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IOWA ACADEMY OF SCIENCE 
Family VI. 
Microthamniaceae. 
No species of this family have as yet been reported from the state, though 
some probably occur. 
Family VII. 
Trentepohliaceae. 
1. Trentepohlia ( Chroolepus ) 
82. T. odorata Wittr. (umbrina). 
Fayette. Fink. 
Grinnell. Fink. 
Order III. 
Ulvales. 
No species of this order have been reported from the state. 
Order IV. 
Schizogoniales. 
No species of this order have as yet been reported from the state. 
Order V. 
Microsporales. 
Family I. 
Microsporaceae. 
1. Microspora. 
KEY TO THE SPECIES. 
Filaments large, cell wall 1.5-3 u thick M. amoena 
Filaments smaller, cell walls thin. 
Cell diameter 14-17 u M. fioccosa 
Cell diameter 7.5-9.5 u M. stagnorum 
83. M. amoena Rabenh. 
Fayette. Fink. 
Grinnell. Fink. 
8U. M. fioccosa Thur. 
Ames. College Spring. Floating. Buchanan and Holden. 
85. M. stagnorum Lagerh. 
Eagle Grove. Slough, amid bladderwort. Buchanan. 
Order VI. 
Cladophorales. 
