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i6o ZYGNEMATACEAE
Vegetative cells ^8-44/x x 105-160M, with plane end walls; i chromatophorc;
conjugation scalariform; tubes formed by both gametangia;
fertile cells cylindric or very slightly swollen; zygospores ovoid, 42-45 m x
70-80/1; median spore wall golden-brown, smooth, with suture more
or less prominent. (PI. XXIII, Fig. 10.)
Austria.
Certainly very close to S. porticalis, perhaps merely a clone; apparently
differs in the brown spores with prominent sutures.
35. Spirogyra porticalis (Miiller) Cleve 1868. F6rs6f{ till en
monografi. Nova Acta Reg. Soc. Sci. Upsali. Ser. 3,
6, p. 22, PI. 5, Figs. 8-9.
Vegetative cells 40-50 /a x 66-200 m, with plane end walls; i chromatophore,
making 3 to 5 turns; conjugation scalariform; tubes formed
by both gametangia; fertile cells cylindric or enlarged; zygospores
mostly ovoid to globose-ovoid, 38-50 m x 50-83 /x; median spore wall
yellow, smooth. (PI. XXIII, Fig. 9.)
United States: Very common in the eastern half.
Widely distributed on all the continents. Found hybridizing with 5.
varians at Charleston, Illinois. Hybrid segregates were also present. See
Amer. Nat., 53, pp. 109-19, 1919.
36. Spirogyra sahnii Randhawa 1938. Proc. Indian Acad. Sci.
^> PP- 339-41-
Vegetative cells 48-^0 /x x 40-74 /a, with plane end walls; i chromatophore,
making i or 2 turns in the cell; conjugation lateral; tubes
formed by both gametangia; fertile and sterile cells inflated; zygospores
ovoid, 22-36 /x X 44-68 /x; median wall [?]
similar, 20-24 /x ^ 22-36 /x.
India, Punjab, Dasuya, March, 1931.
yellow, smooth; aplanospores
In the original description the median spore wall is described as
"bluish-green." This appearance is probably due to light refraction and
colored spore contents. Named for Birbal Sahni of Lucknow University.
37. Spirogyra lutetiana Petit 1879. Brebissonia. 1, p. 79, PI. 6.
Vegetative cells 27-40 /x x 70-250 /x, with plane end walls; i chromatophore,
making 3 to 7 turns; conjugation scalariform; tubes formed
by both gametangia; fertile cells more or less variable, cylindric, en-
larged, or slightly inflated; zygospores polymorphic, varying from glo-
bose to ellipsoid and irregular, 25-44^1 x 35-165 m; median spore wall
yellow-brown, smooth. (PI. XXIII, Figs. 11-13.)
United States: Utah; North Dakota; other records very doubtful.
Widely reported from Europe and Asia; also South Africa.
Probably none of the species names of Spirogyra has been more frc-