SPIROGYRA 213 



forma gracilior). Czurda. Susswasserflora Mitteleuropa. 

 9, p. 147 (as S. calospora Cleve). 



Vegetative cells 28-34 /a ^ 1 20-425 fi, with replicate end walls; i, 

 rarely 2, chromatophores, making 2 to 6 turns; reproduction by zygo- 

 spores and aplanospores; conjugation scalariform ; tubes formed by 

 both gametangia; receptive gametangia cylindric or enlarged; zygo- 

 spores ovoid, 30-38 /x X 66-90 iit; outer spore wall of 2 layers, of which 

 the inner is thick, scrobiculate; median spore wall yellow, smooth; 

 aplanospores similar but smaller. (PI. XXXVII, Fig. 19.) 



United States: Common throughout the eastern half. 



Europe, recorded from France to Finland and the Ukraine. 



Bessey in 1884 reported conjugation between S. protecta and S. majus- 

 cula in both directions. Spore forms corresponded to those of the female 

 filament. Under the name S. calospora Cleve described 2 different forms; 

 the first, and larger, had i to 3 chromatophores and a yellow, scrobiculate 

 median spore wall. Wood published an accurate description in 1872. 



238. Spirogyra cleveana Transeau 1934. Trans. Amer. Micros. 



Soc. 53, p. 226. Jao. Sinensia. 6, p. 614, PI. 11, Fig. 120, 

 Vegetative cells 34-40 /x x 140-465 ^u., with rephcate end walls; i, 

 rarely 2, chromatophores, making 3 to 6 turns in the cell; conjugation 

 scalariform; tubes formed by both gametangia; sterile cells often greatly 

 inflated; fertile cells cyhndric or enlarged; zygospores ovoid to cylin- 

 dric-ovoid, 34-50 m x 70-125/*; outer spore wall hyaline, of 2 layers, 

 of which the inner is thick and coarsely scrobiculate; median spore wall 

 smooth, yellow. (PL XXXVIII, Fig. i.) 



United States: Common in the eastern half. 



China, Szechwan; probably includes the larger forms of S. calospora 

 (Cleve) in Europe. 



239. Spirogyra denticulata Transeau 1934. Trans. Amer. Micros. 



Soc. 53, p. 226. 

 Vegetative cells 42-56^ x 160-400 /x, with replicate end walls; i, 

 rarely 2, chromatophores, making 3 to 6 turns; conjugation scalariform; 

 tubes formed by both gametangia; fertile cells cylindric or enlarged; 

 sterile cells sometimes inflated; zygospores ovoid, 45-60 ju. x 76-130 ^c; 

 outer hyaUne spore wall of 2 layers; the outer thin, smooth; the inner, 

 thick, scrobiculate; median spore wall yellow, smooth. (PI. XXXVII, 



Fig- 15-) 



United States: Mississippi; Illinois; Indiana; Ohio; Massachusetts. 



240. Spirogyra areolata Lagerheim 1883. Of vers. Kgl. Vet.-AI{ad. 



Forhandl. Stockholm. 40 (2), p. 56, PI. i, Figs. 18-20. 

 Vegetative cells 30-36 /x x 120-600 /x, with replicate end walls; i or 



