabris. (R.) Species nrihi iynota.

Syn. — St. crenatum, BAILEY. RALFS, British Desraidicte, p. 214. RABENHOBST, Flora Europ.
Algarum, Sect. III. p. 220.

" Segments cuneate ; outer margins crenate ; end view with three truncate and crenate angles."

3. Semicellulet vertice 3-7 radiatee ; radii in apice plerumque bi- tri-fidi vel bi- tri- gpini.
Semicells 3-7 radiate at the vertex; radii bi- or tri-fid, or bir or iri-spinous at the apex.

M. polymorphiim, BREB.

St. semicellulis ellipticis, subtiliter grannlatis vel tennysime spinulosis, in medio mapis mintisve
inflatis, baud raro ventricosis, rectis, nonnunqiiain incurvis, ntrinque processn plus minus
elongato, lineari, in apice 3-4 fido vel apinulis 3-4 tenuissimis instructis, a vertice 3-4—5-6-7
radiatis, radiis achrois, ant trifidis ant rotnndatis, trispinis. (R.) Species mihiignola.

,S'yn. — St. polymorphum, BREBISSON. RALTS, British Desmidiem, p. 135. RABENOOBBT, Flora

Europ. Algarnm, Sect. III. p. 209.
Dioni.— Long. 0.001". Lat. 0.00087". (R.)
ll,ib. — Florida; Bailey.

Segments in f. v. broadly elliptic or almost circular, rough with minute grannies (sometimes
with a few minute scattered spines), processes short, stout, tipped by three or four divergent
spines ; e. v. with three, four, five, or six angles each produced into a short, stout process.
Sporangium orbicular, beset with elongate spines, forked or branched at the apex. Archer.

Far. cyrtocerniii. (St. cyrlocerum, BREB.)

Majus, ad ,y, longnm, ficmicelltilis introrsum vontricosis, dorso late rotundatis, utrinque pro-
-u elongato, plerumque incnrvo apice bi- vel tri-cnnpidato instructis, a vertice triradiatis,
radiis rectis vel leniter curvatis, in apice aut bi- aut tri-cuspidatis. (R.)

152 FRESH-WATER ALG^E OF THE UNITED STATES.

Syn. Var. St. cystocerum, BREBISSON. RABENHORST, Flora Europ. Algarum, Sect. III. p. 210.

Hah.— Rhode Island ; (S. T. Olney) Thwaites.

Segments in f. v. subcuneate, gradually widening upwards, truncate at the end margin, rough
with minute granules, the lateral processes incurved, divided at the apex ; e. v. triradiate,
processes short, curved, sides slightly concave. L. -gJY'- !*• E!I/'- (Archer.)

St. p:i rodoMim. MEYEN.

St. semicellulis inflatis, dorso rotundatis vel rectilinearibus, angulis superioribus in radium
elongatum achroum hispidum, apice trifurcatim productis, so:pius radio a-quali interposito
a vertice tri- vel quadriradiatis, radiis strictis, trifurcatis, longitudine corporis diam. a;quau-
tibus vel superantibus. (R.)

Diam. — Cum rad. .0015".

Syn. — St. parodoxum, MEYEN. RABENHORST, Flora Europ. Algarum, Sect. III. p. 210.

Hab. — In lacu Saco, New Hampshire ; (Lewis) Wood.

Semicells inflated, dorsum rounded or rectilinear, with superior angles produced into elongate,
transparent, hispid radii with trifurcate apices, often furnished also with intermediate equal
radii ; from the vertex three or four radiate, radii straight, trifurcate, equalling or longer than
the diameter of the body.

Remarlcs. — I am indebted to Dr. Lewis for specimens of this species, which he
collected at Saco Lake.

Fig. 20, pi. 21, represents the end view of an emuty frond.

St. arachne, RALFS.

St. parvum, gracile, granulato-asperum ; semicellulis introrsum ventricoso-globosis, angulis
superioribus in cornu gracile, incurvum, apice obtusum, elougatis, a vertice pentagonis,
quinque-radiatis, radiis elongatis linearibus achrois, obtusis, rectis vel leniter curvatis asperis.
(R.)

Diam.— Sine rad. .0005", cum rad. .00167".

Syn. — St. arachne, RALFS, British Desmidiese, p. 136. RABENHOBST, Flora Europ. Algarum,
Sect. III. p. 210.

Hab. — In lacu Saco, New Hampshire, (Lewis) Wood.

Segments in f. v. stiborbicular, rougTi with minute granules, lower margin turgid, outer convex,
tapering at each side into an elongate, slender, incurved process having the granules thereon
.in transverse lines, entire at the apex; e. v. circular, bordered by five slender, linear, colorless
marginal rays.

Remark. — Fig. 21, pi. 21, represents an outline of the end view of the semicell.

St. gracile, RALFS.

St. mediocre, granulate asperum, granulis in series transversas ordinatis; semicellulis ventre
valde inflatis, dorso truncatis, angulis in cornu rectum achroum gracile apice trifidum pro-
ductis, a vertice triradiatis, lateribus sinuatis. (R.) Species mihi ignota.

Diam.— 0.0022". (R.)

Syn. — St. gracile, RALFS, British Desmidiese, p. 136. RABENHOBST, Flora Europ. Algarum,
Sect. III. p. 211.

Hab.— South Carolina ; Florida ; Georgia ; Rhode Island ; Bailey. Rhode Island ; (Olney)
Thwaites.

K II KSH-W ATKR A L G .V. OF THE UMTKD STATES. 153

• nts in f. T. triangular, ends truncate, rough with minute granules, tapering at each side
into elongate, straight, slender, lmri/.ontul processes, terminated by three or four minute
.--pino ; u. v. trirudiiite, processes utraight, sides concave. (A.)

( I YTIOHEKMA 1'll.ciM M, M'lM LO8UM VEL ACULEATl M.
CVTIODEUM IMLOKK, 81'INfI.OSK OK THORNY.

«»l. |>ol> lri« limn l'i :., ,

St. mediocre, turn longum quani latum, profunde constrictum, 8inu acntangulo ampliato, super-
ficie undic|iie setosiini ; Kemicellulis elli|iticis vcl gubellipticis, divcrgcntilius, dorso subplanis,
M-iitre tumidis, margiiie setoso-ciliatis, a Tcrtice triaugularibus, augulis obtusis, lateribus
•ubrectis. (II.)

Diam.— 7i J«" = .0017".

$yn. — St. polytrichum, PERTY. RABENIIORST, Flora Europ. Algarum, Sect III. p. 214.

llab. — Prope Philadelphia ; Wood.

Moderately large, about as long as broad, profoundly constricted, with the acute angled sinus
widened, surface everywhere furnished with setae; semicells elliptical or subelliptical, diver-
gent, the dorsum nearly plane, their belly swollen, the margin setose-ciliate, from the vertex
triangular, the angles obtuse.

Remarks. — This desmid appears to be rare in this country, as it probably is also
in Europe. I have seen but a single specimen, which I found amongst other alga;
near flu-Hen Hills, north of the city. It agreed in all respects with the descrip-
tion of Ilabenhorst, as given above.

Fig. 12, pi. 13, is a drawing of this plant, also fig. 23, pi. 21.

M. Ravenelii, WOOD. (sp. nov.)

St. mediocre, paulo longins qnam latum ; semicellulis a fronte ellipticis, a vert ice triangularibu.s
• urn lateribus convexis vel leniter retusis et angulis rotundatis ; i.-thmn connexivo subnullo,
lato ; sinu acutangulo ; cytiodcrmate epinis acuti.s, robustis numcrosis armato.

Diam.— Long. ^\0" = O.OOU". Lat. „<„" — 0.001".
//,,/,._South Carolina ; (Ravenel) Wood.

.Mediocre, a little longer than broad; semicells from the front elliptical* from the vertex trian-
gular, with the sides convex or slightly rctuse, and the angles rounded ; connecting isthmus
obsolete, broad sinus acute-angled ; cytiodcrm armed with numerous acute robust opines.

Remark. — Fig. 22, pi. 21, represents the front view of an empty frond of this
plant ; fig. 22 o, the side view, and fig. 22 t, the end, all magnified 750 diameters.

*l. liirMiitimi, (EHRB.) BREB.

St. magnum, tertiam partcm circitcr quam longins qnam latum, plus minus dense Rpinulosum,
sinu plus minus linear!, acutangulo ; semicellulis late cllipticis vel subsemiorbicnlaribns,
spinis tenuibns etrictis hirsutis, a vertice triangnlaribus, angulis obtuse rotnndatis, lateribus
rectis vel leniter convexis. (R.) Species mihi ignota.

Diam. — Sine spinis 0.0015". Zygospor. 0.0022". (R.)

Syn. — St. hirsutum, (EiiRENBERn) RREIIISSON. RABENIIORST, Flora Europ. Algarum, Sect
III. p. 211.

Hob.— Florida; Rhode Island; Bailey. Rhode Island; (S. T. Olney) Thwaites.

20 August. 1873.

154: FRESH-WATER A L G JE OF THE UNITED STATES.

Segments in f. v. semiorbicular, separated by a linear constriction, covered with very minute,
very numerous close set hair-like spines ; e. v. with three broadly rounded angles, the spines
evenly and numerously scattered ; sides slightly convex. Sporangium orbicular, beset with
short spines, branched at the apex. (A.)

St. Hystrix, RALFS.

St. parvum, tertiam partem longius quam latum, angulis aculeatum (cseterum loevc), sinu acu-
tangulo ; semicellulis subquadratis, angulis late rotundatis, dorso planis, a vertice 3-4 angu-
laribus, angulis late rotundatis, plus minus dense aculeatis. (R.) Species mihi ignola.

Diam.—0.00l"—0 00089". (R.)

Syn. — St. Hystrix, RALFS, British Desmidieae, p. 128. RABENUORST, Flora Europ. Algarum,

Sect. III. p. 213.
ffab.— Rhode Island ; (S. T. Olney) Thwaites.

Segments in f. v. subquadrate, extremities somewhat rounded, end margin nearly straight, fur-
nished with a few scattered, subulate, acute spines, chiefly confined to the lateral extremities;
c. v. with three or four broadly rounded angles, the spines scattered, chiefly confined to the
extremities, sides concave. L. TnVi?"— nrW- Br- nW — ffk"-

St. Cerberus, (BAILEY) ARCHER.

St. parvum, tarn longum quam latum, sinu rotundato, snperficie laevi ; semicellulis oblongis
utroque fine sinuato-truncatis, angulis in aculeum cnspidutum productis, in medio sursum et
deorsum prominentiis geminis in aculeum elongatis instructis, a vertice triangularibus, angulis
in apice truncate- vel sinuato-bi-cuspidatis, sub apice aculeis geminis brevibus praditis. (R.)
Species mihi ignota.

Diam.—Cum. acul. 0.00114"— 0.0013". (R.)

Syn. — Didymocladon Cerberus, BAILEY, Microscopical Observations.

St. Cereberus, (BAILEY) ARCHER. RABENHORST, Flora Europ. Algar., Sect. III. p. 215.
Hob. — Florida ; Bailey.

Small, deeply constricted, segments three-lobed, lobes with four teeth, two of which project
upwards and two downwards at each truncated angle. (A.)

D. CYTIODERMA PROCESSIBUS NUMEROSIS, APICE PLERUMQUE TRUNCATIS ET DENTATO-FISSIS

MUNITUM.

CYTIODERM WITH NUMEROUS PROCESSES, WHOSE APICES ARE MOSTLY TRUNCATE AND DEN-
TATELY TORN.

St. ftircigeruin, BREB.

St. validum, subraagnum, circiter tarn longum qnam latum, laeve vel subtiliter granulatnm,
plernmque profundissime copstrictum, sinu angusto lineari ; semicellulis oblongo-ellipticis,
plus minus tumidis, angulis in processns bifurcum aut rectum aut divergentem longe pro-
ductis, dorso processibus similibus 2, 3, 4, instructis, omnibus processibus achrois granulato-
dentatis, granulis in series transversas ordinatis, a vertice 3-, 4-, 6-, 7-, 8-, 9-angularibus vei
radiatis, angulis plus minus tumidis, in processus crassum achroum asperum in apice fissuin
productis. (R.) Species mihi ignola.

Long. Sine process, 0.0018"— 0.0019" ; c. pr. 0.003'"— 0.0032". Lat. sine proc. 0.00185";
c. pr. 0.0027". (R.)

Syn — Stauraiitrum furcigerum, BREBISSON. RABENHORST, Flora Europ. Algar., Sect. III.
p. 219.

Didymocladon fur tigerus, RALFS, British Desmidieae.
ffab. — South Carolina ; Florida ; Rhode Island ; Bailey.
St. miinil urn. WOOD.

St submagnum, fere £ plo longius quam .atum, medio leviter constrictum, semicellulis a fronte

FRKSII-\V A I ]• II ALG.i: 01 THE UNITED STATES. 155

ennrinitrr lii-xair'uiis, niiirulis in processna rectos et divergentes productis, dorso processibui
hiinililnis 4-;"> in.-iriirio ; •.emirellulis a vert ice polygouis vel sulioruieularihuH uiuririnc proces-
s-Mills niimiT'iM-, |ilrniiui|iic '.' in-tni'-in ; ilorso processibus 5-8 instruct!* ; processibus omni-
l>ii- .Miiiilihus, granulutu-ilentati.s, apice achroo siuiplicibus, bifurcatis vel fissis.

Diam. — A venire cum proccssibus, yVoW = .00475". Sine process. iAW ~ -002".
Syn.—St. mttnitum, Wood, Proceed. Ac. NatSc., 18G9.
Hub. — In lacu Saco, New Hampshire; (Lewis) Wood.

S. rather large, about one-half longer than broad, slightly constricted in the middle ; semicelle
fn>m the front irregularly hexagonal, the angles prolonged in straight divergent processes,
and the surface furni.-hed with four or five similar ones ; scmicells from the vertex polygonal
or siiliurhiriilar, the margin furnished with numerous processes, mostly about nine, and also
with 5-8 on the dorsuni ; processes all similar, granulate-dentate, their transparent apices
.simple, bifurcate or torn.

k*. — This species is most closely allied to St. furcigentm, Br^b., from
which it is at once distinguished by the orbicular vertex. The constriction between
thr srinirrlls is also very different. In St. iminilnm it is a gradual, not very deep,
hour-glass contraction ; in St. furciymtm it is very narrow and linear.

Fig. 13 a, pi. 13, is a front view of this plant magnified 260 diameters ; fig. 13 6,
the c'lul view of the same.

St. eiiwtcplianum, (K"RB.) Ii.vi.rs.

St. laterum integrorum angulis productis apice spinulosis, spinularum furcatarum corona media

dorsali. (II.) Species mihi ignota.
Syn. — Desmidium euslephanum. EHRENBERO, Verbrcitung and Einfluss dcr Mikrosk. Lebcus

in Siid- uud Nord-Amcrika, t. 4, f. 23.

Staurastrum eustephanum, (EiiRB.) HAI.KS, British Desmidieffi, p. 215.
Stephanoxanthiumeustephanum, KLTZINO. UABENUOOST, Flora Europ. Algarum, Sect.

III. p. 221.

Nauraslriim euglephanum, UALFS. RABENHORST (loc. tit.)
Hab. — West Point, New York ; Bailey.

Knil view triangular with six emarginate spines on the upper surface; each angle terminated
by a short ray tipped with spines. (Ralfs)

St. senarium, (EIIRB ) RALFS.

Antecedent! simile sed laterum parictibus spinulis furcatis binis (sex), corona dorsali senaria.
(II.) Species mihi ignota.

Syn. — Desmidium senarium, EiiRENnER», Verbrcitung. T. IV.

Slephanoxanthium senarium, KUTZINU. RABENHORST, Flora Europ. Algarura, Sect. III.

p. 220.
Slauraslrum senarium, (EiiRB.) RAI.FS, British Desmidieas. RABENUORST, (loc. cit.)

Segments smooth in end view with three angles, each terminating in a short process tipped by
minute spines, without lateral processes, but with six others confluent at their bases on the
upper surface, divergent and forked. (Archer.)

Genus XANTHIDIUM, EHRB.

Cellnlaj singular vel geminee concatenatas, inflatc-rotundatae, profunde constrict® ; semicellulae
compress*, oblongee, hemispherice vel subquadrangnlares, centre in tnberculum rotundatum vel
truncatura et denticnlatum protnberantes, ex transverse oblongo-rotundatse. Cytioderma firmum
setis, aculeis vel spinis simplieibus aut bi- tri-furcato-divisis armatum. Massa chlorophyllacea
ndiatim expansa. Zygosporie arniatae. (R.)

156 FRESH-WATER ALG^E OF THE UNITED STATES.

Cells single or geminately concatenate, inflated, profoundly constricted ; semicells compressed,
oblong, hemispherical or subquadrangular, protruding in the centre as a rounded truncate or den-
ticulate tubercle Cytioderm firm, armed with setae, or simple, or bi- tri-furcately divided spines.
Chlorophyl radiately expanded. Zygospores armed.

Remark. — It has so happened that I have identified but a single species of this
genus.

X. aculeatum, EHRB.

X. parvum, singulum, sparsum, diametro ipse subtequale, ex obliquo ellipsoideum, diametro
duplo longius, constrictione obtusa lineari, semicellulis oblongis subreniformibus, basi sub-
planis, dorso late rotundatis, tuberculo centrali minus elevato, truncate, marginc autem crenato-
dentato ; cytiodermate undique aculeis subulatis obsito. (R.) Species mihi ignota.

Diam— (Sine aculeis) 0.0025"— 0.0029". (R.)

Syn. — Xanihidium aculeatum, EHRENBERG. RABEMIIORST, Flora Europ. Algarum, Sect. III.
p. 222.

Hab. — Prope Savannah, Georgia ; Bailey.

Frond inf. v. broader than long; constriction deep, linear; segments somewhat reniform ;
spines subulate, short, scattered, chiefly marginal ; central protuberance cylindrical, truncate,
border minutely dentate. (A.)

X. Arctiscon, EHRB.

X. semicellulis globosis, binis, aculeatis, aculeis numerosis undiqne sparsis crassis asperis apice
trilobis. (R.) Species mihi ignota.

Syn. — X. Arctiscon, EHRENBERG. RABENHORST, Flora Europ. Algarum, Sect. III. p. 224.
Hab. — America borealis ; Ehrenberg.

Frond in f. v. about as long as broad ; constriction forming a wide notch ; segments narrowed
at the base, with broadly rounded ends ; spines numerous, restricted to the outer margin,
scattered, elongate, stout, terminated by three or four diverging points. (Archer.)

AL, a mint ii HI, (BREB.) RALFS.

X. maximum, validum, solitarium vel binatim conjunctum, diametro plerumque duplo longius;
semicellulis subcordatis vel angulari-rotundatis tuberculo centrali subelevato, truncate, mar-
gine granulato-dentato prseditis ; cytiodermate verruculoso et processibus saspius geminatis
truncatis apice inciso-furcatis instructo. (R.)

Syn. — Xanihidium armatum, (BREBISSON) RALFS, British Desmidieaa et RABENHORST, Flora
Europ. Algarum, Sect. III. p. 222.

Hab. — South Carolina ; Florida ; Bailey. Saco Lake ; (Lewis) Wood.

Frond large, in f. v. twice as long as broad ; constriction deep, linear ; segments broadest at
the base ; ends rounded or somewhat truncate ; spines in pairs, principally marginal, short,
stout, terminated by three or four divergent points ; central projections cylindrical truncate,
the border dentate ; e. f. punctate. Sporangium large, orbicular, with depressed tubercles,
perhaps immature. L. T|T". B. ^v". (A.)

Remark. — Fig. 17, pi. 13, is a front view of a frond, magnified 260 diameters.

X. bixciiariiim, EHRB.

X. semicellulis globosis subangulosis, binis, aculeatis ; aculeis fasciculatis, fasciculis in quovis
globulo senis. Species mihi ignota.

Syn. — X. bisenarium, EHRENBERG. RABENHORST, Flora Europ. Algarum, Sect. III. p. 224.
X. Brebissonii, RALFS. ARCHER, PRITCHARD'S Infusoria, p. 736.

i i; i-:s ii -\v ATI: i: AI.<;.I: OK TIM: I.MTKD STATES. 157

//•ill. — America ; Klircnlicrg.

Frond in front view broader than lonp; constriction deep, acute not linear; segments nuln-l lip-
tic, sometimes irrcirulur spines subulate, geminate, marginal, central protulHTanee cylindrical,
truncate border minutely dentate. L. (not including spines) jj¥". B. ?J," to jjj".

JL rriotntiim, HKKII.

X. ]>arvuni, lu-ve ; scmicellulis subhasmispherico-rcniformibus, utroque polo aculeo unico in-
curro, ainbitu aculcis octo geminatia, a dorso ovato-ellipticis, utroque polo aculeis tcruiH, in
incdin plcniini|iic aculco abbreviate. (R.) Species ntihi ignota.

lHam.— 0.00196". R.

A . rifliilinn, HiiKiiissox. RALF8, British Desmidieae, ct RABENIIORST, Flora Kurop.
Algarum, Sect. III. p. -JiM.

Hub. — South Carolina; Georgia; Florida; Bailoy.

Frond rather longer than broad; constriction deep, linear ; segments subreniform or truncate
at ends ; spines straight or curved, subulate, marginal, one at each side, at the base of the
segment, solitary, the others geminate, in four pairs ; central protuberance short, conical. (A.)

\.coroiintiim. K.mui.

X. scmicellulis subglobosis binis, aculeatU, ubique aspcris, aculois crassis apice truncatis triden-
tato-coronatis quatuor utriuque dorsalibus, uno utrinquo laterc uiedio. (R.) Species mihi
ignota.

Syn. — X coronatum, EHRE.NBERO, Vcrbreitung, p. 138, ct RABENIIORST, Flora Europ. Alga-
rum, Sect. III. p. 224.
Asteroxanthium coronatum, KUTZINO. RABENHORST, (loc. tit.)

JIdb. — America ; Ehrenberg.

/,'• mark. — Mr. Archer appears to think that this species is simply a form of
iraslrum furcigerum. (BREB.); see Pritchard's Infusoria, p. 743.

X. f;i«< i< iilntiim, KIIKH.

X. parvum, singulum, constrictiono profundo linear! ; cytiodermatc Irevi vcl Rubltcvi ; semieel-
lulis oblongo-reniformibus vel hexagonis, diametro duplo longioribus, ambitu aruleis gracililms
geminatis 4-C, a dorso ellipticis, utroque polo aculcis quatuor instructis. (R.) Species mihi
ignota.

Diam.— 0.00228"— 0.00256". (R.)

Syn. — -.Y./aaei'cu/a/uwi.EnRENBERa. RABENHORST, Flora Enrop. Algarnm, Sect. III. p. 223.

Hab. — South Carolina ; Georgia ; Florida ; Rhode Island ; Bailey.

Frond about as long as brood ; constriction deep, linear ; segments somewhat reniform or sub-
hexagonal, twice as broad as long, spines slender, subulate geminate, marginal, in four or six
pairs ; central protuberance short, conical, somewhat truncate. (A.)

Genus ARTHRODESMUS, EHRB.

Cellulaj profunde constrictae ; semicelluloe compresses aut oblongee, utroqne polo acnleo subulato
firmo instructor, aut quadrangularcs, angulis in aculenm rectum vel ciirvum prodnctis, a dorso vel
elliptic® vel fusiformes. Massa cblorophyllacea in fascias quatuor radiantes disposita. (R.)

Cells profoundly constricted; semicells compressed or oblong, furnished at each end with a subu-
late spine, or else quadrangular with the angles produced into straight or curved spines, the dorsal
aspect, elliptic or fusiform. Chlorophyl masses disposed in four radiating fascia.

158 FRESH -WATER A L G M OF TUE UNITED STATLS.

Remarlcs. — I have found only a single undescribcd species of this genus, but the
following European forms have been detected in this country by Prof. Bailey. The
genus appears to be, as Prof. Rabenhorst says, scarcely distinguishable from Xa«-
thidium or Staarastrum.

A. octocornis, EURB.

A. parvns, Isevis, constrictione lata excavata; semicellulis trapezoideis, inciso-quadriradiatis,
radiis in aculeum acutissiinum strictum porreetis, a latcre clongato-ellipticis, diaruetro fere
triplo longiorilms, utroquc polo aculeum singulum gercntibus. (R.)

Diam.— 0.00065". (R.)

Syn. — Xanthidium octocorne, RALFS. BAILEY, Microscopical Observations, p. 29.

Arthrodesmus octocornis, EURENBERG. RABENHORST, Flora Europ. Algarum, Sect. III.
p. 223.

Hab. — Florida ; Rhode Island ; Bailey.

Frond smooth, minute, about as long as broad ; constriction a wide notch ; segments much
compressed, trapezoid, each angle terminated by one or two straight, subulate, acute spines,
the intervals between the angles concave. (A.)

a. Spine solitary at each angle. L. T3Vr"- B. TjVs"- (-A-)

b. Larger spines geminate at each angle. L. -roVs"- B. $iY'. (A)

A. quadridcns, WOOD.

A. late ovalis, vel suborbicularis, paulum longior quam latus, cum margine crenato-undulato;
semicellulis nonnihil reniformibus, ntroque fine aculeo subulate, modice robusto, acuto, re-
curvo, armatis ; cytiodermate cum verruculis paucibus modice minutis in seriebus paucibus
dispositis instructo; semicellulis a vertice acute ellipticis, et cum margine crenato ct super-
ficie sparse verruculosa.

Diam.— Lat. ^^" = .00075" ; long. ?5V' = .00125".
Syn. — A. quadridens, Wood, Proc. A. N. S. 180 9.
Hab. — In lacu Saco, (Lewis) Wood.

Broadly oval or suborbicular, a little longer than broad, with the margin crenately undulate ;
semicells somewhat reniform, at each end armed with a subulate, moderately robust, acute,
recurved large spine ; cytioderm with a few smallish tubercles arranged in three or four rows ;
semicells from the vertex acutely elliptical, with the margin crenate and the surface sparsely
•warty.

Remarks.— This species approximates A. divergens, from which it differs in the
arrangement of its granules, its attaining not one-half the size, and, I believe, in
the larger and more robust spines.

Fig. 2, pi. 20, represents an empty frond of this species.

A. Incus, (BREB.) HASSAL.

A. parvus tarn longus quam latus, constrictione linear! obtusa vel late excisa; semicellulis
oblongo-quadrangularibus, angulis externis aculeatis, internis rotundatis inermibus, aculeis
longis singulis divergentibus. (R.)

Diam.— Max. 0.00098". Long. 0.00091". Spor. (sine acul.) 0.00085".

Syn.— A. Incus, (BREBISSON) HASSAL, Fresh-Water Algse, p. 357, et RABENHORST, Flora

Europ. Algarum, Sect. III. p. 226.
flab — Georgia; Florida; South Carolina ; Rhode Island ; Bailey.

Frond minute, smooth, as long, or longer than broad, constrictions a deep notch or sinus; seg-
ments with inner margin turgid, outer truncate; spines subulate, acute ; sporangium orbicular,
spinous; spines subulate. (Archyr)

FUKSII-W ATKll ALUJ-: OF T II K UNITED STATES. 159

A. converifen*, F.HRB.

A. la- vis mediocri.s, profnndc ct an^ustu constrictus, aculcia conrcrgcntibuB armatus; semicel-
luli.s elliptic.!* vcl ovato-oblongis, nonnuuiiuaiu n-nitorinilius, utroque line uculuu longo Grnio
incurvo instruct!*. (II.)

JUam.— 0.00185"— 0.0016". (U.)

.s'yu. — .t. convergena, EHRENBERU. KAIIKNIKUIST, Flora Europ., Algarum, Sect III. p. 227.

II, ih. — South Carolina; Georgia; Florida; Rhode Island ; Bailey.

Fr.>nd smooth, l.r.'.uler than long; constriction duep, acuto ; segments elliptic, each having its
lateral spines curved towards those of the other; ends convex. L. 1J39" — jjj" B. H'TT" —
4J¥". (Archer)

FAMILY ZYGXEMACEjE.

CYllulffl cylindrical osquipolnres, similes, in familias filamentosas arcto conjunct®, ct cytioblasto

mitrali plasuiule plerumquo radiunte inroluto, et plasmate chlorophylloso aut effuso, ant effigurato,

nut i plcrniin|iie j in foscias spirales ordinato, et granulis amylaccis instructs. Filum simplex. Pro-

• io fit zyir»-|Hiris conjugatione cullularum binarum ortis. Conjugatio triplici uiodo, aut latcralis

ant scalarifonnis vcl gcnuflcxa. Vcgetatio fit divisione transversali rcpetita.

Cells cylindrical, the samo at both ends, closely conjoined into filamentous families, furnished with
a central eytioblast wrapped up in generally radiating protoplasm, and with chlorophyllous proto-
n i tl'n-. '1 in shapeless masses or arranged in spiral filaments, and also with scattered starch-
prannlcs. Filament simple. Propagation takes place by means of rygospores, arising from the
conjugation of two cells. Conjugation occurring in three ways, lateral, scalariform, and genufloxuous.
tir.'M ih taking place by means of transverse division of the cells.

/,' • murk*. — The family under consideration is among the commonest and most
widely diffused of all the fresh-water algae. In almost every ditch or spring, or
dripping moss-covered rock representatives of it are to be found, so that wherever
quirt \\iitcr is they may be confidently looked for. The single filaments are so minute
that 1'ivqiirntly the unaided eye cannot distinguish them, but multiplication with
tin-in is such a rapid process, that wherever found they are in great masses. These
musses, when growth is active, are of a beautiful intense green, glistening and
shining with the gelatinous matter which coats the threads and makes the mass so
sliiijM-ry. They may be found in greater or less abundance at all seasons, but as
tlie specific characters are largely of sexual origin, non-conjugating specimens arc
of little value. For this reason, Zygnemos are only worth gathering when in fruit.
The spores appear to be formed only in the spring and early summer, at least these
are the only times in which I have found fertile filaments. In this neighborhood
I have collected them in excellent condition as early as the beginning of April and
as late as the latter part of June. Further south, conjugation of course commences
earlier, and fine fruiting specimens received by myself from Mr. Canby were col-
lected in Florida by him in February.

"When conjugating freely the mass of Zygnema or Sptrogyra loses its beautiful
bright green color and become dingy and even brownish, often very dirty looking.
The collector soon learns to pass by the beautiful vivid mass, as comparatively
worthless, and fasten upon the pale, wan, sickly, apparently dying specimens as
pri/es worthy of a place in his cabinet.

In the Zyynemacece the individual plant, as ordinarily considered, is a filament

160 FRESH-WATER ALG^E OF THE UNITED STATES.

composed of a varying number of cells placed, end to end, all alike, and each of
them apparently independent of its associates. Each cell in one sense is, therefore,
a perfect, complete individual, capable of living dissociated from its companions.
How far the life of one of these cells is influenced by that of its neighbors is un-
certain, probably to a slight extent, possibly not at all. At any rate, they are so
far independent that the filament is rather a composite body than a unit of life.
These cells are cylindrical, with the ordinary cellulose wall, which can commonly
be stained blue by iodine and sulphuric acid, and is often distinctly composed of
layers, but never has any " secondary markings," each layer being precisely like
that superimposed upon it. Outside of the wall is a jelly-like sheath, which is
mostly not discernible from its thinness and transparency, although it no doubt
exists, as is proven by the slipperiness of the general mass. The primordial utricle
is always present. The chlorophyl is variously arranged, most generally in bands,
either straight or spiral, sometimes in definite irregular masses, sometimes diffused
through the cell. Imbedded in it are, at certain seasons, numerous minute, gene-
rajly shining, granules, which are either minute specks of starch, or little drops of
oil. Besides these there are contained in it, especially in the bands of chlorophyl,
more or less numerous comparatively large, oval or roundish bodies, with a distinct
outline and a deeper color than the surrounding portions. These masses are pro-
toplasm, dyed with chlorophyl-green, and are believed to be especially active in
the formation of starch. At times, iodine turns them simply brown ; at others it
colors their inner portions blue and their outer brown, showing them to contain
starch. The general cavity of the cell is occupied by fluid, in which is placed the
nucleus. This is mostly single, but rarely, according to Naegeli and other authori-
ties, double, and De Bary states that he has seen three nuclei in a single cell. I
have "never seen more than one, and think that even this is not rarely absent, having
certainly repeatedly failed to demonstrate its presence. It is colorless, often with
a nucleolus, transparently bright, irregular in form, placed in the centre of the cell
•with numerous arms radiating out from it, some of them ending within the cell,
others connecting it with the primordial utricle. De Bary states that this nucleus
occasionally is tinged green with chlorophyl, I do not remember ever to have seen
it so.

I have not infrequently seen numerous minute dark granules, similar to those
seen in Closterium, scattered through the inside of the cell, in active motion. Some-
times they are to be found collected in vast numbers near the ends of the cells,
dancing and swarming about one another, and passing off in small streams from
one end to the other, coasting along close to the primordial utricle, in a word, ex-
hibiting precisely the same motions as are so common among the desmids.

The Zygnema filament grows in length by a process of cell multiplication by
division of the simplest kind. It seems to be somewhat uncertain whether the
nucleus always divides into two as a part of the process or not. These plants
multiply both by the separation of cells and their subsequent growth, and, by
means of resting spores, the so-called Zygospores.

The first appearance of separation of the cells is an evident disposition to the
rounding off of the ends of the cells. The corners are first rounded and separated

FKKMl-W ATKK A.LGJB OK T 11 K V N 1 T K D STATES. 161

and this continues until only the centre's of the ends are in apposition, and in a
little while esen these separate. This certainly, at least, is the. process in certain
species; but 1 have thought, that in other cases cells were separated by a simple
splitting of the end wall, each cell retaining its half of the partition.

The zi/'ji*i>»rtx are produced by a process of union of two cells, to which the
name of r<niju<jnti<m has been given. Very rarely, if ever, is there any difference
between the cells before conjugation, and it has not existed in any species which has
come under my notice; but, after conjugation, the receiving cell is frequently
enlarged, the other remaining cylindrical. De Bary, however, states that he has
found a .small but constant difference between the fertile and sterile cells of

The first perceptible change in a cell about to produce a resting spore, appears
to be a loosening of the primordial utricle from the outer wall, and a contraction
of it upon the cell consents, which thus are crowded together and more or less
deformed. Simultaneously with this, or a little after or before it, the side wall of
the cell is ruptured and a little pullulation or process is pushed out, which directly
itself \\ith cellulose and rapidly enlarges to a considerable diameter, at the
same time growing in length until it meets a similar process pushing out from an
opposing cell, or has attained as great a length as its laws of development will
;.llow. "When two processes meet they become fused together, the end walls arc
ruptured, and the contents of one cell passing over are received within those of the
other, or else the contents of both cells meet within the connecting tube and there
fu-e together. This is the more common mode of conjugation, in which two cells
of distinct filaments become joined together by a connecting tube. It is evident,
that, if the filaments arc fertile to their fullest extent, there will be as many of these
connecting tubes as there are pairs of cells in the filaments, and a ladder-like body
will be formed, the original filaments corresponding to the side pieces, the connect-
ing tubes to the rounds. Hence this method of conjugation has received the name
oalariform.

In the so-called "lateral conjugation" instead of cells of different filaments join-
ing, adjacent cells of one filament unite together to complete the process. The
union of the two cells appears to take place in several ways. In accordance with
one plan (fig. 1 o, pi. 14), connecting tubes, pushed out from near the ends of
the cells, grow for a short distance nearly at right angles to the long axis of the
filaments, and then bend at a right angle to themselves so as to run parallel to
the filament-cells. The ends of these processes are, of course, opposed to one
another, and coming in contact fuse together so as to form a continuous tube for
the passage of the endochrome. Another method by which neighboring cells are
sometimes connected is by the formation of coadjaccnt pouch-like enlargements of
the opposing ends, and a subsequent fusion of these newly formed enlargements
by the absorption of the end wall between them. (See fig. 2, pi. 1 4.)

Sometimes I think the union of two neighboring cells is facilitated by a curved
v forming to one or both of them, so that they are bent at an angle to one
another, and can readily be united by means of a straight tube.

There is still another method of conjugation, the so-called genvjlexuou*, in which,

21 August, 1873.

162 FUESU-WATER ALCvE OF THE UNITED STATES.

instead of a connecting tube being formed as the medium of union, two cells of
opposing filaments become sharply bent backwards, so that their central portions
are strongly thrust forward as obtuse points, which, coming in contact, adhere and
allow of a passage-way between the cells being made by the absorption of their
cohering walls.

A curious modification of, or departure from, the ordinary method of conjugation
is sometimes seen, in the union of three instead of two cells. This is, I think, -
very rare, but has been seen by Meyen in the genus Zyynema, as well as by
Schleiden and De Bary in Spirogyra. I myself have observed it once or twice in
the latter genus. One of the cells plays the part of the female, receiving the con-
tents of the other two, so that in it the primordial utricles of the three, with their
contracted protoplasm, arc fused into a zygospore.

The zygospore, however formed, varies in shape, but is mostly oval or globular,
sometimes cylindrical, and when ripe is in most if not all species of a dark brown-
ish color. It is described both by Pringsheim and De Bary as having three coats,
but I have frequently found it impossible to demonstrate the presence of all of
these, and I believe that not rarely one of them is absent. The outer coat is
developed first and is the thickest and firmest. Occasionally it is double, i. e.
composed of two distinct layers or parts, as in Sp. protecta, in which species the
outer of these layers is the thickest, firmest, and most evident, whilst the inner
layer is translucent and much less apparent. The second coat contains the
coloring matter, which is sometimes brown, sometimes decidedly yellowish. The
inner coat is not readily seen. It is elastic, thin, and is the last of the three to be
formed.

The principal contents of the ripe spore are protein compounds (protoplasm),
oil-drops, starch granules, and pigment. The oil is generally much more abun-
dant than the starch, and not rarely the minute, bright drops entirely replace
the little granules. According to Prof. De Bary, the pigment frequently, but not
always, reacts with sulphuric acid, as does that of the fungal family, Uredinece,
striking with it a deep blue.

The germination of the spore, both in the genus Spirogyra and Zijgnema, is
very simple. The first step is an elongation and growth of the protoplasmic
central mass, together with the inner transparent cellulose coat, and a consequent
rupturing of the outer two coats, through which the newly forming plant protrudes
and finally escapes. In this way in the genvis Spirogyra an elongated club-shaped
cell arises, one end of which is much larger than the other and contains all the
chlorophyl. Sometimes a nucleus is perceptible in this cell, sometimes it is not.
The larger end now becomes cut oif by a partition wall from the smaller ; if no
nucleus has been previously apparent it now becomes so, and the first stage of
development is completed. The filament after this grows by a simple repetition
of the process of division in the larger end and the cells formed out of it. The
smaller end undergoes little or no change. In the genus Zygnema, the cell that
first emerges from the germinating spore is a perfect one, similar in all respects to
those seen in the fully formed filament, which is developed out of it, by a simple
process of cell division.

r i: I.SH-W ATKII AMJ.I: or TIM: r N i T i-: D STATES. 163

the true /fi/i/'i.-/'!!,-' -. I lassall many years since descrilx-d bodies (Fre&-
w;itcr Alir.r, Mil. i. pp. 1 :>•.', l-"ii>, 170), which lu- found in filaments of thisfamih,
and which resemble in all respects nrdinary ^fyj/fwywrai, but arc produced each
in ;i single cell wulnmt any aid from a second celL He affirmed that he had
observed this phenomenon especially in two species, Spirogyra mirabili* and
Zy</iinnn ii<>ttiltHI*. These observations were doubted by some, whilst others, as
Alexander Hnum, suppost •<! that there was a division of the cell protoplasm into
two distinct portions, and then a conjugation of these within the original cell, and
that Mr. Hawaii had overlooked these changes. Prof. DC Bary, however, -states
that he has seen a great many instances of this production of spores without conju-
gation (all in one species), and that there can be no doubt that HassaH's obser-
vations are substantially correct, and that no division of the primordial utricle such
as \\as imagined by Prof. 13raun takes place. Spores formed in this manner, as
yet have not been seen to develop. There is, therefore, no certainty that they are
capable of doing so. It is possible that they are merely the results of abortive
attempts at reproduction, wanting the power of development because not fertilized.

I'riiig^heim and others have drawn from these bodies strong argument against
the idea, that conjugation is to be looked upon at all as a sexual process.

The arguments both for and against regarding conjugation as the simplest ex-
pression of sexual life are ably elaborated by De Bary, Untermdtungen iit>er die
l-'uiiii/i,' i/i r <\>i<jii<ititcin, p. 57, to which I must refer those desirous of following
the subject further, contenting myself with expressing an agreement with the con-
elisions there arrived at, namely, that in conjugation the first dawnings of sexuality
are to be found. Looking at it in this light Prof. Uc Bary states his conviction
that the spores formed in the manner last described, bear the same relation to the
true Xt/</"*/><>re that the bud of a Phanerogam docs to its seed, or the Zoospore of
an (!•'.< 1 1 ><j< in i nm does to its resting spore.

Quite a number of bodies have been described by the older authorities as being

found within the cells of plants of this family, which more recent observers have

proven to be parasitic. Such arc the "Spermatic spheres," transparent spheres

motile by virtue of vibratile cilia, various monads, &c. &c., bodies for which it has

D claimed, from time to time, that they were sexual elements, spermatozoids.

Genus SPIROGYRA, LINK.

C'rllulip vegetative cylindrical, fnsciis cliloropbyllosis spiralibus instructs:. Conjugatio aut later-
alls am M-iilariformis aut ct latcralis ct scalariforuris.

. — Spirogyra el Rhynchonema, K i T/.INU, RABENHGRST, et auctorea.
Salmacis, BORT.
Zygnema (pnrtim), HASSAI.I..

••tntive cells cylindrical, furnished with spiral rhlorophyl bands. Conjugation either lateral
or Bcalariform or both latcrul and Bcalariform.

Remark*. — The genus Spirogyra, as defined above, has been divided by Kiitzing,
Rabenhont, and others into two genera, the characters being drawn from the
method of union of the conjugating cells; in the one case the neighboring cells of
a single filament (Rhyiichonema), in the other cells of distinct filaments

164 FRESH-WATER ALG^E OF THE UNITED STATES.

uniting to form the spore. This at first sight appears to be a good ground for sepa-
ration, but there are certain species in which, undoubtedly, both the former and
the latter method of conjugation take place indifferently. Such species make a
third group so precisely between the two others as, to my mind, to fuse them toge-
ther and necessitate either the acknowledgment of three genera or the denial of
more than one. The latter seems to me the more philosophical course.

A. CONJUGATIO LATERAUS (RlIYNCHONEMA).
A. CONJUGATION LATERAL.

Sp. elongata, WOOD.

Sp. articulis vegetativis diametro 7-20 plo longioribus; articulis sporiferis multo brevioribus,
valde tumidis ; cytiodermate utroque fine protenso et replicato ; fascia uuica, laxissime spiral!;
anfractibus plerumque 7 ; sporis ellipticis, diametro 1-2^ plo longioribus.

Diam.— Spor. y/^" = .00106". Artie, vegetat. 7^" =.0005".

Syn. — BhynchonemaelongatumJffoo'D, Prodromus, Proc. Amer. Philos. Soc. 1809, p. 137.

Hob. — In aquis limpidis, prope Philadelphia.

