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ZYGNEMATACEAE
Vegetative cells 8-13 )u x 30-140 m; chromatophore usually occupy-
ing two-thirds of the cell, with 4-8 pyrcnoids; conjugation scalariform;
zygospores formed wholly in the conjugating tube, globose, 13-25 /a in
diameter; spore wall brown, thick, smooth; aplanospores obliquely
ovoid, 16-20M X 20-24/1. (PI. XIII, Figs. 3-5.)
United States: Iowa to Massachusetts; south to Louisiana and Florida.
Widely distributed in Europe; China; Japan; Brazil; Africa.
4. MouGEOTiA TUBiFERA Tiffany 1934. Trans. Amer. Micros. Soc.
53, p. 218.
Vegetative cells 9-10^1 x 90-400/^; chromatophore with 4-12 pyre-
noids in a single, more or less irregular, row; conjugation tubes usually
greatly elongated ( 10-65 /i.), often spirally twisted and nearly as large
as the filaments (7-9 /^ in diameter). Conjugation occurs through the
lateral wall of the papillae as well as through the end. Zygospores
asymmetrically ovoid, usually showing a greater bulge on one side than
on the other, 27-30 /a x 33-45 a^, not including the outer sporangial pectic
layer which is 6-12/1 in thickness; sporangium wall smooth, hyaline;
spore wall colorless, thicker, smooth. It is not certain that the spores
were fully mature. (PI. XIII, Figs. 6-9.)
United States: Florida; North Carolina.
5. MouGEOTiA CALCAREA(Cleve)Wittrock 1872. Bih.Kgl.SvensJ{
Veiensl{. A /{ad. Handl. 1, p. 40, PI. 2.
Vegetative cells 8-1 4 /x x 40-280/1; chromatophores with 4-8 pyrcnoids
in a single row; cells elongating, becoming geniculate before spore
formation; conjugation scalariform; zygospores formed wholly in the
conjugating tube or extending into one or both gametangia, globose,
25-30 /t in diameter, or angular-globose, 22-28/1 x 30-50/1; spore wall
smooth, colorless, or pale yellow; aplanospore globose, lateral to the
sporogenous cell, 17-21 /a in diameter, or rarely trapezoid-ovoid, divid-
ing the sporogenous cell, 15-20/1 x 20-28/1. (PI. XIII, Figs. 10-12.)
North America, British Columbia to Greenland; Dakota to Texas and
eastward to Newfoundland and Florida.
Brazil; Europe; North Africa; southern Asia.
The variety name "bicalyptrata" has been applied to specimens in
which the thickness of the end walls of the sporangium is unusually great.
In some collections the thick polar walls occur in Hlamcnts among spores
with thin uniform walls. Collections may contain only aplanosporic or only
zygosporic specimens, while others may contain both in mixture. In Borge's
type material for M. sphaerospora I found 2 zygospores similar to those of
M. calcarea; moreover, I found no aplanospores resembling those figured by
Czurda from Central Tibet as M. sphaerospora. This figure may represent
a new species but descriptive details are lacking.