Desmids from Thailand and Malaysia

Desmids from Thailand and Malaysia 49
2c. var. undulatum Hirano, var. nov. Pl.23, f.1.
Cellulae mediocres, circiter 2.5 plo longiores quam latae, profunde constrictae ad
medium, sinu angusto-lineari; semicellulae subpyramidatae, marginibus lateralibus 4-un-
dulatis, inter lobos polares et laterales retusis, lobis polaribus subpyramidatis, apice con-
vexo et cum incisionibus apicalibus angusto-lineari, angulis apicalibus late rotundatis,
lobis lateralibus rectangularibus. Long. 81.5 ptm, lat. 33 ptm, lat. isth. 12 xtm.
Type: Pl.23, f.1. Loc. Non Boa Saket, Thailand.
Cells of medium size, approximately 2.5 times longer than the breadth, deeply con-
stricted at the middle, sinus closed; semicells subpyramidate, lateral margins with 4-un-
dulations, incision between polar and lateral lobes shallow and retuse, polar lobe
pyramidate, apex slightly convex with a deep and closed apical incision. L. 81.5 ptm, B.
33 pt m, and I. 12 Ltm. St. 47. Thailand.
3. E. bidentatum Nag. Pl.25, f.13; Pl.26, f.1.
West 1905, 2, 39, Pl.37. f.16-19; Krieger 1937, 601, Pl.85, f.1,2; F6rster 1982, 312,
Pl.42, f.4-6.
L. 40-47 ptm, B. 26.5 -33 ptm, and I. 5.7-6.5 ptm. Sts. 1,10,36,41. Cosmopolitan.
4. E. bilobum LUtkem. var. bilobum Pl.30, f.7.
Migula 1907, Krypt. Fl. 2:1, 493, Pl.27c, f.7; Krieger 1937, 597, Pl.82, f.10-12; Hira-
no 1959, Contr. Biol. Lab. Kyoto Univ. 7, 259, Pl.33, f.22.
L. 26.5 gm, B. 14 ptm, and I. 4.5 ium. Cells small, approximately 1.8 times longer
than the breadth, deeply constricted at the middle, sinus narrowly linear; semicells semi-
elliptic, apical incision deep and linearly open, lateral margins convex with slight 3-un-
dulations; cell wall with a pair of small granules below the apex. St. 31. Japan, Europe.
The specimens examined are smaller than the typical form of E. bilobum given by Migu-
la and Krieger.
4a. yar. thailandicum Hirano, var. nov. Pl.36, f.7.
Cellulae hexagonales, circiter 1.4 plo longiores quam latiores, profunde constrictae,
sinu angusto-lineari sed ad medium leviter dilatato; semicellulae truncato-pyramidatae,
apice cum incisuris medianis profunde lineari-aperto, marginibus lateralibus leviter con-
cavis et paullo undulatis. Long. 44 ptm, lat. 31 ptm, lat. isth. 8 ptm. St. 30.
Type: Pl.36, f.7. Loc. Khao Yai, Thailand.
Cells hexagonal in outline, approximately 1.4 times longer than the breadth, deeply
constricted at the middle, sinus narrowly linear but slightly dilated at the middle; semi-
cells truncate-pyramidate, with a deep median incision and linearly open or closed but
the outer part open, apical angles broadly rounded, lateral margins slightly concave and
delicately undulate in the lower part. St. 30.
5. E. binale (Turp.) Ehrenb. var. hians W.West Pl.30, f.12.
West 1905, Brit. Desm. 2, 53, Pl.38, f.33 (forma); Krieger 1937, 13:1, 551, Pl.75, f.16.
L. 12-13 ptm, B. 9-10 ptm, and I. 3 ptm. Sts. 30,35,36,40. Ceylon, Europe,
N.America, Africa.