Sterile joints 7-20 times longer than broad; fertile joints much shorter, greatly swollen ; cell
wall at each end produced or folded in ; chlorophyl filament 1, spiral lax ; turns mostly 7 ;
spores elliptical, 2-2^ times longer than broad.

Remarks. — I found this species about the middle of March, fruiting in a little
pool near Chelten Hills, six or eight miles north of this city. It did not form a
distinct stratum by itself, but was floating, intermingled with great numbers of
other filamentous alga3, such as fragillaricB, zygnemce, &c. It seems to be most
closely allied to the European R. minimum ; it however not only attains a some-
what larger size but also differs from that plant in the proportionate length of the
sterile cells, in the number of the turns of the chlorophyl spiral in the cell, and in
the proportionate length and breadth of the spore.

Fig. 1, pi. 14, represents portions of sterile filaments magnified 450 diameters;
1 a, a part of a fertile filament, magnified 450 diameters.

Sp. pulchella, WOOD.

Sp. articulis sterilibus diametro 2-3 plo longioribus; sporiferis nonnihil tumidis; fascia unica,

anfractibus 3-4 ; sporis ellipticis, diametro fere duplo longioribus ; cytiodermate utroque fine

protenso et replicato.

Diam.— Artie. Steril.^V— 7!^"=. 00033"— .0013". Spor. 7SV_7ig/=.0012"— .00133".
Syn. — Bhynconemapulchellum,Woon,Prodrowu8, Proc. Amcr. Philos. Soc. 1869, p. 138.
Hob. — In stagnis, prope Philadelphia.
Sterile' joints 2-3 times longer than broad ; fertile joints somewhat swollen ; chlorophyl band

one ; turns of spiral 3-4 ; spores elliptical, almost twice as long as broad ; cell wall at each

end produced or folded in.

Remarks. — This species was found by myself fruiting in April, 1869, in stagnant
ditches below the city, and in similar localities near Camden, New Jersey. It did
not occur in masses but singly, intermixed with great numbers of other fruiting
spirogyras. Most of the filaments seen were about .0010" in diameter; in but a
single instance did they come much short of this. This species differs from R.
elongatwm, among other points, in the shortness of the tubes connecting the fertile

i i; i:s n-\\ A i i: n A.LQJE OF TLIK INITED STATES.

cells. I have never been able to identify an entirely sterile filament of this species;

the measurements and des< nation of the sterile cells were taken from infertile cells
in filaments which in other places had produced spores.

l-'ig. '2, pi. 14, represents a fertile filament, magnified '.'(it) diameters.

B. Co.NJ UOATIO 8CALARIFOKMI8 (Sl'llUKITKA VKRA).

a. Cytiodermait! utroque fine ]>rult:ngum et rejilicatum.
a. Cytioderm folded in at the end».

* Fascia tpiralis unica.

* Spiral filament single.

Sp. Welicri, KTZ. ?

S|>. Nitunite viridis, lubrica ; articulis Yegetativis diamctro 3-20 plo longloribns; fructiferis
nonnihil inflatis; fascia dcnttitu, jtlcruiuquc unica sed fasciis duabus in quavis cellula; spine
anfractibus 3-8; cytiodermate pleruiuque utroque fiucprotenso ct replicato ; zygoHporis ellip-
UeU.

l>i,im. —Artie, stcril. TjW'— T&TT" — -0008"— .0012".

. — ,s. Weberi, KCTZI.NO. KAUEN HURST, Flora Europ. Algarum, Sect. III. p. 233.

llnli. — In stagnis, prope Philadelphia.

I»r,-|> LTITM, slippery; sterile joints 3-20 times longer than brpad; fertile joints not swollen;
riili>r"]iliyl liluiiK'iits mostly single, but sometimes two in certain cells, dentate; turns of the
spiral 3-8 ; cytioderm protruded or infolded at the ends ; zygoeporcs elliptical.

.1. — This species, which is abundant around Philadelphia in stagnant
ditches, 1 have found fruiting in the month of April. The number of spirals fre-
quently varies even in the same filament. The infolding of the walls at the end
of the cells is very often wanting in the fertile cells and occasionally is absent from
one end of an ordinary vegetative cell. The American form agrees pretty well
with the European, but is, however, larger, and also attains in its cells a greater
proportionate length and has more turns of its chlorophyl spirals. The lower
limits of the American form arc, however, so overlapped by the upper limits of the
European, that it seems to me they must be considered identical.

I ;:,'. 19, pi. 12, represents a pair of fertile filaments of this species, magnified
260 diameters; 19 o, part of a sterile filament, magnified 260 diameters ; 19 b, out-
line of a couple of fertile cells, magnified 260 diameters.

Sp. prolecta, WOOD.

Sp. saturate viridia.lnbrica; articulis sterilibns diametro 6 plolongiorihus; sporifcrisvix tumidis;

cytiodermate utroque fine protenso et replicato; fascia uuica; aufractibus 6; sporis oblongis

vel ellipticis : menibrano crassissimo.
Diam.— Art. stcril. TJJ0" =.00146" ; epor. lat. Tlg0"— j\fa" = .00133"— .0016" long. 7»20"

= .0033".

Syn.—Sp. protecta, WOOD, Prodromus, Proc. Am. Philos. Soc. 1869, p. 131.
Sp. deep proon, slippery ; sterile joints 6 times longer than broad ; fertile cells scarcely swollen ;

cell wall folded in at the ends; chloropbyl band single ; turns 6 ; spores oblong er elliptical,

spore wall very thick.

Remark*. — I found this species in the latter part of April fruiting in a ditch
in a meadow a little south of the mouth of AVissahicon Creek, near this city,
and as late as the 25th of May in the "neck" below the city. It is remarkable

166 FRESH- WATER A L G YE OF THE UNITED STATES.

for the very great thickness of the walls of the spore. There are two very appa-
rent coats separated by a thin not very evident one. The outer is the thickest ;
it is very thick, firm, and nearly colorless. The inner coat is of a decided orange-
brown. The parent-cells which give origin to these spores are slightly enlarged
in diameter. Sometimes the spores, instead of being elliptical, are irregular in
shape.

Fig. 3 a, pi. 14, represents a sterile filament, magnified 250 diameters ; fig. 3, a
mature spore, magnified 450 diameters.

Sp. insignis, (HASSALL) KTZ.

Sp. articulis sterilibus diametro 5-14 plo longioribus ; fasciis 2 (rarius 1-3), laxe spiralibus,
angustis, crenatis ; articulis fructiferis nomiihil tumidis ; cytiodermate utroquc fine replieato
vel protenso ; zygosporis rubido-brunneis, ovato-ellipticis.

Diam.— 0.0015".

Syn. — Zygnema insigne, HASSALL, Fresh-Water Algae, p. 440.

Spirogyra insignis, (HASSALL) KUTZINQ. UABENHORST, Flora Europ. Algarum, Sect.

III. p. 235.
Hub. — In stagnis, prope Philadelphia.

Sterile joints 5-14 times longer than broad ; chlorophyl filaments mostly 2 (rarely 1-3), laxly
spiral, narrow, crenate ; fertile joints somewhat enlarged ; cytiodenn at each end folded in
or produced ; zygospores reddish-brown, ovate elliptical.

BemarJc. — Fig. 6, pi. 16, represents this species.

b. Cytioderma cellulsefine nee protensum nee replicatum.

Cytioderm not infolded in the end of the cell.
* Fasciae spirali unices (raro duse).

Chlorophyl band single (rarely two).
Sp. longata, (VAUCH.) KTZ.

Sp. dense caaspitosa, Isete luteolo-viridis, valde lubrica; articulis sterilibus diametro 2-6 plo '
longioribus, fertilibus saepe tumidis abbreviatis ; fascia spirali lata, dentata ; anfractibus sub-
laxis 2-5 ; zygosporis ellipticis.

Diam.— 0.001".

Syn. — Conjugala longata, VACCHER, Histoire des Conferves d'Eau douce, p. 11.

Sp. longata, ( VAUCH.) KiliziNG. RABENHORST, Flora Europ. Algarum, Sect. III. p. 238.

Hab. — In stagnis, prope Philadelphia; Wood. Rhode Island; (S. T. Olney) Thwaites.

Densely caespitose, bright yellowish-green, very slippery ; sterile joints 2-6 times longer than
broad ; fertile articles swollen, often abbreviate ; chlorophyl filaments broad, dentate ; turns
of the spiral somewhat loose, 2-5 ; zygospores elliptical.

Remarks. — According to Prof. Rabenhorst, this species attains in Europe a
diameter of .0011" and the cells a length of 8 times their breadth. The same
authority also describes the fertile cell as being either not swollen, or moderately
so (" aut non aut-modice tumidis"). In all the specimens of our American forms
which I have seen, the sporangial cells are very decidedly swollen.

Fig. 4, pi. 34, represents portions of sterile filaments, magnified 250 diameters,
and fig. 4 a, a part of a fertile pair of filaments containing immature spores enlarged
260 diameters.

FKESH-WA Ti: K ALU-^OF Till: I MTED STATES. 167

Sp. quiiiina, i A., > Ki i /.

Sp. satunite viridis, vulde liiliricata; nriieiilis Bterilibns diaroetro 1-6 plo longioribns ; articulis
frrtililms vi-l huud tuinidis vel nonnihil tumidis ; fascia unica ; spine anfractibus roodo den-
Biorilms, IIP »lii laxioriliux, ni)iiiiun<|iiuin la.xissimis, plerumque 3, intcrdum 1 J-4 ; cytiodermate
cfllulic iiir.i,|iic line nee pmti-n.-io m-c replicato ; zygosporis aut globosia aut ovalibug aut
cyliudricis.

J>i,im.—\rt\<: M.-ril. 7IS0"— rloff" - .0013"— .0017" ; sports TU,,"-.0014".

.S'I/H. — S/'. i/iiinina, (AuAai>u)KtTZiNU. KABE.MIUHST, Flora Europ. Algarum, Sect. III. p.

IM.
Jlnl,. — Iii -uignis, propc Philadelphia.

peep sin-en, MTV .slippery, sterile articles 1-fi times longer than broad; fertile joints scarcely
or not at all tumid ; chlorophyl filament single; turns of the spiral sometimes denser, some-
times laser, sometimes very lax, mostly 3 in number, sometimes 1^—4 ; cytioderm neither
infolded nor protruded at the end ; zygospores polymorphous, globose, elliptical or cylindrical.

/,'• murks. — This species is very abundant in the ditches around Philadelphia,

i >i>c( i;illy in the "neck" below the city. I have found it fruiting profusely in the

month of April. The spores vary very much in form, some of them being globose,

others elliptic, and still others cylindrical, with obtusely rounded ends. All these

t'onns may occur in a single filament. The spore cell also varies in the amount of

;ilar^( inent. In many cases it preserves its cylindrical shape completely; in

>llicr instances it is markedly swollen.

1 IL,'S. 4 e, 4c, pi. 19, represent portions of sterile filaments of this species; figs.
• •', 1 /', and 4 <Z, portions of fertile filaments.

ff Fasciae spiralec dux vel plures.
ft Chlorophyl filaments two or many.

fp. decimina, (MULLEB) Kxz.

Sp. Minliilr viridis, labrica; articnlis sterilibus diamctro (0.00135" — 0.00159") plcrnmque
dnplo-, quadruplo fere longioribns, nonnunquam subtcquulibus, fertilibus aut non aut modice
tmniilis; fasciis epiralibus plcrumque 2, latis, decussatis, rurius 1 vcl 3, aufractibus laxis
1-1 J; zygosporis aut ovalibus aut late cllipticis vel subglobosis. (II.)

£i/n. — Sp. decimina, (MiJLLEB) KUTZINO. RABENHORST, Flora Europ. Algarum, Sect III. p.
242.

Hab. — Prope Philadelphia.

I>irty green, slippery; sterile joints mostly from 2-4 times as long as broad (0.00135" —
0.00159"), sometimes about as long as broad; fertile joints either moderately or not at all
swollen; spiral filaments mostly 2, broad, decussating, rarely 1-3, turus loose 1-U; zygo-
spores either oval, broadly elliptic, or snbglobose.

Remarks. — I find this species marked in one of my note-books as having been
found by myself near this city. I have no distinct recollection of seeing it, and,
lia\iii"; preserved neither figure, specimen, nor description, am forced to content
myself with copying the description of Prof. Rabcnhorst.

Sp. diibia, KTZ.

Sp. viridis in frncte dilute viridis; articnlis sterilibus cylindricis diametro 1^-2 J plo longioribns ;
fasciis ppiralibns 2-3, angustissimis, nodosis, anfractilnis la.xis 1-2 (=3-6); cytiodermate
utroque fine nee protcnso uec replicato, nonnihil crasso ; zygosporis polytnorphis, aut sub-

168 FRESH-WATER A L G M OF T II E UNITED STATES.

globosis aut ovalibus, aut subcylindricis, diametro tcqualibus aut | plo longioribus; articulis
fertilibus cylindricis, baud tumidis.

Diam.-A.rl. stcril. Tl£/ = .002; spor 7|gT"— .002".

gyn. — Sp. dubia, KUTZING. RABENHORST, Flora Europ. Algarum, Sect. III. p. 243.

Hab. — In stagnis, prope Philadelphia.

Green, in fruit light green; sterile joints cylindrical, 1^-2 J times longer than broad; spiral
filaments 2-3, very narrow, nodose, lax, turns 1-2; cytioderin neither infolded nor protruded
at the end, rather thick ; zygospores polymorphous, either subglobose, oval, or subcylindrieal,
as broad as long to f times longer ; fertile articles cylindrical, not enlarged.

Remarks. — I have found this species growing in the ditches below the city, fruit-
ing abundantly in May. When in this condition it forms masses of a dirty, lightish,
yellowish-green. The spores mostly fill pretty well the fertile cells. My specimens
do not agree completely with the descriptions given of the European. The two
forms, however, completely overlap one another, except in one character, namely,
the shape of the sporangial cell. I have never seen it swollen or at all tumid in
American specimens, whilst in the European it is said to be " modice tumidis."
This difference alone does not, however, seem to me sufficient to characterize a
new species. I have seen specimens of this plant collected by Dr. Lewis at Cobble
Mountain. They agree well with the Philadelphia specimens, except in attaining
a little larger size, .0021", and in the sterile filaments having their walls very thick.
The character of non-inflation of sporangial cells is perfectly preserved.

Fig. 4, pi. 17, represents this species.

Sp. ri vulari*, (HASSALL) RABENH. (non KTZ.)

Sp. saturate viridis, lubrica; articulis sterilibus diametro 7-11 plo longioribus; fertilibus cylin-
dricis aut vix tumidis; cytiodermato tcuuissimo, utroque fine nee protenso nee rcplicato,
fasciis 4, laxe spiralibus, modice angustis, nodulosis et serratis, anfractibus 2£ ; zygosporis
ellipticis, diametro 2-2| longioribus.

Diam.— Art. ster. rfas"—iW = .0012"— .00146" ; spor. TJ8/— ri8ff".
Syn. — Zygnema rivularis, HASSALL, Fresh-Water Algas, vol. i. p. 144.

Spirogyra rivularis, (HASSALL) (non KUTZING) RABENIIORST, Flora Europ. Algarum,
Sect. III. p. 243.

Hab. — In rivulis, Florida ; (CANBY) WOOD.

Deep green, slippery ; sterile articles 7-11 times longer than broad, fertile cylindrical or slightly
tumid ; cytioderm very thin, neither infolded nor protruded at the end ; chlorophyl filaments
4, laxly spiral, moderately narrow, nodose and serrulate, turns 2£ ; zygospores elliptical,
2-2£ times longer than broad.

RemarJcs. — This species was collected by Mr. Wm. Canby in Pine Barren Run,
near Hibernia, Florida. It is rather smaller than the European forms, but docs
not appear to be distinct from them. Rabenhorst, indeed, states that there are
only two or three, chlorophyl spiral bands in a cell, but Hassall in the description
of the type states distinctly that in some instances there are four bands, and also
figures the plant so.

Fig. 5 a and 6, pi. 17, represents sterile cells of this species, magnified 260

FKKS II -\v A T K K A I. <;.!•: ()! T II K UNITED STATES. 169

diameters. Fig. 5 c is an outline of a pair of fertile cells enlarged to the same

nt.

Sip. partispora, WOOD.

Sp. articulis sterililms diainetro 2-4 plo longioribus ; fructifcris baud tumidis, diametro 1-2J plo
lougioribus; fu.-ciis spirulibus 4, angustis, nodosis, aufractibus pluribus ; zygosporis parvis-
simis, clliptit-iu, diuiuctro 1^-2 plo longioribus; cytiodenuate utroque fine nee protenso IK-C
rr|>licato.

Diam.-A.ri. steri! T!3B"-.003"j spor.diam. transv. Ti8a"— rifo"-- 003"— .0023", long. TJ10"

SO "

- T»00 •

. — S. parvisjwra, WOOD, Prodromus, Proc. Am. Philos. Soc. 1869, p. 139.
/fab. — In stagnis, llibcrnia, Florida. (Wst CANBY )

Strrilr joints 2-4 times longer than broad; fertile not tumid, 1-2$ times longer than broad;
rlilnrip|iii\| liiimls 4, narrow, nodose; turns many; zygospores very small, elliptical, 1^-2
times IniiLri r than brood; cell wall not infolded at the end.

l.-x. — I am indebted to Mr. Wm. Canby for specimens of this species,
which lie collected in a pond in the Pine Barrens near Hibernia, St. John's River,
Florida. It is remarkable for the comparatively small size of the spores, which do
not nearly lill the perfectly cylindrical mother-cells ; indeed they are only about as
lonir as the latter are wide. This species closely resembles S. majuscula, but is
r, does not, that I have ever seen, vary like it in the number of spores, and is
especially separated from it by the very small size of the latter.

Fijj. 7, pi. 15, represents a fertile pair of filaments of this species magnified 125
diameters.

•»!>. in.i |«>-< nl.i. KTZ.

Sp. pallide et sordide viridis, frnctus tempore fusceseens ; articulis sterilibus diaraetro (0.002U"
— 0.0025") 2^-4-10 plo longioribns; cytiodermate tcnui homogenco ; fasciis 3-4— 5 (rarius
7), modo subrectis longitudinalibus, modo laxissiuie spiralibus, nodosis; zygosporis globosis
TC! ovalibus. (R.)

,s'i/n. — S. majnacula, KUTZINO. RABENHORST, Flora Europ. Algarum, Sect. III. p. 244.
//,;/,. — Projie Philadelphia. ?

Pale and sordid preen, fuseescent at the time of fruiting; sterile joints 2^-4-10 times longer
than broad (.0022" — 0 0025") ; cytioderm thin, homogeneous ; spiral filaments 3-4-5 (rarely 7)
partly straight ish and longitudinal, partly laxly spiral, nodose ; zygospores globose or oval.

Ii'i»it<i-k«. — Shortly after I commenced to study the fresh-water algse, I found
below the city a fruiting Spirogyra, of which I preserved only a drawing, which I
have since identified as apparently specifically one with the European S. majuscn?<i,
it differing only in not being quite so large; my measurement was TJT" = 0.002".
Not having any specimens at hand, I have copied the description from the work of
Prof. Rabenhorst.

Fig. 1, pi. 15, was copied from the drawing alluded to.

*!•• nitida, (DILLW.) LINK.

Sp. ctespitibns, lubricis, saturate viridibus; articnlis sterilibns post dirisionem diametro sub-
cqualibus, ante divisionem 2—3 plo longioribus ; articnlis fertilis aliis simillibus, baud tumidis ;
fasoiig spiralibus 4(3-4 R.), niodice latis, anfractibus 1-2; zygosporis ellipticis.

23 Augu«t. 1873.

170 FRESH-WATER ALG.E OF THE UNITED STATES.

Diam.—Q 0025".

Syn. — S. nitida, (DILLWYN) LINK. RABENHORST, Flora Europ. Algarum, Sect. III. p. 245.

Uab. — Prope Philadelphia.

Occurring in lubricous turfy masses, of a deep green color ; sterile joints after division about
as long as broad, before division 2-3 times longer ; fertile joints similar to the others, not
tumid; spiral filaments 4, moderately broad, turns 1-2; zygospores elliptic.

Remarks. — This species appears to be somewhat rare, at least I have found it
but once, and then only in small quantity. Rabcnhorst states that there are occa-
sionally only three spirals, and his maximum diameter is 0.0031"; he also speaks
of the fertile joints as " vix tumidis."

Sp. diluta, WOOD.

Sp. articulis sterilibus diametro snbsequalibus ad duplo longioribns, fructiferis hand tumidis ;
fasciis spiralibus 5, angustissimis, laxis, valde nodosis; anfractibus plerumque \, interdum
1 ; zygosporis sparsis, late ellipticis vel ovatis aut globosis; cytiodermate modice tenue, in
utroque fine nee protcnso nee replicato.

Diam.— Artie, stcril. T*gff" = .003".

Syn. — S. diluta, WOOD, Prodromus, Proc. Am. Philos. Soc. 1869, p. 139.'

Bab. — In stagnis, prope Philadelphia.

Sterile joints about as long as broad to twice longer, fertile cells not swollen ; chlorophyl bands
5, exceedingly narrow, lax, strongly nodose ; turns mostly ^, sometimes 1 ; zygospores few,
broadly elliptical, ovate or globose ; cell wall moderately thin, not infolded at the ends.

lvs. — I have found this species several successive seasons growing in the
ditches in the Neck, below the city, especially in the neighborhood of the large
stone barn, built by the great millionaire, and still known as " Girard's Barn."
The spirals are very narrow and slender, and are moderately close to one another.
They are chiefly made up of a number of chlorophyl nodules, the connecting thread
between which is often very faint. In all the fruiting specimens, as I have seen
them, the spores have been very few in number, most of the cells of the fertile
filaments appearing to have aborted, so that they are simply empty. In most cases
only about every third or fourth cell contained a spore.
Fig. 2, i)l. 15, represents this species.

Sp. setiformis, (ROTH) KTZ.

Sp. saturate viridis, lubrica ; articulis sterilibus diametro paullum brevioribus ad l£ plo lon-
gioribus ; articulis fructiferis haud inflatis ; fasciis 3-8, latis, dentatis, interdum nonnihil
remotis, sed saepe arete et dense conjunctis, nodosis ; zygosporis globosis vel late ovalibus.

Diam.— .0035".

Syn. — S. setiformis, (ROTH) KUTZINQ. RABENHORST, Flora Europ. Algarum, Sect. III. p. 246.

Hab. — In stagnis, prope Philadelphia.

Deep green, slippery ; sterile joints a little shorter to one and a-half times longer than broad ;
fertile joints not inflated ; spiral filaments 3-8, broad, dentate, sometimes somewhat remote,
sometimes closely and densely conjoined, nodose ; zygospores globose or broadly oval.

Remarlcs. — None of the descriptions which I have seen of this species state the
number of the spiral filaments, but the other characters of the American form so
agree with those of the European plant that it is probable that this one does also.
The plant is not uncommon in the Neck, fruiting in the spring.

FUKSll-W A TKK A !.<,.!: <>1 Till! I N 1 T I! H STATES. 171

Fi£. Ha, pi. 1"), represents part of a sterile filament of this species; 3 J, portion
of u pair of fertile filaments, both magnified TJ") diameters.

. « ra*«a,

Sp. Imte viridis, denique sordido viridis; articulia stcrilibus diametro Rulxequalibus, post divi-
Bionem iiitcrduiii fere ^ plo brevioribus, ante diviaioncm ssepo fere 2 plo longioribus; cytio-
dcrmatc tfiiui, houinirriic.), utroque fine ncc protcnso nee replicato ; fasciia spiralibus 4,
driitutis M! tiilifrriilutis, stepe arctis, snbtransversis, tenuibus ; anfractibns 1}-I; ccllulis
fructiferis aliis .similliiiiis, huud iuflatia ; zygosporis globosis vel ellipticis.

,s'i/;i. — Sj>. ,-rii.i.iii, KT/. KABENHORST, Flora Europ. Algarum, Sect III. p. 240.
Huh. — In stagnis, prope Philadelphia.

Bright irrrm, but finally a dirty green ; sterile articles about as long as broad, sometimes after
division only half as long, sometimes before division twice as long; cytioderm thin, honio-
•_'•• ..... ins. nut infnMrd ur produced at the ends; spiral filaments 4, dentate or tuberculate,
often close, subtransverse, thin; turns from 1J to 4; fertile cells very like the others, not
inflated ; zygospores globose or elliptical.

/,'- murk*. — This species is very common in the neighborhood of this city, occur-
ring in springs, &c., but especially in the ditches in the Neck. It forms long,
lubricous masses, of a bright green color, readily distinguishable by the size of the
filiiiiicnts, which are separated with ease by the unaided eye. I have gathered it
repeatedly, in fruit, from the middle of April to the middle of June. In this state
the iiia^s lias lost its bright green color, and when the filaments are closely examined,
even without a glass, minute dark points mark the positions of the spores.

l''i.il. -1 ". pi. 15, represents part of a filament commencing reproduction ; 4i, fila-
m.'iits which have matured the spores; 4 c, a pair of conjugating filaments.

Genus ZYGNEMA.

Ccllulic vcgctativtB cyliudricte. Massa chlorophyllacea initio rfTusa et snbhomogenea, postca dis-
tiuctc grauulosa aut per cellulae lumen distributa, granula amylacea duo centralia involrens, ant in
ror|i<iribus duobus (in quaque cellula) plus minusve distincte stellatim radiantibua juxta nuclcum
cfiitraluiu granum amylaceura unicnm involvcntibus collocata. Conjugatio scalariformia vcl late-
ral is.

-'•tative cells cylindrical. Chlorophyl masses in the beginning effused and Kubhomogencona,
aftiTwards distinctly granular, either distributed throughout the cavity of the cell, involving two
mitral starch granules, or gathered together into two masses (in each cell), with more or less dis-
tinctly stellate radii and a central starch granule placed near the nucleus, one on each side of it.

Z. inwigne, (HASBALL)

Z. caespitibns ct plernmque natantibus vel in aqua diffusis, saturate viridibus vel ssepe sordide
fiavo-viridibus ; articulis sterilibus diametro circiter Kqnalibns vel duplo longioribus ; conju-
gatione scalariforme (et ssepe simul lateral!, R.); zygosporis globosis; sporodermate l;evi.

Diam.— Cell. ^n" = .00126"; spor. Ts'oV'— rAW - 0.00093"— 6.00016".
S>jn. — Tyndaridva insignia, HASSALL, Fresh-Water Algte, vol. i. p. 163.

Zygnema insiyne, ( II ASSAM.) KUTZINO. RABENHOBST, Flora Enrop. Algte, Sect. III.
p. 249.

Bab.— In stagnis, prope Philadelphia ; Wood. Rhode Island; (S. T. Olncy) Thwaitea,

172 FRESH-WATER ALG^E OF THE UNITED STATES.

Caespitose and mostly floating or diffused in the water, deep green, or a dirty yellowish-green ;
sterile joints about as long as broad, or twice as long; conjugation scalariform (according
to Rabenhorst sometimes at the same time lateral) ; zygospores globose ; spore coat smooth.

Remarks. — This species is very common around Philadelphia, forming great
masses in the ditches of the " Neck," growing in the semistagnant water along the
railroads, and forming with other algee slimy coatings on the dripping rocks of the
Wissahicon and various railroad cuttings. At certain times the cells are found
crowded with endochrome, at other times they are almost empty. At certain
seasons this plant multiplies with great rapidity after a somewhat peculiar fashion.
Constrictions first appear in the filament at the junctions of the cells, which thus
look as though their ends were rounding off. This goes on until the ends of the
cells are greatly rounded, and are attached simply by their central parts, which
soon separate. In this way ('fig. 8b, pi. xv.) the filament is resolved into its com-
ponent cells, or more generally into as many pairs of cells as compose it, which
when once set free in the water rapidly grow into filaments by the ordinary pro-
cess of cell multiplication by division. In most cases the zygospores are placed
in one of the parent-cells, but I have seen instances in which some of them were
formed in the connecting tubes.

Fig. 8, pi. 15, represents this species.

Z. cruciatum,(VAucH.) AG. .

Z. pallide viride, siccatum fuscescens vel fusco-nigrescens ; articulis sterilibus brevicylindricis
diametro (0.0016" — 0.00195") aequalibus vel dimidio longioribus, rarius duplo longioribus,
post divisionem factatn haud raro dimidio brevioribus, fructiferis non tumidis; zygosporis
plerumque globosis, maturis obscure fuscis, sporodennate subtiliter punqtatis. (R.) Species
mihi ignota.

Syn, — Zygnema cruciatum, (VAUCHER) AGARDH. RABENHORST, Flora Europ. Algarum, Sect.

III. p. 251.
Tyndaridea cruciata, HASSALL, Fresh-Water Algae, vol. i. p. 1GO. — HARVEY. BAILEY,

Microscopical Observations, p. 21.
Eab. — Northern States ; Virginia ; Florida ; Bailey.

Pale green, when dried subfuscous or blackish fuscous. Sterile joints shortly cylindrical, equal or
alittle longer, or more rarely twice as long as broad (diam. 0.0016" — 0.00195"), after division
sometimes shorter than broad ; fruiting cells not tumid ; zygospores mostly globose ; when
mature, obscure fuscous, their coat minutely punctate.

Genus SIROGONIUM, KTZ.

" Cellulae vegetativse cylindricse, sporiferse subinflatse orculiformae. Fasciae chlorophyllosse longi-
tudinales, parietales, leviter flexuosae, nodosse (plerumque 2-3, rarius 4 in quaque cellula), granula
amylacea 7-8 involutae. Copulatio genuflexa, sine tubo connexivo." R. In specie Americana
fasciae chlorophyllosje spirals et Spirogyrae illis similes.

Vegetative cells cylindrical, spore bearing cells somewhat inflated, or orculiform. Chlorophyl fila-
ment longitudinal, parietal, somewhat flexuous, nodose (mostly 2-3 rarely 4 in each cell), containing
7-8 starch granules ; conjugation genuflexuous, without any connecting tubes. (Rabenhorst). In
American species the chlorophyl filament spiral and like to that of Spirogyra.

Remarks. — This genus was originally made by Kiitzing to contain a single
species, which possesses the characters given in the diagnosis of Prof. Rabenhorst

FRESII-W A TKK ALQ^E OF THE UNITED STATES. 173

I have met with an American plant, which has some of these characters, and at the
same time other* "Inch have been supposed to belong to the genus Sjriroyyra. It
unites the method of reproduction of Siroyotiium and the arrangement of the
chlorophU liand of Xj'ii-<>>/i/r<i, standing as it were midway between them. It is
not midway, however, lint mneh nearer Sirogonium, for the passage from a very
loose spiral to a longitudinal hYxuous filament is a brief one, and although in some
cells of S. n ( r»r> rsum the spiral makes a number of turns; in other long cells it
scarcely gets around once, in other words the chlorophyl band is nearly straight.
On the other hand, the reproduction is strictly that of & stricttim, at least in
all cases which have come under my notice. There is, therefore, but one of two
things to he done, either to unite Siroyotiium with Spirogyra, or else to give up
the arrangement of the chlorophyl as an essential character of the former genus.
The great variance, in the latter respect, in our American species, greatly weakens
the value of any such character, and I have, therefore, preferred tlie latter of the

t\M) OOUJ

v i < 1 1 ovtTMim, WOOD.

S. articulis sterilibua diamctro 7—15 plo longioribus ; fnsciis epiralibns 1, rare 2, latis, grann-
laiis ; uiifrartilms 1-9; articulis fcrtilibus valdu tumidis, retrovereis ; conjugationc genuflexaet
sine tubo connexivo ; cytiudurmate nonnibil crasso, utroque fine proteuso vel rcplicato ;
eporis ellipticia.

Diam.— Art. stcril. T|J,," =.00146"; spor. lat TUo"— 7i!ff"~.00133"— .0016"; long, ^j"
= 0033".

n. — S. n-troversum, WOOD, Prodroraus, Proc. Am. Phil. Soc. 18C9, p. 139
Huh. — In stagnis, prope Philadelphia.

Sterile joints 7-15 times longer than broad; chlorophyl band 1, rarely 2, broad, granulate;
turns 1-9 ; fertile article very tumid, retroverted ; fertile cells scarcely swollen ; cell wall folded
in at the ends; chlorophyl band single; turns 6; spores oblong or elliptical, spore wall very
thick.

Remarks. — I have found this species growing in stagnant ditches in the Neck
helow the city. In fruit the cells are almost always very markedly bent backwards,
and have a broad pouch-like dilatation in front. The spores are elliptical, and, as
I have seen them, greenish and with a thin coat, but may not have been completely
matured.

Fig. 1, pi. 16, represents this species.

Genus MESOCARPUS, HASSALL.

i '• lUilae mnssa chlorophyllosa initio diffusa, postea in fasciam longitndinalem, hand raro flexnosam
contracta; niirluum contralem et granum amylaceum unicam vcl duo involvens. Zygospora globosa
vel ovata, in tnbo connexivo inter cellulas binas plus minus genuflexas formata.

Clilorophyl mass in the beginning diffused in the cell, afterwards contracted into an often flexuons
fascia, and involving a central nucleus and one or more starch granules. Zygospore globose or
ovate, formed in the connecting tube between two more or less bent cells.

*, HASSAI.L.

M. cellulis sterilibus diamctro 3-6 plo longioribus, fertilibus valdu cnrvatis ; zygosporis ovalibns.
Diam.— Max. Tf S5 = .0011".

174 FRESH-WATER ALOJE, OF THE UNITED STATES.

Syn. — M. scalaris, HASSALL, Fresh-Water Algae, vol. i. p. 1G6, et RABENIIORST, Flora Europ.
Algarum, Sect. III. p. 257.

Hab. — In fossis, prope Philadelphia.

Sterile cells 3-6 times longer than their diameter, fertile strongly curved ; zygospores oval.

Remarks. — This species is abundant in the stagnant ditches near Camden. It
agrees well with the descriptions of the European form. I have, however, never
seen it in the state in which it has " fuscous spores." They have always been
greenish, but very possibly were not fully matured.

Fig. 5, pi. 15, represents a pair of cells of this species just commencing to con-
jugate.

M. par vu Ins, HASSALL.

M. cellulis diametro (0.00031" — 0.00041") 5-12 plo longioribus; zygosporis globosis, plerumque
0.00062" latis, sporodermate fusco Isevi. (R.) Species mihi ignota.

Syn. — M. parvulus, HASSAL, Fresh-Water Algae, vol. i. p. 169, et RAB^NHORST, Flora Europ.
Algarum, Sect. III. p. 257.

Hab.— Rhode Island ; (S. T. Olney) Thwaites.

Cells 5-12 times longer than their diameter (0.00031" — 0.00041") ; zygospores globose, mostly
0.00062" broad, spore coat fuscous smooth.

Genus PLEUROCAKPUS, A. BRAUN (1855).

Cellular eaedem qua? in Mesocarpo ; copulatio lateralis et sporifera, nonnunquam genuflexa et
plerumque sterilis. (R.)

Cells like those in Mesocarpus; conjugation lateral and sporiferous, somewhat genuflcxuous and
mostly sterile.

P. mirabilis, BRAUN.

P. cellulis diametro (0 0011" — 0.0013") 2-5 plo longioribus; zygosporis subglobosis, fuscis,
Irevibus. (R.) Species mihi ignota.

Syn. — Mougeotia genuflexa, AGARDH. BAILEY, Silliman's Journal. New Series, vol. iii.

Pleurocarpus mirabilis, A. BRAUN. RABENHORST, Flora Europ. Algarum, Sect. III. p.
258.

Hab. — West Point, New York; Providence, Rhode Island ; Detroit, Michigan ; Fort Winne-
bago, Wisconsin ; Bailey.

Cells 2-5 times longer than their diameter (0.0011" — 0.0013") ; zygospores subglobose, fuscous,
smooth.

ORDER Si phopll \<'C;r.

Algse nnicellulares. Cellula ntriculiformis, plerumque ramulosa ; ramuli vegetatione terminal!
praditi, ssepe demum septo discreti, et alteri in oosporangia, alter! in antheridia traiismutantur.
Cytioplasma viride, granulosum, mneilaginosum, vesiculis chlorophyllosis et granulis atnylaccis
repletum. Propogatio fit aut cytiogenesi libera, aut zoogonidiis aut oosporis.

Unicellular algae. Cells utriculiform, mostly branched ; branches with a terminal vegetation,
often finally cut off by a partition wall and transformed into antheridia or oosporangia. Cytioplasm
green, granular, mucilaginous, filled with chlorophyl vesicles and starch granules. Propogation
either by forming minute spores by free cell formation, or by zoosporcs, or by oospores.

FKKSH-W ATE 11 ALG^E OF Till'. IMTKD STATES. 175

FAMILY HYDKOGASTRK/E.

rianlulie minim:!1, tcrrestres, gregariie. Cellula initio globo.su, postca clavato- vcl pyriformi-
iiilumescens, lui.-i atteuuata elongata ct in ramulos subtilligsiiuos hyalinos partita. Cytioplasma
MUfilairiiiii.-iiiii, ii-tutc pmvcrta gonidia dtvi.sione siniultanea transforraaturu. Cytiodenua lamellotmm
let ate jmiveetii dilubeiis ct coutabescens ct gonidia libcrans.

Plants very small, terrestrial, gregarious. Cells in the beginning globose, afterwards clavate or
jivrifiirm, with an elongated, attenuated base, divided into very fine, hyaline branches. Cytioplasm
mucilaginous, at imiturity transformed by a simultaneous division into gonidia. Cytiodcrm lamel-
late, at maturity wa.-tinir, withering away and setting free the gonidia.

kK. — The Hydrofjtistrece are curious little unicellular plants, which grow
upon wet earth. The matured frond is swollen up at one cud to form a subglobular
or pyriform head, whilst at the other end it is produced into a long, much-branched,
line root-like portion which enters the earth and maintains the little plant in
its upright position. The green endochrome is contained almost entirely in the
head, and forms generally a coat or layer in the outer portion of its cavity, the inner
part of which appears to be occupied by a water)' fluid.

The only specimens which I have seen of this family were found growing in the
mud left by the receding water of a recently drawn mill pond, by Dr. Billings, U. S. A.
When I got them they were thoroughly dried up, and consequently no opportunity of
studying their development was afforded. According to Kiitzing and Braun, the
speeics is propagated ordinarily by the breaking up of the chlorophylous layer of pro-
toplasm lining the wall of the cell into a larger number of very small globular spores.
These, although not endued with the power of motion, seem from their method
of formation and history to be homologous with zoospores. In most cases they
are set free by the membrane of the parent-cell becoming gelatinously softened,
swelling up, collapsing, and finally dissolving away. The little protococcoid cells
then enlarging, develop at one end a hyaline prolongation which penetrates into
the Around. Growth and development continuing the upper end of the cell swells
up into the ovate or globular head, whilst the lower becomes the hyaline, branch-
in;,'. root-like portion of the new frond. No indication of this method of repro-
duction was discoverable in the plants which Dr. Billings sent me. The evident
affinities of the family with the Vaucheriaccce render it exceedingly probable that
there is in it some method of sexual reproduction, as yet undiscovered, allied to
that which occurs in the latter. In some of the specimens sent me, there were
what appeared to be resting-spores (pi. XVI., fig. 2 a), occupying the whole of the
cavity of the cell, from which they appeared to be finally discharged by a decav
and rupture of the outer coat or wall. How these bodies were formed, and whether
they really have power to reproduce the species I cannot telL

Genus HYDEOGASTRUM, DESV.

Character idem ac familite.
Characters that of the family.

H. ffranulatnm, (LINN.) DESV.

H. plemmqne gregarium, sicpe npgregntum, hand raro eonflticna ; cellula e globoso-pyriformi,
magnitudine scminis papavcris vcl sinapios et ultra, prasino-viridi supcrficic pulverulent*. (R.)

176 FRESH-WATER ALG^E OF THE UNITED STATES.

Syn. — Botrydium argillaceum, WALLROTII. RABENHORST, Flora Europ. Algarum, Sect. III.

p. 265.
Hydrogastrum granulatum, (LINNAEUS) DESV. HABENIIORST, loc. cit.

Hob. — Delaware ; (Dr. Billings) Wood ; West Point, New York ; Providence and Newport,
Rhode Island ; Bailey.

Mostly gregarious, often aggregate, not rarely confluent; cells pyriform, of the size of a poppy
or mustard seed and larger ; pea-green ; surface pulverulent.

Remarks.— The above description is taken from Rabenhorst's work, and applies
to the specimens collected by Dr. Billings in the State of Delaware, excepting that
I did not discover any of them to be confluent, nor was their surface distinctly
pulverulent. Prof. Kiitzing gives as a comparative character between this and //.
Wall-ratlin, the smaller size of the spores ; but Prof. R. says nothing about this.
There were no spores in any of the American specimens, and I think it somewhat
uncertain whether or not the plant is or is not either of the European species. It
is very probable that it will be discovered that the only true specific characters are
sexual, and consequently have not as yet been made out in any of the forms.
Certainly the descriptions of the species as at present given seem to me not to
contain any reliable characters.

Fig. 2 a, pi. 16, represents a very young state of our American plant ; fig. 2 is
the perfected frond, both magnified ninety diameters ; fig. 2 a shows what is sup-
posably a perfected resting spore magnified 160 diameters.

FAMILY VAUCHERIACE^E.

Algse monoicse, csespitosse, unicellulares. Cellula vegetiva (thallus) vegetatione terminali, utriculi
formi-elongata et ampliata, prominentiis plus minus elongatis ramosa.

Propagatio aut sexualis, fit oosporis ope spermatozoidiorum fecundatis, ant non sexualis zoogonidiis.
Fructificatio triplex (melius organa fructificationis tria) : —

1. Sporangium terminals, ex thalli apice plerumque globoso-clavato-tnmido formatnm, septo dis-
cretum, cytioplasmate obscure viridi, demum in zoogonidiuin (zoosporam, Thur.) unicum permag-
num, ciliis vibratoriis dense obsitum abeunte farctum.

2. Oogonium (oosporangium) laterale, sessile vel prominentia, plus minus elongata vel simplici
vel partita pedicellatum, cytioplasmate setate proyecta in oosporam singulam transmutato fetum.

3. Anlheridium laterale, sessile vel e ramuli lateralis parte suprema septo discreta formatum, in
quo spermatozoidea (antherozoidca, Thur.) numeros issima nascuntur, denique erumpunt. Sperma-
tozoidea oblonga, ciliis duobus insequilongis, subpolo antico ortis instructa. (R.) •

Monoecious algae, caespitose, unicellular. Vegetative cells (thallus) growing at the ends, elongate,
utriculiform, and ampliate, more or less profusely branched.

Propogation either sexual, with oospores which are fecundated by spermatozoids, or non-sexual,
by means of zoospores. Organs of fructification of three kinds : —

1. Sporangia, which are terminal and mostly formed from the separation of clavately swollen,
globose apex of the thallus (often of a branch) by means of a partition ; in the sporangium arises
a single, very large zoospore, which is densely clothed with cilia.

2. Oogonia (oosporangia), lateral, sessile or pedicelate simple bodies, whose eytioplasm is finally
converted into an oospore.

3. Antheridium lateral, sessile, or formed out of the end of a branch ; the spermatozoids formed
in them oblong, furnished with two unequal cilia, arising near the front end.

