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196
ZYGNEMATACEAE
iform; tubes formed by both gamctangia; fertile cells cylindric; zygo-
spores compressed-ellipsoid, 120-140/1 x 145-255/i; median spore wall
smooth, yellow-brown. (PI. XXXIII, Fig. i.)
United States: Iowa; Illinois; Ohio.
Resembles S. elUpsospora, but the form of the spores is quite distinctive.
It should not be confused with S. crassa, as was done by Czurda 1932, page
216, although on page 202 he republished the figures of the "crassoidea"
spore (Fig. 217b) as that of S. elUpsospora, which further confused the iden-
tity of this species. In i plane the spore is distinctly ellipsoid, in the plane
at right angles the spore is ovoid.
176. Spirogyra rectispira Merriman 1922 [Char, amend J. Amer.
Jour. Bot. 9, p. 283.
Vegetative cells 150-180 ju. x 75-320 /x, with plane end walls; 11-16
chromatophores, straight or making .1 to i turn; conjugation scalar-
iform; tubes formed by both gametangia; fertile cells cylindric or en-
larged on the inner side; zygospores compressed-ovoid, 140-152/1 x
168-185/i. X 110-130/^; median spore wall minutely vcrrucose, brown.
United States: New York City, Van Cordandt Park.
Original description is incorrect in several particulars. This description
is based on the original material kindly sent me by Miss Merriman.
PLANE END WALLS
CONJUGATING TUBES BY MALE GAMETANGIA
177. Spirogyra hydrodictya Transeau 1915. Ohio fonr. Sci. 16,
p. 28.
Vegetative cells 75-100 /j. x 210-360/'., with plane end walls; 7 to 10
chromatophores, straight or making .1 to .5 turn; conjugation scalar-
iform and lateral; tubes formed by the male gametangia; fertile cells
shortened and enlarged, or slightly inflated; zygospores lenticular to
lenticular-globose, So-120/^ x iio-195/t; median spore wall brown,
pitted. (PI. XXXIII, Figs. 2-4.)
United States: Illinois, Coffeen, Prairie Pond, May 23, 191 5. Great
masses of the tangled filaments of this species were present on this date, but
it was not found there again in subsequent years although it was searched
for annually.
178. Spirogyra texensis Taft 1944. 0/iio Jour. Sci. 44, p. 238.
Vegetative cells 50-55/^1 x 90-530/'., with plane end walls; 3 to 5
chromatophores, making 1.5 to 3.5 turns in the cell; conjugation scalar-
iform; tubes formed by the male gametangia; fertile cells shortened
and enlarged; zygospores ovoid, ()()-y6[i. x 99-124/1; outer spore wall
transparent, irregularly corrugate; median wall yellow-brown, con-
spicuously reticulate. (PI. XXXIII, Fig. 5.)