Anahaena Scheremetievi Elenkin 1909, p. 125 

 PL 117, Figs. 11, 12 

 Trichomes planktonic; mostly straight, sometimes flexuous with a 

 gelatinous sheath. Cells spheroidal or barrel-shaped; with pseudo- 

 vacuoles; 8.5-9-(ll)ju, in diameter, 8-ll-(12)|u, long. Heterocysts 

 spherical, 8-10.8^ in diameter. Gonidia spherical to ellipsoid, some- 

 times angular in optical section, not adjacent to heterocysts, (18) 

 -20-22.6/x in diameter, 21-24/x long. 

 Euplankter, Wis. 



Anahaena spiroides Klebahn 1895, p. 268 



Trichomes spiral, solitary, inclosed in a thin mucilaginous sheath. 

 Cells spherical or compressed-spheroidal, 6.5-8/x in diameter. Hetero- 

 cysts spherical, slightly smaller than the vegetative cells. Gonidia 

 spherical, 14/a in diameter; adjacent to the heterocysts. 



Typical form not reported from our region, 



Anahaena spiroides var. crassa Lemmermann 1898d, p. 155 

 PL 117, Fig. 13; PL 118, Figs. 4, 5 

 Trichomes solitary, spirally twisted, planktonic. Cells spherical, 

 10-11.5/x in diameter. Heterocysts subspherical, 10/a in diameter, 12/x 

 long. Gonidia oblong; remote from the heterocysts; 19-20/x, in diam- 

 eter, 25-30;u, long. 



Plankter; in many lakes; especially abundant in late summer, 

 appearing in water blooms with A. circinalis and A. jios-aquae. Wis. 



Anahaena suhcylindrica Borge 1921, p. 12 

 PL 118, Figs. 6-8 

 Trichomes straight; solitary or forming a thin layer; adherent on 

 submerged aquatics and entangled among other algae. Cells short- 

 cylindric, 4-4.5^ in diameter, 5.5-8- ( 10 )/x long. Heterocysts cylin- 

 drical, 5-7.5-(10)ju, in diameter, 15-(18)jU, long. Gonidia cylindrical, 

 adjacent to heterocysts, 7—8.5fi in diameter, 54—57/1, long. 

 Sphagnum bogs; tychoplanktonic in soft water lakes. Wis. 



Anahaena torulosa ( Carm. ) Lagerheim 1883, p. 47 



Filaments somewhat straight or irregularly bent (not coiled); 

 forming sparsely clustered flakes. Cells subspherical or barrel- 

 shaped, 4.2-5fi in diameter; the terminal cell conical. Heterocysts 

 globular, d/x in diameter, Gonidia elongate-ovate to subcylindric, 

 with smooth convex lateral walls; solitary or in a series, on either 

 side of the heterocyst; 7-12/i, in diameter, 18-28/i, long. 



Mich, 



[518] 



