Download PDF

SPIROGYRA 155
matophore; conjugation scalariform; tubes formed by both gametangia;
fertile cells shortened and inflated to 34-39^1; zygospores ellipsoid,
24-31 ju, X 45-55/^; median spore wall yellow-brown, smooth. (PL XXII,
Fig- 4-)
Finland; China, Szechwan; South Africa.
Distinguished from S. parvula by the much smaller vegetative cells; and
from S. pratensis by the absence of cells with 2 chromatophores, and by the
absence of globosely inflated sterile cells.
17. Spirogyra parvula (Transeau) Czurda 1932. Siisswasserflora
Mitteleuropa. 9, p. 170, Fig. 174.
Vegetative cells 20-24 /x x 50-105^1, with plane end walls; i chromatophore,
making i to 6 turns; conjugation mostly lateral, sometimes
scalariform; tubes formed by both gametangia; fertile cells inflated up
to 37 /x, often separating from one another but held in place by the male
filament; zygospores ellipsoid, 20-27 /x ^ 40-60 a^; median spore wall
yellow-brown, smooth; aplanospores similar in size and shape to zygo-
spores. (PI. XXII, Figs. 5-6.)
United States: Iowa and Texas, to New York.
Norway; India; China.
18. Spirogyra gibberosa Jao 1935. Sinensia. 6, p. 586, PI. 4, Figs.
50-51.
Vegetative cells 19-21^1 x ^^-10^^, with plane end wall; i chro-
matophore, making 2 to 8 turns in the cell; conjugation scalariform,
sometimes lateral; tubes formed by the male gametangia; fertile cells
inflated on the conjugating side, to 45 /i, often separating from each
other as the spores mature; zygospores ellipsoid with more or less
pointed ends, 22-29 /a x 38-50 /x; median spore wall smooth, yellow at
maturity. (PI. XXII, Figs. lo-ii.)
China, Szechwan.
Separation of the sporiferous cells after conjugation is similar to that
frequently seen in S. parvula. Placed here because of doubt that tubes are
formed by the male gametangia. This may be only apparent, because of
subsequent enlargement of the receptive gametangia.
19. Spirogyra borgeana Transeau 1915. Ohio Jour. Set. 16, p. 23.
Vegetative cells ju- 30-35 x 50-200 /x; with plane end walls; i chromatophore,
making 1.5 to 5 turns; conjugation scalariform; tubes
formed by both gametangia; fertile cells inflated on the outer side,
cylindric on the conjugating side; zygospores ellipsoid, /it 30-40 x ;ix; 54-70
median spore wall yellow, smooth. (PI. XXII, Fig. 8; PI. XXIII,
Fig. 16.)
United States: Iowa; Illinois; Michigan; Indiana; Ohio.