FKKSH-W ATKK .\i.<;.i; UK TIII: r.\iTKD STATES. 177

!!• murk*. — Tin- Yniii-Ji' r'tuoea arc amongst our most common fresh-water alga?.
They occur generally in the form of vast numbers of individuals interwoven into
broad mats, which have often both a felty look and feel. When growth is going
on rapidly, these mats arc of a beautiful vivid green; but when the process of
M '\ual reproduction has checked the life of the individual they become dingy and
dirty looking. The thallus is composed of a single cell and is almost always
branched. The branches never have, at least in any of our species, a definite
arrangement, save only in that they always arise from the side and not from the
point of the thallus. In the European species, V. tubtrosa, however, the branches
are said to arise both from the point and sides of the frond.

The frond cell is generally nearly uniform in diameter and has a thick outer
wall, which is composed of cellulose, as is proven by the action upon it of iodine
and sulphuric acid and of the iodo-chloride of zinc solution. Within the cell are
chlorophylloua protoplasm, starch granules, watery fluid, and a few scattered
raphides or inorganic crystals. There is never any nucleus. The protoplasm is
often very granular, and is mostly collected in a thick green layer upon the inner
surface of the cell wall, leaving the centre of the cell free for the more watery
contents.

(irowth, except in the very young fronds, consists exclusively in an increase in
length, and takes place only at the ends of the thallus or in the portions near it.
The branches are almost always simple, but arc said in some species to give origin
to secondary branchlcts, and even, at times, to tertiary ones. They grow in the
same manner as the main thallus, t. e. by additions to their ends.

When the thallus of a Vaucheria is ruptured by external injury, or, at times,
when it is dying from some hidden cause, a number of bright green globes of
various sizes are formed out of the endochrome. These appear to have the power
of independent existence for some time, but whether or not they ever actually
grow into new thalli I am unable to state.

M. Walz asserts that he has observed in certain species the formation of a quiet
spore without the intervention of sexual organs, and that the process is as follows.
The end of a long or short twig swells up, and the chlorophyl and protoplasm from
the neighboring parts accumulate in the enlarged portion. A partition wall then
forms at the base of the latter, which is thus changed into a closed chamber, a
sporangium. The- green contents then slowly gather themselves together into a
denser and denser ball, becoming more and more separated, in so doing, from the
wall of the sporangium, and finally secreting around themselves a distinct mem-
brane. After the formation of a spore in this way, the sporangium opens at the
I and allows it to escape. The spore, after remaining quiet for some time in
the water, at last germinates into a new frond, in a similar manner to an ordinary
zoospore. In my earlier studies of fresh-water algae, I noticed something very
similar to this in one of our species, but convinced myself that the little body was
nothing but a zoospore, whose normal development had been perverted by unto-
ward influences, and therefore paid no more attention to the matter. It is proba-
ble that the life-history of the bodies observed by M. Walz is capable of the same
explanation.

23 August, 1873-

178 FllESII- WATER ALGJS OF THE UNITED STATES.

Although I have very frequently cultivated Vauchcrias, I have never been so
fortunate as to see them form their zoospores, nor indeed to see a zoospore in its
motile state. The life-history of these bodies has, however, been fully and repeat-
edly worked out by other observers. It is described by such as occurring in the
following manner. One end of a branch first enlarges into a bulbous, often conical,
point, into which the neighboring endochrome crowds itself. This point is next
divided off by a partition wall from the remainder of the thallus and constitutes the
soosporai/gium, the contents of which rapidly condense into one or two masses,
generally oval in shape, each of which eventually forms a zoospore. When the
latter are matured, the apex of the zoosporangiwm opens, and the little bodies
•within slowly and gradually emerge, without any apparent cause for their motion.
Sometimes, according to Cohn, instead of this steady outAvard passage, there are
repeated forward and backward movements of the zoospores within the case. The
zoospore after its perfection is generally oval, and very large. Within it there are
one or more vacuoles, and surrounding it is a layer of colorless protoplasm. It is
remarkable for having its whole surface densely covered with short cilia. Its period
of motile life appears to be very brief; according to Walz, that of the zoospore of
V. sericea, Lyngb., lasts only from one-half to one and a half minute, after which
time the cilia are lost and a cellulose wall secreted around the mass. Germina-
tion takes place by the growth of the cylindrical thread out from each end of the
zoospore.

True sexual reproduction takes place in this family by means of anlherulia and
oogonia, male and female organs. All known species are mostly if not absolutely
monaBcious, both organs being contained in the one individual and always placed
in proximity. All of the species in which the development and structure of the
sexual organs have been studied, agree in the essential points.

The first appearance of the antheridium is as a little pouch projecting out from
the side of the thallus. This increases in size and soon assumes the peculiar shape
of the species. At the same time there is a diminution, according to M. Walz, of
the chlorophyl in the antheridium, so that, when the partition wall forms and shuts
off the cavity of the latter from that of the thallus, there are only a very few scat-
tered green granules remaining. The antheridium at the time of separation con-
tains, therefore, only transparent protoplasm, which soon becomes granular, and
shortly afterwards exhibits the moving spcrmatozoids, which appear to be formed
out of the thick layer of protoplasm that lines the inner surface of the cell wall.
The point of the antheridium opens so soon as the spermatozoids are perfected,
and allows them to escape.

The formation of the oogonia takes place very similarly to that of the antheridia.
There is the same little protrusion from the side of the thallus in the commence-
ment of the process, the same after-growth and increase of this pouch, and the same
formation of a separating wall between it and the main body of the frond. A very
marked difference, however, is to be found in the contents of the two, the oogonium
from the very commencement being crowded with chlorophyl and oil globules.
When the oosporangium is completed, the end of it opens, and, at the same time,
the contents gather themselves into a dense protoplasmic ball, which lies in the

F u i: s ii . w \ T i: u A L G JE o v T H K r x i T i: i> STATE s. 179

centre. The spermato/.oids, which arc at this time already free in the water, are \cr\
minute, longish, ellipsoidal or ovate masses, provided with two unequal cilia. These
commonly l)otli arise together from one end of the body, and arc directed in oppo-
site directions — one backwards, tlie other forwards. According to M. Wai/, how-
ever, in T. *<//',,/ the <ilia arise from the opposite ends. According to De Bury,
the spermato/oids of V. aversa, llassall, contain reddish pigment-grannies. M.
Wai/, states that he has twice seen the process of impregnation in V. neriwa, Lyngb.,
and describes it essentially as follows: After the bursting of the antheridium and
tin formation of the opening in the oogonium, the spermatozoid clustered around the
little orifice in the latter, but were apparently debarred entrance by the presence of
a glutinous jelly. After a time, however, one, and then another, forced a passage
through this obstacle until finally a number gained access to the protoplasmic ball
within. Over this they swarmed, pushing it and retiring and butting against it
until some of them actually forced their way into it and were absorbed by it. Im-
pregnation being how completed, the oospore acquired a very sharp definite outline,
and secreted in a very short time a membrane around itself. The changes which
followed during its maturing consisted of the acquiring of a thick coat and the
replacing of the chlorophyl within by a reddish-brown coloring matter. The ripened
resting spore of almost all the Vauchcria is provided with three coats, of which the
middle is the thickest. The contents consist of protoplasm, reddish-brown pigment,
and numerous oil globules.

Genus VAUCHERIA.

Genus unicum, character idem ac faiuilisc.

The only genus of the family, having the same characters.

V. sessilis, (VAUCH.) DE CANDOLLZ.

V. laxe intricata, pallide et suhsordide viridis; thallo capillari, parcc ramoso; oogoniis 3-3
approximates, rarias singulis, ovatis vel ovaH-oblongis, plus minusvc obliquis, rostratis; anthc-
riilin iiiirniii'ilin, rarnuli niodo brevi hamato, modo recto snbuluto, subclavato, modo clongato
et incurrato, hand raro circiuato sustentato; oosporis maturis fusco-puuctatis, ineinbruna
triplici involutis. (R.)

Syn. — V. sessilif, (VAUCU.) DK CANDOLLR. RABENIIORST, Flora Enrop. Algar., Sect. III. p.

267.
V. ctespitosa, (VAUcn.) AOARDII. RABEMIOIIST, loc. cit.

IIili. — Salem, North Carolina; Sclnvcinitz. Common at West Point, New York ; Waterville,
Maine; Calpepper Co., Va. ; Bailey. %

Laxly intricate, pale and subsordid green ; thallus capillary, sparsely branched ; oogonia 2-3,
approximate, rarely single, ovate or oval-oblong, more or less oblique, rostrate; anthcridia
intermediate, sustained upon branches partly shortly hamate, partly straight subulate, sub-
clavate, partly elongate and incurved, and not rarely circinnate ; oospores at maturity, fns-
cous-punctate, surrounded by a three-fold membrane.

Remark. — I think I found this species near Philadelphia in my earliest re-
arijches, but cannot speak certainly, having preserved neither notes nor specimens.

180 FRESH -WATER ALG^E OF THE UNITED STATES.

V. v< hilina. AG.

V. tballo repente, raraulis erectis, numerosis, fastigiatis, in caespitem velutinum laete viridem
iutricatis ; oogoniis lateralibus singulis, globosis, sessilibus, antheridio paulo longiore unico
subulate leviter incurvato consociatis (R.) Species mihi ignota.

Diam.— Oogonii 0.0023"— 0.0027". (R.)

Syn. — V. velutina, AGARDH. RABENHORST, Flora Europ. Algarum, Sect. III. p. 274.

Hab. — Salem, North Carolina; Schweinitz. Common at West Point, New York; Waterville,
Maine; Culpepper Co., Va. ; Bailey.

"Filaments exceedingly tough, interwoven into a dense, velvety, green stratum, pellucid below
and creeping over the mud; branches near the extremity erect, fastigiate, and more or less
crooked; vesicles solitary, globular, on short lateral peduncles." Carmichael.

V. geminata, (YAUCH.) DE CANDOLLE.

Y. obscure vel sordide viridis, in casspites dense intricata; thallo capillari, tenaci, dichotomo ;
oogoniis duobus (rarius 1 vel 3),ovatis vel obovatis, oppositis, distincte pedunculatis, antheridio
intermedio subulato, plus minus recurvo ; oosporis inaturis fusco-maeulatis, sporodermate
achroo e stratis tribus composite involutis; sporangiis in eodem vel proprio thallo, cyathiformi-
ampliatis truncatis et angulato-cornutis. (R.)

Syn. — V. geminata, (YAUCH.) DE CANDOLLE. RABENHORST, Flora Europ. Algarum, Sect. III.
p. 269.

Hab. — In stagnis, prope Philadelphia; Wood.

Obscure or sordid green, densely interwoven into a turfy mass; thallus capillary, tenacious,
dicbotomous ; oogonia two (rarely 1—3), ovate or obovate, opposite distinctly pedunculate,
antheridia intermediate, subulate, more or less recurved ; oospores at maturity spotted with
fuscous, their coat transparent and composed of three strata ; sporangia in the same or a sepa-
rate thallus swollen cup-shaped, truncate and horned at the angles.

Remarks. — I have found this species in fruit but once, then it grew in a ditch
below the city. Not having mounted any of it, nor having written a description
of it at the time, I have been forced to simply copy that of Prof. Rabenhorst.

V. polymorpha, WOOD.

V. in caespites dense intricata ; thallo capillari, tenui ; antheridiis corniculatis ex ramuli lateralis
apice formatis ; ramulis fertilibus interdum et oogoniis et antheridiis instructis, interdum
antheridiis solum ; oogoniis plerumque geminis, iuterdum singulis, globosis vel ovatisi saepe
breve rostratis, plerumque distincte pedunculatis sed rarius sessilibus ; oosporis enormiter
subglobosis vel ovatis; sporodermate achroo, e stratis duobus composite.

Syn. — V. polymer pha. WOOD, Prodromus, Proceedings Amer. Philos. Society, 1869, p. 140.
Hab. — In aquis, prope "Buffalo Bayou," Texas; (Ravenel.)

Csespitose ; thallus fiair-like, thin ; antheridia corniculate, formed of the apex of lateral branches ;
fertile branches sometimes furnished both with oogonia and antheridia, sometimes with
antheridia alone ; oogonia sometimes single but mostly in pairs, occasionally shortly rostrate,
generally distinctly pedunculate but sometimes sessile; oospores irregularly subglobose or
ovate, surrounded by a transparent double spore coat.

Remarks. — This species was collected by Prof. Ravenel near the city of Houston,
Texas. As I received the mass, it was labelled as being obtained from "a shallow
slimy pool formed by drippings from the side of a ravine near Buffalo Bayou."
The species probably grows in the water, evidently forming turfy mats. It is

FRE.SII \\ AT i:R ALG^E OF THE UNITED STATES. 181

remarkable from the fact that, whilst in many cases the little branches which pro-
duce tlif anthcridia gi\»- origin to the spores also, in others they do not; so that
there are numerous antheridia, which are unconnected with any female organs.
When a branch does produce both of the reproductive organs it usually forks into
three short hranclilets, thus giving origin to a pair of sporangia and a single curved,
hooked antheridia. Sometimes, however, there is but a single female branchlet,
and I have even seen a sporangium, immediately sessile upon a branch, which at
its ape\ .rave origin to a male organ. In the coat of the perfected spore, I have
not been able to find more than two distinct strata.

Figs. 3 and 3 a, pi. 20, represent sporangia and antheridia of this species ; 3 i,
a simple, young and only partly formed antheridia, magnified 160 diameters; 3 c,
a perfected spore magnified 260 diameters.

V. sericea, I.YNUBYE.

V. aquatica vel terreatris, cseapitosa, vel aordide vel laete vel lateolo-viridis ; thallis tcnuibns,
dense intricatis, laxe et vage ramosis, ramisquc saepe adseemlentibus vol erectia ; oogoniis ses-
silibus vel brevissime pedicellatis, 1-6 scriatis, nnilatoralibus, oblique et enormiter ovalibua,
ore lateral! producto rostellutis ; antheridiis in thallo ips<> jnxta oogoniia sessilibus* cylin-
drareo-subclavatis, deflcxis; apcrmatozoideis oblongis, puncto rubro notatis (teste de Bury),
in utroque polo cilio uuico pneditia.

Syn. — V. ai-ersa, HASSALL, Freah- Water Algaa, p. 54.

V. sericea, LYNQBYE. KAHKMIUHST, Flora Europ. Algarum, Sect. III. p. 271.

Hub. — I* rope Philadelphia; Wood.

Aquatic or tcrreatrial, occurring in turfy mats of a yellowish, dirty, or bright green color; fronds
thin, densely intricate, laxly and vaguely branched, often together with the branches ascending
or erect; oogonia sessile or very shortly pedicellate, 1-6 seriate, unilateral, obliquely irregu-
larly oval, their lateral mouths produced into a rostellum or beak ; antheridia sessile upon the
thallus itself near the oogoniura, somewhat cylindrical, subclavatc, deflexed especially in age ;
spermatozoids (according to De Bary) oblong, marked with a red point and furnished with a
single cilia at each end.

rks. — I can perceive no constant differences between V. sericea, Lyng. and
V. az«rsa, Hass. The extreme forms differ somewhat, but both are very common
about Philadelphia, and everywhere grade into one another. Prof. Rabenhorst
thinks that the two forms are scarcely distinct, and states that the most character-
istic differences are, that in V. aversa, the thallus is much thicker, and the oogonia
larger and more erect, whilst the oospores are smaller and consequently do not fill
the cavity of their case. These differences are, except the last, simply differences
in size, and seem to me to depend simply upon circumstances of growth. The rela-
tively smaller size of the spore is a very frail hook indeed to hang a species upon.
The plant grows in springs and actively running water abundantly in this neigh-
borhood ; also on very wet ground, especially on that which is habitually overflowed,
such as the face of dams, neighborhood of springs, &c. In the water, it is frequently
on the ground, but also often clothes such objects as stones, largish sticks, &c.

ORDER Neinatopliycere.

Algae mnlticelnllarea, chlorophyllosoe, metnbranacote vel filamentosse, ramiflcatione ant instruct*
aut destitute. Propogatio fit aut ooaporis aut zoogonidiis, scd nunqunnt cnnjugationc.

182 FRESH-WATER ALG^E OF THE UNITED STATES.

Multicellular, chlorophyllous algae, membranaceous or filamentous, furnished with or destitute of
branches. Propagated by oospores or zoospores, never by conjugation.

FAMILY ULVACE^E.

Thallus membranaceus vel foliaceus, vel filiformis (Schizomeris ?) rarius crustaceus, e cellularum
strato unico formatus, aut expansus aut tubuloso- vel vesiculoso-concretus.

Propogatio fit zoogonidiis, cytioplasmatis divisione repetita ortis. Zoogonidia oblonga, polo
antico ciliis vel binis vel ternis vel quarternis instructa.

Thallus membranous or foliaceous, rarely crustaceous, composed of a single stratum of cells, either
expanded or tubularly or vesicularly concreted.

Propagation by means of zoogonidia, formed by the repeated division of the cytioplasm. Zoogoni-
dia oblong, furnished with two, three, or four cilia at the anterior end.

Genus PKOTODEKMA, KTZ.

Thallus crustaceus, indeterminatns, substrate arete adhserens, e cellulis anguloso-rotundatis,
irregulariter ordinatis, arete connexis compositus.

Propagatio ignota.

Thallus crustaceous, indeterminate, closely adherent to the substratum, composed of closely con-
joined irregularly arranged angularly rounded cells.

Propagation unknown.

P. Tiride, KTZ.

P. viride, lubricum.

Syn. — P. viride, KUTZING. RABENHORST, Flora Europ. Algarum, Sect. III. p. 307.

Jlab. — In aquario; Wood.

Green; slippery.

Remark. — I have seen a plant, which I take to be this species, growing on the
glass and on pebbles in the aquarium of ray friend, Dr. Fricke.

Genus ULVA, LINN.

Thallus membranaceus, plane expansus, angustus vel latus, nonnunquam latissimus, magis minusve
nndulato- crispatus, saspe laciniatus, hand raro perforatus, e cellularum strato unico formatus, callo
disciformi parvo affixus, astate provecta saepe libere natans. Cellulae anguloso-rotundatae, cceloplas
maticae, parenchymatice connexse.

Vegetatio cellularum divisione in duas directiones repetitia. Propogatio fit zoogonidiis, in cel-
lulis quibusdam cytioplasmatis divisione 4, 8-16 ortis, ciliis vibratoriis quaternis longitudine cor-
poris longitudinem vix superantibus instructis.

Thallus membranous, expanded, narrow or broad, sometimes very broad, more or less undulately
curled or crisped, often laciniate, not rarely perforate, formed of a single stratum of cells, fastened
by a small discoid thickened portion, in advanced age often swimming free. Cells angularly glo-
bose, joined into a sort of parenchyma.

Growth occurring by the repeated division of the cells in two directions. Propagation by
zoospores, 4-8-16 of which are formed at once by a division of the endochrome of certain cells,
and are furnished with four vibratile cilia scarcely longer than the body.

U. merismopedioides, WOOD.

U. ampla, membranacea, late expansa, dilute viridis, tennis, radiatim et enormiter plicata, ambitu
saepe subrotundata; margine undulato, interdum subcrcnato ; cellnlis enormiter ovalibus vel
angularibus, nucleo destitutis, quarternariis et in familias Merismopediarum modo obscure
associatis.

Diam.— Cell. max. „{},„?" = .00041', plerumqne T2§Tri>"_T3gTO" = .00016'— .00025.

FK !•:> II -WATER ALG.K OF THE UMTI 1> STATES. 183

. — i'. mi-ri.<m»/.fi/«)/i/i-u, Woun, Botanical Report of the United States Geological Ex-
ploration of the Fortieth Parallel, p. 415.

JIuli.— In torre»tibu8, Diamond llauge(alt. 6000 ft.), Rocky Mountains; (Sen-no Watson) \\ <•«>{.

Thallus ample, broadly expanded, membranaceous, dilute green, tbin, radiately and irregularly
])licate with Us outline often somewhat rounded; its margin undulate or at times almost
erefiate; the cells irregularly oval or angular, destitute of nucleus, quarteruary and obscurely
arranged in families after the manner of a merisiuopedia,

Remark*. — The largest fronds of this species that have come under my notice
arc about three inches long hy two broad, thin, easily torn, and not all gelatinous.
The portion hy which they have been attached is very evident, near one of the
margins, and from it broad undulations or folds radiate. Sometimes the frond is
split up into palmate, lobe-like parts.

The cells are not closely approximate, but are placed in a homogeneous translucent
membrane, in such a way as to remind one of a Merittwpedia,

I do not feel certain that this plant is distinct from U. orlriculata of Rabenhorst,
though for the present I have preferred so to consider it. His description is very
brief and incomplete, as is also the original one of Thuret, which I have con-
stilted. Prof. 11., however, gives U. latissima of authors as a synonym of U. or-
liriilnin, and certainly this plant is distinct from U. latissima, Harvey, of our
coast. Again it seems impossible that a plant growing near the summit of the
Km ky Mountains should be identical with one found on the coast of France.
1'rnf. Sereno Watson found this plant growing on rocks in a mountain stream of
the Diamond Range, at an altitude of 6000 feet.

Genus ENTEROMORPHA, LINK.

Thallus membranacens, tubulosus vcl ntricaliformis, basj affixus (saltern initio, postca saepc lil>ere
n.-it.i!i-i. e cellulnrum strato unico compositus, saepe raraosus, baud raro ramosissimus. I'rnpogatio
/••niiliis. II.ee zoogonidia proceantur in cellulis quibusdam 8-16 cytioplasmatis divisione
•a, in polo antico rostriformi ciliis duobus corpus duplo supcrantibus pradita. (R.)

Thallus membranaceons, tabular or bladder-shaped, affixed by the base (at least in the beginning,
often afterwards floating freely), composed of a single stratum of cells, often branched, not rarely
very much branched. Propagation by means of zoospores, 8-16 of which are formed by the
repeated division of the protoplasm of a cell Their anterior beak-like portion provided with two
cilia whose length is not less than twice that of the body.

K. inlcMtinalis, (LINN .) LINK.

K. tcrrs, forma et magnitudine admodum varia, ssepe pedalis etiam supra, leptodcrma, saturate

Tel pallide viridis, lilifonnis vel intestiniformis, plana vel bullosa; cellulis 3-5-6 angularibus.

(R.) Species mihi iynota.
/Worn.— 0.00048" — 0.0008". (R.)
Syn. — E. intestinalis, (LiNN-SVs) BAILEY, Silliman's Journal, N. S., Vol. III., ct RABENHOROT,

Flora Europ. Algarnm, Sect. III. p. 312.

Hab — Hudson River, from Newburgh to New York City; Xarragansett Bay, Rhode

I -land; Bailey.
Terete, very various in size and shape, often a foot or more in length, smooth, deep or pale

preen, filiform or intestiniform, plain or Imllose ; cells 3-5-6 angular; their diameter 0.00048'

— 0.0008".

184 FRESH-WATER ALG^E OF THE UNITED STATES.

Genus SCHIZOMERIS, KTZ. 1

Thallus filliforrais, cylindricus, hie illic valde contractus, basi attenuata affixus. Vegetatio fit cel-
lularura divisione initio in duas postea in tres (?) directionem. Propog.atio fit zoogonidiis. Zoogo-
nidia in thalli juvenis cellulis orta, ovata, polo antico ciliis tribus instructa.

Thallus filiform, cylindrical, here or there strongly contracted, adnate by the strongly contracted
base. Growth in the beginning by the division of the cells in two directions, afterwards in three
directions. Zoogonidia formed in the cells of the young thallus, ovate, their anterior end furnished
with three cilia.

Remarks. — The plant from which the above generic description has been drawn
up grows abundantly in our ditches below the city. Whether it really belongs to
the genus Scldzomeris or is the representative of a new group is somewhat uncer-
tain. I have never seen the European plant, but, if I understand the descriptions
of it, the cells in it are all arranged in a single plane. This certainly is not the
case in the old plants of our North American form, for in them the cells are so
placed as to make a thick opaque filament, the outside of which everywhere pre-
sents the outer Avails of cells. The life history of the European species has not
been at all worked out, and I have refrained from actually indicating a new genus,
in the absence of absolute knowledge upon the subject, because the specific cha-
racters of the two plants are so much alike.

I have had some opportunities for studying the life history of our American
plant. The zoospore (Fig. 1 c. pi. XVIT.) is of the ordinary conical or ovate form,
with a very decided transparent anterior end, from which arise three cilia. As the
number three is a rare one for cilia to exhibit, I have examined several zoospores
with care, and am very certain that they had no more or less. It is, therefore,
probable that the number is fixed for the species, although just possible that my
finding several individuals in agreement was accidental. The zoospore after a
period of free life, during which its motion is very active, becomes quiescent, and,
its cilia withering away, attaches itself by its smaller end to some twig, stone, or
other support. At the same time it appears to change its shape somewhat, grow-
ing longer and narrower, and the smaller end spreading out to form a little foot.
Simultaneously with these changes the young plant acquires a cellulose coat, and
so becomes a perfect cell, in which I have never been able to detect any nucleus.
After a while the cell thus formed divides transversely into two, which, of course,
lay end to end. Each of these cells then grows until it attains a certain size, and
then the transverse division is repeated. In this way the process goes on until
finally a long filament is produced, which is composed of but a single series of
cells. These cells are much broader than long, and are placed end to end, so that
the cylindrical frond is made up as it were of disks laid one upon the other.
When the filament has in this way reached a certain stage of development, one of
two things occurs, either the cells begin to divide at right angles to the plane of
their previous division, or else the production of zoospores takes place. In the
first instance each cell divides into two, four, or more cells. This division, I believe,
occurs in three if not all directions, so that each original cell is represented by a
number of cells, and a sort of compound filament arises, out of which the matured

1 KKS11- WATER ALOJS OF Til K UNITED 8TATI 185

large trichoma is formed by a continuation of growth, and, perhaps, by a repetition
of the division. 1 have never been able to discover that any reproductive process
whatever takes place in this compound filament, and am very confident it never
produces /oo.-pores. It is very possible, however, that it may in some way give
origin to renting spores, although, as above stated, no indication of this has ever
come under my notice. The zoospores are formed in the young fronds as follows:
The endochrome in the cell concerned gradually separates in the ordinary manner
into several distinct masses, which soon assume a more or less irregularly globular
or pyriform shape. Whether the number of these masses is fixed for the single
cell or not I am unable to state. These changes occur almost simultaneously in a
number of consecutive cells, commencing with the most distal and rapidly spread-
ing towards the base of the filament. When they are pretty well advanced, the
walls of the cells undergo some alteration, probably a gummy degeneration, whereby
they become soluble in the water. As the division of the endochrome occurs first
in the most distal cells of the filament, so does also this change in the cellulose coat.
When the endochrome masses arc well shapen and distinct, they begin to exhibit
motion, becoming uneasy, restless, changing their position, rolling on themselves,
and pushing against one another. At the same time solution of the cell walls com-
mences, the partitions between the cells disappearing, and the outer walls spread-
in;,'. These changes go rapidly forward, and in a little while the zoosporcs stream
out from the fading end of the frond, jostling and crowding as though eager to
•liter upon their new life.

1 a. pi. 17, represents the basal portion of an old filament which has failed
to form zoospores, magnified 125 diameters. Fig 1 b was drawn from a young
filament during the process of forming zoosporcs; owing to their rapid motion, the
cilia of the latter could not be seen. This figure is enlarged 250 diameters. Fig.
1 <• represents a zoospore which has just become quiescent, and still retains its
cilia, although they have lost their motile power. Fig. 1 d, e, c, represent the very
young plant in different stages of growth. They are all magnified 450 diameters.

8. Leibleinii, KTZ. ?

S. lictu viritlis vel saturate nigro-viridis.
Diam.— Max. TJ5". =.08".

n. — S. Leibleinii, KLTZINQ. RABENUOKST, Flora Europ. Algartim, Sect. III. p. 311.

h — In fossis, prope Philadelphia.
Bright green to deep blackish-green ; largest diameter of the frond TS i"-

Remark*. — Owing to the profusion of zoospores produced by a single filament
at one time, it is very usual to find large numbers of the younger plants attached
BO closely to some central body as to form dense masses of a beautiful green color.
The support of these small masses is often entirely concealed, and I have frequently
seen them moving freely about the jar, without any apparent cause, until the mystery
was solved by finding that some unfortunate snail carried the forest on his back.

The oldest filaments are perfectly opaque, showing, under the microscope, by
transmitted light, no trace of their structure.

24 August, 1373.

186 FRESH-WATER ALG^E OF THE UNITED STATES.

The species is exceedingly common in the later summer and early fall months
in the ditches and sluggish streams around the city, especially in the Neck.

FAMILY CONFERVACE^E.

Fila articulata aut simplicia ant ramosa, vegetatione terminal! non limitata instructa. Articuli
plerumque plus rainasve elongati, sed nonnunquam diamctro breviores, cylindrici, ran us tumidi.
Cytioderma plerumque manifesto lamellosum. Massa chloropliyllosa granulata, vesiculas amylaceas
involvens, parietalis vel in setate provecta ssepe in cellules centre contracta.

Vegetatio fit utriculi priinordialis divisione semper in unam eandemque (transversam) directionem
repetitia. Propagatio fit zoogonidiis.

Filaments articulate, simple or branched, growth terminal, unlimited. Joints mostly more or less
elongated, but sometimes shorter than long, cylindrical rarely tumid. Cytioderm mostly plainly
lamellate, chlorophyl masses granular, surrounding fine starch granules, parietal or often in the centre
of the cell.

Growth taking place by division of the primordial utricle always in one direction, namely trans-
versely. Propagation by means of zoospores.

Genus CONFERVA, (LiNN.) LINK.

" Fila articulata simplicia. Articuli cylindrici. Massa chlorophyllosa homogenea vel granu-
lata, vesiculas amylaceas involvens. Propogatio ignota." (R.)

Threads articulate simple. Articles cylindrical. Chlorophyl mass homogeneous or granulate,
including amylaceous vesicles.

Remarks. — A large number of forms of the genus Conferva have been described
as distinct species by Kiit/ing and other authors. The characters assigned to
these species, however, do not seem to me in any way distinctive. I cannot believe
it possible at present to recognize, define, and describe species in this genus, and
believe that further studies must be made in their life-history, and other characters
discovered before the different forms can be separated. Probably, as was the case
with the CEdogoniacece, when their sexual life is made out, in it will be found the
vital differences. No doubt there are many species common to Europe and Ame-
rica, but I have been entirely unable to determine them. Among the very earliest
of my observations upon the fresh-water alga3, before experience had taught how
and what to observe, was one made upon what I suppose was a species of this
genus. I have never met with the plant since, but as the observation has direct
bearing upon the method of propagation, I mention it here, imperfect as it un-
fortunately is. The plant was found growing on the mud along the Schuylkill
River, near Gray's Ferry Bridge, below the city. The filaments were simple, of
great length, and uniform in diameter ; fig. 7 a, pi. 18, represents a portion of
one magnified 500 diameters. The cells varied from about as long as broad to
three times as long. The amount of endochrome in the cells also varied very much.
In most of them, it was not nearly sufficient to fill the cavity, and was arranged as
a central superficial band. Many of the cells were seen engaged in the production
of zoospores. (Fig. 7 &, pi. 18.) Such were well filled with endochrome, which
gradually condensed itself into a globular or pyriform mass in the centre of the
cell. This, after a short time, began to exhibit activity, rolling upon itself and
finally pushing about as much as its confined quarters would allow, until at last it

i r. i:s ii \\ AT i: it ALG.E OF THE UNITED STATES.

escaped iiiti) tin- water, through tin- cell wall. Each cell in this way gave origin
to a single /.ooNpore. The walls did not nu It away in the water, and, as a nuinlicr
of conse< utivc cells underwent these changes at the same time, the filament or a
portion of it was left as an empty shell. The zoospores were of the usual shape,
witli a bright anterior spot or beak. The number of cilia was not noted. After
a time they settled down generally in clusters, attaching themselves to some foreign
particle, dropping their cilia and acquiring a cellulose wall. (Fig. 1 e, pi. 18.) They
then elongated, underwent the ordinary cell division in a transverse direction, and,
by the repetition of this, gradually grew into filaments similar to that from which
they sprang.

1 ii,'. "i '/. pi Itf, represents a young filament just formed in this manner, magni-
fied 500 diameters.

Genus CLADOPHORA, KTZ. (1843.)

Fila ri.'llularuin serie siuiplici formats, rarie ramosa. Rami Clo ccntrali similes. Cytioderma
jilt Tiini.|u.- crusbum, lamellosum. Cytioplasma parietale.

Filaments r< imposed of a simple series of cells and variously branched. Cytiodcrni mostly thick
and hum-Hull-- Cytioplasni parietal.

Remark*. — The Cladophora are branched plants of rather rigid habits, which
gmsv both in salt and fresh water. They are readily recognizable by their
comparatively still appearance, the absence of gelatinous matter about them, and
by the want of regularity in their branching. A large number of species have
been described, most of which are marine. They are exceedingly difficult to define,
and it is very jxissible that their hitherto undiscovered sexual reproduction maybe
finally found to afford the only true characters. I have identified two European
forms as growing near this city, and a third has been recognized by Prof. Harvey,
as found in our northern States.

I have never seen the production of zoospores in this family, but they are said
to be formed by the simultaneous division of the layer of chlorophyllous proto-
plasm, which fills the outer part of the cell cavity. They exhibit the power of
\i iy active motion even before their exit from the cell, which occurs through a
papilloid orifice, mostly at the end of the cell, sometimes in its side. Their cilia
are sometimes two, sometimes four in number, and their life-history appears to be
precisely similar to that of other zoosporcs.

€1. glomerata, (LINN.)

Kamuli till primarii in parte saperiore atque ramornm ordinis second! et tcrtii plerumque
fasciculate- Tel penicilliformi-aggregati. Cellulte maxima; vegetse cytioplasmate cellularum
parieti retifonni- vol snbspiraliter applicato. Cellulae fructiferse semper terminates, inferiores
semper steriles videntur. (R.)

Syn. — Cl. glomerata, (KOrziNG) RABENHORST, Flora Europ. Algarnm, Sect. III. p. 337.

Hob. — Lake Ontario; Pickering. Falls of Niagara; Lakes Erie, Huron, and Michigan;
Fourth Lake, near Madison, Wisconsin ; Bailey.

" Filaments tufted, bushy, somewhat rigid, much branched, bright grass-green ; branches
crowded, irregular, erecto-patent, repeatedly divided ; ultimate ramuli secund, subfasciculate ;
articulations 4-8 times ns long as broad."

188 FRESH -WATER ALG.E OF THE UNITED STATES.

RemarJcs. — Prof. Harvey says (Smithsonian Contributions): "I have received
North American specimens from Milton, Saratoga County, N. Y., and from Lake
Erie ; also from the Mexican Boundary Surveying Expedition."

CI. fracta, DILLW.

Clad, prima juventute affixa sed postea libere natans et csespites formans ; ramis ramulisque
sparsis, divaricatis, nonnunquam refractis ; ramulorum cytioplasmate non spiraliter ordinato ;
cytioderrnate saepe crassissinio ; cellulis fertilibus baud tcrminalibus, pleruinquc in ramulorum
medio, aut eorum basi.

Syn. — Cl. fracta, (DiLLW.) RABENUORST, Flora Europ Algarum, Sect. III. p. 334.

Hab In flnmine Schuylkill, prope Philadelphia; Wood. West Point, New York; Provi-
dence, Rhode Island ; Bailey.

In the young state fixed, but afterwards floating free and forming matted masses ; branches and
branchlets scattered, divaricate, somewhat refracted ; cytioplasm of the branches not spirally
arranged ; cytioderm often very thick ; fertile cells not terminal, mostly in the middle of the
branches, sometimes in their base.

Cl. brachystelecha, RABENHORST.

C. per totam vitam innata, obscure viridis, sicca pallida, pygm^a, 2-4, rarius 6 linea longa,

ramosissiraa, intricata, plerumque culmigena ; ramis priraariis ^V" — ?V"= 0.00295" 0.0022"

crassis, ramulis ultimis ^'" — Jo" = 0.00147"— 0.00128" crassis; articulis diaraetro 4-12
plo longioribus ; eytiodermate subcrasso, hyalino, subtiliter plicato-striato ; cytioplasmate
imprimis cellularnm snperiarum laxe spiraliter ordinato. (R.)

Syn.—Cl. brachystelecha, RABENHORST, Flora Europ. Algarum, Sect. III. p. 343.
Hab. — Prope Philadelphia; Wood.

Fixed through the whole life, obscure green, pale when dried, dwarfish, 2-4, rarely 6 lines long,

very much branched, intricate, mostly attached to culms; primary branches 0.00295"

0.0022" thick, ultimate ramuli 0.00147" — 0.00128" thick; articles 4-12 times longer than
thick ; cytioderm thickish, hyaline, subtilely plicately striate ; cytioplasm, especially of the
upper cells, laxly spirally arranged.

Remarks. — I have notes of having identified this species at some time, but,
having kept neither specimens nor detailed memoranda, have simply copied the
description of Prof. Rabenhorst.

FAMILY OEDOGONIACE^E.

Alg33 monoicae vel dioicse. Fila articulata aut simplicia aut ramosa, cellula basali obovato-clavata,
basi plerumque lobato-partitia vel seutata innata. Propagatio fit turn zoogonidiis turn oosporis
fecundatione sexuali ortis. Zoogonidia formantur singula in quavis cellula, forma late ovali vel
globosa, polo antico achroo corona ciliorum vibratoriorum prsedita.

Oogonia singula vel plura (2-5) continna, plus minusve tumida, in quoque oospora singiila,
matura rubro- aut flavo-fusco-colorata, ante germinationem in zoosporas plerumque quatuor dilabens
se format.

Antheridia brevi-filiformia, 1 -2-3-1 0-articnlata, plernmque singnla aut oogonio aut filo vegeto in-
sidentia aut in individuis variis ssepe cellula obovato-clavata subtentata.

Monoecious or disecious algse. Filaments articulate, either simple or branched, fixed by the basal
cell which is obovate-clavate, mostly with its base lobately parted or shield shaped.

Propagation sometimes by zoospores, sometimes by resting spores, the result of sexual impregna-
tion. Zoospores formed simply in certain cells, broadly oval or globose, their anterior end trans-
parent, and furnished with a crown of vibratile cilia. Resting spores single or in series of from

FKESII-W ATK II ALG^EOF T II K I N I I ' K D STATES. ls|)

two to five, more or loss tumiil, single in each sporangium, at maturity reddish or yellowish fuwou.?,
licfoiv germination dividing llii-msrlvi-. into {mostly lour) zoospores.

Anthcridia shortly filiform, 1-3-3-10 articulate, mostly single, either upon the Rporangium or

ilion evil.

/A iniirl-x. — Thr (J:'ilit,j»ni<ifnr have been by previous writers simply divided into
tun genera, (!:'< !"</' m iin/i ;iiid Jtn//>i*'/«r/c. The plants represented by these two
have certainly many characters in common, as in the production of their
and BpermatoKoidfl as well as in their peculiar method of cell division.
^ they are so very diverse in some particulars in regard to the latter, as well as
in their habit of growth and in the formation of their sporangia, that it has
seemed to me that the differences between them were more than sufficient to cha-
racterize merely genera, and that to each of these groups should be awarded the
rank of a sub-family.

A^ain, in the old genus of CEilogoniimi, we have very distinct groups, separated
by differences in the most important of all the characteristic portions of the plant —
the sexual apparatus. These groups arc the so-called Monaxiam, Gynandroun, and
I>iiii-;,,iix CEdofjonia; the monoecious division comprising those plants in which one
individual i,'i\< s origin both to the female and male germs; the gynandrou*, those
species in which the plant that produces the female germ gives origin also to a
peculiar zoospore, the so-called androspore, which, after a period of motile life,
settle> down and develops a dwarf plant, the andrcecium, in which the epermalo-
are developed ; and the d'uccions group containing species in which the male
and female plants arc distinct individuals. Dr. Pringshcim states (MorjJtologie der
/on., p. 4:J) that these groups pass into one another, but in my opinion, by his
own showing, they arc sharply distinct. The nearest approach to such passage is
between the first and second groups, and consists simply in the fact that in certain
species the androspore when it settles down develops into a one-celled instead of a
two or three-celled antheridium. This to me does not seem to indicate a union of
the groups, for the essential difference is not in the form or complexity of the an-
theridinm, but in the circumstance that in the one case the female filament develops
a sperniatozoid capable of fertilizing the germ, whilst in the other it gives rise to
a body which does not possess that power at all, but does have the capability of
giving origin to a second plant, in which the spermatozoid is developed. The
groups, therefore, appear to be sharply and distinctly definable.

In the Biilbochcetite but a single genus has as yet been discovered, and tins is
distinctly gynandrous, but it seems probable that hereafter other plants of this
subfamily will be found which are monsecious or disecious, so that we will have
in the two subfamilies two parallel groups of genera.

For the reasons above indicated I have ventured to divide the family into two
subfamilies, the one comprising three, the other a single genus. The peculiarities
of growth, production of zoospores, and sexual development will be found described
under the particular subfamilies.

190 FRESH-WATER ALG^E OF THE UNITED STATES.

SUBFAMILY CEDOGOXIE^E.

Filamenta stricta, baud ramosa, sine setis veris, sed ssepe apice setiforma, elongata, hyalina.

Filaments simple, not ramose, without true seta, but often with their apex seta-like, elongate,
hyaline.

Remarks. — The CEdogoniacece are small filamentous plants, whose size is sufficient
to render them visible to the unaided eye, and yet not sufficient to make each indi-
vidual distinctly apparent. They grow mostly in quiet water, attached to almost
any and every thing that can afford a foothold, fringing with apparent indifference
stones, twigs, sticks, dead leaves, bits of glass, boards, etc. I have seen such
masses of them crowding the whole surface of a physa as to entirely conceal the
animal and its shell, and present the curious spectacle of a perambulating, waving
forest of bright green. The individual filament is composed of cylindrical cells,
which are always without a nucleus, and have their chlorophyl diffused instead of
being collected into bands or stripes. The walls are mostly quite thick and
marked near the distal end with circular stria3, whose numbers bear relation to
the edge of the cell, for these striae are the results of the peculiar method of cell
multiplication by division, each one marking one such division. When an cedo-
gonium cell has attained sufficient maturity and is about to divide, the first per-
ceptible change is the appearance of a little circular line or streak near its distal
end. About the same time and in the same place a fine partition is formed by an
outgrowth from the primordial utricle, a probably double delicate wall of con-
densed protoplasm separating the upper end of the parent cell from the lower or
main portion. The upper end now begins to develop into a new cell. This de-
velopment takes place by the formation of an entirely new layer of cellulose
inside the little cell, i. e. between the new primordial utricle and the old cell wall,
and afterwards by the lengthening of this layer by interstitial deposit in the usual
way; the thick wall of the parent cell in no way directly participates in the
growth (fig. 2 &, pi. 17). It is evident tha-t as the new wall grows the old cell
wall must be as it were raised up upon it, borne away as a little capping from the
basal portion of the parent cell. Consequently when a young cell is watched
during this process the little line-like incisure of the parent cell is seen to widen
until it becomes an evident trench, and this trench grows wider and wider, until
at last it is so broad as to be no longer a trench, and the little end of the parent
cell simply caps its offspring. When the latter has fulfilled its allotted period 01
growth, the process is repeated, the line of separation appearing this time just
below the edge of the first cap. It is plain that the second new cell when formed
must have a double cap crowning its extremity. At each repetition a new layer
is added to the thickening cap, until at last it may be composed of six distinct
layers, each projecting just beyond the next older one. Under the microscope the
increased thickening of the distal end of a cell bearing such a crown-piece is not
sufficiently evident to at first attract attention, whilst each edge of a layer appears
as a stria. It is plain that the number of these strise represents the number of

FUKSII-W ATEU ALUJi OF T II K UNITED STATES. 191

times division has occurred ; if there be four stria-, four times; six stria?, six

times, &C.

