Microchaete Goeppertiana Kirchner in Engler & Prantl 1900, p. 76 



PI. 127, Figs. 3, 4 

 Filaments usually solitary or a few together, straight or slightly 

 curved away from the substrate to which they adhere; cells short 

 cylindric, 3.7-6/a in diameter, often slightly separated from one 

 another; heterocyst basal only, ovate or globose, 6.5/i, in diameter; 

 sheath thin and close, without lamellations; filaments 5.7 fi wide. 

 On filamentous green algae. Wis. 



Microchaete robusta Setchell & Gardner 1903, p. 194 



PL 127, Fig. 5 



Filaments solitary or several ( 4 ) radiating from a common center, 

 enlarged at the base, slightly tapering distally; cells spheroidal or 

 quadrate to slightly longer than wide, 12ju, in diameter, (6)-10-16ju, 

 long; cell contents granular at the cross walls; basal heterocyst glo- 

 bose, intercalary heterocysts quadrate; sheath thin but lamellated; 

 filament 16-18/i. wide. 



Our specimens do not show granulations at the cross walls, but 

 they have been assigned to this species on the basis of size and other 

 characteristics which are in agreement. 



On filamentous algae. Wis. 



Microchaete spiralis Ackley 1929, p. 302 

 PI. 131, Fig. 3 

 Filaments in small tufts, straight or curved, with spirally lamellose, 

 rather close, thick sheaths; vegetative cells 6-8/a in diameter, some- 

 what quadrate-cylindric at the base of the trichome, becoming 

 subglobose in the apical region; heterocysts ovate, 4— 4.5/x in diam- 

 eter, 6/i, long. 



Tychoplankter; in a roadside ditch. Mich. 



Microchaete tenera Thuret 1875, p. 378 

 PI. 127, Fig. 6 



Filaments slender, long, but not tapering, straight or little-curved, 

 either solitary or more usually in stellate tufts on larger algae, and 

 other submerged aquatics; cells quadrate, shorter or a little longer 

 than wide, 4-5/a in diameter; basal heterocysts quadrate-cylindric; 

 gonidia short-cylindric, 6.8fx in diameter, 6.8-8/i, long; arranged in 

 a basal series; sheaths thin, firm, close, without lamellations; fila- 

 ments 12-14/x in diametef. 



Common on large filamentous algae, on Utricularia, Myriophyllum, 

 etc.; usually in soft water or acid lakes. Mich., Wis. 



[542] 



