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 222 μm long, 26 μm wide, L/W=8.5,
x 400, x 640, No.1, Iyari marsh, Omachi city, Nagano Pref., Japan, June 4, 2007 by Y. Tsukii 31 μm
63 μm
94 μm; x 640
Images of collecting locality:
No.1, Iyari marsh, Omachi city, Nagano Pref., Japan, June 4, 2007 by Y. Tsukii