cells sometimes inflated. Zygospores ovate to subglobose-ovate; 

 median spore wall smooth and yellow; 38-50/* in diameter, SO-SS/i 

 long. 



Common in shallow water of lakes, swamps, and roadside ditches. 

 Mich., Wis. 



Spirogyra pratensis Transeau 1914, p. 292 



PI. 75, Figs. 4-6 



Filaments of rather slender cells, 17-20/x in diameter, 80-95-(240))u. 

 long, with plane end walls; chloroplast solitary (rarely 2), making 

 1 to 8 turns. Conjugation by tubes from both gametangia; fertile 

 colls inflated. Zygospores ellipsoid to subcylindric-ovate; median 

 spore wall smooth, yellow at maturity; 24-36/1, in diameter, 50-60- 

 (70)/. long. 



In a small pooled stream. Mich. 



Spirogyra protecta Wood 1872, p. 165 

 Vegetative cells 32-36- ( 44 )/x in diameter, 120-475/x long, with 

 replicate end walls; chloroplast solitary making 4 to 5 turns. Con- 

 jugation by tubes from both gametangia; fertile cells cylindric or 

 slightly enlarged, sterile cells becoming inflated during conjugation. 

 Zygospores ovate or cylindric-ovate; median spore wall smooth 

 and yellow, inner scrobiculate; 36— 42— (50) /i in diameter, 66— 

 130/i long. 



Mich. 



Spirogyra pseudofloridana Prescott 1944, p. 360 

 PI. 75, Figs. 7-9 



Filaments of stout cells, 51-60/i, in diameter and 3-5 times the 

 diameter in length, with plane end walls; chloroplasts 4 (rarely 5), 

 narrow, making Vo to l^^ loose turns. Conjugation by geniculate 

 bending of filaments, without tubes being formed; gametangia 

 becoming shortened and thickened and apparently cut off from 

 vegetative cells; fertile cells becoming slightly inflated. Zygospores 

 ellipsoid, with narrowly rounded poles; median spore wall rough- 

 ened with irregular granulations and wrinkles (not regularly re- 

 ticulate), brown; 63-70/1 in diameter, lOO-120/i long. 



This species should be compared with S. illinoisensis Transeau and 

 S. floridana Transeau. It is smaller than the former and has fewer 

 chloroplasts. From the latter it differs chiefly in the decoration of 

 the mesospore. 



Floating in a lagoon. Wis. 



Spirogyra reflexa Transeau 1915, p. 28 



Vegetative cells 30-40/t in diameter, 120-300/i long, with plane end 

 walls; chloroplast solitary, making 3 to 8 turns. Conjugation by tubes 



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