Species [ var. cylindrus ]: Cell body cylindrical, both ends truncated with rounded corners,
(48-56)-58 μm long, 8-(11-13)-21 μm wide, L/W=5.0;
cell wall dotted, brownish in color when aged, bands present.
[ var. cuticulare ]: Smaller than var. cylindrus,
19-34 μm long, 8-10 μm wide, L/W=3;
(Illustrations of The Japanese Fresh-water Algae, 1977).
Penium cylindrus (Ehrenberg) Brébisson var. cylindrus,
cell body 39 μm long, 11.5 μm wide, L/W=3.4,
x 640, No. 3, Iroha-numa (marsh/bog), Zao mountain, Yamagata city, Yamagata Pref., Japan, August 2, 2006 by Y. Tsukii
31 μm
63 μm
94 μm; x 640
Cell body 35 μm long, 11 μm wide, L/W=3.2, x 640
Images of collecting locality:
No. 3, Iroha-numa (marsh/bog), Zao mountain, Yamagata city, Yamagata Pref., Japan, August 2, 2006 by Y. Tsukii