Species:
Cell body cylindrical, large in size, slightly constricted at the center, bands present,
77-325 μm long, 15-30 μm wide,
L/W=5-10; cell wall brownish, striated (striae slighlty slanted)
(Illustrations of The Japanese Fresh-water Algae, 1977).
Penium spirostriolatum Barker var. spirostriolatum,
cell body 173 μm long, 23 μm wide, L/W=7.5,
x 640, No.2, Ko-numa (pond/marsh), Minakami town (formerly Tsukiyono town), Gunma Pref., Japan, October 12, 2008 by Y. Tsukii
31 μm
63 μm
94 μm; x 640
Cell body 142 μm long, 24 μm wide, L/W=5.9, x 640
Images of collecting locality:
No.2, Ko-numa (pond/marsh), Minakami town (formerly Tsukiyono town), Gunma Pref., Japan, October 12, 2008 by Y. Tsukii