tangia; fertile cells cylindric. Zygospores ovate or elongate-ovate; 

 median spore wall smooth but with a longitudinal suture, brownish; 

 30- (38) /I in diameter, 50-(83)m long. 

 Mich. 



Spirogyra majuscula Kuetzing 1849, p. 441 

 PI. 74, Fig. 10 



Filaments of stout cells, 50-80/u, in diameter, 80-500/a long, with 

 plane end walls; chloroplasts 3-8, nearly straight or making less 

 than % turn. Conjugation by tubes from both gametangia; fertile 

 cells cylindric (sometimes slightly swollen). Zygospores lenticular 

 or spheroidal, laterally compressed; median spore wall smooth and 

 brown; 57-72/1 in diameter, 45-60^ wide. 



Mich. 



Spirogyra maxima ( Hass. ) Wittrock 1882, p. 57 



Filaments of rather stout, short-cylindric cells (118)-145-153/>i 

 in diameter, with plane end walls; chloroplasts 6-8, making Yi to % 

 turn. Conjugation scalariform by tubes from both gametangia; fertile 

 cells cylindric. Zygospores compressed-globose or lentil-shaped; 

 median spore wall finely reticulate; 100-120ja in diameter, 70-95;a 

 wide. 



In an alkaline bog lake. Mich., Wis. 



Spirogyra micropunctata Transeau 1915, p. 27 

 PL 73, Fig. 9 



Filaments of fairly stout cells, 30-33- ( 36 )/>t in diameter, 108-114- 

 (300)/x long, with plane end walls; chloroplast solitary, making 2 to 4 

 turns. Conjugation scalariform by tubes from the male gametangium 

 only; fertile cells becoming slightly inflated. Zygospores ellipsoid, 

 the poles broadly rounded; median spore wall finely and densely 

 punctate; 37-42/x in diameter, 57-70- ( 100 )/t long. 



In bogs and ditches. Mich. 



Spirogyra mirabilis ( Hass. ) Kuetzing 1849, p. 438 

 PI. 77, Fig. 1 



Filaments of slender cells, 24-26- (27) /a in diameter and up to 10 

 times the diameter in length, with plane end walls; chloroplast soli- 

 tary, making 4 to 7 turns. Conjugation by tubes from both game- 

 tangia; fertile cells inflated. Zygospores ovate to ellipsoid; median 

 spore wall smooth and brown; 24-29yu, in diameter, 50-83/1, long. 



Mich. 



[317] 



