IOWA ACADEMY OF SCIENCES. 
23 
Three species of Oedogonium have been collected in the 
two localities, but the specific names are reserved for 
further study. Draparnauldia plumosa (Ysiuch.) Ag. is fre- 
quent at Grinnell and at Fayette, and Chaetomorpha pisi- 
formis (Roth.) Ag. and Chaetomorpha cornudamae (Roth) Ag., 
occur at Fayette, the last species being new to the state. A 
species of Stigeoclonium was kept in the college aquarium 
at Fayette for two years. The plant failed to produce 
the zoogonidia, but in all respects the vegetative structure 
agreed with Stigeoclonium nanum (Dillw.) Kg., a plant not 
previously reported from Iowa. The same species has been 
found clinging to the limestone riprap in Arbor lake at 
Grinnell, and another form has also been found in the 
lake, provisionally referred to Stigeoclonium radians Kg. 
The polymorphous Cladophora glomerata (L.) Kg. is a 
common plant in the Volga river at Fayette, var. genuina 
Kirchn. occurring on stones in rapids and the varieties 
.rivularis Rabenh. and pumila occurring in more quiet 
water. The three varieties have not been previously 
reported from Iowa. During the second summer after its 
construction (1904), the artificial Arbor lake at Grinnell 
became so filled wfith Cladophora fracta (Dillw.) Kg. as to 
interfere seriously with boating. The outing club spent 
a considerable sum in dredging without more than 
alleviating the difficulty, but in August or September the 
plant disappeared so completely that diligent collecting 
and microscopic examination of many filamentous algae 
brought to light only one or two specimens of this partic- 
ular species of Cladophora. At the present time, April 
21, 1905, there is no evidence of the plant in the lake, 
and it may well be doubted whether it will again appear 
in any considerable quantity. However, if it should, thq 
copper sulphate treatment will be tried. Cladophora 
fracta rigidula (Kg.) Rabenh. occurred with the species and 
has not been hitherto reported in Iowa. Two other 
Cladophoras were collected at Grinnell, one of which has 
been provisionally referred to Cladophora crispata (Roth.) 
Kg. " • 