Besides tliis iiicthod of development, in many species new cells are formed by a
sort of pullulution, occuring in the end cell of the filament. The primordial
utricle appears to rupture the wall of the distal extremity of the latter and grow
out into a little pullulation, or teat, which very soon becomes separated from the
pan-lit c-c-11, by the reformation, as it were, of the end wall of the latter. The
new little cell thus formed coats itself with cellulose, and rapidly grows, especially
in length, always, however, or at least for a length of time, remaining of a smaller
diameter than the cell tnmi which it sprang. By a repetition of this process a
succession of cells is formed, each one of which, like the successive joints of the
field telescope, is a little smaller than its proximal neighbor and contains less
chlorophyl, until finally the cells are reduced to exceedingly fine, perfectly trans-
parent, colorless cylinders, which together form a seta or hair.

K« production takes place among the (Edogoniaceae, both by means of zoospores
and sexual organs. The former of these are quite peculiar, and, therefore, require
especial notice.

Only a single one is ever produced in a cell, and there is consequently no divi-
sion of the chlorophy lions protoplasm preceding their formation. The first change
noticeable is a sort of confusion of the cell contents, the protoplasmic portion of
which loosens itself, as it were, from the walls, and collects in a mass at the
distal end of the cell. This mass after a short time assumes a more or less irregu-
larly globose shape, and simultaneously the parent cell begins to separate from its
distal neighbor. This separation appears to take place commonly by a solution
of an exceedingly fine ring of the wall of the parent-cell, just at the origin of the
transverse partition separating the two cells, and it is therefore brought about not
by a splitting of the end partition wall, but by a circumcision of the side walls of
the- cell, and consequently the cavity of the latter is thrown open, the end Avail
remaining with and closing the distal cell, whose contents have not undergone
change. On the other hand, observation leads me to think that sometimes there is
a splitting of the end wall. According to my observation, sometimes the filament
is Completely broken in two, but very commonly the two cells remain attached by one
corner, opening from one another as it were on a hinge-joint (fig. 2/, pi. 17).

Tlie gathering of the protoplasm, already spoken of, into a ball, is a slow process,
and the escape of this ball, through the opening formed in the manner described,
takes place even more slowly. The motion is not at all perceptible, with a power
of a thousand or twelve hundred diameters. During the passage the ball becomes
more or less twisted and deformed, but as it emerges the uncompressed portion
shortens and swells out, and when the mass of protoplasm is at last free in the
water, it Soon assumes a globular or regularly ovate shape. The mother-cell, thus
bereft of its contents, is left dead and void. The primordial utricle indeed still re-
mains within, but it has lost all its wonderful powers, and is nothing but a shrunken,
twisted, or folded dead membrane. What is the cause of the motion of the
/onspore within the cell it is very difficult to determine. It certainly is not vibrating
cilia. When the zoospore first escapes, it is, as already stated, an irregular lump

192 FRESH-WATER A L G M OF THE UNITED STATES.

of strongly chlorophyllous protoplasm, homogeneous or with one or more roundish
masses of darker green within it. As it assumes its shape, however, a very dis-
tinct transparent spot appears at its smaller end. Whether this is an absolute
vacuole or not, I have never been able to satisfy myself, but I am rather inclined
to believe that it contains highly refractive transparent protoplasm. As this spot
is perfected the cilia make their appearance. Whether they are actually first
formed there, or whether, as is more probable, they are formed inside the cell, and
are so folded against the general mass as to be invisible, I have never determined.
Dr. Pringsheim, however, figures them within the cell. I have seen them in
their early development long before motion commenced in them, but they were
always perfectly formed as soon as apparent. They are present in great numbers,
making a crown or ring around the edge of the transparent beak-like end. When
they commence to vibrate, their action is at first very slow, and the waves of
motion run through them deliberately from one cilium to the other, but soon,
however, the motile impulses succeed one another more and more rapidly, until
the general mass of the zoospore begins to tremble, then to rock, and finally dart-
ing off the little body hastens hither and thither through the water. The zoospore
of an CEdogonium is always readily distinguished from most other similar bodies by
its large size and peculiar motion, which is a forward movement combined with a
distinct rolling on its long axis. After a time the zoospore, coming in contact
with some speck of matter to which it can attach itself, ceases its movements,
the cilia rapidly wither away, and the end to which they have been attached
swells out or elongates into a broad, or narrow, simple, bifid, or trifid process,
placed at an angle to the main axis of the cell, BO as to form the so-called foot, the
holdfast that anchors and fixes the new plant. Whilst this is taking place, the
general form of the zoospore alters into that of a cylinder, a cellulose wall is
secreted all about it, and the first cell of the new plant is complete. As soon as
this cell is sufficiently matured, it begins to undergo division in the manner already
described, and to develop into the new filament.

In regard to the time when these zoospores are given off most abundantly, and
the circumstances that influence the process, I can only state that it occurs when
there is least tendency to the production of resting spores, probably in youngish
plants, and I have thought was favored by a full supply of light, with a moderate
temperature.

Sexual reproduction occurs among the (Edogoniacece in accordance with three
distinct types, to which the name of moncecious, dicccious, and gynandrous has
been severally applied. The characteristic differences are to be looked for in the
production of the antheridise or male plant, the female germ being always pre-
pared in essentially the same way. In most instances two cells are requisite for
the production of the latter. At first there is nothing by which cells set apart for
the formation of the female germ can be distinguished from ordinary cells. The
proximal one of the pair finally, however, undergoes changes similar to those
seen when a zoospore is to be formed, namely, a sort of confusion of the endo-
chrome, and finally a gathering of it into a mass at the distal end of the cell. In-
stead of there being a solution of the side wall of the cell, however, the end wall

FKKSH-W ATKR ALG^E OF T1IE UNITED STATi 193

undergoes absorption, so that the cavities of the two cells are more or less com-
pletely thrown into one. All or nearly all of the contents of the proximal cell
now slowly pass into the distal one, which thus becomes crowded with chloro-
ph\ lions protoplasm. At or before this period, the distal receiving cell undergoes
u change in form, widening out greatly, and sometimes appearing actually to
shorten, so that it is in most instances resolved into a more or less regular globose
or oval cell. As the sporangium or spore-case thus formed perfects itself the endo-
chronies of the two cells become completely fused into one mass, which gradually
condenses and armies a regular shape, until, in the form of the perfected female
or receptive germ, it is a dark, opaque ball more or less completely filling the spo-
rangial crll. At the same time, in order to afford passage for the male germ, an
opening is formed through the walls of the sporangium. This happens in two ways.
The simplest of these is by the formation of one or more circular openings or
pi >res in the wall. This pore is sometimes below, sometimes above the equatorial line.
Its portion, numbers, and form afford good specific characters. The second method
is l>y the development of a little trap-door entrance at the distal end of the spore-
ca»e. This method is unknown in our American flora, and, never having seen it,
I mn>t refer to the papers of Pringsheim for details.

The above-described mode of origin of the sporangium is the common one. In
O. iiiiriitilft; WOOD, however, but one cell is concerned. This cell grows to an
enormous size, far beyond that of its fellows, and its endochrome collects into the
upper half of it, to be at last shut off from the lower half of the cell by the forma-
tion of a new cellulose partition or end wall; or, in other words, the parent cell
divides by a modified process of cell division, different from that common in the
family. The distal daughter-cell contains all the endochrome. After the changes
are completed, the appearance is the same as ordinarily presented, namely, an empty
cell surmounted by the sporangium. Sometimes, even in plants in which the ordi-
nary process occurs elsewhere, a single cell appears at times to have sufficient
vitality to develop into a sporangium without aid from its neighbor, so that the
latter will preserve its integrity, and the resting spore finally lie in proximity to a
cell full of endochrome.

In the motHtcioiu (Edogoniacecp, a single filament produces both the male and
female germs. Certain cells appear to be set apart to develop into sporangia, whilst
others give origin to the spermatozoids. No such plants have as yet been detected
in North America, and I, therefore, pass on without speaking more in detail.

The second method in which the spermatozoids are produced is the most com-
mon in our flora ; it is the so-called gynantlrmu plan. In this the single filament
produces the female germs directly and the male germs indirectly. The former
ari»c in the way previously described, whilst the latter are the resultant of a
complex series of life actions, as follows : One of the main cells of the originating
filament, differing in no perceptible way from its fellows, instead of like them
developing new cells, divides up by a simple process of cell division into two or
more cells, each one of which contains very largely of chlorophyllous protoplasm. The
protoplasm within each of these secondary or daughter-cells soon condenses into an
irregularly ovate or conical mass, which often, even within the cell, may be seen to

25 Boptombor, 1872.

194 FRESH-WATER ALG^E OF THE UNITED STATES.

have the transparent beak of the zoospore (pi. 18, fig. 2 d). Inside of the cell
the androsjjore, as it is called, shows no cilia, but when it is set free by a more or
less complete solution of the cell wall, it assumes the form of the ordinary (Edoyo
nium zoospore, with a crown of cilia, whose vibrations soon cause it to dart through
the water. These androspores are of course much smaller than an ordinary
zoospore, and after a period of active motion, they attach themselves to the parent
filament, generally cither on or near the sporangial cell. Their first life-actions,
after settling, are precisely like those of the zoospore, namely, dropping of the
cilia, enlargement of the smaller end into the so-called " foot," .an elongation of
the general mass, and the secretion of an outer coating of cellulose. In this way
a peculiar-shaped, somewhat ovate cell is formed, which contains a great quantity
of rich protoplasm with mostly a small amount of chlorophyl. From such cells are
developed the mostly two- or three-celled, perfect antheridia, which in gynandroua
(Edogonia are generally to be seen, during the period of fructification, in numbers
attached to the filament, mostly in the neighborhood of the sporangium. Their pro-
toplasmic contents are remarkable for the activity of their movements, and I have
seldom seen more beautiful and rapid cyclosis than they display — currents setting in
all directions — particles actually brushing against one another (pi. 17, fig. 27t).
The spcrmatozoids are formed in the distal cell, sometimes one, sometimes more.
In the species 0. mirabile, WOOD, (pi. 18, fig. 2 #, 2 6) in which I have most
carefully studied their origin, two are produced in the single cell. This cell is in
the commencement of the process, although comparatively poor in chlorophyl,
crowded with a rich solid protoplasm, which divides into two distinct masses, some-
what in the manner seen in the commencement of ordinary cell division. As
there is no distinct nucleus, of course there are no precedent nuclear changes.
The masses thus formed gradually assume a more or less perfectly globular shape
inside the cell, although I have never been able to see that they there develop cilia,
and finally are set free by the lifting up of the end of the" mother-cell, like a little
trap-door. Their mode of escape through the exit thus offered is similar to that
of the ordinary zoospore, which they resemble, except that they are much smaller,
are much less rich in chlorophyl, and have the anterior clear space less defined.
They are said to be furnished with a crown of cilia similar to that of the zoospore,
I myself have never seen these, but do not doubt their existence.

In the dicecious (Edogonia, there are distinct filaments, male and female, one of
which produces the oosporangium with its contained germ, whilst the other gives
rise directly to the spermatozoids.

The resting spore which develops after impregnation is variously shaped, but in
most instances is round or oval. It is often, if not always, furnished with two coats,
the outer of which is thick, firm, and 'frequently provided with surface appendages,
such as tubercles, ridges, spines, etc. Besides these there is also, probably, a very
delicate inner coat. The spore appears to be set free from its case by the decay of the
latter, there being never, at least that I have seen, any regular dehiscence. Although
I have made several attempts, it has never been my good fortune to observe anything
like germination of these resting spores. Prof. Chr. Vaupell, however, has published
an account of the manner as observed by himself. Some water containing fruitful

FRKSII-W A T I- K ALG^E OF Till: r.NMKD STATES. 195

'/' ;/«-///.; \\as allowed tn <li\ in a L;lass, towards the close of September, and the
•jreeniM1! n 'Milne \v;is placed in water in the following January. By March the
resting spores were r\er\ \\ln-re in active germination. The first change was a
rupture of the two outer coats and the escape, through the slit, of the contents,
still surrounded hy a very delicate hyaline membrane. By this time the proto-
plaMii had divided into usually four (sometimes only twoor three) greenish masses,
each of which was oval in shape and had its own extremely thin, hyaline coat,
and was therefore a perfect cell. The old outer shell of the spore laid discarded
in the water and soon decayed, and in a little while the hyaline sac surrounding
the four daughter-cell! itself disappeared, leaving them exposed and naked. After
awhile each of these cells opened at one end by means of an annular split, cutting
off the apex of the wall and allowing it to lift off like a little lid. Through the
circular opening thus made, the contents now emerged. The point of the inner
mass was colorli ss and directed towards the orifice, and the whole moved vigorously
backwards and forwards until it finally escaped, as a perfected zoospore. This
little body simulated very closely the ordinary zoospore, both in appearance and
lite-history, growing, after a brief period of activity, into an ordinary filament, in
precisely the same manner as the zoospores.

Genus (EDOGONIUM.

Anthcridia ct oogonidia in individuo unico.

A nt lii-riil i:i and oogonidia in the same individual.

A'- mark. — No species of the genus (Edogonium, as here defined, has as yet
been discovered in this country.

Genus PRINGSIIEIMIA.

Diuicft. Antheridia et oogonidia in indi viduis distinctis orta.

Antheridia and oogonidia arising in distinct individuals.

P. inequnlis, WOOD.

P dioica; ccllnla basali biloba; plantis femineis quam .plantis masculis permulto majoribns;
oogoniis enonniter globosis vel subovoideis, poro latcrale supra medium posito instrnctis;
oosporis forma eadein, sed paulo minoribus.

i>ijn.—(Edog<nnum inequale, WOOD, Proc. Arner. Philos. Soc.. 1869, p. 141
lldl>. — In stagnis, prope Philadelphia.

0. dioecious, basaj cell bilobate; female plant very much larger than the male plant; oospo-
rangiura irregularly globose or subovoidal, opening by a lateral pore above the middle ;
resting spores of the same form as the sporangium, but a little smaller.

A'' marks. — This plant seems to be more closely allied to 0. gemeUiparum,
Vringsheim, than to any other species. It agrees with it in the inequality of the
male and female plants, in the shape of the sporangium, and the position of the
lateral pore. The diameter of the female plant is often nearly four times that of
the male, and the difference in length is much more apparent. The mother-plant is
composed of from 3-6 cells in the most distal of which the spermatozoids are formed.
I am not able to state how many of these bodies arc formed in" a single cell, having

196 FRESH-WATER ALG^E OF THE UNITED STATES.

only seen the latter when more or less completely emptied, but, judging from the
relative sizes, there must be several. In a cell containing a single spermatozoid, that
body moved about freely, and at last escaped, apparently through an orifice in the
end wall of the cell. It made two attempts before getting out, and during its
passage was distinctly constricted in the middle. It resembled in appearance an
ordinary zoospore, but was of course much smaller, and was nearly devoid of color,
having but a slight greenish tint. I found this species growing abundantly in the
stagnant ditches of the Neck, below the city.

Fig. 1 a, pi. 18, represents a young female plant; 1 6, a fertile plant with imma-
ture spores. 1 c was taken from the supposed male plant alluded to in the text.
The latter figure is magnified 450 diameters, the others 250.

Genus ANDROGYNIA.

Gynandra. Androsporce in plantis femineis ortse ; postea hanc affixse et in antheridiis se formant.

Gynandrous. Androspores arising in tbe female plant ; after affixing themselves to this and
developing into antheridia.

A. multispora, WOOD.

A. oogoniis singulis, vel binis vel ternis continuis, globosis instructa; poro laterale distale;
oosporis globosis, oogonii lumen replentibus ; antheridiis plerumque pluribus, plauta feminea
insidentibus, cellula inferiore multo majoribus.

Syn. — Oedogonium multispora, WOOD, Proc. Amer. Philos. Soc., 1869, p. 141.
Hab. — In stagnis, prope Philadelphia.

Oosporangia single or bi- or triseriate, globose with a distal lateral pore ; oospore globose,
about the same size as the sporangial cavity; antheridia bi- or tricellular, curved, with the
lower cell much the largest, generally adhering in considerable numbers to all parts of the
female plant.

Remarks. — This species differs from its nearest European congeners, CEdogon.
Rothii and (E. depressum, very markedly in the bicellular antheridia. I have never
seen the spermatozoids actually emerging from their mother-cell, but have seen in
the terminal antheridial cell a pair of oval bodies, which I took to be those bodies.
Fig. 3, pi. 17, was taken from a filament of this species magnified 500 diameters.
It shows spores in different stages of maturity, with an empty basal cell in one
case, and in the others without. Also male plants, one of them containing partially
formed spermatozoids. The small arrows indicate the direction of cyclotic
currents.

A. mirabilis, WOOD.

A. rare setigera ; articnlis diametro 2-8 plo longioribus ; oogoniis plerumque singnlis, rare
geminis, nonnihil ovatis, infra latis sed supra contractis et medio tumidis ; poris lateralibus
duobus supra medium positis ; oosporis aut late ovalibus aut subglobosis ; sporodermate baud
signato ; antheridiis plerumque bicellularibus, interdum tricellularibus, plerumque in filo
vegetativo infra oogonium aut in oogonio insidentibus ; spermatozoideis singulis et geminis.

Diam.— Artie, veget T;anr"_7i3/=.o004"— 0017". Spor. T^"_7f<>V'.0024"— °02?"-
Syn. — (Edogonium mirabile, WOOD, Proc. Amer. Philos. Soc., 1869, p. 142.
Hab. — In rivulis quietis, prope Philadelphia.

FRESH-WATER ALO^E OP THE UNITED STATES. 197

A. rarely sctigerous ; article' -2 -s time- longer lhaa broad; oosporangia mostly single, rarely
geminate, sulmvutr, i:i tin- lnwi-r |mrtii>ii lirmul, in the middle Kwolli-n, in the upper port con-
tracted ; the 2 lateral pores situated above the middle ; oospore euhglobose or broadly

. ovate, it> r"uu witlimit markings; antheridia generally bicellular, sometimes tricellular,
.-, pUu-i-d generally upim tin- femule filament either upon or below the oosporangia.

-lc*. — Tliis species was found growing in a rather stagnant brook in the
meadow l>y " llol.inson's Knoll," at the junction of the Schuylkill River and Wissa-
hickon Creek, near Philadelphia. The filaments, which vary very greatly in size,
arc in their early history attached to dead leaves and sticks, but finally, I think,
float free in the water. The larger, fruit-bearing filaments are remarkable for their
crookedness. None of the threads that I have seen ended in a seta-like portion.

The fruit is produced in abundance, but very rarely is there more than a single
spore iii any one place. The method of the formation of Jhe sporangia differs from
that of all the other (Edoyonia which have come under my notice. Instead of
two cells being concerned but one cell is employed. The cell (fig. 2 a, pi. 18) that
is to be used for such a purpose grows much beyond the ordinary size, until' it is
nearly or quite twice as large as its neighbors. All the time it is well filled with
chlorophyllous protoplasm. This now contracts and finally is all packed into the
upper half of the cell. At or even before this time the lateral openings become appa-
rent. There are two of them, situated just in the angle where the cell at its upper
end commences to contract to the size of its fellow. At this time I think fertiliza-
tion takes place, although I have never actually seen the spermatozoids enter the
orifice*. The cell (fig. 2 ft, pi. 17) now divides into two by forming a wall separa-
ting the lower empty half from the upper full one, which is to be the sporangium.
The contents of the latter now condense into a ball, and it itself becomes more tumid
in the middle. Finally a reddish-brown broadly globular spore (fig. 2 c, pi. 18)
is formed. I have not been able to make out more than one distinct thick coat.
The surface of the spore is smooth. The androspores are formed in a cell (fig.
'2 </. pi. 18) which has grown beyond the normal size and then divided into four
or five short cells, each of which gives origin, I believe, to a single androspore
in its interior. The antheridia are numerous, from 2 to 6 being commonly attached
to the lower portion of the sporangium, or to the cells just beneath it. They
(fig. 2e, pi. 18) have a rather large foot, and are generally curved at the base. The
distal of the two cells composing them is crowned with a little cap, and produces
one or sometimes two spermatozoids. These (figs. 2 b and 2 g, pi. 18) during their
escape are always very much squeezed out of shape, but when free become globular
or slightly pear-shaped. They are highly transparent and contain a few green
granules. Their motion is at first slow, but soon becomes very active. The mode
• t egress from the cell is obtained by the cutting off of the upper end of it, the
little cap opening like a trap-door. After this cell has been emptied, sometimes a
second similar one is formed, which bears it aloft. I have never seen spermato-
zoids produced by this second cell.

A. Iliuitii. WOOD.

Filuma plerumqne in sctam longam, terminalem coloris expertam productum ; oogoniis pler-
umquc singulis, globosis, interdum nonnihil bexugoniis, medio nounihil tumidis, poro laterale

198 FRESH-WATER A L G JE OF THE UNITED STATES.

infra medium posito ; oosporis globosis, oogonii lumen haud replentibus, superfieie lineis
elevatis spiralibus quatuor instrueta ; antheridiis bicellularibus (inturdum tricellularibus ?).

Diam.— Spor. 5>y=.002".

Syn. — CEdogonium Huntii, WOOD, American Naturalist, 1868.

Hob. — In aquario meo.

Filaments mostly produced into a long apical seta; oogonia mostly single, globose, sometimes
somewhat hexagonal, somewhat tumid in the middle, the lateral pore placed below the
middle ; oospore globose, not filling the cavity of the spore case, its surface with four spiral
elevated lines or ridges ; antheridia bicellular (sometimes triccllular ?).

Remarks. — This little plant appeared in my aquarium some years since, forming
a delicate fringe upon the various aquatic plants growing therein. Its color is a
bright yellowish green, deepening to a very dark green in cells which are crowded
with granular protoplasm. The filaments vary very greatly in size, the largest I
have seen were •$%•$ of an inch in diameter. They are provided with long, termi-
nal seta, which are much more universally present than in any of the other species
I have met with. The first step in the formation of a spore is the emptying of a
cell into its distal neighbor, so that each spore case is placed at the end of an empty
cell. These sporangia may be single or they may be in series of two or more,
separated only from one another by the eruptive cells just spoken of. The color
of the mature spore is a very dark reddish-brown. The antheridia is bicellular,
slightly curved, somewhat stipate, with a distinct foot. Its most common position
is on the vacated cell just below the spore case. The zoospores, as I have seen
them, are always globose.

I have named this species after my friend, Dr. J. Gibbons Hunt, a well-known
microscopist of this city, to whom I am greatly indebted for aid in my earlier
microscopic studies.

Fig. 2, pi. 17, represents different forms and parts of this plant. 2 a shows
the end of a filament and the long seta-like lip. 2 b was taken from two cells,
one of which had just undergone division, and shows very plainly the method of
procedure ; lying as it were between the cells, and bearing the end of the lower
one upon it, is the new little cell. Fig. 2 c represents a fertile filament with two
mature spores and one not fully grown. Fig. 2 d was drawn from a filament just
forming a spore, and shows the male plant in situ. Fig. 2 e represents a male
plant (magnified some 1300 diameters) with the outer terminal cell scarcely more
than a primordial utricle. The contents of the lower cell were in a state of in-
tense motion; and the arrows are meant to indicate the directions of the currents.
Fig. 2 / represents a portion of a filament with a zoospore just escaped and still
quiescent.

A. echinata, WOOD (sp. nov.)

A. valde elongata ; articulis diametro 6-14 plo longioribns; oogoniis globosis, plerumque do-
pressis, ad .0014" crassis; oosporis oogonii forma et cjus lumen replentibus, valde aculeatis;
poro laterale supra medium posito ; antheridiis bicellularibus ?

Diam.— Spor. r5VW"= .001". Cell. ^"—^TS" = .00033" — .0005".
Hob. — In stagnis, Alleghany Mountains.

FHKS H- WATER ALGJ3 OF THE UN I T K I> STATES. 199

O. pynandroiiR, yery elongate ; joints C-14 times longer than broad ; sporangia globose, mostly
(Ic|ire8.sed, about .0014" in diameter; OOB| the same form as gporangia, whoso cavity

they almost fill; covered with (.harp spines; the lateral pore pluccd above the middle; an-
tberidiu bicfllular ?

Remark*.— I found this distinct species in a little stagnant pool in the
wilderness, known as Bear Meadows, in Centre County, of this State. The fila-
ments are very lout,', and were matted together into a sort of fibrous mass. The
malt- plants were t'rw in number, and were attached to the female plant in the
neighborhood of the sporangia. I have not seen any composed of more than two
cells. They are furnished with a well-marked foot, above which there is a short
in-ck. As I have seen them they are nearly straight.

1 have not been able to make out more than one coat to the spores. This coat
i- MTV thiek, and is furnished with numerous thorn-like spines. These are very
.sharp at the points, but at their bases are mostly very robust.

1 ::,'. 3, pi. 18, represents a spore of this plant magnified 750 diameters.

SUBFAMILY BULBOCH^TILE.

Filmmi ratnostirn, setia strictis hyalinis iichrois c Imsi bulbosa et plus minus elongatis instructum.
Filaments braucbing, furnished with straight, hyaline, more or less elongated seta, arising from a

bulbous b:iM-.

/.'• mark*. — The Bull>ocli(ete(e are at once separated from their allies the CEdogo-
by their bushy, branched habit of growth. The shape of the individual
cell is also entirely different, for instead of being regularly cylindrical they are
almost always markedly dilated at their distal end, so as to be somewhat clavatc,
nor is the filament or its branches ever ended by a long seta-like series of narrow
colorless cells. Many or all of the cells are, however, furnished with a single
M iv long unicellular unbranched hair. These hairs are colorless, hyaline, and
profiled with a markedly and abruptly bulbous base. The Bullxxlueleae grow in
similar positions to their allies, but are not nearly so common, nor when present
do they grow in such abundance, very rarely, if ever, forming the dense forest-like
fringes or the matted masses that some species of the (Edogoni&e do. They are
reproduced both by zoospores and resting spores.

The manner of the development of and growth of the plant from the zoospore
ry peculiar. I have never myself studied it, but Prof. Pringsheim gives the
following account: When the zoospore first settles down it produces a cell closely
resembling that of an (Edogonium. The first change which occurs in this cell is
the formation of a small, conical, transparent, colorless space at the apex, which
spate in a little while becomes separated from the mother-cell by a distinct par-
tition-wall, and at the same time the apex itself is ruptured, and the point of the
little growing cone pushed through the opening. This rupture does not take
place irregularly, but by a sort of circumscribed dertiscence, similar to that of the
(Edogoninm, the top of the mother-cell being lifted up like a little trap-door, and
finally pushed aside as the new conical cell grows elongate and becomes converted
into a hair. After the formation of this apical hair, the mother-cell undergoes
division in a manner similar to that of an CEdogonium. Near its distal end a

200 FRESH-WATER ALG.E OF THE UNITED STATES.

circular slit appears, and at the same time a partition forms, so that from the
mother-cell are developed a small apical and a large basal daughter-cell. The his-
tory of the former of these is simply one of growth as regards the main axis. It
increases in size but does not give origin to new cells. All such cells are formed
out of the basal daughter-cell, which, as already described, divides into a new
apical and basal cell — the apical only to grow in the main filament — the basal to
divide anew. It is always the basal cell that undergoes division, throughout the
whole life-history of the plant, one cell alone contributing to the growth of the
main filament. The filament thus formed bears upon its distal end the hair which
grew upon the original spore-cell, and this hair is, save only the basal cell, the
oldest part of the filament. The cell upon which it rests is the next oldest, the
next to it in position, the next in age, and so on (from older to younger) down to
the basal cell, the oldest of all, lying next to the latest born.

Although the cells of the main filaments do not contribute to its development,
yet it is from them that the lateral branches are formed. The production of a
branch begins by the appearance of a clear space near the apex of the cell, but this
clear space is placed, not exactly at (he apex, but a little to one side. It soon becomes
distinctly conical, enlarges, bursts through the old cell-wall, is cut off by a cellulose
partition from its parent, and develops into a hair similar to that first formed, but
placed at an angle to the long axis. It is remarkable that the opening for the
exit of the growing hair occurs, not by a circular transverse slit, but by a longi-
tudinal one, the two halves of the old cell-walls separating as the little cone pushes
its way between them and persisting as a sort of sheath to its base. When the
hair is perfected the cell from which it grew undergoes division in the usual way,
save only that the cutting off of the old wall is done obliquely instead of trans-
versely, so that the partition is oblique instead of horizontal, and the new cell
grows at an angle to the old, instead of in the line of its axis. The new cell,
consequently, is the starting point to a branch at an angle to the main filament.
This branch, like the main filament, grows only by the repeated divisions of its
primal basal cell, and bears aloft its seta. Secondary branches may arise from it
precisely in the way that it arose from the parent stem, and thus at last is formed
the bushy plant of the Bulbochcetece.

The zoospores closely resemble those of the CEdogoitiece, and are oval or glo-
bose masses of chlorophyllous protoplasm, with a transparent space at the smaller
end, surmounted by a crown of cilia. Their mode of formation and whole life-
history are also similar to that of the GEdogoniece zoospores, up to the time when
in their germination they begin to produce new cells.

Sexual reproduction amongst all the known BulloclKetece is similar in its general
aspect to that seen among the gynandrous CEdogoniece, but differs considerably in
detail. The oogonia are mostly formed in lateral branches. Their position in these
branches varies in the various species.

Since any cell from the next to basal to the most distal of all crowned with the
terminal seta may be converted into a oogonium, according to Pringsheim, the
cell which is to form the oogonium arises in the usual way, by the division of a
cell into two daughter-cells. The new daughter-cell, which is to develop into the

PRKSH-WATEH A L 0 -tt OF TIIK I'NITKD STATES. 201

sexual part, diM-s not, however, rupture the old wall of tin- mother-cell, but grows
out beyond it, and there dilates. The new cell is therefore di\ isible into two parts,
a proximal cylindrical portion, contained within the walls of the mother-cell, and
a distal more or less jjlohular piece beyond the latter. The chlorophyllous proto-
plasm now collects in this dilated portion, leaving the basal cylindrical part bare and
empty. The oo^onium is not, however, formed directly from this upper portion
(the primitive oogonitun, as it may be called), but a new wall forms within the latter
and then it undergoes di\i»ion much as did the primary cell. In this way it is that
the upper and lower portions of the old wall, t. e. that of the primitive oogonium,
remain us a sort of basal sheath and cap to the fully-formed sporangium. The
little hole by which the spermatozoids find entrance to the contents- of the oogo-
nium is always formed in the upper half of the wall of the latter.

\> stated, all the species of Bulbochcetece as yet known are gynandrous. The
antheridia resemble those of similar (Edogoniete, and their life-history is very similar.
The development of the resting spores is said to take place as follows: The first
change is in the color of the spore, the bright red becoming green, especially near
the margins of the cavity. The outer wall is then ruptured and the spore grows
into a lonij o\;d body, whose contents are chiefly green with a sprinkling of the
original red. The protoplasm of this oval body gradually divides into four masses,
which become more and more distinct, until they are at last well formed zoosporcs,
similar to those produced in the more ordinary method, except, perhaps, that they
are redder. They are finally set free in the water by a solution of the cell wall
Mirroundini,' them, and enter upon a brief free existence, to settle down after a
little and grow into a fully-formed plant.

Genus BULBOCILETE.

Amlriispora! in planta femincA ortse, postca lianc affixic ctin anthcridiis se formantcs.
Androspore arising in tbc female plant, afterwards affixed to it and developing into the autbcridia.

B. i£iiot:i, WOOD.

1!. sparse ramosa, clongata; articnlis diametro max. (r^ns" = -00077") l|-3 plo longioribus;
oogoniis long. ¥J0" = .0025", lat. »JJff" =.0018", interdum lateralibus et scssilibus, inter-
dnm inter ramulorum cellulas vegetativas positis, dissepimcnto nullo ; oosporis ovalibus, longi-
tudinaliter nonnihil oblique ct distante costatis, in aetatc provecta aurantiaco-brunneis, sporo-
dcrmate crasso ; anthcridiis 3-4 cellularibus, stipitatis.

Syn. — n. ignola, WOOD, Prodromus, Proc. Amer. Pbilos. Soc., 1869.
Hab. — In aquis quietis, prope Philadelphia.

B. sparsely branched, elongate with the joints 1^-3 times longer than broad (T3Vtf" ** -00077") ;
oosporangia .0025" long by .0018" broad, sometimes lateral and sessile, sometimes placed
upon the apex of a branch, sometimes situated in the length of the branches between their
cells; the empty cell which supports the sporangium without dissepiment; oospores, oval,
filling rather closely the cavity of the spore-case, longitudinally somewhat obliquely and dis-
tantly costate, when mature orange brown ; spore-coat rather thick ; antheridia 3-4 celled,
scarcely stipitate.

Remarks.- When I described and figured this species I had never seen the
mature fruit, but very recently Mr. Quimby has communicated specimens to me.

26 September, 1873.

202 FRESH-WATER A L G^ OP THE UNITED STATES.

The color of the spore is orange brown, and the thick coat is slightly tinged with
yellowish. The mature oosporangium is somewhat flattened at the sides, not so
elliptical as the young spore, which I have figured.

Fig. 5 a, pi. 18, represents a fragment of a filament showing young sporangia!
cells magnified 260 diameters ; 5 6, represents a branch with a youngish spore in it,
magnified 460 diameters; fig. 5 c, was taken from a male plant.

IS. duniosa, WOOD.

B. articulis diametro 1^-2 plo longioribus ; oogoniis pleriimque in ramornm brevissimorum
apicibus positis sed interdum lateralibus, plerumque sctam tcrminalem gereutibus; oosporis
enormiter ovalibus aut ovatis, nonnihil indistincte longitudinaliter oblique subarcte. striatis ;
antlieridiis bicellularibus, stipite instructis, cellula basale medio tumida, supra soepe contracta.

Syn. — D. dumosa, WOOD, Prodromus, Proc. Amer. Philos. Soc., 1869, p. 142.
Hob. — In aquario meo.

Joints 1^-2 times longer than broad; oosporangia generally placed upon the ends of short
branches but sometimes lateral, mostly carrying a terminal seta; resting spores irregularly
oval or ovate, somewhat indistinctly obliquely longitudinally and rather closely striate ; an-
theridia bicellular, furnished with a little stipe, their basal cell tumid in the middle, frequently
contracted above.

Remarks. — This species appeared spontaneously during the latter part of the
winter upon some large fresh-water algae which I was cultivating. It branches
irregularly and sometimes somewhat profusely, so as to have quite a bushy habit.
The antheridia appear to produce a single spermatozoon in the terminal cell ; at
least as far as my observation has gone this is true. I think I have always found
the distal cells of fertile plants emptied of their contents, as though they had fur-
nished the androspores which had grown into the antheridia. This species is
closely allied to B. gracilis, of Pringsheim, from which it differs in the position of
the oogonia, in the relative breadth and length of the cell, and the number of cells
composing the antheridia.

Fig. 6 a, pi. 18, represents a filament of this species magnified 260 diameters;
6 b, a male plant magnified 750 diameters.

B. Canbyii, WOOD.

B. permagna ad .035" longa, sparse ramosa; articulis sterilibus diametro-2-8 plo longioribus:
oogoniis lateralibus vel in ramulorum apicem positis, transverse enormiter ovalibus; oosporis,
transverse enormiter ovalibus, plerumque nonnihil triangularibus, oogonii lumen replentibus;
sporodennate crasso, baud costato, enormiter punctato ; antheridiis bicellnlaribiis.

Diam.— Cell, steril. 71JV— ^V = .00066—001. Spor. transv. TJfo" = .00226.

Syn. — B. Canbyii, WOOD, Proc. Amer. Philos. Society, 1869, p. 142.

Hab. — In aquis quietis, prope Hibernia, Florida ; (William Canby).

B. very large, attaining a length of more than one-third an inch, sparsely branched ; sterile
joints 2 to 8 times longer than broad ; oosporangia lateral or placed upon the ends of branches,
irregularly transversely oval ; oospores of a similar shape, often a little triangular, filling the
cavity of the sporangium ; spore coat thick, not costate bnt irregularly punctate.

Remarks. — It affords me great pleasure to dedicate this very handsome species
to Mr. William Canby, by whom it was collected in Florida, as an acknowledg-
ment of favors received, and as a testimony of respect and high regard for him

I UKSH- WATER ALQ^J OF T II K UNITED STATES. 203

penonallj, and as being among the foremost students of American phanerogamic
botany.

This species is more nearly allied to ,V. minor than to any other of the European
forms, hut differ* from it very essentially in size and hahit. It is always, as 1 have
sec n it, except in \ery young plants, sparsely and mostly dichotomously hranchcd,
and attains a \. r\ threat length, at times probably exceeding the third of an inch.
The spore is nn.-tly sessile upon the distal ends of the cells of the filament; in all
such cases 1 have noticed that the cell upon which it was borne was divided in its
middle h\ a partition into two cells. Not unfrequently the spore is raised upon a
short branch. The male plants are attached to the female filaments generally in
the neighborhood of the sporangium, to which they sometimes fasten themselves
immediately. They arc shortly stipitate, and composed of two cells. The mature
spore is transversely oval, now and then slightly triangular, and is nearly of the
color of burnt sienna. Its coat is thick, often slightly yellowish, and has on its
outer surface irregular punctations, looking like corrosions. These arc not detach-
able, except when the ruptured spore is more or less completely emptied of its
contents. The sporangium closely invests the spore, and when the latter is matured
undergoes a circular division, so that the top falls off and allows the spore to escape.

Fig. 6 c, pi. 16, represents a portion of a filament, magnified 260 diameters,
with a young sporangium and young male plants attached; 6 b, represents a very
yomii; plant, magnified C60 diameters. Fig. 6 a, was taken from a mature plant,
and shows the mature spore. Fig. 6 e, shows in outline a sporangium and male
plants attached ; whilst 6 ft7, was drawn from a sporangium which had perfected
its spore and undergone the natural dehiscence.

FAMILY CHROOLEPIDEjE.

Algae acre ic, aurco-, aurantiaco- vel rubro-fusco-coloratse, siccatie saepe cans. Fila varic ramosa,
rytiudrrniute crasso vel subcrasso, Grmo, subcartilagineo pracdita, in pulvinulos rainutos vel in stra-
tum tciuiu aut incrassato-tomentosum densissime aggrcgata vel implioata. Cytioplasma oleosum vel
L'r:iniil.'>ii:ii, aut rubcllum, aureum, aut flavo-fuscum, interdum viridc tinctum, post mortem pleruni-
ij-.i'- ' \i>;illescens. Propagatio fit zoogonidiis.

n\ algse. Golden orange, or reddish fuscous, often grayish when dried. Filaments variously
branrhril, furnished with a thick, or thickish, subcartilaginous cytioderm, densely aggregated into
minute cushions, or a thin or tomcntosely thickened stratum. Cytioplasm granular or containing
oily particles, reddish-golden, or yellowish-fuscous, sometimes tinged with green; after death often
colorless or nearly so. Propagation by zoospores.

Remark*. — The plants of this family are so different from the others of the
order, that it is a matter of considerable doubt whether or not they should be
classified with them. They rarely possess distinct, well-pronounced chlorophyl,
and form mats or strata of some shade of reddish, grayish, or brownish, so that
they are very different in appearance from the other Confervacete.

I do not think their position can be certainly fixed until their life-history has
been more fully developed. In assigning them this place I have simply followed
Prof, kabcnhorst.

204 FRESH-WATER ALG^E OF THE UNITED STATES.

The only specimens that have come to my notice are in a dried condition, and
consequently no possible opportunity has been afforded of studying the manner of
reproduction. No one has as yet, at least to my knowledge, discovered any sexual
reproduction in the family, but the method in which the zoospores are produced
has been carefully studied, especially by Drs. Caspary (Regensburg Flora, 1858)
and Hildebrand (BotaniscJie Zeitung). The little motile bodies are not produced
in the cells indiscriminately, but in certain ones set apart for the purpose, to which
the name of zoosporangia is very applicable. These are large, globular, thick walled
cells, which are generally provided with a protuberance at the top and marked by
transverse wrinkles. They are most frequently situated upon the end of the filament
or one of its branches, but are rarely placed in the middle of the thread, and still
more rarely the cell next below the zoosporangium elongates itself sideways and up-
wards into a thread, so that the reproductive cell is left as a lateral one-celled branch
or process. When the zoosporangium is sufficiently matured the endochrome
breaks up into a number of minute masses, the future zoospores. Finally the
crowning papilla of the mother-cell ruptures and allows the contents to escape as
a well-formed vesicle, containing the perfected zoospores. It is said, however, that
sometimes the vesicle is wanting, and the zoospores are discharged into the water.
In the ordinary course, after a little while the vesicle lying in the water bursts
and sets its motile contents free. The zoospores themselves are very small, accord-
ing to Hildebrand, -g-f -^-^f umm. in length, by •^•5— g^mm. in breadth. In accord-
ance with the same authority they are, when first discharged, cylindrical, but in a
little while become flattened, and shaped like a flaxseed. They are biciliate and
contain a large number of small, orange-colored particles. From thirty-two to
sixty-four of them are formed in one zoosporangium, and neither light nor time of
day appear to have any influence upon their birth. Hildebrand states that their
motile life lasts from eighteen to thirty-six hours, but according to Caspary, after
continuing in motion for about an hour, they grow sluggish, sink, become globular,
then elongate themselves and shortly undergoing transverse division, actively com-
mence to form the new filament.

Genus CHROOLEPUS, AG.

Fila distincte articulata, intricata, enormiter raraosa.
Filaments distinctly articulate, intricate, irregularly branched.

C. aureum, (.LINNE.) KTZ.

C. filis ramossimis, in stratum aureo-brunneum, ad duas trcs lineas crassum, ccespitosum ct molle

intricatis vel in caespitulos aggregatis ; articulis enormibus, diametro sesqui-, duplo triplove

longioribus.
Diam.— Max = .001".

Syn. — C. aureum, (LINNE.) KUTZINO. RABENHORST, Flora Europ. Algarum, Sect. III. p. 371.
Sab. — Little Falls, New York ; Godwinsville, New Jersey ; (Austin). Texas ; (Ravenel).

Filaments very much branched, interwoven to form a yellowish-brown softish mat, two or
three lines in thickness ; joints irregular, 1^-3 times longer than broad.

Remarks. — I am indebted to Mr. Austin for specimens which are labelled
" Forms dense yellow-brown cushions on rocks, at Little Falls, New York and

FRESH-WATER ALO^E OF THE UNITED STATES. -JO.*)

Godwinsville, New .l<r-r\." \-, dried, the plant is in extended, gray, felt-like
ma-M>. '1 he ualls of the articles as seen with the microscope are thick and
irregular, and the joints theiiiv l\es are also very irregular, the end ones being often
swollen and rounded M> as to give the branches a sort of bulbous termination.

Among the Alga' collected in Texas by 1'rof. Ravenel, is a dried specimen (No.
100), labelled "On Bark, Houston, Texas," which I cannot separate from this
species. It occurs in small tufts, which, as dried, are of a very decided orange,
and, no doubt, were still brighter during life. The articles are not so irregular as
in Mr. Austin's specimens, but excepting in this and color when dried they agree
very well. Besides these I have several specimens from the game source, which
are in extended mats and agree in all respects with their northern brethren.

