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 202 μm long, 23 μm wide, L/W=8.8,
x 400, x 640, Ohnuma (a pond at Ohnuma enchi), Nasu-shiobara city (formerly Shiobara town), Tochigi Pref., Japan, April 1, 2007, by Y. Tsukii
31 μm
63 μm
94 μm; x 640
Images of collecting locality:
Ohnuma (a pond at Ohnuma enchi), Nasu-shiobara city (formerly Shiobara town), Tochigi Pref., Japan, April 1, 2007, by Y. Tsukii