Species:
Cell body cylindrical, medium in size, both ends broadly rounded,
(56-65)-80 μm long, 20-31 μm wide,
L/W=2-2.5; cell wall thick, densely dotted, transparent or brownish in color
(Illustrations of The Japanese Fresh-water Algae, 1977).
Penium rufescens Cleve,
cell body 67 μm long, 24 μm wide, L/W=2.8,
narrowed toward the center (22 μm wide),
x 640, No.6, Omine-numa (pond/marsh), Omine, Minakami town (formerly Tsukiyono town), Gunma Pref., Japan, April 15, 2007 by Y. Tsukii
31 μm
63 μm
94 μm; x 640
Images of collecting locality:
No.6, Omine-numa (pond/marsh), Omine, Minakami town (formerly Tsukiyono town), Gunma Pref., Japan, April 15, 2007 by Y. Tsukii