Our American form appears to attain a greater diameter in its individual fila-
ments than does the European variety, but I know of no other character separating
it from the latter; and consequently must consider them identical. The measure-
ment given is an extreme one, .009" being commonly the limit.

Genus BULBOTRICHIA, KUTZ.

Filtt iiiili.-tinrtr urtirulata, achroa, finna, ramosa ; mini in apice intumesccntes, sporangia con-
tUtuentcs.

Fil:iin< nis indistinctly articulate, translucent, firm, branched; the ends of the branches swollen so
as to form sporangia.

B. albida, WOOD (sp. nov.).

13. strato albido, coriaceo vel crustaceo ; fills arete intertcxtis, enormiter ramossissimis, coloris
expert il)iis; spojangiis viridibus.

llab. — In muscis, Northern New Jersey ; (Austin.)

Forming a white leathery or crustaceons stratum ; thread closely interwoven, irregularly and
plentifully branched, colorless ; sporangia greenish.

/,'• murks. — This curious little plant, which was sent me by Prof. Austin, occurs in
minute white patches growing on mosses at the base of stumps in woods. Some-
times tin -e are encrusted abundantly with the carbonate of lime, when they are
hard and crustaceous. The sporangia appear to vary greatly in size ; sometimes
they resemble very closely a single spore (probably their commencing stage). The
s of the branches are rarely, if ever, furnished with the bulbous swelling, given
by Rabenhorst as a generic distinction, but such enlargements do occasionally
occur in the course of the filaments and branches. The filaments are composed
of a series of cells, which are in places long, and have their end walls thin and not
readily seen.

Fig. 5, pi. 16, represents a part of a plant magnified 460 diameters.

FAMILY dLETOPHORACELE.

Algae aquatics vel pnlustres, rarios terrestres, plcrnmqne monoicte vel dioicae. Fila varia, saepe
dichotomc ramosa, hund rnro fasciculatim ramnlosa, plerumque in caenpites vel pulvinulos curaulata,
in iniic-ii frcliitinoso aubliquido vel firmo nidulantia. Propagatio fit turn oosporia, tuin zoogonidiis.
Zoogouidia oriuuturaut singula aut gerainis aut cytioplasmatis divisione 8-16 in quoque sporongio.

206 FRESH-WATER ALG^E OP TUB UNITED STATES.

Aquatic, paludal, or rarely terrestrial algae, mostly monaecious or dieecious. Filaments various,
often dichotoraously, but not rarely fasciculately branched, mostly aggregated into turfy masses or
little cushions, and generally surrounded by a firm or subliquid gelatinous mucus. Propagation both
by zoospores and resting spores. Zoospores arising either singly or by the division of the cytioplasm
into 8-16 in each sporangium.

Genus STIGEOCLONIUM.

«

Fila articulata, simpliciter ramosa; rami ramulique sparsi, rarius faseiculatim approximati, in
apicem acutum, saepe piliferum achrouni attenuati et plerumque longe protensi, saepius ramellis
brevibus subulatis instructi. (R.)

Filaments articulate, simply branched ; branches and branchlets sparse, rarely fasciculately ap-
proximated, with their ends acute and frequently prolonged into an attenuate transparent seta or
hair, and very often furnished with short subulate branches.

Remarks. — Plants which are certainly referable to this genus are abundant in
every place in which I have ever locked for fresh-water algae. I confess, how-
ever, that although very much time has been given to their study, I- have not been
able to make out any distinct specific characters, nor any identifications from the
diagnoses of M. Rabenhorst. In a certain spring northeast of the city, there grows
one of these forms, which I have closely watched for several seasons. In the
earlier state it appears at times to possess the characters of a young CJtcEtopliora
(pi. 19, fig. 1), forming a small gelatinous base out of which the threads soon
escape as they lengthen. It constituted a sort of mucoid layer adhering to the
boards lining the stones with waving masses of projecting filaments six or even
eight inches in length. The filaments were mostly about ^^W in diameter and
much interlaced.

The cells varied greatly in length, some being scarcely as long as broad, whilst
others were eight or ten times longer. The short cells were generally densely
filled with endochrome, whilst the long ones were nearly empty. The branches
often ended abruptly, but were more frequently tipped with a long seta-like
point. The method of branching is as varied as can be imagined, as is shown
by fig. 4, pi. 16, and fig. 1, pi. 20, all taken from different plants of this species.
I have frequently seen the production of zoospores, but no other method of repro-
duction. In all cases a single motile body (fig. 4, pi. 16) was formed in each
cell. These minute bodies are globular or pyriform, and within the cell exhibit
no motion whatever. Their escape takes place very slowly through a lateral slit
in the wall. No cause of the motion is visible, and during the passage the
zoospore is often very much squeezed out of shape. According to Braun (Ver-
jungung), these zoospores possess a red eye-spot. I had not read his description
at the time my observations were made, but did not notice any. The zoospores
germinated in the usual way, elongating and growing into a cell with a transparent
seta-like end, and finally undergoing repeated divisions to form the plant.

M. Braun states that he has observed another process, in which the contents of
a single cell undergoes a perpendicular division, so as to form four small zoospores,
which escape from the cell in the same way as the larger one, and further says
that he has never known these microgonidia to germinate.

1 UK S 11 -WATER ALG^ O F Til E U M T E D 8 T A T E S. 207

Genus DRAPARNALDIA, Ao.

Filaartirnlata rnmosa. c n-llulis magnis, maximc hyalinis, fascia chlorophyllosa lotinsoulo ornatis,
.-. ni|"-r Mrrililms furinutu, fasciculi* penicillato-raiuulogiBsimis, e ccllulis ininoriluis fcriililnis com-
l, plus minus di-n>r obtsessa, Articuli UTtuiualcs omnium ruuiuluruiu iuaiius achroi utcriles, in
jiiiniu hvalinum plus minus clougatL

Filaments articulated, branched, formed of large cells which are chiefly hyaline, but famished with
a inin.-ver.-c chlorophyllous fascia, more or less densely clothed with penicillately ramulose fasciculi,
firmed of smaller fiTtilc cells. Teruiiual articles of all the joints empty, transparent, sterile, aud
elongate, in a more or less hyaline hair.

D. £lomrrata, (VAUCH.) Ao.

D. filis rnmi.-i|iie primariis achrois yel snbachrois, ad 0.00147" crassia, articulis inferioribus
diamctro xqualibus vel paulo brevioribus, guniculis manifesto constrictis, fasciis chlorophyl-
losis angustis dilute viridibus; raniis primariis snbrectangiilo-patcntibus, saepe oppositis ;
ramiilnnini fasciculis confertis, patcntibus, altvnyutibus vt-1 oppositis, dense ramellosis, sub-
ovalibus, obtusis. (11.)

Syn. — D glomerata, (VAUCDER) AoARDn. BABENHOBHT, Flora Europ. Algarum, Sect. HI.
p. 38.

Hal. —Rhode Island; (S. T. Olney) Thwaitcs.

Fihiint-iit and primary branches colorless or Bubcolorleas, and reaching 0.00147" in diameter,
I.'U.T articles about as long or a little shorter than broad, manifestly constricted at the
joints, chlorophyl fascia narrow, light green ; primary branches subrectangularly patent,
often opposite; fasciculi of branches crowded, patent, alternating, or opposite, densely
ramellose, suboral, obtuse.

Renwrks. — According to M. Thwaites the true Dr. glomerata grows in Rhode
Inland, as he so identified specimens sent to him by Mr. Olaey. These specimens
ui re, however, in all probability dried, and if this was so, I confess not to attach-
ing much weight to the identification. The Draparnaldia, common near Philadelphia,
once so like and yet so different from the description of D. glomerata, that I
;iin unable to fully satisfy myself whether it be a variety of the European species
or distinct from it. It differs very greatly in the thickness of the stem and pri-
mary branches. I have given above P'-of. Rabenhorst's description of the Euro-
pean variety, and now append one of tin plant growing in this neighborhood.

Tar. maxima.

Dr. filis achrois, ad 0 004" crassis, articnlis plerumqne diametro duplo longioribns, in mcdio
«epe valde tnmidis; ramis primariis achrois vel subachrois, oppositis vel alternantibus vel
ternatis, elongatis, dense ramellosis, cum ramulis lanceolatis ; ramalornm extremorum
fasciculi's dense raraelosis, ovatis vel late lanceolatis, plerumque confertis; ramulorum
articnlis inferioribns plernmque diametro (ad YiW) subaequalibus, articulifl superioribus
diamctro duplo ant triplo longioribus, plerumque piliferis.

Hah. — Prope Philadelphia ; Wood.

Filament transparent, attaining a diameter of 0.004", its articles mostly twice as lonjr ns
broad, strongly swollen in the middle ; primary branches colorless or subcolorless, opposite,
alternate or ternate, elongate, densely ramellose with the ramuli lanceolate ; fasciculi of
extreme branches densely ramellose, ovate, or broadly lanceolate, mostly crowded, inferior
articles of the branches mostly about as long as broad (nV«"). superior articles two to three
times as long, mostly pilifcroua.

208 FRESH-WATER ALG^ OF T II E UNITED STATES.

Remarks. In this form there are almost always numerous little clusters of branch-
lets, growing immediately from the main stem or large branches; such clusters are
more ri°id, more open, more broadly ovate, and less markedly piliferous than the
others.

D. plumosa, (VAUCHER) AQARDH.

D. filis ramisque primariis hyalinis, plernmqne J^"" = 0.00179" crassis; articulis diametro
sequalibus vel dimidio brevioribus, rarius paulo longioribus, geuiculis vix aut modice con-
strictis, fasciis chlorophyllosis angustis laete viridibus ; articulis inferioribus ramulorum dia-
metro ( Tsg'" — 5*3"') sequalibus vel subduplo longioribus, paene torulosis, superioribus cylin-
dricis ad 5^3'" attenuatis, diametro duplo triplo-quintuplo longioribus, plerumque non pili-
feris ; ramulorum fasciculis dense ramellosis, elongatis, acute lanceolatis, erecto-subap-
pressis. (R. )

gyn. — Dr. plumosa, (VAUCHER) AGARDII. RABENHORST, Flora Europ. Algarum, Sect. III.
p. 382.

Hob. — In rivulis et aquis quietis.

Filament and primary branches hyaline, mostly fa'" = 0.001 T9" in diameter; articles as long aa
broad or one-balf shorter, rarely a little longer, scarcely or slightly constricted at the joints,
chlorophyl fascia bright green, narrow ; lower articles of the branches about as long as
broad (ris"' — sia"') or nearly twice as long, somewhat torulose, the upper ones cylindrical,
as small as 5^3"', two to five times longer than broad, mostly not piliferous ; fascicles of
branches densely branched, elongate, acutely lanceolate, actually subappressed.

Remarks. — I have found a Draparnaldia frequently, which I believe to represent
the European D. plumosa. As I have preserved, however, no specimens or
descriptions, I have simply copied the description of Prof. Rabenhorst.

D. Billingsii, WOOD.

D. valde gelatinosa ; filis et ramis primariis achrois ad 7!"^" crassis, sparsissime ramosis,
articulis diametro 2-6 plo longioribus, ssepe medio valde tumidis ; fasciis chlorophyllis dilute
viridibus, ssepe nullis aut subnullis ; ramulornm fascicnlis distantibus, late ovalibus vel late
triangularibus, alternantibus vel oppositis vel triplice verticellatis, sparse ramosis, patentissi-
mis ; ramulis pilis longissimis robustis terminalibus instructis ; oosporis globosis, moniliforme
conjunctis ; sporodermate crasso.

Syn.—D. Billingsii, WOOD, Proc. Am. Philos. Soc., 1869, p. 14a
Hab. — In aquis qnietis, pfope Philadelphia.

Frond very gelatinous, filament and primary branches attaining a diameter of 7i</', ver
sparsely branched, their articles 2-6 times longer than broad, often very much swollen
the middle ; chlorophyl band light green, frequently almost or entirely wanting ; fascicle
of branches distant, broadly oval or triangular, alternate, opposite, or in whorls of three,
very open ; ultimate branchlets terminating in a long, robust, hyaline hair ; resting spores
globose, with thick walls, arranged in long moniliform sometimes branched filaments.

RcmarJcs. — I found this plant about the middle of March, 1869, floating on tht
surface of a little pool in the woods near Chelten Hills, a few miles north of
Philadelphia. To the naked eye it appears as a gelatinous mass, resembling
Tetraspora, but when closely examined this translucent jelly is seen to be filled
with rather distant greenish points, which are the little clusters of branches. The
largest specimens I have seen had attained a length of nearly two inches. The
filaments are very transparent and have the branches placed at long intervals.

FKKS II -\\ATEK ALUJi OF THE U i\ J T K 1> STATES. 209

The ultimate l>r:mrh groups aro ovate or oviil, and are remarkable for their open-
ne-s. the hranchlets being few in number and widely separated. Most of the ulti-
mate branchlets are prolonged into a remarkably strong long hair.

The cells of the main filaments are beautifully transparent, and are sometimes
cylindrical but more generally are barrel-shaped. Both secondary and primary
bruin-lies are often arranged singly, sometimes in pairs, not unfrequently in threes.
\Ylien placed between two plates of glass and examined closely by the unaided
this .species is readily distinguishable from our other DraptiniahUa, by its fas-
ciculi of branches being so widely separated as to be not at all confused with one
mother.

I have a single specimen which I believe to be in fruit. The resting spores
iiiu'. ('. pi. 14) are in long branched chains. They are more or less globose, with
a \<ry thick outer transparent wall, and an inner green endochrome, which very
probably becomes brownish at maturity. Except when they are branched, these
scries of spores remind one very strongly of the filaments of some nostocs.

1 dedicate this very beautiful species to Dr. J. S. Billings, U.S.A., to whom I
am under the greatest obligations for aid in the prosecution of this research, and
whom 1 have ever found to unite the greatest scientific liberality with a strong en-
thusiasm for and able prosecution of the study of these lower vegetable forms.

Since describing this species I have received the Microscopical Journal for 1869,
containing Dr. Hicks's paper upon D. cruciata. The original description in the
Limuean Transactions had escaped my notice. D. cruciata and D. Billingsii are
edingly closely related, yet if Dr. Hicks's description and figures be accurate
they arc probably distinct. Thus in the last species the ramuli are not placed at
ri^lit angles to the main filament, nor are they ever in fours, both of which are
given as characters of D. cruciata. They are, on the contrary, in D. Billingrii at
various angles, and commonly arise singly, but not unfrequently in pairs, and very
rarely in threes. It is worthy or remark, on the other hand, that the figures of
Dr. II. do not entirely agree with his description, as in no case are there more than
two and frequently but a single branch at one place. The cells of the main fila-
ment are also more barrel-shaped in our species than one would infer to be the
• with D. cruet a fa.

After all, however, I think it very possible that both forms belong to the one
species.

Fig. 6, pi. 14, represents a small portion of the frond with fertile branches mag-
nified 460 diameters.

Genus CILETOPHORA, SCHRANK.

Fila articulata ramique primarii radiatim dispositi, e cellulis vegctativis elongatis, fascia cbloro-
phyllosa in niorcm Draparnaldiae et Stigeoclonii ornatis compositi, sursum in ramnloa numero-
aissimos, brevius articulates, articulis extremis attcnuatis rape inanibns non ant vix piliferis in-
•trnctos, fasciculatos plus minus dense congestos divisi, massa gelatinosa firma, coriacea vel dura
involuti, thulium globosum vel snbglobosura nut plane expangura varie lobatnm et fissum con-
itituentes. (R.)

Filaments articulated, with the primary branches radiately disposed, composed of elongated vege-
tative ri'lU. ornamented with a chlorophyllous fascia like a Draparnaldia or Stigcoclonium, distallr
27 September. 1873.

210 FRESH-WATER ALGJi OF THE UNITED STATES.

resolved into very numerous fasciculate, more or less densely congested branches, with shorter
joints, their end joints alternate, often empty, either not or scarcely piliferous ; surrounded by a firm
coriaceous or hard jelly, so as to form a globose, subglobose, or expanded thallus.

Remarlcs. — I have never seen the production of the zoospores in this genus, but
they are said to arise one in a cell, and to escape by a sort of lateral splitting of
the wall.

C. elegans, (ROTH) AGARDH.

Ch. thallo globoso vel subgloboso, pisi vel ccrasi magnitudine, dilute vel saturate viridi, nitido,
superficie Isevi vel quasi tuberculata, elastice molli, nonnunquam indurato ; fasciculorum
ramulis laxis vel confertis, articulis extremis brevi-cuspidatis, soepe piliferis.

Syn. — 0. elegans, (ROTH) AGARDH. RABENUORST, Flora Europ. Algarum, Sect. III. p. 384.
Hob. — United States.

Thallus globose or subglobose, of the size of a pea or cherry, light green, with the surface
smooth or quasituberculate, elastic but soft, sometimes indurated ; branches of the fasciculi
lax or crowded ; end articles shortly cuspidate, often piliferous.

EemarJcs. — One of the commonest of our fresh-water algae is a plant belonging
to this genus, which I think is probably the O. elcgans of Roth. I am, how-
ever, unable to discover any characters separating C. pisifdrmis, C. elegans, and
perhaps C. tuberculosa, and hardly know by which of the three names our Ameri-
can form should be known. Our plant grows generally in shaded pools, springs,
and ditches in great abundance, adhering as little translucent balls to grasses,
leaves, twigs, or anything that may be in the water. The size of the frond varies
from the young one, not so large as a pin's head, to the old matured one, which
may be nearly an inch in diameter. The color also varies greatly. It is always
some shade of a pure green. The surface is mostly smooth, but sometimes it is
so puckered up as to be a mass of large flat tubercles. It is these forms that I
suppose to represent C. tiiberculosa. The thallus is generally elastic, but at the
same time soft, so that although readily compressed and pushed out of shape, it is
entirely mashed with some difficulty, especially as, owing to its slipperiness, it
constantly escapes from the grasp.

In regard to the individual filaments, the method of their branching and the
proportionate length and breadth of the cells vary very much in different in-
dividuals and probably at different ages of the same individual.

Fig. 5, pi. 6, represents rather indifferently well a young individual of this
species.

C. endiviaefolia, (ROTH) Ag.

Ch. thallo linear!, subplano, semipollicari vel pollieari, nonnunquam valde elongate, hete vel
obscure viridi, dichotomo-subreticulatum-laciniato (nonnunquam habitu Ricciae fluitanlis) ;
filis ramisque primariis plerumque achrois, passim viridi-zonatis, para'llelis ; ramulorum fasci-
culis lateralibus, plus minus densis, divaricato-patentibus ; articulis plus minus tumidis,
diametro sequalibus vel subaequalibus ; geniculis constrictis ; cytioplasmate granuloso
effuso. (R.) Species mihi ignota.

Syn. — C. endiviaefolia, (ROTH) AGAHDH. RABENHORST, Flora Europ. Algarum, Sect. III.
p. 383.

FHES11-WATKU A L U M OF TUB UNITED STATES. 211

;/,,/,.__South Cur.ilimi; (lluvciiel) Wood. Rhode Island; (S. T. Olncy) Thwaites.

Thullus linear, (lutti.-li, of half to a whole thumb's breadth, sometimes greatly elongate, bright

or obscure green, dicliotoiuously subreticulately laciniato (sometimes with the habit of

in jluitunx) ; filament and primary branches mostly colorless, sometimes coned with green,

parallel ; lateral fu.-riculi of branches more or less dense, divaricately patent ; joints more or

less tiimiil, (liiiiin ii-r fi|ual o'r subequal ; joints constricted ; cytioplasm effused granulate.

L'I nntrk*. — I have never seen a living or well-preserved specimen of this species,
and have, therefore, here simply copied the description of Prof, llabenhorst. Prof.
Ravenel has sent to me dried alga; labelled, and I think correctly, as belonging to
this species, lint their condition did not allow any scientific study of them.

Genus PILINIA, KTZ.

Fila artirulata, crccta, simplicia vel dichotonic ramosa, basi nffixa, in stratum criistaccum sub-
sponjrioMiiii, fragile aggregata. Propagatio adhuc ignota.

Filaments articulate, erect, dichotoroonsly branched, fixed by the base, aggregated into a some-
what spongy fragile crnstaccous stratum. Method of propagation unknown.

P. dilula, \Vii.in, (sp. nor.)

1'. rupicola, in strato cano-viridi disposita ; filis ramisque fasciculatis, apice obtusis ; articulis

diametro 1^ plo— 3j plo longioribus.
]>,«m. —Max. 0.0004".

Hub. — lu fontibus maximis, prope Bellefonte, Centre County, Pennsylvania ; Wood.
Growing on stones and roeks, forming a grayish-green stratum ; filaments and branches fasci-

culate, witli the apices obtuse ; joints l£-3$ times longer than broad.

Remarks. — Near Bellefonte, Centre County, Pennsylvania, there issues from the
linn •stone rocks the largest spring I have ever seen, giving rise to a creek-like tor-
rent, which supplies the city with water, and passes on scarcely diminished in
volume. In this spring grows the curious algae under consideration, forming a
somewhat lubricous crustaceous and stony stratum on the stones and rocks in the
basin. This stratum is of a grayish-green color, and is quite friable, breaking in
the direction of the filaments with the greatest possible readiness. \Vhen placed
under the microscope it is seen to be composed of filaments whose course is a
direct one from the under to the upper surface. They are apparently rigid, pre-
serving their courses, and not being intermattcd. They are composed of cylindri-
cal, confervoid cells, and are dichotomously branched, and yet when viewed as
a whole the filament and its branches form a sort of fasciculus. The basal cell
ir cells appear to be globular. When I collected this plant I was forced by cir-
nunstances to put the specimens in carbolic-acid water for future study, and,
therefore, I have had no opportunity of studying their method of reproduction.
I am not altogether satisfied in referring this plant to the Pilinia, and yet all the
most important of the characters given by Rabenhorst are preserved by it. It
certainly, however, differs very greatly from P. rimosa, Ktz.

Genus APHANOCHJETE, BRAUN.

Fila distincte articulata, prostrata, repentia, interdnm in stratum irregulare plus minnsve concreta;
ramulig repentibus vel adscendentibus ; cellulis chlorophyllaceis, apice vel dorso setigeris. Propa-
gatio zoogonidiis.

212 FRESH-WATER ALGJ3 OF THE UNITED STATES.

Threads distinctly articulate, prostrate, creeping, sometimes more or less concreted into an irregular
stratum ; branches creeping or ascending ; chlorophyllous cells with the dorsum or apex setigerous.
Propagation by zoospores.

Remarks.— Sexual reproduction has not as yet been discovered in this genus.
According to Dr. Braun (Verjiing., Translation of the Kay Society, p. 184, &c.)
two zoospores are generally formed in a cell by a division of its contents parallel
to the septa, but occasionally this division not taking place, the cell contents are
resolved into a single zoospore. The zoospores themselves are nearly globular,
biciliate, and unprovided with any reddish eye-spot.

A. repens, BRAUN.

A. filis procumbentibus plerumque simplicibus ; articulis cylindricis aut tumidis, diametro sub-
sequalibus ad 1-2 plo longioribus ; setis e cellularum dorso egressis, plerumque singulis sed in-
terdum geminis, interdum nullis.

Diam.— Artie. T,f TO"— riW = .00055— .0004".

Syn. — A. repens, BRATJN. RABENHORST, Flora. Europ Algarum, Sect. Ill p. 391.

Bab. — In (Edogoniis, prope Philadelphia ; Wood.

Filaments procumbent, mostly simple; articles cylindrical or tumid, from as long as broad to
twice as long ; seta arising from the back of the cells, generally single, sometimes geminate,
sometimes wanting.

Remarks. — The specimens from which the above description was drawn up, were
found growing on the filaments of (Edogonium mirabile, WOOD. They were re-
markable for the rarity with which they were branched, for in but two or three
cases out of a great number, were any branches detected. The articles were fre-
quently twice as long as broad. In both these particulars the plant differs from
the typical European A. repens, but the descriptions of that form are so short and
imperfect that I have preferred retaining the name for the American plant.

Fig. 5, pi. 14, represents an ordinarily formed specimen magnified 460 diameters.
It had been kept for some time in weak carbolic-acid solution, and although the
green of the chlorophyll was perfectly preserved, the stumps only of the setae
were visible. How long the perfect setae are I canndt at present say, not having
made any notes on the fresh specimens.

Genus COLEOCH^TE, BREB. (1844).

Fila articulata ramosa aut in pulvinulum conjuncta ant in thallum planum subdisciforraem
parenchymaticum concreta ; articuli oblongi, antice plus minus dilatati, angulo superior! vel dorso
saepe in setam basi vaginataro producti. Propagatio fit turn oosporis foecundatione sexuali ortis,
turn zoogonidiis. Zoogonidia in quaque cellula fructifera unica, forma subglobosa vel late ovalia,
polo antico ciliis vibratoriis binis instructa. (R.)

Filaments articulated, branched, either conjoined into a little cumulated mass or parenchematously
concreted into a plain subdisciform tnallus ; articles oblong anteriorly, more or less dilated, often
furnished with a long seta on their dorsnm or superior angle. . Propagation occurring by means of
oospores, formed by sexual organs or by zoospores. Zoospores subglobost or broadly oval, formed
singly in the fertile cell, furnished at their anterior pole with vibratile cilia.

Remarks. — I have seen a large number of specimens of, as I believe, two distinct
species of this genus, but never having found any fruiting fronds, have not been

PRESH-U' ATER A L 0 ^E OF THE UNITED STATES. 213

able to identify tin-in. One of the forms «,TO\VS in this immediate locality, and is very
probably ('. .V//AI/U, Hroh. The other was collected in Northern Michigan. It is
charaeteri/.ed l>y its frond never being disciform, although composed of a single
plane of cells parenchematously united.

CLASS KIIOIH'I'IM < i: I .

Alga} multicclliilarcs, vegctatioue terminalis non liuiitata pra}dita3
plrnimqiie trioiea1.

Thallus c cell iihi rum serielms vel stratis singulis vel pluribus compo-
situs, uut niidus aut e ccllularuin strato corticatus, forma quarn maxime
vaiius; int'inbranaceiis (Porphyridium), crustaceus (Hildenbrandtia),
tilaiiicnloHis et verticillatim raiuosus (Batrachospermuin, Thorea), fascii-
formis (Bangia), foliacetis, etc.

C\ til-plasma ]>l<Tinn<iuo rhodophyllo (Colm), rarius phycho-cbromatc
coloi at urn, granula amyloidea vel amylacea et sajpc guttulas oleosas
includens.

Propau-ationis organa triplicis indolis, saepissime in plantas distinctas
disjxisita.

1. (h-ijnna mascula vel anflicrida e fasciculis celhirartim plenimque mo-
nilifonniluis ramosis, denique in Rpermatozoidea vel spermatia fo;ciin-
dantia (Sporidia I. Ag.) oblonga vel ovalia, achrod, iniiuobilia dissolutis
formata.

2. Oruttnafeminca vel cystocarpia Ktz. e soris nonnunquam monilifor-
miluis iumiata, qui e placenta saepissime corticali evolvuntur, nudi vel
nitiriila inucilaginosa vel involucre inclusi, denique sporas (j)dysporas}
niinierosas iinuiobiles mox germinantes emittimt. Foecundatur cysto-
carpiiim statu priuiordiali ope organi piliformis (triclioyyHe Thuret et
Bonu-t) quorum spermatia copulantur.

3. Ti-ti-tix/>orfinf/ia e cellula corticali unica valde intumescente formata,
<ln isione utriculi primordialis cruciata quadrilocularia ; in quoque loculo
(<•<•// H/I'S secundart'is, sororiis) spora unica (tctrasjwra) Be format, quae sine
foecundatione geruiinat. (R.)

Multicellular algae, mostly trisecious, furnished with unlimited not ter-
minal vegetation.

Thallus composed of cells in rows or in a simple or multiple stratum,
cither bare or provided with cortical strata of cells, exceedingly various
in form; mcmbranaceous (Fophyridium), crustaceous (Hildenbrandtia),
filamentous and verticillately branched (Batrachospermum, Thorea),
laM-iate (Bangia), foliaceous, &c.

Cytioplasm mostly rhodophyllous, rarely phycochromatously colored,
including amyloid granules or starch and frequently oil drops.

Propagation by means of three iminotile organs, generally placed
upon distinct plants.

1. Antheridia composed of mostly moniliformly branched fascicles of

214 FRESH-WATER ALG^E OF THE UNITED STATES.

cells, which dissolve into oblong, oval, transparent immotile.spermato-
zoids (Sporidia Ag.).

2. Cystocarpia Ktz., or Pistillidia, formed of somewhat moniliform sori,
which are evolved from a generally cortical placenta, and are naked or
surrounded by a mucilaginous cuticle or involucre, and finally emit
numerous immotile spores (polyspores), which quickly germinate. The
fecundation of the cystocarpia occurs in their primordial state by con-
tact of the spermatia with a piliform organ known as trichogonia.

3. Tetrasporangia formed of single, greatly swollen cortical cells, be-
coming cruciately quadrilocular by division of the "primordial utricle; in
each loculus (secundary or sister cells] a single spore (tetrasporc) forms,
which germinates without fecundation. .

FAMILY PORPHYRACE^E.

Thallus mucoso-rnembranaceus, foliaceus vcl filamcntosus, e ccllularum seriebus vel strato uuico
formatus, plerumque purpurascens, valde lubricus.

Vcgetatio fit cellularum divisione in duas vel omnes directiones rcpetita.

Propagatio fit tetrasporis. Cystocarpia nondum observata.

Thallus mucous-membranous, foliaceous or filamentous, formed of cells in series or in a single stra-
tum, mostly purplish, very slippery.

Growth taking place by repeated division of the cells in two or all directions.

Propagation by means of tetraspores. Cystocarps not yet observed.

Remarks. — The only species of this family as yet observed in North America
can hardly be said to have a definite thallus. They are rather multitudes of cells
heaped together and closely attached to one another into a shapeless expanded
mass.

Genus POKPHRYDIUM, NAEG. C1849).

Thallus mucoso-membranaceus, subcrustaceus, longe lateque expansus, e cellulis globosis vel
polyedricis compositus. Propagatio adhuc ignota.

Thallus mucous-membranous, subcrustaceous, long and widely expanded, composed of globose or
polyhedral cells. Propagation unknown.

P. crueEitum, (Ao.) NAEG.

P. thallo saturate purpuro-sanguineo, lubrico ; cellulis anguloso-rotundatis. (R.)
Diam— 0.00027"— 0.00035". (R.)
Hob.— New York.

Syn. — P. cruentum, (AGARD.) NAEGEL. RABENHORST, Flora Europ. Algarum, Sect. III.
p. 39?.

Thallus deep crimson purple, slippery ; cells angled and rounded.

Remarks. — The only specimen I have seen of this species was a little speck,
adherent to a bone picked up on Governor's Island, in New York Harbor. It is
very probable that it was a recent arrival, brought over, perchance, by some emi-
grant. For it I am indebted to Dr. Billings, TJ. S. A. The description and

FKKS II- WATER A LG X, O F T II E U N I T E D ST A TE 8. 215

inr;i>tirement.s given above are copied from Prof. Rabenhorst's work. My specimen

well with it.

r. iiiaxiiifiriiiii. WOOD.

1'. cdlulis jrlnlnisis TC! snbglobosis, socpe nonnihil polygonis et in massam indefinite expansam

couflueiuibus ; cytioplaswatu purpureo, grunulato; cytiodcrmate crasso, baud lamelloso.
Diam.— CY11 cum. tcgum. ,,J5B — «'oW Tegum. 5BJOD — iiiro-
Hyn.—P. magnificum, WOOD, Proc. Am. Philos. Soc., 1869, p. 144.
JIab. — In terra buniida, Texas; Prof, llavenel.

Cells globose or subglobose, often somewhat polygonal and conjoined into an indefinite mass ;
eudoi-hrouie purple, granulate ; cell wall thick, not laminate.

L'I mil, 7.-x. — This species, which was collected in Texas by Prof. Ravenel, growing,
I believe, on wet sand, is very distinct from the European plant, differing essenti-
ally in size and form. In some instances the cells have a greenish tint, but this is
ltii->ibly owing to immaturity, as such cells seem smaller than others. The whole
m;e.s to the eye has a very rosy purple tint, and although under the microscope it
appears much darker and more purple, yet it often retains some of the roseate hue.
At the edges of the masses the dark-reddish color often gives way to a very decided
greenish tint, presenting an appearance which is very well represented in the
drawing of the preceding species, in M. MENGEHINI'S Monoyraphia NostocJiinearum
llalicantm, cfcc., Memoire ilella Reale Academia delle Scienze di Torrino. The cells
are often closely united by their thick coats into a very coherent mass. With the
ordinary cells I have occasionally seen other larger ones, of an orange color, with
very thick walls. Are these resting spores?

Fig. , pi. 19, represents single cells of this plant magnified 750 diameters.

FAMILY CHANTRANSIACE^E.

Thallus filamentosns. Fila articulata, e cellulamm eerie nnica formata, ramosa, stricta, nuda,
raro passim corticata, rami superne fascicnlatira rarocllosi ; articnli cylindrici. Cytioderma, honio-
p'Mi'uin, niaximc hyalinum. Cytioplasma bomogenenm, plerumqne purpurascens. Propagatio fit
jxilysporis immobilibus, oralibas, in ramellorum apice vel lateraliter formatis, corymboso aggregatis.
Antheridia subglobosa, tcrniinalia. Tetraspora raro observata).

Thallus filamentous. Threads articulate, formed of a single series of cells, branched, straight,
1-are, rarely here and there articulate ; branches above fasciculately branched ; joints cylindrical
Cytioderm homogeneous, mostly hyaline, cytioplasm homogeneous, mostly purplish. Propagation
by immovable oval polyspores formed on the ends of the branches or laterally and corymbosely
aggregate. Antheridia subglobose terminal. Tetraspores rarely observed.

Genus CHANTRANSIA, FRIES.

Familise genus unicnro.

The only genus of the family.

C. expanna, WOOD.

C. caespitosa, in lapide stratum saturate violaceo-pnrpnrenm lubricnm, indefinite expansnm,
formans; filis purpnreis, modice ramoais, fere 2 lineas longis et ramis plerumque strictis et
rectis, ssepe elongatis; raniulis fcrtilibns brevibna, ascendentibus ; articulis diamctro 3-8 plo

216 FRESH-WATER ALG^E OF THE UNITED STATES.

longioribus, extremis obtusis ; polysporis in ramellis lateralibus racemosim et confertira
cumulatis, ovalibus vel uonnihil obovatis.

Diam.—Y\\. 5EV/ = -0004". Spor. transv. g^" = .00027 long. 55V7 = .0004".

Syn. G. expansa, WOOD, Prodomus, Proc. Amer. Philos. Soc., 1869.

Hob. — In rivulis, prope Philadelphia.

Csespitose, forming a dark purple, slippery, indefinite stratum on stones ; filaments purple,
moderately branched, almost 2 lines long, together with the branches strict and straight,
often elongate ; infertile branches sometimes very few, sometimes very numerous ; fertile
branches short, ascending ; joints 3-8 times as long as their diameter, the final articles ob-
tusely rounded : polyspores racemose, crowded on the fertile branches, oval or somewhat
ovate.

Remarks. — This species was found growing in a running stream, forming a felty
slimy coating upon large stones, looking so much like a stratum of Oscillatoria,
that when I gathered it I thought it probably was a representative of that genus.
The stratum, however, when carefully examined, is seen to be made up of an in-
definite number of minute, very closely approximate tufts. The color was a dark
dull purple. The plant may possibly be the CTiantransia violacea, of KUTZING,
which it resembles in many particulars, but it is nearly twice as long and the fila-
ments are considerably thicker. Its habit of growth also seems to be essentially
different from that of the European plant, so that I have finally decided to con-
sider it a distinct species. The exact locality of its growth is in a thickly-shaded
portion of the stream that runs along the North Pennsylvania Railroad, just this
side of Chelten Hills.

Fig. 2, pi. 19, represents a filament magnified 125 diameters; fig. 2 a, a part of
a fertile branch magnified 460 diameters.

C. macrospora, WOOD (sp. nov.).

C. caespitosa, subpollicaris, olivaceo-grisea vel saturate violaceo-purpurea; filis ramosis et
ramis plerumque strictis et rectis, et elongatis ; articulis diametro 3-8 plo longioribus ; ramu-
lis fertilibus brevissimis ; polysporis singulis vel geininis, sparsis, saspe distantibus, globosis,
interdum nonnihil ovalibus.

Diam. — Fil. plerumque .0008 — max. .001. Polysp. .0009.
Hob. — South Carolina ; (Ravenel).

Caespitose, about an inch long, olive-gray to deep-violet purple ; filaments a good deal branched,
with the branches mostly straight and elongated ; fertile branches very short ; articles 3-8
times longer than broad ; spores single or geminate, few, often distant, globose, or sometimes
slightly oval.

Remarks. — I am indebted to Prof. Ravenel for specimens of this species pre-
served in carbolic-acid water. They are labelled, " Dull olive green, growing
against wooden boards in spring, Nov. 5, 1869. Aiken, South Carolina." The
most of the mass is of the color noted, or at least approaches it, but a portion is
almost blackish purple. The species is a very distinct one, characterized by
the larger diameter of its articles and spores, by the paucity and shape of the
latter, as well as by its variance in coloration. In some old specimens the cell
wall is distinctly lamellate. I have only seen fruit on the purple filaments. The

F U K S II W A T K U A L G £ OF THE UNITED S T A T K S 217

spores, apparently not mature, have a greenish-brownish tint. 1 have also received
from Prof. Uavenel dried al^c, \\liich, apparently, are the same species as those
from which this description has been written, but which, not being in fruit, cannot
be absolutely identified. They are, as dried, of a bright bluish-green, and attain
the length of an inch and a half or more.

Fig. :*, pi. 19, represents a part of a branch of this plant magnified 460
diameters.

FAMILY BATRACHOSPERMACK/E.

Alir:r dioipse. Thallus filamcntosus, articulatas, ramosus, aut violaceus, violacco-purpurcua
vrl ciLTuluo-viriilis, muco tuatricali involutus ; fills primariis rauiisque o ccllularuui serie unica
r. -uindi priinuria ct scriebus numerosis sccundariis parallelis continuis vrl interrnptis extcrnis com-
positis, aut nmmlorum fusciculis rerticillatis globoso vel snbgloboso dense conglobatis sequali
distnntia obsitis, aut ramulis simplicibus vel dicbotomis dense ubique vestitia. Ycgetatio
tcrniinalis.

Pitccious alfjie. Thallus filamentous, articulate, branched, violet or violet-purple or bluish-green,
with iniicons; primary filament and branches composed of a single central series of cells,
numeruns external, parallel, continuous, or interrupted secondary series; either furnished with
or subglobosely densely conglobate, equally distant verticillate fasciculi of branches, or
everywhere densely covered with simple or dichotomous branches. Vegetation terminal

Genus BATRACHOSPERMUM, ROTH, 1800.

Thallus filamentosus, moniliformis, e cellularum serie unica medullari, acccssoriis parallelis corti-
cata coiupositis, ramulorum fasciculis snbgloboso-conglobatis obsessus.

Thallus nioiiilifnrm, composed of a simple series of medullary cells and cortical accessory parallel
series, clothed with subglobosely conglobate fasciculi of branches.

Remarks. — The Batrachosperms are amongst the very largest of the fresh-water
alga?, forming gelatinous branched masses from a few inches to even more than a
foot in length. The fronds are very freely and very irregularly branched, and are
evidently composed throughout, ». e., both in regard to the main filaments and the
branches, of two portions, a central axis and much more slender short transverse
branchlets, which often end in a long hair, and are arranged more or less exclu-
sively in groups, so as to form, to the naked eye, at regular intervals, little balls or
knots, the whole plant thus presenting a sort of moniliform aspect. Sometimes,
however, these glomeruli are placed so closely together, and grow so large that
they become confluent, and the branch to which they are attached appears as a
uniform thick and very gelatinous cylindrical cord.

The axis both of the stem and the branches of a Batrachosperm consist ori-
ginally of but a single series of cells. The development of new cells takes place
in two ways, the one of which results simply in an increase in the length of the
axis, the other in the production of branches. .The first of these is the ordinary
process of cell multiplication by division, and occurs only in the end cells, so that
no new cells are ever formed in the central portions of the axis, which increases
in length solely by the addition of new cells at the end, and by longitudinal growth
of the old ones. The first step towards the formation of a branch is the produc-
tion of a little pouch-like protrusion near the upper end of a cell. This increases

28 September. 1872.

218 FRESH-WATER A L G JE OF THE UNITED STATES.

in size and soon being cut off from the parent-cell by a partition, forms a complete
cell, the starting point of a new branch. If this cell has been formed alone, with-
out companions, it is the beginning of a main branch, and divides after a very brief
period transversely, the new cell thus arising in a little while itself divides, and so
the process goes on until the axis of a large branch, similar to the parent axis is
developed, and which, like the parent axis, increases only by a division of the end
cell and longitudinal growth of the central ones.

When a glomerulus is to be formed instead of a single pouch, a number appear
around the upper end of a cell, and become cut off as new cells. Each of these
is the starting point of a new row of cells, which not only grows, at least up to
a certain point, by the division of the end cells, but which also gives rise to a
large number of branches in a way precisely similar to that in which it itself was
developed, i. e., by the formation of-little lateral protrusions, &c. These secondary
branches have a life-history similar to that of the branch whose offspring they are.
They continually give origin to new branchlets in the way just described, which
branchlets themselves produce fresh offshoots, and so it goes on until at last the
forest of branchlets making up the dense glomerulus is evolved. It has been
just stated that the original axis of the main filament or any branch is composed
of a single simple series of large cells ; when an old Batrachosperm is placed under
the microscope, however, it is at once evident that the axis is in reality formed of
such a series lying in the centre and covered over and often hidden by numerous
longitudinal series of smaller cells. These latter do not belong to the original
axis, but are secondary additions to it, and arise in this way. Whilst a glomerulus
is being developed certain of the basal cells of its constituent branches give origin
in the usual manner to branchlets, which, instead of growing outward to form a
part of the glomerulus, grow upwards or downwards, closely hugging and finally
enveloping the original axis, and at last forming a distinct cortical layer to it.

Very frequently in well-advanced Batrachosperms there will be seen scattered
among the glomerulus large, round, firm, dense balls composed of a great number of
small closely-attached cells. These are the reproductive bodies. According to H.
Graf zu Solms-Laubach (Botanische Zeitung, 1867, p. 161), they are the result of
sexual reproduction, and are developed from antfieridia and trichogonia (female
organs) in the following manner : —

The antheridia are small roundish cells full of a colorless protoplasm, which is
remarkable for the very numerous bright granules which it contains. They occur
either scattered or in groups, and are placed upon the upper ends of peculiar ovate
cells, also filled with a colorless protoplasm. Most frequently there is a single
antheridium to the basal cell, sometimes two ; the latter number appears never to be
exceeded. When matured, the antheridia open and allow their contents to escape
in the form of roundish or flattened bodies, which never, as far as known, acquire
cilia, and have, therefore, no power of spontaneous motion. These bodies, which
are believed to be spermatozoids, are unprovided with anything like an external
membrane, and are composed of protoplasm identical with that in the antheridium.

Whilst these changes are occurring, certain cells in other localities are being trans-
formed into female organs, to which our author applies the name of Trichogonia.

