1905] Collins, — Chlorochytrium Lemnae in America 97 
shaded bank at White Lake. Mr. B. D. Gilbert and the writer found 
a single plant on the Whitestown bluffs, in October, 1902, the station 
recorded for Microstylis, and it is of interest to note that Mr. Gilbert 
(Fern Bull. xii..gg) records this Botrychium from Lewis County. 
(To be continued.) 
CHLOROCHYTRIUM LEMNAE IN AMERICA. 
FRANK S. COLLINS. 
PLANTS of the genus Chlorochytrium are of interest from their 
peculiar habitat and their special adaptations to the same. They 
are unicellular algae, and live in the tissues of higher, or at any rate 
larger organisms ; not really as parasites, as they have well developed 
chromatophores and can assimilate their own nourishment; nor does 
it appear to be a case of symbiosis, as it is not easy to see what 
advantage their presence is to the host plants. Another point of 
interest is that Chlorochytrium is one of the relatively few genera 
represented both in salt and in fresh water; of the salt water forms 
three are known as American; C. inclusum Kjellm., in red algae at 
Greenland and from Alaska to Washington; the development of this 
species has been studied by Freeman!; C. dermatocolax Reinke, in 
Chaetopteris and Sphacelaria in Greenland ; and C. Schmitsii Rosenv., 
in various loose tissued algae from Greenland to Maine. C. Cohnii 
Wright is found in EzeromorpAa and some other algae, and in the 
gelatinous sheaths of such diatoms as Schizonema, along the New 
England coast; but this is now usually put in another genus, as 
Chlorocystis Cohnii (Wright) Reinhard. This species has been 
studied by Moore,? and the development well worked out. 
Of the fresh water species the best known is C. Zemnae Cohn, 
which appears to be generally distributed in Europe, and whose 
development is quite well known. The host plant is Zemna trisulca 
1E. M. Freeman, Observations on Chlorochytrium ; Minn. Bot. Studies, Vol. 
II, p. 195. 1899. 
? G. T. Moore, New or little known unicellular algae. I. Chlorocystis Cohnii; 
Bot. Gazette, Vol. XXX, p. 100, 1900. 
