SPIROGYRA 195 



although the tubes become very wide; zygospores lenticular, about i50A'- 

 in diameter; median wall yellow-brown, thick, with round brown 

 papillae irregularly distributed over the surface. (PI. XXXII, Figs. 

 12-13.) 



Austria, Vienna; France. 



172. Spirogyra crassiuscula (W. & N.) Transeau 1934. Ohio 



Jour. Sci. 34, p. 420. Wittrock and Nordstedt Algae 

 Exsiccatae, No. 746. 



Vegetative cells 145-170/1 x 140-300 /<., with plane end walls; 6 to 7 

 chromatophores, making .5 to i turn in the cell; conjugation scalar- 

 iform; tubes formed by both gametangia; fertile cells cylindric; zygo- 

 spores lenticular, 120-150 ^a x 85-100 ft; median spore wall yellow-brown, 

 reticulate. 



England, Essex; South Africa. 



In appearance this and the next species are similar to S. maxima, but 

 are larger in all dimensions. 



173. Spirogyra megaspora (Lagerheim) Transeau 1934. Ohio 



Jour. Sci. 34, p. 420. In Wittrock and Nordstedt Algae 

 Exsiccatae, No. 745. 

 Vegetative cells 170-200^1. x 150-400^1, with plane end walls; 6 to 7 

 chromatophores, making .5 to i turn in the cell; conjugation scalar- 

 iform; tubes formed by both gametangia; fertile cells cylindric; zygo- 

 spores lenticular, 135-170/A x 90-120/^; median spore wall yellow- 

 brown, reticulate. 



Uruguay; Sweden. 



174. Spirogyra lenticularis Transeau 1938. Amer. Jour. Bot. 



25, p. 528, Figs. 18-19. 



Vegetative cells 150-162/^ x (80-) 125-200 (-300) fi, with plane end 

 walls; 9 or 10 chromatophores, straight, or making i turn in the cell; 

 conjugation scalariform; tubes formed by both gametangia; receptive 

 gametangia shortened and cylindric or slightly enlarged on the inner 

 side; zygospores compressed-spheroid, 136-145 /a x 90-1 00 fi; outer wall 

 thin, smooth, transparent; median wall thick, minutely verrucose and 

 with labyrinthine reticulations, brown. (PI. XXXII, Figs. 14-15.) 



South Africa, Cape Town (E. Stephens Coll.). 



175. Spirogyra crassoidea Transeau 1937. Amer. Midland Nat- 



uralist. 18, p. 936, PL 5, Fig. 77. Amer. Jour. Bot. 1, 

 p. 295, PI. 27, Fig. 2. 

 Vegetative cells 140-150 j«^ x 140-560 /a, with plane end walls; 3 to 8 

 chromatophores, making .5 to 3 turns in the cell; conjugation scalar- 



