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SPIROGYRA 175
Vegetative cells 35-45 M x 140-200 /j-, with plane end walls; 3 chro-
matophores, making 1.5 to 3 turns; conjugation scalariform; tubes
formed by both gametangia; fertile cells cylindric; zygospores ovoid,
34-48 A^ X ;t(,; 48-54 median spore wall yellow, smooth.
United States: California; Illinois; Kentucky; Massachusetts.
94. Spirogyra siamensis nom. nov. Bot. Tidsskrijt. 24, p. 161, as
S. decimina var. tropica W. & G. S. West. Transeau 1944.
Ohio Jour. Sci. 44, p. 243 as S. tropica, a name preoccupied
by Kiitzing.
Vegetative cells 46-50 /x x 100-250 /«. with plane end walls; 3 chro-
matophores, making 2.5 to 4.6 turns; conjugation scalariform; tubes
formed by both gametangia; fertile cells cylindric; zygospores ovoid,
46-50 ju. X 81-124 m; median spore wall yellow, smooth.
Siam, Island of Koh Chang.
95. Spirogyra neglecta (Hassall) Riitzing 1849. Species Al-
garurn, p. 441.
Vegetative cells 55-67 /^ x 1 00-300 /x, with plane end walls; 3 chro-
matophores, making i to 2.5 turns; conjugation scalariform and lateral;
tubes formed by both gametangia; fertile cells enlarged, or often greatly
enlarged or inflated, and spores may develop at right angles to the filament;
zygospores and aplanospores ovoid, ju, 54-64 x 75-100 /x; median
spore wall yellow, smooth. (PL XXVII, Figs. 14-15.)
chusetts.
United States: Colorado; Illinois; Indiana; Ohio; Kentucky; Massa-
Germany; Finland; Czechoslovakia; Macedonia; Java; Siam; South
Africa; China; India; West Indies.
The species described by Ripart (1876) as S. ternata frequently has
been found associated with this species, and not infrequently at opposite
ends of the same filaments. The short crowded cells of "ternata" are the
result of more rapid cell division just preceding conjugation.
96. Spirogyra decimina (Miiller) Kiitzing 1843. Phycologia Gen-
eralis, p. 279. Wittrock and Nordstedt Algae Exsiccatae,
No. 1372.
Vegetative cells 32-42 /a x 66-1 50 /x, with plane end walls; 2-3 chromatophores,
making i to 2 turns; conjugation scalariform; tubes
formed by both gametangia; fertile cells cylindric or enlarged; zygo-
spores ovoid to globose, 31-40/4 x 31-68 />(.; median spore wall yellow,
smooth. (PL XXVII, Fig. 16.)
United States: Common in most states from Colorado eastward.
Europe; Asia; Africa; West Indies; Java; South America.
Under this name Czurda (1932) has described a species with ellipsoid