Spirogyra Fuellebornei Schmidle 1903, p. 76 

 PL 73, Fig. 6 

 Filaments of stout cylindrical cells, 40-44/x in diameter, 120-200- 

 (240) /A long, with plane end walls; chloroplasts 3-4, making 1 to 2 

 turns. Conjugation by tubes from both gametangia; fertile cells 

 cylindric. Zygospores ellipsoid, with sharply rounded poles; median 

 spore wall smooth and brown; 32-40|a in diameter, 50-80/x long. 

 In an alkaline bog lake. Wis. 



Spirogtjra gracilis ( Hass. ) Kuetzing 1849, p. 438 



Filaments of rather stout cells, 16-24/a in diameter and up to 5 

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

 solitary, making V2 to 3 turns. Conjugation scalariform by tubes from 

 both gametangia; sporangium inflated on the conjugation side only. 

 Zygospores ellipsoid; median spore wall smooth; 27-30/a in diameter 

 and up to 60/x long. 



Mich. 



Spirogyra gratiana Transeau 1938, p. 528 

 PL 74, Fig. 9 



Filaments of elongate-cylindric cells, 28-33)it in diameter, 144-400/x 

 long, with replicate end walls; chloroplasts (2)^-(4). Conjugation 

 lateral or scalariform by tubes from both gametangia; fertile cells 

 cylindric or merely enlarged. Zygospores ellipsoid or cylindric- 

 ellipsoid; median spore wall smooth and yellow; 35-47;u, in diameter, 

 108-223/x long. 



Rock pool from north shore of Lake Superior. 



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



PL 74, Fig. 11 

 Filaments of rather slender cells, 21-25- ( 28 )/a in diameter and 

 up to 10 times the diameter in length, with replicate end walls; 

 chloroplast sohtary (rarely 2 in each cell), making 4-5 (up to 9) 

 turns. Conjugation scalariform, the tubes formed from the male 

 gametangium only; fertile cells inflated on the conjugation side. 

 Zygospores ovate; median spore wall smooth; 30-36/x in diameter 

 and up to 2V2 times the diameter in length. 

 Mich. 



Spirogyra inconstans Collins 1912, p. 74 



Filaments of rather slender cells, 30/x in diameter and up to 15 

 times the diameter in length, with replicate end walls; chloroplasts 

 3-4 (rarely only 2), making 1 to 3 turns. Conjugation scalariform 



[315] 



