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IOWA ACADEMY OF SCIENCE 
121 . 
122 . 
123. 
12b. 
125. 
126. 
127. 
128. 
129. 
130. 
s. 
dubia Kuetz. 
Iowa City. 
Hobby. 
s. 
fluviatilis. Hilse. 
Iowa City. 
Hobby. 
s. 
tenuissima Kuetz. 
Eagle Grove. 
Slough, amid 
Utricularia. 
s. 
inflata Rabenh. 
Iowa City. 
Hobby. 
s. 
weberi Kuetz. 
Iowa City. 
Hobby. 
s. 
laxa Kuetz. 
Iowa City. 
Hobby. 
s. 
grevilleana Kuetz. 
Iowa City. 
Hobby. 
Eagle Grove. Floating in Hewitt’s Pond. 
S. quadrata Petit. 
Ames. Buchanan. 
Eagle Grove. Buchanan. 
insignis Kuetz. 
Buchanan. 
Buchanan. 
Iowa City. Hobby. 
5. calospora Cleve. (S. protecta). 
Ames. Bessey. 
Eagle Grove. Jenning’s Pond. Buchanan. 
Family II. 
Desmidiaceae. 
KEY TO THE SUBFAMILIES. 
Cell wall unsegmented. Point of division of cells indefinite, and un- 
known previous to the actual division I. Sacodermae 
Cell wall segmented. . Cell division of a fixed type, with interpolation of 
the younger halves between the old ones II. Placodermae 
Subfamily I. 
Saccodermae. 
1. Sjnrotaenia. 
131. S. condensata Breb. 
Eagle Grove. Slough. Buchanan. 
Subfamily II. 
Placodermae. 
KEY TO THE TRIBES. 
Cells of moderate length, straight, cylindrical, sometimes with a slight 
median constriction. Cell wall with or without pores. Point of division 
of cells often variable. The cell often arrives at maturity by periodical 
growth I. Penieae 
