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ZYGNEMOPSIS 57
23-50 Ai, with a more or less prominent suture, yellow and scrobiculate,
with pits 2-3 M in diameter. (PI. IX, Figs. lo-ii.)
India, Fyzabad, U.P., February to April.
20. Zygnemopsis decussata Transeau 1934. Trans. Amer. Micros.
Soc. 53, p, 214. Includes Zygnema pseudodecussatum
Czurda 1932.
Vegetative cells 16-20/t x 24-50 /.i; chromatophores as in Zygnema,
each with i pyrenoid; conjugation scalariform; zygospores extending
far into each gametangium, ovoid to quadrate-ovoid, and irregular,
24-30 /A X 30-48 ju., the angles rounded, retuse, or produced; aplan-
ospores unilaterally ovoid, the plane of the convex side changing in
successive cells, 17-25 i", x 20-40 ^u.; parthenospores 15-20;^, x 20-30 ^u.;
median wall in all the spores scrobiculate; akinetes with smooth, heavy
walls, 1 8-20 /i x iU,. 20-36 (PI. IX, Figs. 12-15.)
United States: Oklahoma; Iowa; Arkansas; Illinois; Kentucky; Mich-
igan.
Canada, Ontario; Europe, Bohemia; China, Szechwan.
Some collections have only aplanospores, others only scalariform conjugation
and zygospores, still others have filaments with both zygospores
and aplanospores. In Illinois the size of the filaments was regularly 18-20M
in diameter, but I have a collection sent me by Dr. Li from Amoy, China, in
which some of the conjugating filaments have diameters as low as 12/x.
The zygospores, however, are of the usual dimensions.
21. Zygnemopsis spiralis (Fritsch) Transeau 1934. Trans. Amer.
Micros. Soc. 53, p. 214.
Vegetative cells 18-25/U- x 26-60 /x, with 2 stellate chromatophores;
conjugation scalariform; gametangia sometimes elongating to 130/^;
zygospores quadrately ovoid, 28-36 /^ x 48-56^1.; outer wall thin or thick,
transparent, usually separated from the median wall and sometimes
covered internally with granules; median wall punctate or finely scro-
biculate. (PL IX, Fig. 16.)
United States: Wisconsin; Michigan (Prescott Coll.).
South Africa, Table Mountain, wet rock on slope, luly 19, 1908; Latvia
(Skuja Coll.).
22. Zygnemopsis fertilis (Fritsch & Rich) Transeau 1934. Trans.
Amer. Micros. Soc. 53, p. 216.
Vegetative cells 20-22 /j. in diameter; slight constrictions between
the cells; chromatophores 2, stellate; zygospores unknown; sporogenous
cells distended in the center; aplanospores compressed-ovoid, 31-32 /j- x
41-49 /x; median spore wall with 3
spores immature. (PI. IX, Fig. 17.)
South Africa.
(or more) longitudinal ridges;