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IOWA ACADEMY OF SCIENCE 
Family II. 
Pithophoraceae. 
No species of this family have been reported from the state. 
Family III. 
No species of this family have been reported as yet. 
Order VII. 
Siphoneae. 
Family I. 
Vaucheriaceae. 
KEY TO THE SPECIES. 
1. Vaucheria. 
Antheridia little or not at all bent, oblong cylindric or lanceolate. 
Filaments thick +100 u., oogonia erect V. aversa 
Filaments thinner, 50-75 u. oogonia lateral V. sericea 
Antheridia bent in the form of a horn or hook. 
Oogonia sesile or nearly so, beside the antheridia on the thallus. 
Oogonia usually single, sometimes two together, globose or ellipsoid . . 
V. Dillwynii 
Oogonia usually in clusters of two or more, ovate or oblong oval 
V. sessilis 
Oogonia on a fruit branch with the antheridia above. 
Antheridia and oogonia bending in opposite planes, forming an angle 
with each other, usually two oogonia V. geminata 
Oogonia 3-10 V. geminata racemosa 
Antheridia and oogonia bending in parallel planes V. terrestris 
93. 
V. 
aversa Hass. 
Fayette. 
Fink. 
9U. 
V. 
sericea Lyngb. 
Iowa City. 
Hobby. 
95. 
V. 
dillwynii Ag. 
Iowa City. 
Hobby. 
96. 
V. 
sessilis DC. 
Iowa City. 
Hobby. 
Ames. Bessey. 
Fayette. 
Fink. 
Grinnell. 
Fink. 
Ames. Pots in Greenhouse. Buchanan. 
Eagle Grove. Hewett’s Pond. Buchanan. 
Fayette Co. Pammel. 
97. V. geminata DC. 
Iowa City. Hobby. 
Ames. Bessey. 
Fayette. Fink. 
Grinnell. Fink. 
Ames. Spring on hillside. Buchanan. 
