96 FRESH-WATER ALGJE OF THE UNITED STATES. 



The following arrangement of our United States species is 

 near in accord with Prof. Wittrock's suggestion. 



BULBOCHAETE. 



SECTION I. OOGONIA GLOBOSE OR STJBGLOBOSE, 



PATENT. 



OOSPORES THE SAME FORM AND FILLING THE OOGONIA. 



DICECIOUS. 



A. Dwarf males unicellular. 

 B. elacMstandra, Wittr. 



B. Dwarf males bicellular. 

 a. Basal cell of the dwarf males shorter than the spermogonia. 



B. intermedia, I). By. 

 B. crenulata, Pringsh. 

 B. polyandra, Cleve. 

 B. setigera, (Roth.) Ag. 

 B. Brebissonii, Kg. 



b. Basal cell of the dwarf males longer than the spermogonia. 



B. gigantea, Pringsh. 



SECTION II. -OOGONIA ELLIPSOID OB SUBELLIPSOID. 



OOSPORES OF THE SAME FORM, FILLING THE OOGONIA ; 



EPISPORE LONGITUDINALLY COSTATE ; COSTJE 



MORE OR LESS CRENULATE. 



SUBSECTION I. SPECIES MONOECIOUS. 



B. mirabilis, Wittr. 

 B. nana, Wittr. 



SUBSECTION II. SPECIES DICECIOUS. 



A. Dissepiment of supporting cells obsolete. 

 B. pigmaea, (Pringsh.) Wittr. 



B. Dissepiment of supporting cells present. 



B. insigiiis, Pringsh. 



B. minor, A. Br. 



B. subsimplex, Wittr. 



B. repanda, Wittr. 



B. rectangularis, Wittr. 



B. rhadinospora, Wittr. 



