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 240 μm long, 20 μm wide,
x 640, Tane-ike (pond), Togakushi highland, Shinano town, Nagano Pref., Japan, May 21, 2006 by Y. Tsukii
31 μm
63 μm
94 μm; x 640
Images of collecting locality:
Tane-ike (pond), Togakushi highland, Shinano town, Nagano Pref., Japan, May 21, 2006 by Y. Tsukii