24 
IOWA ACADEMY OF SCIENCES. 
One or two species of Ulothrix and several of Conferva 
have been collected in the two places, but the determina- 
tions are so uncertain in the present state of knowledge of 
these genera that the specific names are omitted, except 
Conferva (Microspora) vulgaris (Rab.) Wolle and Conferva 
{Microspora) amoena Kg., which have been identified at 
both places, and are new to the flora of the state: 
The Vaucherias common to both places are the common 
species, viz. Vaucheria sessilis (Vauch.) DC., Vaucheria 
geminata (Vauch.) DC., and Vaucheria terrestris Lyngb. 
These species are quite common in both localities and 
have been previously reported from Iowa. But Vaucheria 
Hass, and Vaucheria geminata racmosa (Vauch.) DC., 
found at Fayette, have not been previously reported for 
the state. 
Closely related to the Vaucherias is the cmnocytic 
Botrydium granulatum (L.) Grev. The plant has only been 
reported from the vicinity of Ames, but is common on 
damp soil everywhere in the state. It is easily found along 
ponds, lakes and streams after one has once detected the 
minute globular, greenish, whitish or reddish forms on the 
soil, commonly occurring as the first plant of the society of a 
recently formed mud flat, and later with Vaucheria terres- 
tris. The plant is an exceedingly interesting one for labora- 
tory study, readily yielding the uniciliate and the biciliate 
zoogonidia, the latter also frequently conjugating when 
they are to be regarded as zoogametes. By placing the 
plants in a tumbler of water at night, these motile bodies 
always collect on the side toward the light, and if the hab- 
itual formation of them at night is retarded by keeping 
the plants cold by the use of ice, the zoogonidia and zooga- 
metes may be studied in the forenoon. The stages of 
lateral and end-to-end conjugation may be studied readily, 
and the cilia may be brought out by killing and staining. 
The plant is especially interesting since we have here the 
very beginning of sexuality. Also, besides the conjuga- 
tion of the zoogametes, we were able at Fayette to ascer- 
tain that the cscnocytic mass sometimes, instead of form- 
