26 
IOWA ACADEMY OF SCIENCES. 
Another series of closely related species is found at both 
places. These species are Plemvcoccus vulgaris Menegh., 
Protococcus viridis kg. and T?'entepolia {Chroolepus) umhrma 
(Kuetz.) Born. Of these the last, rare outside of lichen 
thalli, is to be looked for especially on oak trees and has 
not been reported before from the state. The lichen, 
Lepra viridis Schaer,is much more common than the Pleu- 
rococcus, and appears exactly like the alga until careful 
microscopic examination reveals the fungal hyphse in 
close relation with the algal cells. Thus this lichen com- 
monly passes for Pleurococcus vulgaris. Another similar 
lichen is Amphiloma lanuginosum (Ach.) Nyl. {Pannaria 
lanuginosa Kbr.), but this shows the fungal hyphse much 
more clearly than Lepra and frequently shows definite 
form and slight lobing, so that it is not so frequently taken 
for an alga. 
A species of Tetraspora was collected at Grinnell and a 
form of Palmella at Fayette. Ehaphidium polymorphum 
Fresen. is common at both places and var. aciculare (A. 
Br.) Kabenh. has occurred at Grinnell, both forms being 
new to Iowa. Also another form found at Fayette was 
provisionally referred to Rhaphidium convolutum (Corda) 
Rabenh. 
Of the Zygnemacese, the genera Spirogyra, Zygnema 
and Mougeotia were found, Mougeotia genuflexa (Dillw.) 
Ag. was collected at Fayette, and has not been previously 
reported from Iowa. The ten Spirogyras and two 
Zygnemas are reserved for further study. 
Of the NematogenesB a number of genera and species have 
been found in the two places. Isactis fluviatilis (Rab.) 
Rirch., was once collected at Fayette on damp limestone, 
and a species of Rivularia was also collected there. The 
Isactis is new to the flora of Iowa, as is also Scytonema 
myochrous Ag., frequently found at Fayette on damp, shaded 
limestones. Nostoc commune Vauch.,*is common on wet 
soil in both localities, and Nostoc muscorum Ag., was fre- 
quent on mosses, and Nostoc pruniforme (Roth.) Ag., in 
ponds at Fayette, the last often reaching the size of a plum. 