FUESH-W ATKlt ALUJi OF THE UNITED STATES. 219

These arc borne upon cells similar to those supporting the antheridia. At first
tin \ arc not markedly different from the other cells, but soon undergo a very rapid
growth. This is not, however, regular, and is not partaken of by a band of tissue
about one-third way from the basal end, so that at last a long somewhat flask-
shaped cell is produced, with a very marked contraction at the point indicated,
separating it into two portions. The wall of this cell is thin but very distinct, and
the cavity is filled with a homogeneous or very sparsely granular protoplasm, which
is continuous through the narrow neck-like portion. After a time there appear
one or more large irregular vacuoles, with actively moving corpuscles in them, and
at the same time the neck appears to be stopped with a slimy substance. Careful
examination with reagents shows that this is cellulose, and that it does not com-
pletely block the passage-way through the isthmus. At this time there appear lying
upon the free end of the trichogonia globular or flattened bodies, without external
membrane, corresponding in all respects with those already described as being pro-
duced iu the antheridia. The end of the trichogonium generally enlarges at this
period into a sort of roundish knob, and by and by the end wall between this and
one of these globules becomes absorbed, so that there is a free communication
between the two. Whilst this is going on the globule acquires a thin, delicate
coat, and there appears in it a vacuole similar to those preexisting in the tricho-
gonium.

The first result of this impregnation of the trichogonium is the deposit of new
cellulose, and the complete blocking up of the passage-way through the isthmus
or narrowed portion. Already before the fecundation, the upper cells of the
branches supporting the trichogonia have produced numerous branchlets, which
Crowing upwards more or less completely cover that organ. After impregnation
the cells near to the trichogonium become much larger and broader, their vacuoles
disappear, and arc replaced by a dense granular dark greenish-brown protoplasm.

These cells now show a great activity in the production of numerous branches
in the usual way, but it is the upper two alone which, with the trichogonium that
they support, are concerned in the formation of the fruit glomerulus. These put
out all over their surface an immense number of protrusions, which soon in the
ordinary way become the parents of as many twigs or branchlets, which growing
and branching, precisely as do the vegetative branches, soon become excessively
crowded. The base of the trichogonium participates also in this production of
branches, and at last a dense ball is formed of pseudoparenchymatous tissue by
the forced adhesion of the crowded twigs. The central cells of the glomerulus
thus formed are very large and bladder-like. The outer part of the ball is com-
posed of innumerable radiating rows of small cells, the end cell of each branch
being roundish so as to present a convex external face. At maturity these
cells open and allow their contents to escape as round masses, which appear to
have no membrane, but begin at once to grow and secrete cellulose. Their after-
hi-tory has not been made out with absolute certainty, but they are believed to
directly develop the new plant.

220 FRESH-WATER ALGJS OF TUE UNITED STATES.

B. inonilifbrine, (ROTH.)

B. pollicare, bi- tripollicaro, raro pedale, muco gelatinoso pins minus firmo involutum, viola-
ceum, fuscum, rufo-brunneum, purpureum vel ca:ruleo-viridiscens, vage ramossissimum ; ramu-
lorum articulis omnibus conformibus, oblongo-subclavatis, extremis nonnunquam setigeris;
internodiis nudis vel ramulis accessories singulis sparsis instructis.

Diam.— Tetrasp. globulus y*$v = .006.

Syn. — B. moniliforme, ROTH. RABENHORST, Flora Europ. Algarum, Sect. III. p. 405.

Hab. — In aquis puris, Michigan ; Gray. New York ; Bailey. Virginia ; Jackson, Alabama ;
Tuomey. South Carolina ; (Ravenel) Pennsylvania; New Jersey; Wood.

One inch to a foot in length, clothed with a more or less firm gelatinous mucus, violet, fuscous,
reddish-brown, purple, or bluish-green, vaguely and profusely branched ; joints of the
branches similar, oblong-subclavate, the outer ones sometimes setigerous; internodes naked
or furnished with a few scattered accessory branchlets.

Remarks. — This species is very abundant in fresh, cool rivulets, in springs, in
limestone waters, in pine-barren streams, and even occasionally in ditches, wherever
I have botanized in Pennsylvania and New Jersey. It varies greatly in size, in
color, and other particulars.

The branchlets, as I have observed them, are most generally not setigerous, but
at times they are provided with seta of moderate length.

I have found numerous fruiting fronds, but in none of them was the fruit in
great abundance, not nearly so much so as in the Kocky Mountain species.

B. vagiilll, (ROTH) AGARDH.

B. vage ramossissimura, uni- vel tripollicare, fuscum vel cerugineum ; internodiis inferioribus
ramellis numerosis obessis, superioribus nudis vel subnudis ; ramulorum articulis extremis
setis longissimis instructis.

Diam. — Tetrasp. globulus ,1^= .00333.

Syn. — B. vagum, (ROTH) AOARDH. RABENHORST, Flora Europ. Algarum, Sect. III. p. 406.

Hab. — In aquis quietis, Tlintah Mountains, Nevada ; (S. Watson).

Vaguely branched, one to three inches long, brownish or seruginous ; internodes — the inferior
covered with a dense mass of branchlets — the superior naked, or nearly so; last articles 01
the branchlets provided with an extremely long seta.

Remarks. — I have received from Mr. Sereno Watson some half a dozen dried
algae, which I have referred to B. vagum, with some doubt. They are labelled as
having grown in shallow water, in a beaver pond, in Pack's Canon, Unitas, Uintah
Mountains, Nevada, at an altitude of 7000 feet. All the descriptions of B. vagum
which I have seen are singularly imperfect; in none is it stated how large the spore
masses grow, and how plentifully the branchlets are provided with seta. As far
as the descriptions go, however, my specimens agree with them, and I have, there-
fore, refrained from indicating a new species. The plants are. remarkable for the
profusion and extreme length of the seta, and for the quantity of fruit which
they produce. The fruit masses are small but very compact, scarcely more than
half the size of those of the preceding species. The verticles of branchlets are
often completely joined, and as it were almost swallowed up by the mass of inter-
vening scattered branchlets which arise directly from the main axis. In the distal

FKKSH- WATER ALG.E OF THE UNITED STATES. 221

portions of the fronds, however, the glomcruli are more fasciculate and more
distinct, for although sometimes so close as to be almost confluent at their spread-
ing edges, at their bases they are distinct. This species very probably attains a
much larger size than indicated by my specimens, and possibly varies as much in
color as B. inunilifonne.

Genus TUOMEYA, HABVEY.

" Frond cartilaginous, continuous, solid, at first transversely banded, afterwards onnularly con-
stricted ; composed of a longitudinal axis, and two strata of peripheric cells. Axis columnar,
consisting of several longitudinal cohering filaments, beset with closely placed whorls of monilifonn
ramclli, whose branches ann.stomose horizontally and vertically into a cellular periphcric membrane,
which is coated externally with moniliform filaments, gradually developed. Fructification probably
in tin- Mipcrficial filaments.

•
T. llnvinlili-. HARVEY.

Uab. — On stones, in rivers and streams. River in Alabama; Prof. Tuomey. Near Fred-
ericksburg, Virginia; Prof. Bailey.

Fronds tufted, an inch or two in height, scarcely as thick as a hog's bristle, much and irregu-
larly branched, bushy; the branches alternate or secund, scattered or crowded, twice or
thrice divided, and set with scattered patent ramuli which are slightly constricted at the in-
terstices, and taper to an obtuse point. When young the branches and ramuli are perfectly
cylindrical, and when examined under a low power of the microscope show a surface com-
posed of minute, dotlike cells, placed close together, and marked at short intervals with dark-
colored transverse bands. These bands disappear under a higher magnifying power. They
are indications of the nodes of the axis of the frond seen through the peripheric stratum.
In old, fully developed specimens the branches and ramuli are annularly constricted at short
intervals, the nodes becoming swollen, whilst the internodes remain unchanged. When a
young branch is braised between two pieces of glass the axis may be readily extracted. It
consists of several parallel longitudinal jointed threads combined together at closely-placed
nodes, from which issue horizontal dichotomous filaments, composed of roundish or angular
cells. These excnrrent filaments spread both horizontally and vertically, and their branches
anastomose into a cellular mass or fleshy membrane, which forms the inner peripheric stratum.
In young plants a portion of the frond, between the axis and periphery, is hollow, but in
older ones the cavity is quite filled up with cells. The external surface of the cellular peri-
phery is clothed with a coat of moniliform filaments gradually developed, and forms what is
above called the second peripheric stratum. These are found only in fully-grown specimens;
they consist of much smaller cells than those of the inner stratum ; they are more strongly
colored, and I consider them to be connected with fructification. The color is a dark olive.
The substance is brittle, rigid when dry, and the plant scarcely adheres to the paper. The
generic name is in memory of the late Prof. Tuomey, of Tuscaloosa."

Remark*. — I have no knowledge of this plant, and have simply copied the de-
scription of Prof. Harvey ; Smithsonian Contributions, 1846.

FAMILY LEMANEACE^E.

AIg« rivnlares vcl fluviatiles. Thallus e preembryone confervacea enascens, setacens, snbsimplice
Tel fasciculatim ramosns, cavus, nodosns, e cellnlarum stratis internis et corticatis formatus. Noduli
plerumqne papillarum corona instruct!. Polysporse numerosse, in sericbns ramosis moniliformilms
fasciculatim aggregates, sine fccundatione germinantes.

222 FRESH- WATER ALG.E OF THE UNITED STATES.

Algae growing in streams and rivers. Thallus developing from a confervoid prothalloid filament,
setaceous, almost simple or fasciculately branched, hollow, nodose, composed of internal and corti-
cal strata of cells. Nodules generally provided with a corona or papilla. Polyspores numerous,
fasciculately aggregated in branched moniliform series, germinating without fecundation.

Genus LEMANEA, BORY.
Genus unicum.

The only genus.

Remarks. — The plants belonging to the genus Lemanea are quite peculiar in
aspect and habit. They grow exclusively in fresh water, especially frequenting
streams whose current is rapid, and whose waters are chilled by the mountain air.
Their frail, tubular, scarcely-branched fronds offer but little resistance to the
water, whilst their lower end is swollen into a sort of discoid root, which adheres
firmly to the stones. The frond is mostly blackish or brownish, and is formed of
two distinct portions or layers, of which the outer or cortical is composed of small
closely cohering, colored cells ; the inner of much larger cells, which have thick
colorless walls, and are placed so as to leave more or less numerous interspaces.
In the immature frond there is also a longitudinal central column, besides some
slender many-jointed filaments, passing obliquely through the cavity, but as final
development takes place these seem to disappear. The mature frond is alternately
contracted and expanded throughout its length. In the narrow portions the inner
tissue often blocks up the tube entirely, whilst the dilated parts are loosely filled
with the spores, which are produced within the frond. The spores themselves are
oval, thickish-walled cells, whose endochrome changes from greenish to a very
decided yellow during the process of maturing. They are joined together to form
rows or series, which are not simple, but are very much branched, so that from a
central basal row arises a complex bush-like mass (pi. 20, fig. 4). These spore-
clusters are always distinct, a number of them existing in each sporangial node of
the frond.

Dr. B. Wartmann described, nearly twenty years ago, very fully the way in
which the spores germinate and develop into the frond. The first step, according
to this authority, consists in the elongation of the spore and the projection of one
end, which is soon cut off by the formation of a transverse partition, and consti-
tutes a new cell. This multiplying in no strikingly peculiar way soon develops
into a branched confervoid filament. A large number of these filaments are gene-
rally produced in one place at one time and form a very apparent greenish layer.
Finally certain cells in branches of these filaments swell up and become very much
broader than their fellows, undergoing, at the same time, division so rapidly that
they become very short. By and by they divide also in the direction of their
breadth, so that instead of a simple series of cells there arises a compound mass.
This is the beginning of the new frond. At first it is dependent upon the parent
filament, but soon acquires a root-like process at the base and develops rapidly
into the complex cartilaginous plant.

FRESH- WATER ALG.E OF THE UNITED STATES 223

I. inriilc>*a. (KoTii) Ao.

L. subsimplrx, pi. TUMI. (in- arcuata, cartilaginea et nonuiliil rigida, 1-2 poll ices longa; nodulis
upproximuli.s, pupillis u|>|)lunutis, plcruiuque 4-6 enormitcr vurticcllutis, vcl nonnihil spars!*,
iuicnlinii noiinihil ri.ntliu-iiiiliu.- ; sporis uvaiibus.

2>iam.— Sporis. transv. max. T,J,," — rf&v".

.S'J/H. — L. turulvsa (Rorii) Ao. RABEMIORST, Flora: Europ. Algarum, Sect. III. p. 411.

Ilab. — In fluininc, Kentucky; (Short) Harvey. Pennsylvania; Virginia; New York; New

Jersey ; \V<x>U.

Subsimple, mostly arcuate, cartilaginous and somewhat rigid, 1-2 inches long; nodules ap-
proximate, with tlifir papules applanate, mostly 4-6, irregularly verticillate or somewhat
scattered, sometimes slightly confluent; spores oval.

/,'• i/iu i-l.-x. — This plant attains a length of about two inches, and grows in masses
attached to rocks, often forming a sort of turfy covering to them, in rapidly run-
ning water. In mass it has a grayish or blackish appearance. The filament has
a u'raxMi groundwork, with a dark band at the position of the nodes, which are
enlarged and inclose the spores. The transverse outline of the filament is a very
irregular circle. I have found this species very abundant in the rapid water of the
Si hnylkill, just above Flat Rock Tunnel, on the Heading Railroad, eight or nine
miles above Philadelphia. Prof. E. D. Cope has sent me specimens collected by
himself in swift streams in Western Virginia, and Mr. Austin has obtained it in
similar situations in Northern New Jersey. Mr. Austin has also sent me specimens
collected in Canada West.

L. flut iatiliv Ao.

L. simplex vcl parce ramosa, quatuor nnciaa longa (interdum spithameaf), recta vel subrccta ;
nodulis subremotis, pupillis verticillatis uiagnis obssesis; sporis globosis vel subellipticis.

Diam.— Spor. WoV— rVoW-

,s'_i/»i. — L. jlutiatilis, AUARDII. RABENUORST, Flora Europ. Algarnm, Sect III. p. 411.

Unli. — In rivulis, Alabama ; T. M. Peters.

Simple or sparsely branched, 4 inches long (sometimes growing of a span length ?), straight or
nearly so ; nodules rather distant, papilla) verticillate, large, prominent.

Remarks. — The only specimens I have seen of this species were sent me by
Prof. Ravenel. This plant is larger and heavier than L. torulosa, from which it is
also readily distinguished by its very large prominent papillae. These are in
slightly irregular whorls of three or more. The spores vary in shape from that
of a globe to that of a somewhat four-sided ellipse ; in the latter case being some-
times nearly twice as long as broad. Prof. Rabenhorst speaks of the plant attain-
ing the length of a span. I have never seen it over four inches.

L. catenata, KTZ.

L. ad uncias 5 longa, regulariter constricta, simplex, compressa, arcnata, in massa obscure
violacca ; papillis nullis ; sporis enormiter ovalibus vel subglobosis.

Diam — Spor. transv. max y^cre" = -001"-

Syn. — L. catenata, KVJTZINU. RABENHORST, Flora Europ. Algarnm, Sec. III. p. 412.

224 FRESH -WATER ALU^E OF THE UNITED STATES.

Hab. In rivulis frigidis montanis Diamond Range, Rocky Mountains ; (Sereno Watson).

About 5 inches long, regularly constricted, simple, compressed, arcuate, in mass obscure violet;
papules wanting ; spores irregularly oval or subglobose.

RemarJcs. — I have received specimens of the plant from which the above diag-
nosis was drawn, from Mr. Sereno Watson, labelled " Mountain stream, Diamond
Range, altitude 6500 feet." In the dried state they are closely interwoven into a
dark purple, rigid thin mass. When soaked out they preserve the same color in
mass, but each individual stem has a general light yellowish, neutral ground tint,
with dark-purplish or greenish-black bands at regular intervals. At the position
of these bands the filament is nearly round and contracted, whilst between them it
is compressed and enlarged. The spores are placed, not at the swelling, but at
the constrictions, corresponding to the dark rings in position. They are quite
irregular in shape, and of a faint yellow tint. The filaments between the little
knots of spores appear to be hollow. Their walls are everywhere very thin when
compared with L. torulosa, hence they are more flaccid. The species agrees in
every respect with Prof. Rabenhorst's diagnosis of L. catenata, KTZ., a native of
cold mountain streams of Germany and Switzerland. I regret, however, very
greatly that I have had no opportunity of comparison with European specimens, or
a fuller description.

SUPPLEMENT.

TIIK following species, of which the author has not seen specimens, were inad-
vertently omitted from their proper places in the monograph. They are all con-
tained in the Nereis Boreali- Americana of Prof. Harvey. The following descrip-
tions and remarks are simply copied from the work mentioned.

Tetranpora lacunOMa, CHAUV.

Frond at first tubular, then flat, or irregularly lobed, mcmbranaceo-gelatinous, pale-green, every-
where pierced with roundish holes of various sizes. Chauv. Alg. Norm. Breb. Alg. Fal. p.
11, t. 1. A'ttfz. Sp. Alg. p. 227. T. Godeyi, De Breb. Kulz. Tab. Phyc. I. 30, /. 8. T.
pr.rforata, Bailey, M.S.

Hub. — In fresh-water streams. Abundant near Westpoint, Prof. Bailey ; Providence, Rhode
Island, Mr. Olney. (v. 8. in Herb. T.C.D.)

Frond at first funnel-shaped, afterwards splitting open, and then flat, expanding upwards and
irregularly lobed, everywhere pierced with roundish holes of various sizes, large and small
intermixed. These holes increase in size and numbers with age, and thus at last the frond
becomes an open network. The substance is very gelatinous, but rather firmer than in some
other species of the genus. The color is a pale green ; and the hyaline gelatinous membrane
is filled with roundish granules set in fours.

Kiitzing's figure of T. Go'leyi answers well to our plant. I have not seen any
authentic specimens of T. lacunosa, which is referred by Kiitzing to his T. lubrica,
'•<//-. ^., but the description given of it applies to the American plant. When care-
fully dried, it forms a very pretty object for the herbarium. (Chlorospermcce, p.
61.) (Harvey, p. 61.)

ftOMtoc ( IlorniOMiphon) arrticum, BERK.

Fronds foliaceons, variously plaited, green or brownish ; filaments at length (their gelatinous
envelope being dissolved) free. Berk, in Proc. Lin. Soc. fide An. Nat. Hist. 2d Ser. vol.
10, p. 309.

Bab.— On the naked soil, in boggy ground. Assistance Bay, lat. 75° 40' N. Pr. Sutherland, (v.s.)

"Frond* foliaceons, variously plicate, sometimes contracted into a little ball. Qclatinous
envelope at length effused ; connecting cells at first solitary, then three together ; threads,
which are nearly twice as thick as in N. commune, breaking up at the connecting cells, so as
to form new threads, each terminated with a single large cell, the central cell becoming free."
Berk. I. c.

"It grows," says Dr. Sutherland, "upon the soft and almost boggy slopes around
Assistance Bay; and when these slopes become frozen at the close of the season,

28 Ootob«r. 1872. ( 225 )

226 SUPPLEMENT.

the plant lying upon the surface in irregularly plicated masses becomes loosened,
and if it is not at once covered with snow, which is not always the case, the wind
carries it about in all directions. Sometimes it is blown out to sea, where one can
pick it up on the surface of the ice, over a depth of probably one hundred fathoms.
It has been found at a distance of two miles from the land, where the wind had
carried it. At this distance from the land it was infested with Podurce, and 1
accounted for this fact by presuming that the insects of the previous year had de-
posited their ova in the plant upon the land, where also the same species could be
seen in myriads upon the little purling rivulets, at the side of which the Nostoc
was very abundant." At p. 205 of his Journal, Dr. Sutherland further mentions
having tried it as an article of food, and found it preferable to the Tripe de Roche
of the arctic hunters. Its nutritive qualities are probably equal to those of the
jelly derived from other Algae. (ChlorospermeoB, p. 113.)

Nostoc flagelliforme, BERK, and CURT.

Terrestrial ; frond cartilaginous, linear, very narrow, compressed and often channelled, much
branched, irregularly dichotomous; branches solid, densely filled with moniliform curved
threads. Berk, and Curt. No. 3809.

Hab. — On naked aluminous soil, at San Pedro, Texas, Mr. Charles Wright, (v.s.)

Fronds several inches in length, half a line in diameter, lying prostrate on the surface of the
soil, much branched in an irregularly dichotomous manner ; branches exactly linear, com-
pressed, often channelled on one or both sides, thinned in the middle and incrassated to the
edge. Substance firm and elastic, cartilaginous, solid, densely filled with moniliform, curved or
curled, interlaced threads, which are set longitudinally in the frond, and lie nearly parallel to
each other. Color dark olive.

A very curious and most distinctly marked species, differing from others of this
genus, much in the same manner that Cheetophora endivicefolia does from the ordi-
nary globose forms of Chcetophora. (CJilorospermeoz, p. 115.)

Nostoc microscopicum, CAHM.

Fronds densely aggregated, very minute, globose or oblong, immersed in a blackish crust ; fila-
ments few. Carm. in Hook. Brit. Fl. 2, p. 399. Harv. Man. Ed. I, p. 184. N. muscorum,
Hass. Br. Fr. Wat. Alg. p. 292, t. 74, fig. 4.

Hab. — " Stones in a small stream, Baffin's Bay," Dr. Sutherland, fide Prof. Dickie.

I have not seen American specimens. In Britain this species grows among
mosses on exposed calcareous rocks, but not in water. The above specific charac-
ter is taken from the British plant. The fronds are rarely more than the tenth of
an inch in diameter, and contain two or three beaded filaments lying in a copious
transparent jelly. (Chlorospermece, p. 115.)

Genus HYDRURUS, Ac.

Frond fixed at base, cylindrical or compressed, elongated, branched, gelatinous. Structure:
seriated, but separate, cellules, filled with bright-green endochrome, inclosed in gelatinous parallel
tubes, ranged longitudinally in the frond, and surrounded by a common gelatinous envelope.

SUPPLEMENT. 227

Of this genus several species have been described by authors, all having a close
resemblance to each other, and all very variable in ramification. Indeed it is
almost impossible to fix characters by which they can be permanently kept apart ;
and instead of adding another specific name to the already too numerous list, I
prefer to consider the American specimens received as constituting a luxuriant
variety of the best known of the established species. All previously recorded
species or varieties of these plants are natives of rapid rivers and streams in
various parts of Europe. (CfUorVftHMtf, p. 118.)

HydriiriiN penicillatus, var. oecidentaliN, HARV.

Frond very long (1-2 feet or more), much branched; branches Tery irregular, scattered or
crowded, wormlike, tapering to a fine point, naked or clothed with feathery villous ramuli ;
cells ellipsoidal or pear-shaped, twice aa long as their diameter.

Hub. — On the rocky bottom of rivers and streams, in a strong current. Santa Fe, New Mexico,
Mr. Fendler, February to April, 1847. (v.s. iu Herb. T.C.D.)

Fronds attached at base, one or two feet long,' from one to four lines in diameter, very much
and irregularly branched ; branches scattered or crowded, simple or divided, a foot or more
in length, attenuated to a fine point, sometimes smooth and naked, but generally densely
clothed with slender, villons ramenta, spreading to all sides. The gelatinous tubes or sheaths
in which the cells are seriated are very obvious, and lie close together in longitudinal, paral-
lel strata. The cells are of large size, bright-green color, and variable shape ; some are twice
as long as others.

This I had at first supposed to be a new species, but now regard it as a very
gigantic state of //. penicHlattis, Ag., which under various forms and of various
si/.es is common in alpine streams in Europe. I fear characters derived from the
shape, and size of the cellules are not more to be depended upon than are those
taken from the ramification. (ChloroepermecR, p. 118.)

Draparnaldia opposita, Ao.

Frond vaguely much branched ; joints of the main filament as long as broad, or shorter ; pencils
of ramuli mostly opposite, densely set, lanceolate-acuminate in outline, plumose, bi-tripinnate,
the apices much attenuated. Ag. Syst. p. 59. Kutz. Sp. Alg. 357. Lyngb. Hyd. Dan. lab.
65, fig. A. Batrachospermum Americanum, Schweinitz.

ffab. — Iu clear streams. New York, Professor Bailey. New Jersey, Mr. Jackson, (v.s.)

Frond 2-3 inches long, gelatinous, capillary, irregularly much branched ; the branches patent,
lateral, more or less divided, and set with lesser ramuli. Main filaments with short articula-
tions, as long as their breadth, or shorter, transversely banded. At every two or three nodes
and sometimes at every node a pair of opposite penicillato-mnltifid ramuli are thrown off.
These are bright green, ovato-lanceolate in outline, much acuminated and twice or thrice pin-
nate, their pinnules somewhat constricted at the nodes, and tapering at the apex into long,
needle-like, hyaline points. Their cells are commonly nucleated and filled with endochrome.

Whether this be permanently distinguishable from D. glomerata is doubtful. It
has externally the aspect of that species, but its microscopic characters are nearer
those of D. plumosa.

GEOGRAPHICAL LIST OF SPECIES.

CLASS PHYCOCHROMOPHYCE^E.

ORDKR CYSTIPHOU.fi.
Family CHROOCOCCACKJB.

Chroococcua

refractns, \\'owl.
multicoloratus, Wood
thermopliilus, Wood.

Gloeocapsa

sparsa, Wood.

Caelosphserium

dllliiuill. <i:un.

Mcilsmopedia
nova, Wood.
courolata, lirtb.

HaS. near Philadelpbi
Hak. near Pbiladelphi
llab. Benton Springs, Owen
Co., California.

Hal. near Philadelphia

Hab. near Phlladelphi
llab. Spring Mills, Montgomery
Co., Pa.

ORDER NEMATOQENE.fi.

Family OSCILLARIACE.S.

Osclllaria

chlorina, A '--.
corinm, Ag.
decortirans, Cener.
Pruhllchii, Kit.

Imperator, Wood.
limosa, Ag.
nmscorum, Ag.
ueglecta, Wood.
nigra, Vauch.

Bab. near Philadelphia.

llab. New York.

Il.tb. Northern U. States.

llab. Schnylkill River, near

Philadelphia.

llab. near Philadelphia.

llab. near Camden, New Jersey.

llab. West Point, New York.

llab. near Philadelphia.

Hub. New York ; Philadelphia.

tenuis, Ag. Hub. Rhode Island; New York;

Virginia.
Bab. Warm Springs of Washita.

tenaisslma, Ag.

Chthonoblaatus
repens, Kit.

Lyngbya

bicolor, Wood.

mnralis, Ag.

Hub. New York; Massachusetts;
Rhode Island.

Hab. Schnylkill River, near Phila-
delphia.

Bat,. Whale Fish Islands, Darts
Straits, British America.

Family NOSTOCHACK^E.

Sab-Family Nonrocua.
Nostoo

Anstiuii, Wood. Hub. New Jersey.

alplnum, Kit. Hab. Allrgliany Mountains ; Clover

Mis., Nevada ; Baffin's Bay, British America.

calcicola, Ag.
calldariam, H'.W.

c»ruleum, Lyn.
Cesatii, Bait.
comminutum, Kt:.
commune, Vaurh.
depressant, Wood.
panctatum, Wood.
pruniforme, AgK.
verrucoaum, Vaurh.

llab. Catoosa Springs, Georgia.

Hal. Beuton Springs, Owen

Co., California.

Hub. New Jersey.

llab. Kansas.

Bab. near Philadelphia.

Bab. New Jersey ; Rio Bravo.

Bab. New Jersey.

llab. New Jersey.

Hub. New Jersey.

Bab. Maine.

sphasricnm, Vouch. llab. Centre Co., Pennsylvania.
Sab-Family SpEBMoeiBEJt.

Anabtena

gelatiuosa, Wood.
gigantea, Wood.
flos-aque, Kt;.

Bab. near Philadelphia.

Hub. near Philadelphia.

Bab. Round Pond, West Point,

New York.

Cyllndrospermum
comatam, Wuud.
fleznosnm, Rab.
macrospermnm, Kit.
minntum, Wood.

Dolichospermum

polyspermam, Kit.
sabrlgidam, Wood.

Bab. Niagara, Canada.

Bab. near Philadelphia.

llab. South Carolina.

llab. near Philadelphia.

Bab. near Philadelphia.
Bab. New Jersey.

Family RIVULARIACEJE.
Nostochopsls

lobatns, Wood. Bab. Schnylkill River, near Phila-
delphia.
Ololotrlchla

angulosa, Roth. Bab. Hudson Rirer, near West

Point.

(229)

230

GEOGRAPHICAL LIST OP SPECIES.

Gloiotrlchia

incrustata, Wood. Hab. Schuylkill River near

Philadelphia.

Rlvularla

cartilaginea, Wood. Hab. Northern Michigan.

Zonotrlchia

minutula, Wood. Hab. Clear Pond, Adirondack

Mountains.

mollis, Wood. Hab. Cave of the Winds, Niagara,
parcezonata, Wood. Jlab. Cave of the Winds,

Niagara.

Dasyactls

mollis, Wood. Hab. Cass River, Northern Michigan.

Mastlgonema

elongatum, Wood. Hab. Philadelphia,

fertile, Wood. Hab. Alleghany Mountains, Centre

Co., Pennsylvania.

halos, Wood. Hab. Stonington, Connecticut,

sejunctum, Wood. Hab. Cass River, Northern

Michigan.

Mastlgothrlac

fibrosa, Wood. Hab. near Philadelphia.

Family SCYTONEMACE^.
Scytonema

Anstinii, Wood. Hab. Little Falls, New Jersey,

calotrichoides, Ktz. Hab. South Carolina,

cataracta, Wood. Hab. Niagara River, Niagara,

cortex, Wood. Hab. South Carolina.

dubium, Wood. Hab. Cumberland Co., New Jersey.

immersum, Wood. Hab. Cumberland Co., New

Jersey.

Myochrous, Ag. Hab. West of Crow's Neck, West

Point.

Nsegelii, Ktz. Hab. near Bellefonte, Centre Co.,

Pennsylvania.

Ravenellii, Wood. Hab. South Carolina,

simplice, Wood. Hab. Aiken, South Carolina,

thermale. Hab. South Carolina.

Tolypothrlx

distorta, Mul. Hab. near Philadelphia; West

Point, N. Y.; Rhode Island ;
Madison, Wisconsin.

Family SIROSIPHONACEA
Sirosiphon

acervatus, Wood. Hab. South Carolina,

argillaoeus, Wood. Hab. South Carolina,

compactus, Ay. Hab. Salem, Massachusetts ; New

Jersey.

Crameri, Br. Hab. Mount Tahawus, Adirondack

Mountains*

Sirosiphon

guttula, Wood. Hab. South Carolina,

lignicola, Wood. Hab. South Carolina,

neglectus, Wood. Hab. New Jersey,

pellucidulus, Wood. JJab. near Hibernia, Florida,

pulvinatns. Hab. Northern New Jersey,

scytenematoides, Wood. Hab. South Carolina.

Stlgonema

Ravenellii, Berkeley. Hab. Lookout Mountains,

Georgia.

CLASS CHLOROPHYLLACEJE.
ORDER COCCOPHYCE^E

Family PALMELLACE.E.
Fleurococcus

pulvereus, Wood. Hab. Boiling Springs, near Belle-
fonte, Centre Co., Pennsylvania,
seriatus, Wood. Hab. New Jersey.

Palmella

dura, Wood.
hyalina, Lyn.

Jesenii, Wood.

Hab. near Philadelphia.

Hab. From Rhode Island to

Wisconsin.

Hab. near Philadelphia.

Pagerogalla

stellio, Wood. Hab. Bear Meadows, Alleghany
Mountains, Centre Co., Penn-
sylvania.

Tetraspora

bullosa, Roth. Hab. Salem, North Carolina,

gelatinosa, Roth. Hab. Salem, North Carolina ;

Newburgh, New York.

lubrica, Roth. Hab. Northern Atlantic States.

Dictyosphaerlum

pulchellum, Wood.

Rhaphidlum
falcatum.
polymorphum, FT.

Hub. near Philadelphia.

Hab. near Philadelphia.
Hab. near Philadelphia.

Family PROTOCOCCACEJE.

Polyedrlum

enorme, Ralfs.

Hab. Florida.

Scenedesmua

acutus, Meyen. Hab. Rhode Island ; near Phila-
delphia.

obtnsus, Meyen. Hab. Georgia ; Rhode Island,

polymorphus, Wood. Hab. near Philadelphia.

qnadricauda, Tarp. Hab. Rhode Island ; Penn-
sylvania,
rotundatus, Wood. Hab. near Philadelphia.

GEOGRAPHICAL LIST OF SPECIES.

231

Hydrodictyon

utriculatuui, Roth.

Fedlastrum

Boryanum, Tur.

Hab. West Point and Wee-
hawkf n, New York ; Mexi

can lloumlary ; 1'on u-y 1
vaiiia ; New Jersey.

constrictum, Hassall.

Hub. Rhode Island ; Pennsyl-
vania ; Georgia ; Florida.
Hub. South Carolina
Oeorgia ; Rhode Inland.

dnodvnarins. llab. South Carolina ; Rhode Island.

Ehrenbergli, Corda. llab. Rhode Island; South

Carolina ; Georgia ; Florida.

pertusum, Kit. H,ib. Rhode Island.

S lemea, Ku. Il,,b. Rhode Island.

Family VOLVOCINE.fi.
Chlamydococcus

nival is. llab. Greenland; Rocky Mountains.

Volvox

globator, Linn.

Ha!,. United States.

ORDER ZYGOPIIYCE^E.

Family DKSMIDIACE.fi.
Palmoglcra

clepsydra, Wood.

J7ab. near Philadelphia.

Penium

•

, Men. nab. South Carolina.

, Ralft. nab. South Carolina.

I'u-ilus, Ehrb. llab. Pennsylvania; New York;

Georgia.

intf rrnptum, Brio. llab. near Grahamsville, South

Carolina.

Jenneri, Ralft. nab. Florida.

lamellosum, ftrtb. ffab. Rhode Island.

inargaritacenm, l-'.hrb. llab. Rhode Island.

miuutnm, Circe. llab. Rhode Island; South Caro-

lina; Georgia.

Closterlum

aceroauui, Schr.

Amblyonema, Ehrb
angnstatnm, Kt*.
areolatnm, Wood.

Cncnmis, Ehrb.
Diane, Ehrb.

KhrcnWgii, .!/.«.
Jennrrii, Ralft.
jauciitum, Ralft.

Bab. South Carolina ; Georgia ;
Florida.

llab. West Point, New York;
Providence, Rhode Island.
llab. Rhode Island ; New Hamp-
shire; Pennsylvania.
llab. Northumberland Co.,
Pennsylvania.
Hab. New York.

llab. Georgia; Florida; Pennsyl-
vania ; Rhode bland.
llab. Philadelphia.
llab. Rhode Island.
Hub. Saco Lake, New Hampshire;
South Carolina.

Closterlum

Leiblelnil, Ki:.

lineatnm, Ehrb.
Lunula, Milller.

maximum, var.
moniliforum, Dory.
parvulum, \" j.
rostratum, Ehrb.
setacenm, Ehrti.

strlolatnm, Ehrb.
Venus, Kt*.

Tetmemoroi

Brtbissonii, Men.
gigantens, Wood.
grannlatns, Dre'b.

levls, Kt*.

Pleurotsenlum
Bacalum, "Brib.
breve, Wood.
elavatnm, Kt*.
congtrictnm, Bailey.
crennlatnm, Ehrb.

gracile, Rah.
birsntnm, Bailey.
nodosnni, Bailey.

Trabecnla, Ehrb.

nndnlatnm, Bailey.
verrncosnm, Bailey,

nab. Georgia ; Sooth Carolina ;

Pennsylvania.

llab. Pennsylvania.

llab. South Carolina; Florida;

Georgia; Pennsylvania.

llab. Pennsylvania.

Jlab. Georgia ; Rhode Island.

Bab. near Philadelphia.

llab. near Philadelphia.

llab. Stonington, Connecticut ;

Providence, Rhode Island ;

Pennsylvania ; Georgia ;

Florida.

llab. Centre Co., Pennsylvania.
nab. South Carolina.

llab. Atlantic States.
Bab. Centre Co., Pennsylvania.
Jlab. Rhode Island ; Pennsyl-
vania ; South Carolina.
nab. near Philadelphia.

ttab. Georgia.
/A.-'. District of Columbia.
llab. South Carolina ; Georgia.
llab. Rhode Island.
llab. Rhode Island ; New Jer-
sey; Pennsylvania; South
Carolina ; Georgia ; Florida.
Hal. Florida.
llab. United States.
Hah. South Carolina ; Georgia ;
Florida; Pennsylvania.
llab. Pennsylvania ; New Jer-
sey ; South Carolina ;
Georgia ; Florida.

nab. Florida.
Hub. Rhode Island.

Mploceras)

gracilf , Bailey. Ifab. Rhode Island ; New Jersey ;
New Hampshire ; Florida ; Georgia,
verticillatum, Bailey. Hab. with the last.

Jplrotaenla

bryophila, ltr,'b.
condensata, Br(b.

Hal. near Philadelphia.
llab. Pennsylvania; Rhode
Island; Florida.

3airbusina

Brebissonil, Kt*.

Dldymoprium
Grevillii, Kit.

Hab. Florida ; Georgia ; South
Carolina ; Rhode Island.

Hab. Pennsylvania ; South Caro-
lina ; Georgia.

232

GEOGRAPHICAL LIST OF SPECIES.

Sphaerozosma

excavatum, Raffs.

pulchrom, Bailey.
serratum, Bailey.

Hyalotheca

disilliens, Smith.

mucosa, Alert.

Hab. Rhode Island ; South

Carolina ; Georgia ; Florida.

Hab. New York ; New Jersey.

//aft. South Carolina ; Georgia ;

Florida.

Hab. Rhode Island; Pennsyl-
vania ; South Carolina ; Florida.
Hab. Rhode Island.

Desmidium

aptogonium, Breb. Hab. South Carolina ; Georgia,
quadrangulatum, Ktz. Hab. South Carolina.

Swartzii, Ag. Hab. Atlantic States.

Aptogonium

Bailey i, Ralfs.

Cosmarium

anKEiium, Bre"b.
bioculatum, Bre"b.
Botrytis, Bnry.
Brebissonii, Men.

Broomei, Thw.
cselatum, Ralfs.

cpmmissnrale, Bre"b.

oonnatum, Brfb.
crenatum, Ralfs.
cucumis, Corda.

Hab. Rhode Island ; New Jersey.

Hab. Florida ; Rhode Wand.
Hab. Rhode Island.
Hab. Pennsylvania.
Hab. White Mountains, New

Hampshire.

Hab. Pennsylvania ; Georgia.
Hab. near Albany, New York :

South Carolina.
Hab. White Mountains, New
Hampshire.
Hab. Florida.
Hab. Rhode Island.
Ilab. New Hampshire ; Pennsyl-
vania ; South Carolina ;
Georgia; Florida.

Hab. Florida.
Hab. Pennsylvania ; South
Carolina; Florida; Mexico.
Hab. Pennsylvania.
Hab. Rhode Island.
Hab. Pennsylvania.
Ilab. Pennsylvania ; Georgia ;
Florida.

Hab. near Philadelphia.
Hab. Rhode Island ; Georgia ;
Florida.

Hab. Lake Saoo, New Hamp-
shire.

Ilab. New Jersey.
Hab. Florida.

Ilab. Rhode Island ; South
Carolina.
Euastrum

affine, Ralfs. Ilab. South Carolina ; Georgia,

ampnllaceum, Ralfs. Ilab. South Carolina ; Florida.

depressum, Bailey.
margaritiferuvn, Turp.

Meneghenii, Brtb.
ornatnm, Ralfs.
ovale, Ralfs.
pyramidatum, Breb

Quimbyii, Wood.
sublobatum, Brtb.

suborbiculare, Wood.

tetropthalmum, Ktz.
Thwatesii, Ralfs.
nudulatnm, Corda.

Euastrum.

binale, Turp.

Hab. Florida ; Pennsylvania; Rhode
Island.

Hab. Rhode Island.
Hab. United States.
Hab. South Carolina ; Georgia ;
Pennsylvania ; Khode Island.
Hab. United States.
Hab. Rhode Island.
Hab. Florida ; Rhode Island.
Hab. Saco Lake, New Hamp-
shire.

Hab. Rhode Island.
Hab. Saco Lake, New Hampshire.
Hab. South Carolina ; New Hamp-
shire ; Rhode Island.

verrucosum, Ehr. Hab. Rhode Island; South

Carolina ; Georgia; Florida.

circulare, Hassal.
crassum, Bre"b.
Didelta, Turp.

elegans, Brtb.
gemmatum, Brtb.
insigne, Ralfs.
multilobatum, Wood.

oblongum, Greville.
ornatum, Wood.
Ralfsii, Rabenh.

Micrasterias

Americana, Elirb.
arcuata, Bailey.
Baileyi, Ralfs.

denticulata, Breb
disputata, Wood.
expansa, Bailey.
fimbriata, Ralfs.
foliacea, Bailey.
furcnt a, Ag.
granulata, Wood.
Jenneri, Ralfs.
oscitans, Ralfs.
papillifera, Brtb.
pinnatifida, Kiz.
quadrata, Bailey.
radiosa, Ag.
ringens, Bailey.
Torreyi, Bailey.
truncata, Corda.

Stanrastrom

alternans, Brtb.

Hab. Florida ; South Carolina.
Hab. Florida.

Ilab. New York ; Rhode Island ;
South Carolina ; Florida.

Hab. Pennsylvania ; Florida.

Ilab. Atlantic States.

Ilab. Florida.

ILib. South Carolina ; Florida.

J3bi.Worden's Pond, Rhode Island.

Hab. Atlantic States.

Ilab. South Carolina.

Hab. near Philadelphia.

7/a6. Florida ; Rhode Island.

Ilab. Florida ; Rhode Island.

Hab.

Hub. Florida.
Ilab. Florida.
Hab. Florida.

Hab. near Princeton, New Jersey.
Hab. Atlantic States.

Hab. Georgia ; Florida ; Rhode
Island.

arachne, Ralfs. Hab. Saco Lake, New Hampshire,
aristiferum, Ralfs. Hab. Georgia ; Rhode Island.
Cerberus, Bailey. Hab. Florida.

crenatum, Bailey. Hab. Rhode Island,

cyrtocerum, var., Bre"b. Ilab. Florida.

dejectum, Brtb. Hab. New York ; South Caro-

lina.

dilatattim, Eh-ib. Hab. Southern Atlantic States,
enstephauum, Rolfi. Hab. West Point, New York,
furcigerum, BT(\>. Hab. South Carolina; Florida;

Rhode Island.

GEOG K A I'll I C A I, LIST OF SPECIES.

289

Staurastrum
graoile, Ralfs.

birsatom, Ekrb.
Hystrix, Italfi.
Lewisii, H ./.

Sontli Carolina; Georgia;
Florida; New York ; Rhode
Inland.

llab. Florida ; Rhode Island.

ll.ib. Rhode Island.

llab. Saco Lake, New Hampshire.

longispinnin, Arch.
margarltaceum, Ehrb.

nmiiituiii, Wood.
mulicura, Drib.
orbicular*), Ekrb.
paradoxnm, .U>y.

polymorphum.
polytrichuui, Per.
punctulatuin, lirib.
Havenellii, Wood.
seuariam, Ekrb.
tricorne, Men.

