24 ZYGNEMATACEAE 



spores formed in the conjugating tubes, globose to ovoid, 24-32 /^ x 

 26-33 /a; median spore wall brown, scrobiculate; pits about 1.5-2.0/^ 

 in diameter and the same distance apart. (PI. II, Fig. 8.) 



United States: Illinois; Wisconsin; Oklahoma; Kentucky. 



England; Germany; Austria; Belgium; Bulgaria; Russia. 



7. Zygnema skujae Czurda 1932. Siisswasserfiora Mttteleuropa. 



9, p. 109. Skuja. Acta Horti Bot. Ufiiv. Latviensis. 4, p. 40. 

 1929. 



Vegetative cells 20-27 jm -^ 40-1 00 /j.; conjugation scalariform; gam- 

 etangia slightly bent; zygospores formed in the conjugating tubes, 

 globose to ovoid, 40-55/^; median spore wall olive-brown, coarsely and 

 thickly scrobiculate. 



Latvia. 



8. Zygnema lawtonianum Taft 1934. Trans. Amer. Micros. Soc. 



53, p. 209, PI. 17, Fig. 5. 



Vegetative cells 23-27 /x x 23-99 m; conjugation scalariform; zygo- 

 spores formed in the conjugating tubes, globose to ovoid-globose with 

 a distinct equatorial suture, 33-40 /x x 3^-46^^; outer spore wall united 

 with the tube wall; median spore wall brown, coarsely scrobiculate; 

 pits 3-4 M in diameter and about the same distance apart. Spores are 

 cut off from the gametangia by a distinct cross wall. (PI. II, Fig. 9.) 



United States: Oklahoma, Medicine Park, April 29, 1932. 



Burma (Skuja). 



9. Zygnema verrucosum Jao 1935. Sinetisia. 6, p. 566, Pi. i, 



Figs. 3-4. 



Vegetative cells 24-26 m x 29-48 /a; conjugation scalariform; zygo- 

 spores formed in the conjugating tubes, subglobose to ovoid, 32-37 m x 

 38-55 /x; outer spore wall smooth, hyaline; median wall of 2 layers, of 

 which the outer is yellow and irregularly wrinkled, the inner, yellow- 

 brown and densely granulate to verrucose. (PI. II, Figs. lo-ii.) 



China, Szechwan. 



Differs from Z. pawhuskfie Taft in the larger vegetative cells, the 

 absence of a distinct suture on the spore, and the absence of compressed- 

 ovoid spores. 



10. Zygnema chungii Li 1934. Trans. Amer. Micros. Soc. 53, 

 p. 213, PI. 18, Fig. 15. 



Vegetative cells 24-28/-1 x 58-72iM; conjugation scalariform; zygo- 

 spores formed in the conjugating tubes, globose to ovoid, 38-42/i x 

 38-47 /x; outer wall colorless, smooth; median spore wall yellow-brown, 



