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SPIROGYRA 191
cylindric or slightly inflated; zygospores lenticular, '^y-Sin x 45-60/1;
median spore wall brown, smooth; aplanospores similar but smaller.
(PL XXXI, Figs. 14-15.)
United States: Very abundant in late spring and summer throughout
the northcentral states; also reported from Washington and Texas; and
from the eastern states. New England to South Carolina.
Europe; China; South Africa; Brazil; Uruguay.
This is a complex group of elementary forms, differing in dimensions
and numbers of chromatophores. However, among the many collections I
have examined, the overlapping of form characteristics is so continuous from
the smaller to the larger specimens that there seem to be no good bases for
separation as varieties and forms. Czurda (1932, p. 204) discusses smaller
and larger forms. Conard (Beih. Bot. Zentralbl. 55, p. 184, 1936) proposed
to remove certain of the species having lenticular spores from the genus
Spirogyra under the generic name Degagnya. This proposal would require
a restudy of all species of Zygnemataceae, since he introduces new criteria
for the separation of genera. The species Conard designates as D. majuscida
Conard is certainly not our species S. majuscula Kiitzing.
In 1884 Professor C. E. Bessey reported finding this species conjugating
with S. protecta. Conjugation occurred in both directions and the zygo-
spores formed were similar to those of the female filament.
159. Spirogyra submaxima Transeau 1914. Amer. Jour. Bot. 1,
p. 295, PL 27, Figs. 3-4.
Vegetative cells 70-110/1 x 100-300/1, with plane end walls; 8 to 9
chromatophores making .1 to i turn; conjugation scalariform; tubes
formed by both gametangia; fertile cells cylindric, enlarged, or slightly
inflated; zygospores lenticular, 70-110/1 x 50-75/1; median spore wall
brown, smooth.
United States: Missouri and Mississippi eastward to Massachusetts.
China; India.
Found hybridizing with S. maxima at Charleston, Illinois.
160. Spirogyra glabra Czurda 1932. Siisswasserflora Mitteleu-
ropa. 9, p. 206, Fig. 222.
Vegetative cells 145-153 /i x 120-220/1, with plane end walls; 7 chromatophores;
conjugation scalariform; tubes formed by both gam-
etangia; fertile cells cylindric; zygospores lenticular, about 120/1 x 170/1;
outer spore wall about lo/i thick, colorless; median spore wall about
20/1 thick, yellow-brown, smooth. (PL XXXI, Fig. 16,)
Austria, Vienna.
161. Spirogyra bellis (Hassall) Cleve 1868. Nova Acta Reg. Soc.
Sci. Upsali. Ser. 3, 6, p. 18, PL 3, Figs. 2-5.
Vegetative cells 65-80/1 x 90-350/1, with plane end walls; 5 to 6