Xanthldium

.1 uleatum, Ehrb.
.\>. tiscon, Ekrb.
aruiatum, I!r/!>.

bisenarium, Ekrb.
criatatnm, fir/6.
coron.itum, Ekrb.
fascicnlatuui, Ekrb.

Arthrodesmua

convorgens, Ehrb.

Incus, Drib.

octocornis, Ekrb.
quadridens, Wood.

llab. Florida.
Hub. Saco Lake, New

Hampshire.
llab. Saco Lake, New

Hampshire.

llab. Sooth Carolina ; Rhode
Island.

//;>.. Rhode Maud;
Pennsylvania.

llab. Saco Lake, New

Ilampsliire.

//.••'. Florida.

llab. near Philadelphia.

Il<ib. Pennsylvania.

llab. South Carolina.

llab. America.

llab. Georgia ; Florida ; Rhode
Island.

J/ali. near Savannah, Georgia.

Hub. North America.

llab. Sooth Carolina ; Florida ;

New Hampshire.

llab. America.

llab. Sootbern Atlantic States.

//•''•. America.

Hub. Sooth Carolina ;

Georgia; Florida; Rhode Island.

Hub. Sooth Carolina ; Georgia ;

Florida ; Rhode Island.

llab. Georgia; Florida; Sooth

Carolina; Rhode Island.

Hub. Florida; Rhode Island.

//•.•'.. Lake Saco, New

Hampshire.

Family ZYGNBMACK,E.

Splrogyra

crassa, Kit.
declmina, Miil.
diluta, Wood.
dobia, Kli.
elongata, Bert.
insignia, Hat.
longata, Vouch

30

llab. near Philadelphia.
llab. near Philadelphia.
llab. near Philadelphia.
llab. near Philadelphia.
llab. near Philadelphia.
Hah. near Philadelphia.
llab. Rhode Island ; near Phila-
delphia.
October, 1878.

Splrogyra

uiajnacola, A"(».
nitida, DM.
protecta, Wool.
parvispora, Wood.
pulchella, WooJ.
qolnina, Ay.
rivalarla, Ilauall.
Mtirormis, Hoik.
Weberi, Kn.

Zygnema

iusigne, Ilattal.

crucial uui, I'uucA.

Slrogonium

retroversom, Wood.

MesocarpuB

scalaris, Hauall.
parvolas, Ilauall.

Pleurocarpus

mirabilis, liraun.

llab. near Philadelphia.
llab. near Philadelphia.
llab. near Philadelphia.
llab. Hibemla, Florida.
llab. near Philadelphia.
llab. near Philadelphia.
llab. Florida.
Huh. near Philadelphia.
llab. near Philadelphia.

llab. Rhode Island ; near Phila-
delphia.

Uab. Virginia; Florida;
Northern States.

llab. near Philadelphia.

llab. near Philadelphia.
//..•'. Rhode Island.

//oft. New York ; Rhode Island ;
Michigan; Wisconsin.

ORDER SIPHOPHYCE^E.

Family HYDROGASTRE^E.
Hydrogastrum

grauulatom, Limn. Hab. Delaware.

Family VACCHKRIACE*.
Vaucheria

aversa, Ilauall.
geminata, Vauck.
polymorpha, Wood.
sessilis, Vauck.

veliilina, Ay.

Hab. near Philadelphia.
Hab. near Philadelphia.
Hab. Texas.

llab. New York; Maine; Vir-
ginia ; North Carolina.
llab. New York ; Maine ; Virginia ;
North Carolina.

ORDER NEMATOPHYCE^E.

Family ULVACEJE.

Protoderma
Tiride, Ktz.

Ulva

merismopedioides, Wood.

Enteroraorpha

Intestlnalis, Linn.

Schlzomeris

Leibleinii, Ku.

llab. Philadelphia.

//,•''. Diamond
Range, Rocky Mountains.

Hab. Hudson River; Narra-
gansett Bay.

Hab. near Philadelphia.

234

Conferva.

GEOGRAPHICAL LIST OF SPECIES.

Family CONFERVACE^E.

Hub. United States.

Cladophora

brachystelecha, Rub. Hob. near Philadelphia,

fracta, Dill. Hab. Pennsylvania ; New York ;

Rhode Island.

Hab. Lakes Ontario, Erie,

glomerata, Linn.

Huron, and Michigan.

Family (EDOGONIACE^B
Androgynia

echinata, Wood.
Huntii, Wood.
mirabilis, Wood.
multispora, Wood.

Hub. Florida.
Hab. near Philadelphia.
Hab. near Philadelphia.
Hab. near Philadelphia.

Pringsheimia

insequalis, Wood.

Bulbochaete

Canbyii, Wood.
dumosa, Wood.
ignota, Wood.

Hab. near Philadelphia.

Hab. Hibernia, Florida.
Hab. near Philadelphia.

Hab. near Philadelphia.
Family CHROOLEPIDEJE.

Chroolepus
anreum, Ktz.

Bulbotiichia

albida, Wood.

Hab. New York ; New Jersey ;
Texas.

Hab. Northern New Jersey.

Family CH-ETOPHORACEjE.
Stigeoclonium.

Draparnaldla

Billingsii, Wood.
glomerata, Vauch.
maxima, var., Wood.

Hab. Eastern United States.

Hab. near Philadelphia.

Hab. Rhode Island.

Hab. near Philadelphia.

Drapernaldia

pluruosa, Vauch.

Chaetophora
elegans, Roth.
eudiviaefolia, Roth.

Hab. near Philadelphia.

Hab. Eastern United States.

Hab. Rhode Island; South

Carolina.

Pilinla

diluta, Wood. Hab. Centre County, Pennsylvania.

Coleochaete.

Aphanochaste

repeus, Braun.

Hab. Eastern United States.

Hab. near Philadelphia.

CLASS RHODOPHYCE^E.

Family PORPHYRACE.E.
Forphrydlum

cruentum*, Ag. Ilab. New York,

magnificum, Wood. Hab. Texas.

Family CHANTRANSIACE^E.

Chantransla

expansa, Wood.
macrospora, Wood.

Hab. near Philadelphia.
Hab. South Carolina.

Family BATRACIIOSPERMACEJE.
Batiachospermum

moniliforme, Roth. Ilab. Eastern United States.

vagum, Roth. Ilab. Uiutah Mountains, Nevada.

Tuomeya

fluviatilis, Harv. Hab. Alabama; Virginia.

Family LEMANEACE^I.
Lemanea

catenata, Ktz. Hab. Diamond Range, Rocky

Mountains,
fluviatilis, Ag. Hab. Alabama.

tornlosa, Roth. Hab. Virginia ; Kentucky ; Penn-
sylvania ; New Jersey.

BIBLIOGRAPHY.

Agardh (Karl Adolf i.

Dispositio Algarum Snecia. Land*, 1810-12.
Aumirkningar om sliigtet Lemauia, saint benkrifnini;

out tv.-miH nya artc r deraf. Kongl. Svenska Ve-

tenXkaps Akademiens Haudlingar, xzzv., 1814, p. 33.
Begkrifning af en ny art Conferva. Ibid., 1814, pp.

1 95-200.
Synopsis Algaram Scandinavia, adject* disposition!)

universal! Algarnm. Lauda, 1817.
D« metamorpbogi Algaram. 1-is von Oken., 1820.

R*gensburg Flora, vi., 1823.
Species Algarnra rite oognlta cnm synonymig, dlffer-

t-iitiisgpeciflcis et desoriptiouibug suocinolis. Gri-

puie, 1823-28.

Systema Algarum. Lunda, 1824.
Aufxiihlnng einiger in den Oatreichischen Landern

gefnndenen neuen Gattnngen nnd Arten von Algen,

nebst ihrer Diagnostik nnd beigefiigten Bemerkungeu.

Regensburg Flora, z., 1827.

Einlge Bemerknngen Ob«r Hm. Dr. Meyen's kritigulie
H.-itr.iL.-.- /inn Studium der Siisswasser Algen.
Ragensburg Flora, 1829.

Icones Algarum Europaaram. Leipzig, 1828-35.

Agardh (Jakob Oeorg).
Observationer pa Sporidiernes rorelse liog de gruna

Algerne. Stockh. Aoad. Uandl., 1836.
Beobachtnngen iiber die Bewegung der Sporidien in

den grQnen Algen. (Translation.) Regensburg

Flora, 1840.
Bidrag till en noggrannars kannedom af propagations —

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Anadema, ett nytt glagte bland Algerne (Anadema,

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Aoad. Uandl., 184C.
Algologlgka Bidrag. Ofversigt af Konigl. Vetenskapg

Akademlens Fiirhandlingar, Sjefte Argaugeu, l~4'.<.
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Specie*, genera etordineg Algarnm. Lund*, 1848-63.

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On a new flenus of Alga belonging to the family Nos-

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On an nndeacribed Alga allied to Coleocliate gcntata.

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On an apparently nndegcribed genus of Fresh-Water

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On microscopic Alga as a cans* of the phenomenon of

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Alqnen (P. d1).

Notes on the Structure of Osclllatoria, with a descrip-
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Amlcl (Giovanni Battista).

Descriiione dl nn' Oscillarla. Firenie, 1833.

Andrejewsky (Erastes).

Ueber die Vegetation in den Badern von Abano.
Qraefe and Walther's Journal Kir Chirurgie nnd
Angen Krankheiten, 1831. AunaUu dvr Cheuiie
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Note Bar les vegC-taux qni croissent autonr et dans les
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Archer (William).

Description of two new species of Stanrastrum. Dub-
lin Nat. History Soc. I'roceeitingfl, 185ti-9. Nat.
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Society, I860.

Notice on gome cases of abnormal growth in the Deg-
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1860.

Observations on the genera Cylindrocystig, Mesotnnia,
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On the conjugation of SpiroUeuia coudensata. Ibid.,
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Catalogue of DesmMiacea (Dnblin) Nat. Hist. Rev.,
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Supplementary Catalogue of DeKinidiacea (Dublin),
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four new species. Natural Histor. Rev., vol. v.,
1858.

Notice of the occurrence near Dublin of a Unicellular
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Nat. History Review, v., 1858. Dublin Zool. Bot.
Assoc. Proceedings, i., 1859.

On a new species and genus of the Desmidiacea, with
gome remarks on th« genera Miorasterias and Euas-
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On the occurrence, of Zonopores in the family Desmidi-
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Micros. Society, 1860. Nat. Hint. Review, vol. vii.

On Astaridinm occurring in Penium digitata. Micro-
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Record of the occurrence new to Ireland, with a nob* of
a peculiar condition of the Volvocinacenns Alga
Stephauoaphara pluvial!*, Ac. Ibid., vol. vi.

Ou two new species of Saprolegniea. Ibid., vol. vii.

Description of a new species of Cosmarium and of a
new species of Xanthidinm. Dnbl. Nat. Hist.
Soc. Proc. ill., 1859-62. Nat. Hist. Review, vol.
vii., 1860.

(235)

236

BIBLIOGRAPHY.

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237

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Ezamen comparatif dea Hydrophytes non srticulees de
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238

BIBLIOGRAPHY.

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UlBLiOGK A I'll V.

239

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I860, vol. iit., N. 8., p. 251.

Microscop. Journal,

Dncluxean (J. A. P.).
Basal inr I'hUtoire uaturelle des Conferves des Envi-
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Dujardln (Felix).
Histoire Naturelle dea Zoophytes, aveo pi. 22.

Paris, 1841.
Snr qnelques Vc'ge'taux: infi-rieurs et partlculier, Bur le

Noatoc. Annales Kran';ai*t>s et Strangers d'Ana-

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1839.

Ehrenberg (Christian Gottfried).

Die Infusionsthiercben als Torkommene Organismen.
Mil 64 Tafeln. Leipxig, 1838.

Slikroskopische Analyse des cnrlandiachen Metoor-
••ra ron 1686 nnd Erlaoteruug desselben als ein
luot jetxt lebender Conferven and lufusorien.
Mit 2 Tafeln. Berlin, 1838.

•••i'mis and Einflass des mikroskopischen Lebens
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< - 1 . Monatsbericht der k. Preus. Akad., 1841.

Passat-Staub and Blnt-Regen, ein grosses organisohes
ni.-ichthares Wirken nnd Leben in der Atuioaphare.
Mil 7 Tafeln. Berlin, 1849.

Mikrogrologie. Das Erden nud Felsen sohaffende Wir-
ken des nnsicblbar kleinen gelbsstaudigen Lebena
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Neli.-t Fortsetinng (Bogen 1-22). Daselbst, 1856,
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Ueber die seit 27 Jahenr noch wohl erbaltenen Organi-
sations-Praparate des raikroakopiscbeu Lebens. Hit
3 Tafeln. Berlin, 1862.

Zar Mikrogeologle, von Christian Gottfried Ehrenberg.
-r Majestat Friedrich Wilbelm IV., Konig von
Preussen xngeeignet. Ein and vionig Tafeln mit uber
Tiertanseud grossentheiU color! rteu Kigaren, gezeioh-
iift vom Verfasser. Daselbst, 1854, gr. fol. 31
Sviten mlt 41 Taleln and 49 Blattern dazu geburiger
Erklaruug.

Mikroxcopiache Algen and Bryoioa aU Beglelter der im
Kenerstein Fossilen lufnsorien. llonataberiobte k.
Prenas. Akad. WUsens. IU Berlin, 1836, p. 114.

Uebersioht des Mikrosoopisoheu Lebens In Califoruien.
Ibid., 1852, p. 423.

Beitrag xu Beatimmnng dee Station&ren Hikros. Lebens
in bis 20,000 Fuss Alpenhdhe. Monatsber. Akad.
•n. 1858, p. 426.

[For a farther list of microscopic papers by Ehrenberg,
10 doable columns, see Register fur die Monatsbe-
riohte der K<inig. Akademie der Wis»en8ehaften xu
Berlin Tom Jahre 1636 bis 1858. Berlin, I860.]

Ettingshausen (Konstantln von).

I>i» Proteaoeen der Vorwelt. Sitinnpherichte der
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Famiiitxiu (A.) und 3. Boranetxky.

Zur Kntwu-kvluDgj(««obieht« der Qonidioo nnd Zooa-

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Die Wirkung des LiuhUts auf Algen and elnige anderr

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Jahrbucb fur Wisseni. Botan. Bd. ri.
Influence de la lumiera artificielle snr In Splrogjra

Urtho«plra. Anuale* dec Science* Katnrelle, vol.

Til., !-•;;.

Inflnrnoe de la lumiere snr le movement des Chlamedo-
monas, Oscillatoria, &c. Ibid.

Fischer (Leopold Helnrlob).
Beitrage xur Kenntnlss der Noetochaceen.

Berlin,

Der Nostoohaoeen. Botan. Zeitnng, 1853.

Fleischer (Johann Gottlieb).

Ueber Protococcua rdseo-persiciuos Kutz. Wurtemb.
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Flotow (Julius von).

Chroolepis Korberi. Fw. Botanische Zeitong, vlil.,
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Flotow (Julias von) and Ferdinand Julius Conn.
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Focke (Gustav Waldemar).

Pbysiologischen Studien. Ueft i., 1847. Heft ii.,

1854. Bremen.
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Frauenfeld (George lUttrr von).
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Fresenlus (Johann Baptist Georg Wolfgang).

Ueber Bpbssroplea anuliua. Botaniache Zeitung, 1851.

Ueber den Baa and das Leben der Oscillarien. Mu-
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Ueber die Algengattnngen Pandorina. Ooninm, and Ra-
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Fries (Ellas Magnus).

Sy sterna Orbis Vrgetabilis. Pan I., Plants) Homone-

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Corpus Florarum provincialium Suecin. — I. Flora

Scauica. Upsaliw, 1836.

Gaebel (B.).

Beitrag xur Kenntnlss der Spermatozoidien.
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Galllon (Benjamin).

Eauai aur lea causes de la couleor rerte des venires.

Rouen, 1821.
Aperc.n d'histolre natnrelle et observations snr les

limltes qnl apparent le regne vegetal da regne animal.

Boulogne, 1838.
Observations microseopiqnes et physiolopiqnes snr

1'Ulva intestinalis. Precis Analytique dea Travauz

de 1'Academie de Rouen, 1821.
Observations microscopiqnes sur le Conferva comoides.

Dillw. Am. Soi. Nat., 1824.

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240

BIBLIOGRAPHY.

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Grunow (A.).

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Ibid.,

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Hartig (Theodore).

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Ueber das Verhalteu des Zellkerns bei der Zellen-
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Beitrage zur Entwickelungsgeschichteder Pflanzenzelle.
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Harvey (William Henry).

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Harvey (William Henry).— Continued.

Index Generum Algarum. A Systematic Catalogue of
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1860.

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Nereis Borealis Amerieanae. Part III. Chlorospermeae.
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Haasal (Arthur Hill).

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Observations on the growth, reproduction, and species
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Essay on the distribution, vitality, structure, modes of
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Hawlett (Frederick).

On the structure and circulation of Nitella translucens.
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Hazslinkszky (Friedrich).

Die Algen Flora Ungarns und seiner Bundeslander.
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He d wig (Romanus Adolf).

Tremella Nostoch. Commentatio. Lipsise, 1798.

Archly fiir die Botanik (Rcemer), ii. (1799-1801).

Bemerkungen iiber das Studiumund die Untersuchnng
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Hermann (Johann).

Botrydinm argillaceum Wallr., ob Alge Oder Flechte.
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Hicks (John Bruzton).

On Fresh- Water Algae.

Microscop. Journ., N. S., vol.

On the Diamorphosis of Lyngbya, Schizogonium, and

Prasiola. Ibid., N. S., vol. i.
On the Motionless Species (Statospores) of Volvox

globator. Ibid., N. S.,'vol. i.
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iv. p. 253.

On the Amseboid Form' of Volvox globator. Ibid.,

1860, p. 99.
Observations on the Gonidia and confervoid filaments

of Mosses, and on the relation of their Gonidia to

those of Lichens and of certain Fresh- water Algae.

Trans. Liunaeau Soc., 1862, p. 567.

r. i r. LIOGR A I'll v

241

Hicks (J. B.).—

mi l>r.i|'.uii .il I i iTiiciata. Quarterly Journal of

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•vatiuii* uu vegetable aiuwboid boJiea. Ibid.,

Hillabrandt (Franz).

r..|'.T fin CliroulepuA n.it ZooHporeubildung. Sitz
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Nykoloci-rh- IWitrage(Aohlya, &o.). Pringsheim's
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Hilia (Dr.).

Itvitrage «nr Aliii'ii- uu.l Diatomtwn-Knude Schleeieus,
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Hobson (J.).

Noted ou Imlian Desmidec.
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Microscopical Journal,

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TOIUH ii. Cryptogam- n. Krlaugen, 1795.
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Meclianik dor Protoplasiua Bowpgnngen.
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;i llciili-Uwrg. 18G5, Bd. ill. Regeusburg
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Hooker (Joseph Dalton).

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Hooker (William Jackson).
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KinigoBeobaclitangen and Bemerkangen dber die Knt-

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Deberdie Entstehang nnd Metamorphosen der niederen

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De Anim.ilibti-i et Vegetalibna in Corpore Hummo para-
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Itzigsohn (Hermann).

Krvptogamischer Ursprung der Miaamen. Botaninche
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Bar 1'Existence des Bpermatoxoides dang certaines

Algnes d'eaa douce. Anna), des Scien. Natur.

(Hot.) vol. XT!., 1862.
Deber die Sporenbildnng der Cha;tophoren. Botani-

sche Zeitung, z., 1852.
Deber Ulothriz CTlindrorapsa, IU. Hedwigla, 1852,

nnd Regensbnrg Flora, 1852.

Pliykologische Stndien. Nova A-ta, 1S57, bd. zzvi.
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Brannii. Nova Acta. Bonn, Bd. zzv.
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31 October. 187S.

Itzigsohn (Hermann). —

<u Kivularia gigantea, Qrent.

II I.

Ueber den m&nnlichen Q«acblrolit*-apparat bel Spiro-
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Die Nostoc-Diamorphone. Ibid.

Die Portpflanxang der Oscillarien. Ibid.

Kin Wort liber Hralotheoa nnd Mforasteriai. Ibid.,
1853, p. 485.

Ueber die Sporenbildnng der Cladophora. Ibid., 1852,

pp. 549, 569, 723, 785.
Ueber das Stadium der SQuwaueralgen. Regenab.

Flora, 1850.
Zur KntwickelnngfreTbiclite von Cladorporium lierba-

rum. Hedwigia, lb&5.
Ceber die Algxngattuug I'aichohoruiinni. Regens-

burg Flora, 1854.
Wie verhiilt sicli Collema xu Nostoo nnd su den Nosto-

oblneen. Botau. Zeitang, 1854.

Die Oloeocapsen nnd Chroococcaceen Dtamorpbose.

Botang. Zeitung, 1854, zii.
Vegetablllsche Zelle nnd Sexns, eine liypothetische An-

dentnng. Botanigche Zeitung, zv., 1857.
Zur Naturgegohlohte der Sarcina ventricnli, Qoodgir.

Archiv fttr Pathol. Auatomie (Virchow), ziv. 1S58.
Oloeocapsa and Cladonia. Botan. Zeit. ziii., 1855.
Nachtr&gliche Bemerknngen Qber die Fperraatozo'ideen

der Vaucberia. Botan. Zeit. zii., 1*54.

Jenner (Edward).
Flora of Tunbridge Wells.

Tnnbridge Wells, 1845.

Jessen (Carl Friederich Tffilhelm.)
1'raiiol.T generis Algarum Monngraphia.
iuauguralis botanica. Kili;r, 1848.

Dissertatio

Juratzka (J.).

Ueber Conferva anreo-fusca, Kiitz. Verhandlungen der
k. k. xoologisch-botau. Qesellscbaft, Wieu, 1MJ4. Bd.
14.

Karsten (Hermann).

Beitrag znr Kenntnlgg des Zellenlebeng. Botanigcbe
Zeitung, 1849.

Ueber die Bewegnngsorfrane nnd die Betregnngser-
gcheinnngen der Udcillatorieeu. Regeusb. Flora,
1856.

Die Fortpflanznng der Conferva fontinalis. Bota-

nigche Zoitang, 1852.

Cblamydocoooag plnvialig. Botani&clie Zeitang, 1852.

Botanigche Untergucliungen ans dem phyglologisclipn
Laboratorinra der landwirtbschaften Lebranstalt in
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Beriohtignng zn Pringgheim's Nachtrag znr Kritik nnd
Qesoliichte der Untersnchnngen fiber dag Algen-
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Zur Oegchichte der Befrachtang der Algen. Bota-
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Kickjc (Jean).

Flore cryptogamiqnc des Flandreg. Oand et Paris,
1867.

Kingsley C H.).

On cilia npon the surface of Oscillatoria. Microscop.
Journal, 1855, p. 243.

Knlphof (John Hleronymus ).
Pbysikalische Untersncbniigen
Wiesen]. Erfurt, 1753.

des PelUes, [auf

242

BIBLIOGRAPHY.

Kraus (G-.) et A. Millardet.

Etudes sur la uiaterie colorante des Phycochromacees
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Kuhii (Julius).

Ueber eine im Innern des Faulthierhaares lebende Alge,
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Kiitzing (Frtedrlch T.)- •

Algologische Mittheiluugen. Regensburg Flora, 1833.

Beitrag zur Kenntniss iiber die Eutstehung und Meta-
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Ueber Sphaerotilus natans, eine nene Siisswasseralge.
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Ueber Gloionema, Agh. Ueber eine iieue Gattung der
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(Erdmanu), i., 1834.

Verwaudlung der Microcystis umbrina, Ktz., in Aly-
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Die Umwandlung niederer Algenformen in hohere, so
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Phycologia Germanica. Nordhausen, 1845.

Species Algarum. Leipzio, 1859.

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Laooste (C. M., van der Sande), en W. P. R. Su-
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Nieuw Besohrevene en voor onze flora nieuwe Zoetwater-
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Landsbo rough (David).

British Sea- Weeds, with Notes of the Fresh-water Algse.
London, 1857.

Laurent (J. L. M.).

Note sur la reproduction du Volvos globator. Paris,

Soc. Philom. Proo. Verb, 1848.
Sur les deux sortes de corps reprodncteurs du Volvox

globator. Ibid. 1849.
Note sur le Volvox globator. Comptes Rendus et

Les Memoires de la Societe de Biologie, 1850.

Lawson (George).

Report on the Musci and Desraidieae collected during a
trip to West Lomond Hill, Fife. Proceedings Edin-
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On Macadamia, a new Genus of Proteaceae. Trans-
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Note on Letnanea variegata Agd. Ibid., 1863. Edinb.
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Lawson (George). — Continued.

On the Structure and Development of Botrydium granu-
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Lebret (E.).

Note sur les Couferves qui croissent dans les bassins da
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Leidy (Joseph).

On the existence of Entophyta within healthy animals

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A Flora and Fauna within Living Animals. Siaith-

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Lespinasse (G.).

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Iiianteuant.

Beschreibung einiger neueu Algen. Regeusburg

Flora, 1831-1834.
Beitrage zur Algenkunde. Ibid., 1839-1840.

Lindsay (William Lauder).

Protophyta of Iceland. Microscop. Journ., N. S.,

vol. vii. p. 97.
Protophyta of New Zealand. Ibid., vol. vii. p. 197.

Unke (Heinrich Friedrich).

Handbuch zur Erkennung der nutzbarsten und aui
haufigsteuvorkommeudeuGewachse. Berlin, 1829-33.

Linne (Carl von).

Systema Naturae.

(Various editions.)

Lobb (E. G.).

On the Self-Division of Micrasterias denticulata.

Micros. Soc. Trans, ix.,1861.
On Cosmarium radiatum. Microscop. Jonrn., N. S.(

vol. vi. p. 52.

Ludera (Johannes E.).

Ueber Abstammung und Eutwickeluug des Bacterium
Ternio Duj. Vibrio lineola Ehrb. Botauische Zei-
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Lyngbye (Hans Christian).

Account of a New Arrangement of the Algse. Edinb.

Phil. Journ., ii., 1820.
Tentamen Hydrophytologise danicse, adjectis simnl

speoiebus norvegicis. Havuise, 1819.
Efterretning om Hr. Gaillons mikroskopische og physio-

logiske Undersogelser med Conferva coincides Dillw.

Orsted, Tidsskrift, iv., 1826.

Mackay (James Townsend).
Flora Hibernica. Dublin, 1836.

Translated in Bull. Sci.

Martens (Qeorg von).

Reise nach Venedig, 1824.

Nat., vol. vi., 1825.
Algologische Mittheilnngen, zumal liber .Turgens algo-

logisohe Sammlung. Regensb. Botanische Zeitung,

1830.

Ammauria jungermannioides. Ibid. 1836.
Amphicoa pustulata. Ibid. 1836.

Martius (Carl Friedrich Phillpp von.)

Flora Cryptogamica Erlangensis sistens vegetablia
eclaisse ultima Linn, in agro Erlaneensi hncusqua
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Regensbnrg

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244

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II. Saprolegnieen. Ibid., p. 284.

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Prinsep, Macalre, et Marcet.

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Pritchard (Andrew).

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Rabenhorst (Ludwig).

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in it L i o u ii A r 11 Y .

246

Ra bonbon t (Lndwlg).— Continued.

Algol"- -•'"•- I'UIIOMIIII ( Kinfliu* del Dampfuiascuiuen
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Kryptoi<.\inrii flora Tou Sachseu.der Ob*r-LauiiiU,Thiir-
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Species nov» Algarum. Hedwigia, 1854.

li.-itr.-iR lur Crv|itoi:aim'nflor:t Sud-Africaa ; 1'ilxe nnd

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Tbo British Desmidiec. London, 1848.
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4t>5; 1845, pp. 149, 4ol.
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K Inili. Bot. Soo. Trans.. Ir., 1853.
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r.'hnr Conferraanreo-fnlra Kti. Abhandlangen dee

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I .-!'-r ein (nassenhaft«s Anftret«n Ton Cladophora ria-
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Reichert (Karl Bogislans).

Saftstriimnng in den Pflanxenxellen mil Uiicksicht auf
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Relnlcke (Pr.).

Die Bewegnng <l«r Osoillnri-n, besondere der Spirnllna.
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Relnsch (Paul).

De Speoiebns Oenpribnsqne nonnollisnorisez Algarnm
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Die Algenflora des mittleren Theiles von Franken.
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ReUchy.

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Rxgenibnrg Flora, If 41.

Rlohter (P.).

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is-;:..

Hedwigia,

Ripart.

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I'eber Urin-Saroina. Regensbnrg Flora, 1857.
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Beobarhtnngen fiber das pflanzen&hnllche Wesen in
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Klrine Bnitr&ga zur Natnrgeschichte der Infusonen.
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246

BIBLIOGRAPHY.

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Ann. Nat. Hist., ii., 1858, pp. 1-9.

Thwaites (George Henry Kendrick).

On an apparently undescribed state of the Palmelleffi,

with a few remarks on germination in the lower

plants. Annals and Mag. Nat. Hist., vol. ii., lt>48,

p. 312.
Description of Coccochloris Brebisonii. A new species

of Palmellze in Conjugation. Ibid., ]S49, p. 243.
Mode of the formation of spores in a species of Vesi-

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On the early stages of development of Lemanea fln-

vatilis, Ag. Transactions of the Linuaiau Soc.,

1851, p. 399.

Trevisan (Vlttore, Conte).

Prospetto della Flora Euganea. Padova, 1842.
Saggio di una monografia delle Alghe coccotalle.
Padova, 1848.

Nova Actse, Bonn,

Ibid., 1837, Bil.
^

Annal. Soo.
Wien,

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Algologische Beobachtungen.
1832, Bd. xvi.

Mikroskopische Beobachtuugen.

xviii. ^

Sur 1'Oscillatoria labyrinthiformis, Ag.

Nat. (Bot.), vol. xi., 1839.
Die Pflanze in Momenta der Thierwerdung.

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Ueber Vaucheria clavata. Agdh. Sitznngsbericht.

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Beitrage zur Kenntuissz der niedersten Algeuformen,

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Beitrage zur Kenntniss der niedersten Algeiifonnen.

Denkschriften der k. Akademie der Wisseiischai'ten.

Wien, 1854.

Vaucher (Jean Fierre Etienne).

Memoires sur les graines des Conferves. Paris, I860.
Histoire des Conferves d'eau douce, suivie de 1'liis-

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Vogt.

JZdward Desor's Excursions et sejonr dans lea glaciers
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Wallich (Dr. G. C.).

Descriptions of Desmidiacese from Lower Bengal.
Ann. and Mag. Nat. Hist., 1860, p. 184 and p. 273.

i: I liLIOGUA I'll V.

Wallroth (C. Friedrlch Wilhelm).

Annul I'i't.-iiiii'ii-, »ivi< Mi|i|>l>MiifUttim ti-rtium ml Cuitii
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Flora Cryptoiiainica lirruianiip. Pant jio-ti-rior contiu-
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W«l» (J.)-

Beitrii«e xur Ki-nntnis* der ZoosporenbiMnng be! den

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Wartman (B.)-

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Weber (Frledrich) uinl Daniel Matthias Heinrlch

Mohr.
NatDrhistorische R«iM dnrch elnen Thell Schwedens.

UuttiDgvu, l-i '4.

WeUe (Dr. J. P.).

Besnltate r. Terglvich«nd<>n mikrosk. (Jntennchangpn
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Welwltsch (P.).

iimtijche Anfz&hlnngder Susswasser Algen Unter-
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Svn»r«u Nostochiuearuui Austria inferioris. Wien,

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l.-l'.T Kni-ii-liiing von Entomostraoeen nnd rodnn-llrn

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Fortsctinug. Ibid., Bd. xi., p. 641.

TWlllan (Robert).

Observations on tbe Solphnr-watvr at Croft near Dar-
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[A conferva described on p. 9-10.]

•Williamson (W. C.).

On structure of Volvox globator.
Transactions, vol. i.

Microscopical

•Wood (Horatio C.).

Notes on some Alg» from a Ca'lfornian Hot-Spring.
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Prodromus of a Study of North American Frail-Witter
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Observations and experiments upon living organism?
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Zanardlnil (Olovanni).

Synopsis Algarum in Mari Adriatico, cui accednnt Mono-
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Deber Cladophora Henfleri. Verhnn.llni'een Jet

loolog.-botau. Vereins iu Wien, Bd. ii.,

INDEX.

AlAR.VXA. "7

flos-aqui*, h'l;., 38

ci-lntiuosa. Wonl, 38

Kicantea, Wood, 38
Aii'ir..|:yiiia, 198

uta, Wonl, 198

11 until, ll'oo./, 197

mirabilis. IT ..... /, 198

mnltUpora, Wood, 196
AnkUtrodegmna falcatna (Corda), 85
Aph»noch«rte, 211

repenn, Itrntin, 212
Aptogoniura, 126
Aptogonium, Baileyi, Ilalfi, 127
ArtbrodeBmm, 157

conrergens, Ekrb., 159

incus (Drib.), 158

cetocornis. Ehrb., 158

quadridena, It'ood, 158

A, 125
KivbiBaonii, 125

B.itrachogpermacea, 217

Batracboftpermum, 219
moniliforme. Roth, 220
ragam, liotk, 220

Bi.-hstia, 12

Itotrvcliiiiii, 175

argillacenm, 176
listen, 199

Bulbochvte, 201

Canbyii, Wood, 202
dumosa. Wood, 202
Ignota, Wood, 201

BullK.triebia, 205

albiJa, Wood, 205

, 13
dabium, (Iran., 13

Chatophora, 209

elegans (Knth), 210
cndi*i*folia ( A'../A). 210
pisiformis (flnfA), 210
tuberonloB* (fto(A), 210

Cb»topboracec, 205

Cbanlranaia, 21. r>

ezpansa, IK"w/, 215
macrospom. Wood, 216
Tir.lacca, A"/r.. 21'i

Cbantranslaovc, 21 ">

Cblamydococcna, 99
tiir.ilin, 99

Chlorococcam, 87, 88

ChloriipbylUcf », 77

CliroocoocaoeaB, 10

Cbroococcn», 11

nnilticoloratns, Wo-id, 11
r.-fr»otn», Wooil, 11
tbermopbilax. Wood, 12

Chroolrpidec, 2n3

32 October, 1873

Chroolepnn, 204

aurram. Kl:., 204
Chtbonoblagtas, 21

ropens, Klz., 21
Cladonia, 88
Cladophora, 187

bracbystelechn, Rabtnkorit, 188

fracta, Dillvyn, 188

glomertta (Linn.)) 187
ClostvriuDi, 109

acerosum, (ftchr.), Ill

areolatnm, Wood, 111

amblyonema, Ehrb., 116

nngtist.it am, AY:., 110

Cucumin, Ehrh., 113

Dlan», Ehrb., 114

Elirenbergii, Mmgh., 113

Jenneri, Knlft, 115

juncldura, italft, 110

Leibleinii, Kt:., 114

lineatam, Ehrb , 112

Launla (JMfar), 111

maximnm (r<ir.),lll

monilifernm (fiory), 113

parralum, XirijrI., 115

ro-tratmu. A-V/r/i., 115

•etacentn, Ehrb., 116

striolatum, £Ar6., 1^9

trabeonla, Aoi/cy, 120

Venas, A'/.-., 114
Coocophyof», 78
ColeoohBte, 212

scutata, 1Mb., 213
Collema bulbosum, 25
Conferva, 186

mnraliii, f)illw., 22
Conferracew, 188
Conjugal* longata, Vnurhtr, 166
Conjugation, 161
Connecting celU, Thwaitei, 23
Coamarlam, 127

amoonnm, Br/b., 130

biocnlatnm. UrSb., 131

Botrytis, /i.-ry, 128

BK-bissonii, Menegh, 128

Broomel, 7"Air., 133

cnlatnm, 7f'i//i, 133

commissuralrt, firth., 132

oonnatnm, Brfb., 134

crenatnm, Ai//ii, 131

Cucumis, Corda, 130

depreMum, Bailey, 130

nargaritiferam (Turp.), 127

Meneghenii, Ar/A., 131

ornatutu, A'.i//>, 132

orale, Rolf,, 128

prramidatnm, Itr/l,., 130

Qaimbyii, IKoorf, 134

Bablobatnm, /ir//.., 132

suborbiculare. Wood, 129

tetroptbalmuin, tit;., 129

Coemarinm.

Tbwat4»it, 7?a//>, 134
nndulatuni, <'<>nl<i, 132
verrucosuui. Bailey, 121

Cjrllndrospermnm, 39
comatnm, Wuod, 41
flexnosnm. Rabenh., 40
maorospermnin, A'(z., 40
iniiiiituiii, ir»w/, 39

C;itlphor«, 10

Cystococcus, 88

DASTACTH, 50

mollia, Wood, 50
Desmidium, 126

aptogoniuni, Brfb., 126

eustepbanuin. Ehrb., 155

qnadrangolatum, h'l: , 126

senarlntu, Ehrb., 155

Swartzii, Agardh., 126
Dlctyosphcrinm, 84

palcbellum, Wood, 84
DidTmooladon cerberus, Bailey, 154

fnrolgernm, lirib., 154
Didyinnpriuii], 125

BrC-biggonii, AVt., 126

Borreri, Ralft, 125

OreTillii, A/.-., 125
Docidium elavatuni, A"/r., 120

constrictura, Bailey, 121

Ebrenbergil, /^.i//i, 118

liirsutum, Bailey, 121

minutum, Kalft, 107

nodosum, Bailei/, 120

nodnlosum. Brtb., 120

pristi.ljp, Bobion, 122

nndnlatnm, 120

Terrncosnm, Bailey, 121

Tertidllatnm, AV/ir, 121
Dolichogpermnra, 41

polysptTinum, 42

Bubrigidnm, (Food, 43
Draparnaldla, 207

Billingsii, Wood, 208

crucial*, Hirln, 209

glomerat* ( Vouch.). 207

maxima, H',. ,/ 207

opposita, //art!., 227

plamos* ( 1'uucA.), 208

EKTEROMOBPBA intestinalis ( Ax'
183.

Kuactrum, 1S5

affine, ««V», 138
•mpnllaceum, AVi//«, 138
anratnin, Ehrb., 139
binale (7urpin),140
rircalare, llatnal, 139
erusum (Breb.), 137

(249)

250

INDEX.

