Anabaena unispora Gardner 1927, p. 59 

 PL 131, Fig. 5 



Filaments straight or slightly curved, mostly solitary. Cells rec- 

 tangular, 2-4 times longer than wide; 4r-5fji in diameter, 11-20/i, long; 

 slightly constricted at the cross walls. Heterocysts elongate-ovate or 

 subcylindric, 6ju, in diameter, ll/t long. Gonidia solitary; developing 

 near the middle of the filament and close to the heterocyst; elongate- 

 ovate, the margins subparallel or slightly convex; 11-15)U, in diameter, 

 31-35/i long. 



Mich. 



Anabaena variabilis Kuetzing 1843, p. 210 

 PI. 118, Figs. 9, 10 

 Trichomes entangled in a gelatinous plant mass, on damp soil, or 

 floating entangled among other algae. Cells compressed-globose, 

 3.7-4-(6.5)^ in diameter. Heterocysts globular or ovate; 5.5-5.8- 

 {8)fim diameter, 5.8-6.5;u, long. Gonidia ovate; in series; remote from 

 the heterocysts; 6.8-9/x in diameter, 7.5-8.2- ( 14 )yLi long. 



In seeps and ditches. Mich., Wis. 



Anabaena verrucosa Boye-Petersen 1923, p. 299 

 PI. 118, Figs. 11, 12 

 Trichomes straight, parallel, with a wide gelatinous sheath; grow- 

 ing on and adherent to other filamentous algae. Cells short- cylindric, 

 3.3-4/A in diameter, 3.3-6-(8)/a long. Heterocysts cylindrical, 3.6/x 

 in diameter, 5/a long. Gonidia cylindrical; remote from the hetero- 

 cysts; 4— 7(U, in diameter, (10.5)-12-(15)/x long. 



Tychoplankter. Wis. 



? Anabaena Viguieri Denis & Fremy 1923, p. 122 

 PI. 119, Figs. 1-3 



Trichomes planktonic; straight. Cells barrel-shaped to short- 

 cylindric; 7-7.8/a in diameter, (4)-9-10;u, long; with pseudovacuoles. 

 Heterocysts globose to subglobose; 7.6/x, in diameter and up to 9/x 

 long; smaller than the vegetative cells. Gonidia broadly ovate; 

 12-14-(15)/x in diameter, 17-18.5/x. long; solitary or in 2's; not ad- 

 jacent to the heterocyst. 



This interesting plant was found in but one collection made in 

 our area. It agrees in most respects with the description of A. 

 Viguieri, but the cells are slightly longer, 



Euplankter. Wis. 



[5191 



