by tubes from both gametangia; fertile cells inflated. Zygospores 

 ellipsoid; median wall reticulate; 45-75/x in diameter and up to 

 125;u long. 

 Mich. 



Spirogyra inflata (Vauch.) Kuetzing 1843, p. 279 



Filaments of rather slender cells, 15-20/x in diameter and up to 

 8 times the diameter in length, with replicate end walls; chloroplast 

 solitary (rarely 2), making 3 to 8 turns. Conjugation scalariform by 

 tubes from both gametangia; fertile cells inflated, fusiform. Zygo- 

 spores ellipsoid; median spore wall smooth; 42-48/x in diameter and 

 up to 96/1, long. 



Mich., Wis. 



Spirogyra Juergensii Kuetzing 1845, p. 222 

 PI. 73, Figs. 7, 8 



Filaments of moderately stout, long or short cylindrical cells, 

 24-26-(30)/A in diameter, 60-125/a long, with plane end walls; chloro- 

 plast solitary, making 2 to 4 turns. Conjugation by tubes from both 

 gametangia; fertile cells cylindric. Zygospores ellipsoid; median 

 spore wall smooth and brown; 28-30-(33)/x in diameter, 40-75/a long. 



Floating mats in a marsh; in swamps and ditches. Mich. Wis. 



Spirogyra jugalis ( Fl. Dan. ) Kuetzing 1845, p. 223 



Filaments of large, stout cells, 90-100/i, in diameter, 1-1% times 

 the diameter in length, with plane end walls; chloroplasts 3-4, 

 making 1 to 2 turns. Conjugation scalariform by tubes from both 

 gametangia; fertile cells cylindric. Zygospores ellipsoid or cylindric- 

 ellipsoid; wall layers smooth; 87-108ju, in diameter and 11/2 times the 

 diameter in length. 



Mich. 



Spirogyra laxa Kuetzing 1849, p. 438 



Filaments of rather stout cells, 30-33- ( 40 )ja in diameter and up to 

 230/x long, with replicate end walls; chloroplast solitary, making 

 3 to 5 turns. Conjugation by tubes from both gametangia; fertile 

 cells cylindric. Zygospores ellipsoid; median spore wall smooth and 

 yellow; 30-33ju in diameter, 60-82/x long. 



Mich. 



Spirogyra longata (Vauch.) Kuetzing 1843, p. 279 



Filaments of moderately stout cells, 20-36/i, in diameter and up 

 to 10 times the diameter in length, with plane end walls; chloroplast 

 solitary, making 2 to 5 turns; conjugation by tubes from both game- 



[316] 