Euastrum.

didelta (Turpin), 138
elegans (Brtb.), 140
geinmatam (Bre'b ), 136
insigiie, Ralfi, 138
Jenneri, Archer, 139
margaritiferum (Tur/i.), 127
multilobatum, Wood, 135
oblongum (Grevi/lc), 136
ornatum, M^oorf, 137
R.ilfsii, Rtibenh., 13X
verrncosum, Ehrb., 136

Evennia, 88

GEOGRAPHICAL LIST. 229
Globulina, Turpin, 12
Gloeocapsa, 12

spafsa, Wood, 13

Gloeoprium mncosum, Hissal, 124
Gloiotricha, 45

angulosa (Roth.), 47

incrustata, Wood, 45

HETEROCYSTS, 23
Hyalotheca, 124

disillieus (Smith), 124

mucosa (Mert.), 124
Hydrodictyou, 92

utrioulatum, Roth, 95
Hydrogastrese, 17-">
Hydrogastram, 175

granulatum (Linn.), 175
Hydrurus, 226

penicillatus, Ag., 227

occidentalis, Uarv., 227

ISTHMI^B, 123
Isthmo.sira, 123

LKMANEA, 223

catenata, Ktz., 223

fluviatilis, Ag., 223

torulosa (Roth), 223
Lemaneaceae, 221
Lyngbya, 22

bicolor, Wood, 22

copnlata, Harvey, 22

mural is, ^., 22

MASTIGOXEMA, 51

elongatum, Wood, 53
fertile, Wood, 51
halos, Food, 52
sejunotum, Wood, 53

Mastigotlirix, 55

flbrosa, Wood, 55

Merismopediu, 14

convoluta, Bre'b., 15
glauca, 15

Mediterranea, Nay., 15
nova, Wood, 14

Mesocarpus, 173

parvulua, Ilassal, 174
soalaris, Hassal, 173

Mesotsenium, 105

Micrasteriag,141

Americana (Ehrb.), 143
arcnata, Bailey, 141
Baileyi, fla//s, 143
denticulata (Bre'b.), 145
disputata, Tfborf, 142
expansa, Bailey, 141
fimbriata, fla(/s, 145
foliacea, Bailey, 147
furcata, Agardh, 144

Micrasterias.

granu'ata, IToorf, 146

iucisa, 142

Jenneri, Ralfs, 146

oscitans, Ralfs, 142

papillifera, Kreft., 14G

piunatifida, Ktz., 143

quadrat;), Bailey, 142

radiosa, Agardh, 145

rotata, /v'a//s, 144

ringens, Bailey, 143

Torreyi, Bailey, 147

trnncata, Corda, 144
Microcystis, Menegh., 12
Mouactinns duodenarins, Bailey, 98

octeuarius, Bailey, 98

NEMATOOBXE.S, 15
Nostoo, 27

arcticum, Bertflty, 225

Austin i, Wood, 27

alpinum, A(z., 29

caeruleum, Lyngb., 31

calcicola, ^4y., 33

calidarium, H'oorf, 34

Cesatii, JSo/s.,32

comtuinutura, A'(z., 36

commune, Vaurher, 37

cristaturn, Bailey, 29

depressum, H'ood, 30

flagelliforme, Berk, aud Curtis,
226

lichenoides, 30

miorosoopioum, Carm., 226

punctatum, Wood, 32

pruniforme, Agh., 28

sphaericum, FaticA., 30

Sutherlandii, Dickie, 29

verrucosum, Vauch., 28
Nostochaceae, 23
Nostocliopsis, 44

lobatus, H'oorf, 45
Nematophyceae, 181

OSCILLARIA, 17

chlorina, Kutzing, 18

coriuin, Agardh, 17

decortioaus, Gener., 17

Frohlichii, A"/z., 18

imperator, Wood, 20

limosa, Agardh, 19

muscorum, Agardh, 17

neglecta, H^oorf, 20

nigra, FaucA., 17, 19

tenuis, ^f/., 17

tenuissima, ^., 17

princeps, 21
Oscillariacese, 16
Odontella, 123

tridentata, Bailey, 127
(Edogoniacese, 188
(Edogoniese, 190
CEdogonium, 195

Huntii, Wood, 197

inequalis, Wood, 195

mirabilia, Wood, 196

multispora, Wood, 196

PAOEROOALLA, 81

stellift, Wood, 82

Palmella, 79

dura, Wood, 80
hyalina, Lyngb., 81
Jesenii, Woorf, 79

Palmellacese, 78

Paliuogloea, 105

Palmogloea.

clepsydra, Wood, 105

Pediastrum, 95

Boryanum (Turpin), 97
constrictuia (Ilassal), 97
duodeuarius, 98
Ehrenbergii (Corda), 98
pertusum, Kutzing, 97
selenjea, Kutzing, 97

Penium,-106

Brebissonii (Menegh.), 108
closteroides, 7ia//i, 109
digitus (Ehrb.), 106
interruptum, Br£b., 108
Jenueri, Raijft, 1C8
lamellosum, Brtbisson, 107
margaritaceum, Ehrb., 107
miriutum, Clece, 107

Petalonema, 66

alatum, Berkely, 66

Phycliochrom, 10

Phycochromopliyceae, 9

Phycocyan, 16

Phykokyan.16

Physcia, 88'

Piliuia, 211

diluta, Wood, 211

Pleurocarpus, 174

mirabilis, Braun, 174

Pleurococcua, 78

pulvereus, Wood, 79
seriatus, JToorf, 78

Pleurotaeniuin, 118

bacnlurn (Brtb.), 119
breve, Wood, 119
clavatuin (Ktz.), 120
constrictum (Bailey), 121
crennlatum, Ehrb., 119
gracile, Rabenh., 122
hirsutum (Bailey), 121
nodoaum (Bniley), 120
trabecula (Ehrb.), 118
uudulatum (Bailey), 120
verrucosum (Bailey), 121
verticillatum, Ruben., 121

Polyedrium, 88

enorme, 7?a//s, 89

Porphyraceae, 214

Porphrydium, 214

cruentum (^1(7.)>214
magniflcum, IFoot/, 215

'ringsheimia, 195

insequalis, IFoo</, 195

Protococcacea?, 85

Protococcus, 86

Protoderma, 182

viride, Kutzing, 182

ElHAPHIDIUM, 85

falcatum, 85
polymorplium, fresen,85

Shynchonema, 163

elongata, Wood. 164
pulchella, Wood, 164

Jhodophyceai, 213

Jivularia, 47

calcarea, Sm., 50
cartilaginea, Wood, 47

Rivulariaceae, 43

3ALMACIS, 163

Scenedesmua, 89

acutus, Meyen, 90
obtusus, Mei/en, 90
polymorphns, Wood, 91
quadricauda (Turpin), 91
rotundatus, Wooil, 91

i N n i-: \

251

Schiiompri*, 1-1
Loibleiuii, 185

Scytoin-ui.i, 57

Austin! i, Wood, 68
ealotrii'lmi'lf s, hui;iny, 61
cataracts. H'uo</, (i-
cortex, Hi""/, >;4
dubiuui, It'...../, 63

MllllirnMIIll, H'uOtl, 59

HyochrotM, .-I.;., 61
Nielli. A/.-., 59
OceiUtum, //nirrjf, 63
Raronvllii. »',...,/. .;l
limplice, (foot/, 57
thermal*, 60

ScytoneiuaceiB, 55
i iphyvr.v, 174

Siro'ipliun, 73

aeervatu*, TT,»o./. 74
argillacvm, II'.W, 73
compact us (.ly.), 69
eoralloidr
Crameri, />'<u';7, 70
gnttula, II ..../, "3
li(!iiici>l:i, H '• "«/. 72
neglertun, ll',,,*/, 71
pi-lliioidiilus. ll',,,*/, 69
pulviuatus, 75
•cytcnemaloides, IFood, 68

Birogoniuni, 178

retroversmu, Wood, 173

SirMiphonaceB, 07

Speriuatis, 23

Spermogirrn, 37

o8nia, 123

cxcavatum, Ralf*, \-l
pulclinun, /;.ii..//, l^:t
serratom, liailey, l'!4

Bpbsroiyga, 43

Carmiclixlii, Harvey, 43
poljrspenna (Ktz.), 43

Splrogyra,163

~.%, Km zing, 171
doclmina, .l/ii /rr, 167
diliiU, Woof/, 170
dubia, Kitt:in;i, 167
•longata (Bert.), 164
insiguU, Ilaftal, Iti'i
loogaU (KaiK-A.), 166
majasoala, Kiitz.), 169
niti.la (Oilier.), 169
protect*, IPborf, 1U5
p-irvispora, IK«o</, 169

Splrogrra.

patohcUa, WO<K/, 164

quinina, ,-*y., Iti7
rirularU (//n>«>/), 168
letiformin (Hull,), 170
Woberi, A'«., 1U5
Spirotniiia, I--

bryophlla (Orrft.), 122
cuu.lvnsata (ltr/1,.), \.:
iuiu. 123

Slaurastruiu, 147

alli-riians. /.>.'/.., 150
aracbne, /<u//«, 152
aristifurum, KII//I, 149
Cerberus, liailey, 154
crenatutn, liniley, 151
cyrtoceruui, Ui/b., 151
dejactnm, /^r/6., 148
dilaUtam, AVirfc., 150
enortne, /id//i, 89
eaatephanam, Rtilft, 155
farcigorinu, lir'b., 154
gracile, Aa//«, 152
biraatuni, Ehrb., 153
Hyitrix, «.i//i, 1«4
Lewlsii, >Foi</, 149
longispinuin,.lrcAcr, 148
niargariUuxum, Eltrb., 150
mnnitum, lfoo</, 154
muticum, lirtb., 148
orbicalare, A'Arft., 148
paradoxnro, SJeyen, 152
polymorphuin, 151
polytricliuin, i'rrtif, 153
pniictulatum, liifli., 151
Raveuellii, »K««/, 153
tenarinm, Kkrh., 155
tricorne, Mrnryk., 150

Stephanoxanthium eustephanum,

Kiiltiny, 156
senariam, Jfutzing, 155

Stigonuma mammellosum, 77
Ravenelii, Berkeley, 76

Stigeocloninm, 206

TITXIMOBUS, 116

Brtbissonii (J/««<7*.), 116
giganteus, IKoorf, 117
granalataa (lir/h.), 117
lovis (A'iid.), 118

Tetranpora, 82

bullosa (.Roth), 84

Tetraxpora.

gelatinoxa (Roll,), 83

lubrica (/&>/*), 82

perforata, Uarery,SZ
Tolypotlirix, 65

diitorU (Mailer), 65
Triplocuru, 121

gracile, liailey, 122

Tertldllaturn, liailey, 121
Tuomeya, 221

fluviatili*, Harvey, 221
Tyndaridea oruciata, JIaxtal, 172

ItuignU, Uaaat, 171

L'LVA, 182

latiasima, Harvey, 1«3
merigmopedioidun, !('.."</. 182
orbioolata, Rabenhortl, IH3

Ulracoc, 182

VADCBEBIA, 179

a versa, f/aual, 181
cKapitosa ( KuiicAer), 179
geiniuata ( Voucher), 180
polymorplia, Wood, 180
sessilis ( Vaucher), 179
lericea, Lyngbya, 181
Telutiua, Agardh, 180

Vancheriace«, 176

VolrocineB, 99

Vol»cx, 100

globator, 100

XAKTHIDICM, 156

aculeatuiu, Klirb , 156
Arcliscon, Khrb., 156
annatum (llrSL.), 156
biscn.irinm, Ehrb., 156
Bribigsonii, A'.i//:s 156
coronatum, Ehrb., 157
cristatnm, Br/4., 157
fasciculatum, Ehrb., 157

ZOKOTBICHIA, 48

minutula, Waoil, 50
mollis, If.,,,,/, -is
parcezonata, Wood, 49

Zygnema, 171

insifrne (/7n.«n/), 171
craciatim, KaucA., 172

Zygnemacen, 159

Zygophycea, 100

CORRECTIONS OF THE PLATES.

Plate IV., for Zonotricha read ZonotricUa.

Plate VIII., for urn in the terminations of the specific name of figures 2, 3,

and 4, read us.

Plate IX., fig. 3, for argillacea read argillaceus.

Plate X., fig. 4, for Botryococcus pulckellus read Dictyosphcerium pulchellum.
Plate XI., fig. 5, 6, and 7, for Cosmarium read Closterium.
Plate XII., fig. 1 and 20, for Cosmarium read Closterium.
Plate XV., fig. 8, for insiynis read insigne.
Plate XVI., fig. 4, for Bulbotricha read BulbotriMa.
Plate XVIII., fig. 1, for Pringsheimii read Pringsheimia.
Plate XXI., fig. 7, for tetraopthalmum read tetropthalmum.

KXPLANATION OF PLATES.

PLATE I.

1. A single filament of Oscillaloria chlorina, Kiitzing, magnified 750 diameters.

. 2. The end of a filament of an Oscillaloria supposed to bo identical with 0. Frolilichii

Kiitzing.

Fiir. 3. O. nigra, Vaucher.

l-'iir. 3 a. Represents a portion of a mat or mass of Oscillaloria nigra, Vauchcr; there is too
much irrri'ii in the color.

." li. lli-prcsents several filaments separated from the edge ofljie moss and slightly magni-
led

Fig. 3 c. A portion of a Filament.

Fiir. 3 d. A portion of another filament still more highly magnified. The color in 3 c is more
natural than that of 3 d.

Fig. 4. A portion of a filament of 0. limosa, Agardb, magnified 1250 diameters. The articles in
this filament are more distinctly separated than natural.

Fig. 5. 0. neglecla, Wood.

Fig. 5 a. An outline view of a filament, magnified 450 diameters.

Fig. 56. A full figure of the same, magnified 500 diameters.

Fig. 6 0. imperalor, Wood.

Fiir. 6 a. Represents the end of a filament, magnified 250 diameters. In the centre of the plate
is a fragment (marked simply fig. 6.), oat of which the endochrome has been partially squeezed to
show the markings of the sheath at the joints.

Fig. 7. Lyngbya bicolor, Wood. Fig. 7 represents a moderately magnified portion of a filament.
Fig. a (near to fig. 8) represents a portion of an ordinary filament very slightly magnified.
Fig. 7 c. A portion of a filament containing a heterocyst, magnified 800 diameters.
Fig. 7 d. A broken end of a filament showing the sheath extending beyond the endochrome,
magnified 800 diameters.

Fig. 8. A varicty(?) of Lynybya bicolor, Wood, from the Schnylkill River, magnified 200 dia-
meters.

Fig. 9. Coamarium Quimbyii, Wood. The bands between the cells are too heavy and prominent

PLATE II.

Figs. 1 6 and 1 c. Different stages of germination of the spore of a Cylindrospermttm of unknown
ipecies, magnified respectively 800 and 1200 diameters.

Fig. 1 a. A chain of spores, believed to belong to the same species; one of these spores has
commenced to germinate.

Fig. 2. A portion of the upper surface of a frond of Nostoc calidarittm, Wood.

(253)

254 EXPLANATION OF THE PLATES.

Fig. 26. A "first form" filament of the same species.

Fig. 2 a. A filament from an old frond of the same plant.

Fig. 2 c. Fragments of tissue from the upper surface of a mature, actively growing plant of the
same species.

Fig. 3. A filament of Nosloc comminutum, Ktz , magnified 800 diameters.

Fig. 4. A filament of Anabaena gelatinosa, Wood, magnified 750 diameters, showing the large
globular body at the end, supposed to be a spore.

Fig. 5. A filament of Anabaena gigantea, Wood, magnified 750 diameters.

Fig. 6. A portion of a filament of Cylindrospermum minutum, Wood, magnified 800 diameters.
The number has been omitted from this figure on the plate ; the figure is immediately under A.
gigantea, Wood; the hairs on the heterocyst are too coarse and rigid.

Fig. 7. A spore and outline of heterocyst of Cylindrospermum macrospermum,Klz., magnified
750 diameters.

Fig. 8. The end of a filament of Cylindrospermum comatum, Wood, magnified 1375 diameters.
The appendages to the heterocyst are coarser than natural.

Fig. 9 a. A section of an immature frond of Rivularia cartilaginea, Wood.
Fig. 9 b. The base of a fertile filament, showing the spore and basal cells, magnified 800 dia-
meters.

Fig. 10. An ordinary filament of Nostoc sphsericum, Poiret.

Figs. 10 a and 10 c. Filaments enlarging preparatory to longitudinal division.

Fig. 106. A filament already partially divided into two.

PLATE III.

Fig. 1 a. Cylindrospermum jlexuosum (Ag.), a fertile filament, magnified 450 diameters.
Fig. 1 6. The end of a fertile filament, magnified 750 diameters.

Fig. 2. Dolichospermum (Spheerozyga) subrigidum, Wood, magnified 975 diameters.

Fig. 3. Portion of a fertile filament of Dolichospermum (Sphserozyga*)polysperma, Ktz., magnified
750 diameters.

Fig. 4 a. A section of a frond of Oloiotrichia incrustata, Wood, showing youngish filaments,
masses of lime, and an organic body of unknown nature, all inclosed in a transparent jelly.

Fig. 4 c. Single filaments with immature spores, magnified 260 diameters.

Fig. 4 6. The base of a filament, showing the nearly matured spore, and empty cells situated
beyond it.

Fig. 5. Chlorococc'us of undetermined species.

Fig. 5 a. The motile state.

Fig. 5 b. The condition of the plant after having lost its cilia and commenced its quiescent
life.

Figs. 5 and 5 c. Different stages in this life after division.

Fig. 5 d. The Hxmatococcus or resting condition, the form assumed by the plant during slow
desiccation.

Fig. 6. Nostochopsis lobatus, Wood.

Fig. 6 a. Part of a section, from within outwards, of the frond, showing the tortuous branched
filaments, without sheaths in the gelatinous matrix.

Fig. 66. A portion of a fertile filament with the lateral spores.
Fig. 6 c. A sterile filament.

Fig. 7. Protococcus of undetermined species.

Fig. 7 a. A cell supposed to belong to the resting or winter condition of the plant.

KXPLANATION OP THE PLATES. 255

Fig. 7 b. The first broaking-up of the contents of the large cell into a brood of cells.
Figs. 7 d ami 7 c. Different stages in the life of the latter brood-cells and their progeny.

PLATE IV.

Fig. 1. Mastiyonema fertile, Wood, a single plant (not magnified 750 diameters, as marked on
tbi- plutc).

Fig. 1 b. A hcterocyst magnified 750 diameters, also a spore cell and spore similarly amplified.

Fig. 3 o. A portion of the frond of Mastigonema scjunctum, Wood, amplified 250 diameters.
Fig. 2 b. A single filament magnified 800 diameters.

Fig. 3. A single filament of Zonotrichia mollis, Wood, enlarged 260 diameters.

Fig. 4. A section of the frond of Zonolrichia parcezonala, Wood, magnified a few diameters.

Fig. 5. The base of a filament of Dasyactis mollis, Wood.

Fig. 5 a. Section of the frond, magnified 450 diameters.

Figs. 5 b and 5 c. Young filaments; each magnified 450 diameters.

Fig. 0. Fronds of Caelosphaerium dubiitm, Wood.

PLATE V.

Fig. In. A portion of the frond of Masligonema elongatum, Wood, slightly magnified to show
tin' filaments radiating from the fragment of matter to which they are attached.
Fig. 16. A single filament magnified 4GO diameters.

Fig. 2 c. A cluster of youngish filaments of Mastigonema halos, Wood.

Fig. 26. A portion of an older filament to show the spore-like divisions of the cndochrome, miig-
nified 400 diameters.

Fig. 3. A pair of young connate filaments of Masligoihrix fibrosa, Wood, magnified 450
diameters.

Fig. So. An old filament magnified 800 diameters.

Fig. 36. A young filament with heterocyst, enlarged 450 diameters.

Fig. 3d A filament with two basal cells magnified 450 diameters.

Fig. 4 o. A portion of filament of Scytonema Ravenellii, Wood, magnified 160 diameters.
Fig. 4 6, The end of a branch magnified 450 diameters.

Figs. 5 o, 6, c, &c. Different forms of Chroococcus refraclus, Wood. Fig. 5 A is not a good
one. I was not able to express well the peculiar translucent shining tint, and the artist who copied
my drawing failed even more decidedly in simulating it ; the pink shade is altogether wrong, I
never saw any such color in the plant.

Fig. 6. Different forms of Chroococcus multicolor at us, Wood.

Fig. 6 c. Represents what was thought to be possibly a hybernating form of the species.

PLATE VI.

Fig. la. A portion of a frond of Scytonema thermale, Ktr., magnified 260 diameters.
Fig. I 6. Outline sketch, showing the form of the heterocyst, magnified 750 diameters.

Fig. 2. Trichoma or frond of Scytonema callitrichoides, Ktz., amplified 250 diameters.

Fig. 3 a. Outline sketch showing the cells or chambers of Scytonema dubium, Wood, magnified
750 diameters.

Figs. 3 6 and 3 c. Portions of the filaments or tricboma, magnified 460 diameters.

256 EXPLANATION OF Til E PLATES.

Figs. 4 and 4 b. Scytonema cortex, Wood. Portions of filaments, magnified 750 diameters.

Fig. 5. Piece of a small twig with a well-formed and also a very young frond of Chsetophora
elegans, Ag., growing upon it, magnified a few diameters.

PLATE VII

Fig. 1. A perfect tricboma of Scytonema cataractum, Wood.
Fig. 16. A terminal part of a filament, magnified 250 diameters.

Fig. 2 a. A portion of a filament of Scytonema immemum, Wood, magnified 750 diameters.
Fig. 2 b. Nearly a whole filament or trichoma, amplified 260 diameters.

Fig. 3. Rhaphidium polymorphum, Wood, different forms, magnified 750 diameters.

Fig. 4. Protococcus of undetermined species.

Fig. 4 a. The largest and most mature form, probably the hibernating or Winter cell.
Fig. 4 b. The same, commencing its active life.

Fig. 4 d. Colony cells believed to have been developed out of the cell represented by fig. 4 6,
magnified 750 diameters.

Figs. 4 and 4 c. The motile state of the species.

PLATE VIII.

Fig. 1 b. Portion of the frond of Tolypothrix distorta (Miiller), magnified 500 diameters.
Frg. 1 a. Heterocysts magnified 800 diameters.

Fig. 2. Portion of a frond of Sirosiphon pellucidulus, Wood, magnified 260 diameters.
Fig. 2 a. End of the branch.

Fig. 3. Portion of a frond of Sirosiphon compactus (Ag.), magnified 260 diameters.

Fig. 3 a. End of a filament, magnified 160 diameters.

Fig. 3 c. Portion of a filament showing the heterocyst magnified 460 diameters.

Fig. 4. Portion of a frond of Sirosiphon neglectus, Wood.

Fig. 5. Frond of Sirosiphon guttula, Wood.

Fig. 5 b. End of a branch, magnified 460 diameters.

Fig. 6. Portion of a frond of Scytonema Nsegelii, Ktz.

Fig. 7. Different forms of Qlceocapsa sparsa, Wood, magnified 700 diameters.

Fig. 8. Merismopedia nova, Wood, magnified 400 diameters.

PLATE IX.

Fig. 1. Fragment of a frond of Sirosiphon scylenematoides, Wood.

Figs. 2 and 2 c. Portions of fronds of Sirosiphon lignicola, Wood, magnified 260 diameters.
Fig. 2. The end of a branch of the same, magnified 460 diameters.

Fig. 3 a Portion of a very old frond of Sirosiphon argillaceus, Wood, magnified 460 diameters.
Fig 3 b. A terminal branch of a growing frond of the same.

Fig. 4 a. A frond of Stigonema RaveneMi, Berkeley, magnified 125 diameters ; also a fragment
of the same plant, magnified 450 diameters.

K X I' I. A N A T 1 <> N O F T II F PLATES. 257

PLATE X.

Fig. 1 a. A frond of ,s'/rox//./i»n j'uldnalus, Brib., var. paw/*, from a specimen collected by
Ih. .1. (I. Hunt, near rhiluili-l|ihia. The (T round color of this figure is too yellow.
Fig. 16. A fragment of the same, magnified 4CO diameters.

Fijr. '2. A row of colls of Pleurococcun gerialun, Wood, magnified 460 diameters.

Fig. So. A portion of the old external part of a mass of Palmclla Jessenii, Wood, magnified 750
diameters.

Fig. .'! l>. \ fragment from the interior of such a mass of the same amplification.

Fig. 3 c. A portion of the soft jelly of a young actively growing muss, magnified 750 diameters.

Fig. 4. A frond of Dictyosphserium pulchellum, Wood, magnified 460 diameters. I at first
referred this plant to the genus BOTBYOCOOCUS, and distributed some specimens under that generic title,
and so marked my original drawing.

Fig. ft. A slice of a youngish frond of Palmella dura, Wood, magnified 460 diameters.
Fig. .ri /-. A fragment from an old frond, showing the spores in various stages of growth. The
color of the large spores is not nearly dark enough, it should be much more brownish.

PLATE XI.

Fig. 1. Different forms of Scenesdesmus polymorphic, Wood, magnified 450 diameters.
Fig. 2. Scenedftmtu quadricauda, Breb., magnified 750 diameters.
Fig. 3. Scenedesmus rotundalus, Wood, magnified 750 diameters.

Fiir. 4. Ordinary vegetative cells of Falmogitra clepttydra, Wood, in different stages or con-
ditions of life-history, magnified 750 diameters. Those cells which have the cndochronic much
broken up are believed to be preparing for conjugation.

Fig. 4 a. A pair of cells uniting in conjugation.

Fiir. 4 6. Cells which have united so that the young spore is very apparent with the empty semi-
cells of the parents attached to it

Fiji. 4 c. A more advanced spore and empty semi-cells.

Figs. 4 d and 4 e. Matured or nearly matured spores, as seen with different focussing; in Ihe
first the upper surface of the spore is especially brought out. All these figures, except 4 b, are
magnified 750 diameters.

Figs. 5 and 5 a. Different forms of Closlerium acerosum (Scbr), magnified 250 diameters.
Fig. 5 6. Empty conjugating cells with nearly matured spore.

Fig. 6. Outline of Closlerium areolalum, Wood, magnified 160 diameters.
Fig. 6 a. End of a dead, empty frond, enlarged 1375 diameters.

Fig. 7. Outline of Closterium Venus, Ktz., magnified 450 diameters.
(These last three species are incorrectly labelled on the plate, Cosmarium.)

PLATE XII.

Fig. 1. Closlerium lincatum, Ehrb. (Incorrectly labelled on the plate Cosmarium.) Magni-
fied ICO diameters.

Fig. 2. Closlerium Ehrenberyii, Menegh., magnified 160 diameters.
Fig. 3. Closte.rium rostratum, Ehrb., magnified 260 diameters.
Fig. 4. Closterium Dianse, Ehrb., magnified 260 diameters.

Fijr. ft. riimfrriiim jwrrulum, Nieg., magnified 450 diameters.
33 October. 1872.

258 EXPLANATION OF THE PLATES.

Fig. 6. Closterium Leibleinii, Ktz., magnified 260 diameters.

Fig. 7. Tetmemorus giganteus, Wood., magnified 260 diameters.

Fig. 8. Tetmemorus granulatus (Breb.), magnified 450 diameters.

Fig. 9. Pleuroteenium Trabecula (Ehrb.), magnified 160 diameters.

Fig. 10. Spirotsenia bryophila (Breb.).

Fig. 11. Spirotaenia condensata, Breb.

Fig. 12. JSyalotheca dissiliens, Breb.

Fig. 13. Didymoprium Orevillii, Ktz.

Fig. 13 a. End view.

Fig. 14. Cosmarium Botrytis (Bory.), magnified 460 diameters.

Fig. 15. Cosmarium Cucumis, Corda.

Fig. 15 d. A frond in which the neck or isthmus has begun to elongate previous to division.
Fig. 15 b. An abnormal frond which has attempted division, but in which the inner senucells of
the new frond have failed to form perfectly and to separate.
Fig. 16. Euastrum multilobatum, Wood ; front view.
Fig. 17. Micrasterias Americana (Ehrb.).

Fig. 18. Cosmarium Meneghenii, Breb., magnified 750 diameters. The sinus should be very
narrow but distinct, instead of being absent as in the figure.

Fig. 19. Spirogyra Weberi, Ktz., portions of conjugating filaments, magnified 260 diameters.

Fig. 19 a. A portion of a sterile filament, magnified 160 diameters.

Fig. 19 6. Conjugating cells with nearly mature spores, magnified 260 diameters.

Fig. 20. Closterium juncidum, Ralfs., magnified 260 diameters.

Fig. 21. Cosmarium margaritiferum (Turp.), magnified 460 diameters.

PLATE XIII.

Fig. 1. Front view of Euastrum Ealfsii, Rabenh., magnified 450 diameters.

Fig. 2. Front of Euastrum elegans, Breb., enlarged 750 diameters.

Fig. 3. Front view of Euastrum binale (Turp.), magnified 750 diameters.

Fig. 4. Front view of Micrastejria dispulata, Wood, drawn from a Philadelphia specimen.

Fig. 4 a. The same after a figure drawn by Dr. Jos. Leidy, from a Newport specimen.

Fig. 5. Micrasterias furcata, Agardh., front view, magnified 260 diameters.

Fig. 6. Front view of Micrasterias denticulata, Breb., magnified 260 diameters.

Fig. 7. Micrasteria Jenneri, Ralfs. Front view.

Fig. 8. Staurastrum orbiculare (Ehrb.). Front view.

Fig. 9. Staurastrum dejectum, Breb. Front view, magnified 750 diameters.

Fig. 10. Staurastrum punctulatum, Breb. Front view.
Fig. 10 a. View from the apex.

Fig. 11. Front view of Staurastrum Lewisii, Wood, magnified 750 diameters.
Fig. 12. Front view of Staurastrum polytrichum, Perty.

Fig. 13 a. Front view of Staurastrum munitum, Wood.
Fig. 13 b. End view of the same.

Fig. 14. Cosmarium pyramidalum, Brebisson. Front view.

KX P LA NATION O F T II E P L A T E S. 259

Fig. 15. Cosmaritim Hroomei, Thw. Front view, mairiiilinl 4GO diameters.
Fig. lt>. Cwmuriinn cnmmiissurale, lln li. Front view, magnified 7 f>0 diameters.
Fig. IT. Xuiit/itiltuni annul um. Ureli. Front view, luagniQed 2CO diameters.

PLATE XIV.

Fig. 1. A sterile cell of Rhynchonema clongatum, Wood, magnified 450 diameters.
Fig. 1 a. Portiuu of a liluuieiit coutaiuing a fertile cull, with tin- sport) nearly matured, amplified
450 diameters.

Fig. 2. A filament of Jlhym-honema pulchellum, Wood, containing both fertile and sterile cells,
magnified 2(10 diameters.

Fig. 3. The ripened spore of Spirogyra protecla, Wood, magnified 450 diameters.

Fig. 3 a. Outline of conjugating filaments, and figure of a sterile filament, enlarged 250 diameters.

Fig. 4. Sterile cells of Spirogyra longala (Vauch.), magnified 250 diameters.
Fig. 4 a. Fertile filaments, magnified 2GO diameters.

Fig. 5. A filament of Aphanocheete repen«,Wood, which has lost its cilia, magnified 4GO diameters.

Fig. (i. A fertile branch of Drapamaldia Billingsii, Wood, showing the chains of spores, mag-
nified 4i;o diameters.

PLATE XV.

Fig. 1. Portion of a filament of Spirogyra majugcula, Ktz., containing cells with mature spores
and others just commencing the process of conjugation.

Fig. 2. A portion of a sterile filament of Spirogyra diluta, Wood, magnified 125 diameters, also
the outline of a pair of conjugating filaments of the same amplification.

Fig. 2 b. Conjugating filaments of Spirogyra diluta, Wood, magnified 125 diameters.

!•'••_'. 3 a. Portion of a sterile filament of Spirogyra setiformis (lloth) Ktz., magnified 125
diameters.

Fig. 3 b. Conjugating filaments of the same species, similarly amplified.

Fig. 4 a. Cells of Spirogyra crassa, Ktz., preparing for conjugation.

Fig. 4 c. Conjugating cells of the same plant in the first stage of nnion.

Fig. 4 b. Conjugating cells containing nearly matured zygosjwres, enlarged 125 diameters.

Fig. 5. Filaments of JHesocarpwt scalaris, Ilassall, commencing the process of conjugation, mag-
nified 125 diameters.

Fig. 6. Sterile cells of Spirogyra insignia (Ilassall) Ktz.
Fig. 6 6. Conjugating filaments of the same species.

Fig. 7. Conjugating filaments of Spirogyra parvispora, Wood, containing nearly matured
spores, magnified 125 diameters.

Fig. 8. Portion of an ordinary sterile filament of Zygnema insigne (Ilassall) Ktz.
Fig. 8 a. Fertile filaments of the same, magnified 250 diameters.

Fig. 8 6. Sterile filament in which multiplication of the species is taking place by the separation
of the cells, magnified 260 diameters.

PLATE XVI.

Fig. 1 o. Cells of Sirogonium relroversum, Wood, just commencing the process of conjugation.

Fig. 1 6. Sterile cells.

Figs. 1 d and 1 e. Outlines of fertile cells ; all of these figures are magnified 260 diameters.

260 EXPLANATION OF THE PLATES.

Fig. 2. A matured froud of Hydrogaslrum yranulatum (Linu.), enlarged 90 diameters.

Fig. 2 a. A resting spore of the same, enlarged ICO diameters ; also a minute, very young frond,
magnified 90 diameters.

Fig. 4. A branch of a Stigeoclonium, emitting zoospores, enlarged 4GO diameters.

Fig. 5. Bulbotrichia albida, Wood, magnified 460 diameters.

Fig. 6 a. A fertile branch of Bulbochaete Ccmbyii, Wood, showing the matured spore, magnified
2(50 diameters.

Fig. 66. A young plant.

Fig. 6 c. A branch with young male plants, and a forming zoosporangium, magnified 260
diameters.

Fig. 6 d. The empty cup left after the discharge of the oospore.

Fig. 6 e. Outline of sporangium.

Fig. 9. A young plant of Stigeoclonium.

The globular figures in the lower part of the plate are separate cells of Porphrydium magnificum,
Wood, magnified 760 diameters. The numbering of the figures at the bottom of the plate are
wrong, fig. 3 should read fig. 4, 4, 5, &c.

PLATE XVII.

Fig. 1 a. The basal portion of an old frond of Sohizomeris Leibleinii, Ktz., ? magnified 120
diameters.

Fig. 16. A filament emitting zoospores, magnified 250 diameters.

Fig. I c. A perfected zoospore.

Figs. 1 d, 1 e, 1 c. Young plants formed by the germination of the zoospore, magnified 450
diameters.

Fig. 2 a. The distal end of a filament of (Edogo>.iium Huntii, Wood.

Fig. 2 6. Cells showing the formation and growth of a new cell.

Fig. 2 c. A portion of filament containing spores in different conditions of maturity.

Fig. 2 d. A young female plant with attached dwarf plant.

Fig. 2f. Cells emitting a zoospore, magnified 250 diameters.

Fig. 2 g. The perfected zoospore.

Fig. 2 h. Outline sketch of a young male plant, magnified about 1200 diameters. The arrows

are meant to represent cyclotic currents.

Fig. 3. A fertile filament of (Edogonium multispora, Wood, showing spores in different states of
maturity, and dwarf male plants.

Fig. 4 e. Sterile cells of Spirogyra dubia, Ktz., enlarged 260 diameters.

Figs. 4 and 4 d. Outline sketches of cells containing spores, magnified 260 and 160 respectively.

Figs. 5 a and 5 b. Sterile cells of Spirogyra rivularis (Hassall), magnified 260 diameters.
Fig. 5 c. Outline sketch of conjugating cells with spore similarly amplified

PLATE XVIII.

Fig. 1 a. A young female plant of Pringsheimia insequale, Wood, magnified 250 diameters.

Fig. 1 b. A portion of an adult female plant, containing immature spores, and showing in out-
line in the upper sporangium the orifice through which the spermatozoa enter, magnified 250 dia-
meters.

Fig. 1 c. The supposed young male plant, magnified 450 diameters.

Fig. 2. (Edogonium mirabile, Wood. A portion of a filament with a partially matured spore.

I \ I' I . A N A T I 0 N OP T II K P L A T K S. 261

Fig. - "• -V portion of a female plant, .showing the beginning of the development of the fcmulo
gi-rin, i. <• the formation of u very large coll.

Fig. '2 l>- A further stage of the process, showing the cell divided into au upper and lower por-
tion, with the outline of the attached male plant.

Fig 2 o. A fertile filament containing u matured spore. All of these figures are magnified ICO
diameters.

Fig. -2 d. A couple of cells, one of which lias divided into four daughter-cells, each of which
contains u nearly perfected andm-pore, magnified -ir.i) diameters.

Figs. 2 6 and 2 <j. Different views of dwarf male plants discharging spermatozoids, the first figure
offering a profile view of the cap, the second a view from behind, magnified 400 diameters.

Fig. -2 e. A three-celled dwarf male plant, magnified 4CO diameters.

Fig. 3. Matured spore of (Edogonium echinatum, Wood, uncolored and magnified 750 diameters.

Fig. 4. Spores in sporangia of a Florida (Edogonium of undetermined species.

Fig. 5. Jinlbockxte ignola, Wood.

Fig. 5 a. Branches of a frond, showing different stages in the early development of the female
germs.

Fig. 5 6. Sporangium containing a nearly matured spore. All magnified 400 diameters.

Fig. 6 a. Part of a frond of Dulbochede dumosa, Wood, with female jrerms and dwarf male plants
in iliflVrcnt stages of development, magnified 2GO diameters. The fine markings on the spores have
not been reproduced in the chronio-lithograph from my drawing.

Fig. 6 6. Male plant discharging spermatozoid, magnified 750 diameters.

Fig 7 i. Part of a sterile filament of a Conferva of unknown species.

Fig. 7 6. The same discharging zoosporcs.

Fig. 7 c. A cluster of germinating zoospores.

Fig. 7. A young plant. All these figures are magnified 500 diameters.

PLATE XIX.

Fig. 1. Sligeoclonium, showing chtctophoroidal stage.

2. Portion of a fertile filament of Chantransia expama, Wood, magnified 125 diameters.
Fig. 26. A fragment of a fertile branch, magnified 2CO diameters.

Fig. 3. A portion of a fertile filament of Chanlransia macrospora, Wood, magnified 460
diameters.

Fig. 4 a. Outline of some fertile cells of Spiroyyra quinina, Ag.
Fig. 4 b. Filaments in an advanced stage of conjugation.
Figs. 4 c and 4 e. Fragments of sterile filaments.

PLATE XX.

Fig. 1. Stigeoclonium, found near Philadelphia.

Fig. 2. Arthrodesmus quadridens, Wood, as viewed from the end, and magnified 259 diameters,
also a front view of similar amplification.

Figs. 3 and 3 a. Different forms of fructification of Vaucheria polymorjjha, Wood, showing the
emptied antbcridia and fertile sporangium.
Fig. 3 ft. An immature antheridium.
Fig. 3 c. Spore of same species,

Fig. 4. Section through fertile node of Lcmanca lortilosa (Roth).

262 EXPLANATION OF THE PLATES.

Fig. 5. Outlines of Euastrum multilobatum, Wood. The lower figure represents a lateral view ;
the upper a two-thirds view.

Fig. 6. Outline of Penium digitus, Breb.

PLATE XXI.

Fig. 1. Pleurot&nium. crenulalum (Ehrb.), an outline view, magnified ICO diameters.
Fig. 2. Pleurotcenium breve, Wood, the empty dead frond, magnified 750 diameters.

Fig. 3. Tetmemorus Brebissonii (Mengh.), an empty semicell.
Fig. 3 a. Outline of a whole frond.

Fig. 4 b. Closterium lineatum (Ehrb.), an empty semicell, magnified 2CO diameters.

Fig. 5. Cosmarium Botrytis (Bory), an empty frond, magnified 750 diameters.
Figs. 5 a and 5 b. Outlines of semicells to show the variety of form.

Fig. 6. Cosmarium Brebissonii, Menegh., an empty frond, magnified 750 diameters and outline
of apex view.

Fig. 7 a. Cosmarium tetropthalmum (Ktz.), outline of the empty frond, magnified 4GO diame-
ters.

Fig. 8. Cosmarium margariliferum (Turp.), view of an empty semicell, magnified 750 diame-
ters; the outline of this should be more regular.

Fig. 9. Cosmarium suborbiculare, Wood, an empty frond, magnified 750 diameters.

Fig. 9 a. An outline of end view of similar amplification.

Fig. 10. Cosmarium Broomei, Thw., lateral outline of the frond.

Fig. 1 1. Micrasterias Jennerii, Ralfs, an empty semicell.

Fig. 12. Euastrum ornatum, Wood, front view, magnified 450 diameters.
Fig. 12 a. Lateral view.

Fig. 13. Euastrum Didella, Turpin, outline of the front view.

Fig. 14. Euastrum elegans, Breb., outline of the lateral view.

Fig. 15. Micrasterias truncala, Corda, outline of front view, magnified 2CO diameters.

Fig. 16. Micrasterias granulata, Wood, front view of an empty frond, magnified 460 diameters.

Fig. 17. Staurastrum orbiculare, Ehrb., outline of the end view.

Fig. 18. Staurastrum dejectum, Breb., outline of the end view, magnified 750 diameters.

Fig. 19. Staurastrum Lewisii, Wood, outline of the end view, magnified 750 diameters.

Fig. 20. Staurastrum paradoxicum, Mey., outline of end view.

Fig. 21. The five radiate figure is an end view of Staurastrum Arachne, Ralfs, the triradiate of
Staurastrum paradoxum, Meyen, magnified 750 diameters.

Fig. 22. Staurastrum Ravenellii, Wood, Front view of the empty frond, magnified 460 diameters
Fig. 22 a. The side view of an empty semicell, magnified 750 diameters.
Fig. 22 6. The end view with the same amplification.

Fig. 23. Slaurastrum Polytrichum, Perty, outline of the frond as seen from the end.

FRESH WATER ALG*

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FRESH W»T£R ALG>€

PUTE II

— 1

•I 1 CYLINOPOSPEMMUM

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. NOSTOC COMMINUTUM

Fi| II C COMATUM
* » R'VULARIA CAR1ILAGINEA

' ., « AN«R<CNA HLATINOM

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PLATE Ml.

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F,g 3. S POLVSPERMA
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Fig. ». CMLOROCOCCW • ', ;,. • '- • -
- «. HOSTOCMOPSIS LOBATUS
" 7. PROTOCOCCUS.

FRESH WATER ALG-t

PLATE IV.

W» • A'

.<*'•'•• . fi '•'•&
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v y..%» i

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F.|. 1. MASTIGONEM* FERTILE.
- 1 MAST1GONEMA SEJUNCTUM

F.( 3 ZONOTRICHA MOLL'S
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fig. 6. OASVACTIS MOLL'S.
* t CCXLOSPH/CRIUM DUBIUM.

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PLATE v.

• ' MB* •* D* H c WOOO

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- X. MASTIGONEM* HALOS.

Flf. 3. MASTIGOTHRIX FI8ROSA.

- 4. SCYTONEMA RAVENELH.

- ». CMROOCOCCUS REFRACTUS.

Fig. 6. CHROOCOCCUS MULTICOLOR-
ATUS.

FRESH WATER ALG>€

PLATE VI.

A'tCA *A7UNC »v OH M C WOOO

Fig I. SCVTONEMA THCMMALE.
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-IS. DUBIUM

Fig. 4. s. CORTKX.. : ;-. : :

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f ?••

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PLATE VII

Tla MtTUKf *v D4I M. c. VOOO

f.f 1. SCYTONEMA CATARACTUM
- t. SCYTONEMA IMMERSUM

3. RHAPHIDIUM PO

4. PROTOCOCCUS

e »

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PLATfc VIII.

»««tUM *1 00 M C WOOD

f>t I. TOLYPOTMRIX DISTORT*

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• *. SIROSIPHON COMPACTUM.

Fig. 4. SIROSIPHON NEGLECTUM
" I. SIROSIPHON GUTTULA.
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Fif. 7. GLOEOCAPSA SPARSA.
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PUTE IX.

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- t PLEOROCOCCUS SERI»TUS

Fi( -X. PALMCLLA JESSEMII.

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PLATE II.

. I. SCENEOESMUS fOLYMORPHUS.
t. SCENEOESMUS QUAORICAUOA.

Fi«. S SCENEOESMUS ROTUNOATUS
4 PALMOQLOEA CLEPSYDRA
S. COSMARIUM ACEROSUM

F>( «. COSMARIUM AREOLATUM.
•• 7. COSMARIUM VENUS. .

tSH WATER ALG/f

PLATE XII

-000

^L COSMAKIUM LiNCATUM Fig ( C LElBLEINII.

•JBLHGl: : CTMEMORUS

JM • t 'MEMOHUS QRANULATUS

</€ '• t PLEUROT/CNIUM TRABECULA

PAHVULUM spiROT/tNiA BUYO^

'. .• : '-;.ic. JJi«. ••••

II. SP1ROT/€NIA CONOENSATA
MYALOTHECA OISSILIENS
DIOYMOPRIUM GREVILLM
I COSMARIUM BOTRYTIS
UCUMIS

JriCiHf *»\i'-

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- Zl C MAAGARITI'tRUM.

PLATE XIII

.100

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PLATE XIV.

•I •' 0* M c WOOD

- -

F I 1. RHYNCHONEMA ELONGATUM
' '1. RMVNCHONEMA PULCHELLUM.

Fig. .1 SPIROGVRA PROTECTA.
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. 5. APHANOCHAETE REPENS.
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; fc • • • « fc t .;

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PLATE XV.

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t MM4M.AI* • •«•.

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4. SPIROGYRA CRASSA

» MtSOCARPUS SCALARIS

F.g e SPIROGYRA NHSIGNIS.
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FRESH WATER ALG*

PLATE XVI

Fif. 1 SIROGONIUM RETROVERSUM.

* L HYDROGASTRUM GRANULATUM.

- 3 STIQEOCLONIUM.

r.g.4.

•• 6. BULBOCH^TE CANBYll.
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FfUSH WATER ALG>£

PLATE XVII

• • •• DM

Fig. I. SCHIZOMCRIS LEIBLEINII.

- S. OEOOSONIUM HUNTII

- 1. O. MULTISPORA

Fig. 4. SP1ROGYRA OUBIA
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FRtSH WATER ALG*

PLATE XVIII.

•»'!• -.TU., ., .„ „ c VOOD

Fi( 1. PRINGSHEIMII INAEQUALC.

" 1 OEDOGONIUM MIRABILE.

* ». OEOOGONIUM ECHINATUM

• * OCDOOONIUM.

Fig. & BULBOCM/CTE IGMOTA.
- • BULBOCH/CTS DUMOSA
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FRESH WATER ALG/C

PUTE XIX

*«Tu«t •» on « c wooo

Fig I. STIGEOCLONIUM

: CHANTRANSIA EXPANSA

Fig *. CHANTRANSIA MACROSPORA
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SH WATER ALG/t

PUTE

c ' l STIGEOCLONIUM

: AHTHROLESMUb QUAORIOENS

Fi( .1 VAUCMCRI* POLYMORPMt
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FRESH WATER ALG*

PLATE XXI

' I 1 PLEUROTCZNIUM CRENULA

run

' 1 PLEUROTCENIUM BREVE

• & TETMEMORUS BR^BISSONII

1 «. CLOSTERIUM LINEATUM

' t CCKMARIUM BOTRVTIS

F,(. «. COSMARIUM mfrlMONM. > Ft* IU COSMARIUM BROOMEI

• 7. COSMARIUM TETRAOPTMAL i - ji. MICRASTERIASJENNERM

MUM.

I. COSMARIUM M'RGARlTiff.
RUM

I? EUASTRUM ORNATUM

- III. E DIOELTA

- 14. E ELESANS.

Fif If. STAURASTRUM ORBlCU

LARE

* 11. ST. DEJECTUM

• 1». ST LEWSH.

- JO ST PARADOXICUM.
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*. COSMARIUM SUBORBICU " IS MICRASTFRIAS TRUNCATA

LARE ' " 16 MlCRAiTfRIAS &RANUIATA. ' •• .-? i 1 RAVENEILH

" 23 ST POLYTHICHUM.

14 DAY USE

RETURN TO DESK FROM WHICH BORROWED

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