Desmids from Thailand and Malaysia

84.
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land.
Desmids from Thailand and Malaysia 83
St. striolatum (Ntig.)Arch. var. divergens W. & G.S.West Pl.49, f2.
Krieger 1932, 207, Pl.15, f.8.
L. 17.6-19.8 xtm, B. 19-20 Ltm, and I. 6.5-7 ptm. Sts. 10,20. Ceylon, Indonesia
(Java). New to Thailand.
St. subarmigerum Roy & Bisset
Roy & Bisset 1886, Journ. Bot. 24, 239, Pl.268, f.2.
Lspr. 22 xtm, Lcpr. 30.8 Ltm, Bcpr. 26.4 ptm, and I. 6.5 ptm. Sts. 19,31. Japan. New
to Thailand.
St. subcornutum DeToni PL39, f.7.
Prescott et al. 1982, 2:4, 320, Pl.348, f.13.
L. 81.4 gm, B. 70.4 ptm, and I. 16.3 xtm. Cells large, 1.2 times longer than the
breadth without spines, deeply constricted at the middle, sinus open acutely; semicells
transversely rhomboid-elliptic, apex strongly convex, lateral angles acute and with a
long, stout, incurved spine, spines directed downward, ventral margin slightly convex;
semicells in vertical view triangular, side view slightly concave, angles rounded, with a
long spine. The specimens examined from Malaya are somewhat larger than the form
described by Prescott et al. St. 9. N. & S.America. New to Thailand.
St. subgracilimum W.&G.S.West PL40, f.8.
West 1896, Trans. Linn. Soc. Bot. II, 5:5, 263, Pl.17, f.3,4; Prescott et al. 1982, 2:4,
323, Pl.404, f.12.
L. 16.7-19.8 Ltm, Bcpr. 28.6-35 ptm, and I. 6-6.5 ptm. Sts. 36,40. Europe, Austral-
ia, New Zealand. New to Thailand.
St. sublaevispinum W.West Pl.37, f.7.
West 1898, Journ. Linn. Soc. Bot. 33, 314, Pl.18, f.20-22; Prescott et al. 1982, 2:4,
323, Pl.386, f.11, Scott & Prescott 1961, 110, Pl.53, f.5.
L. 26-28 "m, B. 38-40 ptm, and I. 7-8 ym. St. 41. Indonesia (Sumatra), U.S.A.
New to Thailand.
St. submanfeldtii W.&G.S.West Pl.46, f.8,9.
West 1902, 188, Pl.22, f.16.
L. 36 ptm, Bcpr. 57 ptm, and I. 8.5 "m. Cells of medium size, approximately 1.6
times broader than the length including processes, moderately constricted, sinus open;
semicells cyathiform, apical angles produced into a long, horizontal process, apex slight-
ly convex, verrucose from the centre to the basal part of a process with 2 or 3 verrucae
disposed, part of a process with a simple and sharp spine, ventral side of the basal part
of a process with a emarginate verruca; vertical view of a semicell triangular, side con-
cave, with an intramarginal series of verrucae in the central part of a semicell, and a
series of simple granules at the process. St. 10. N. & S.America, Africa. New to Thai-
land.