ZYGNEMA 23 



United States: Florida, Oveida Springs, and Fort Myers; Louisiana, 

 Alexandria. 



2. Zygnema carter ae Czurda 1932. Siisswasserfiora Mitteleuropa. 



9, p. 1 14. Carter. ]our. Linn. Soc. of London Bot. 46, p. 62. 



Vegetative cells 13-16^ in diameter; conjugation lateral or scalari- 

 form; zygospores formed in the conjugating tubes, globose, 30-35 /a; 

 median spore wall brown, scrobiculate. 



New Caledonia (Carter). 



3. Zygnema laevisporum Jao 1935. Trans. Amer. Micros. Soc. 



54, p. 56, PI. I, Figs. 7-8. 



Vegetative cells 13-16/x x (48-)64-i28m; chromatophores usually 2, 

 sometimes 3 or 4, occupying the middle of the cell; conjugation usually 

 lateral, rarely scalariform; zygospores compressed-globose, formed in 

 the conjugating tubes, 35-42 ju x 32-35 a<.; median spore wall smooth and 

 yellow-brown at maturity. (PL II, Figs. 5-6.) 



United States: Massachusetts, Falmouth. 



4. Zygnema decussatum (Vaucher) Agardh 1824. Systema Al- 



garum, p. 78. 



Vegetative cells 16-20/^ x 35-ioo/i. (2-5 diameters long); conjuga- 

 tion scalariform; zygospores formed in the conjugating tubes, globose 

 to ovoid, 24-33 ju. ^ 26-36 ju; median spore wall brown, finely scrobicu- 

 late. (PI. II, Fig. 7.) 



United States: Illinois; Indiana; Michigan; Massachusetts. 



Widely reported from Europe; India; New Caledonia. 



This form is not identical with Zygnemopsis decussata Transeau as 

 transferred by Czurda. Both species have been found in the same pond. 

 Their reproductive structures are quite dissimilar. (See PI. IX, Figs. 12-15.) 



5. Zygnema himalayense Randhawa 1940. Proc. Indian Acad. 



Sci. 12, p. 129. 



Vegetative cells 20-22 ju. x 60-1 20 /x; conjugation lateral and scalari- 

 form. In lateral conjugation the gametes unite directly after solution 

 of the wall between the gametangia. Zygospores formed in the conju- 

 gating tubes in scalariform conjugation; spores subglobose to ovoid, 

 36-40 /A X 45-72 m; median spore wall scrobiculate, yellow-brown; pits 

 1-1.5AC in diameter, 3-4^". apart. (PI. II, Fig. 4.) 



India, Loharkhot, stream at an elevation of 5,750 feet in the Himalaya 

 Mountains, September 15, 1939. 



6. Zygnema coNSPicuuM(Hassall) Transeau 1934. Trans. Amer. 



Micros. Soc. 53, p. 208, PI. 17, Fig. 2. 

 Vegetative cells 22-27 /x x 50-90 /u; conjugation scalariform; zygo- 



