Section [Margaritiferae]:
Cell surface granulated, gnarled or spiny; semicells pyramidal with flattened apex or trapezoid
(Illustrations of The Japanese Fresh-water Algae, 1977).
Species [f. arcticum]:
Cell body 35 μm long, 24 μm wide, isthmus 12.6 μm wide,
both sides with 6 waves (including basal and apical corners), apex with 2 corners and 2 waves
(Illustrations of The Japanese Fresh-water Algae, 1977).
Cosmarium notabile Brébisson f. arcticum Kossinskaja ??,
cell body 41 μm long, 31 μm wide, L/W=1.3, isthmus 15 μm wide,
x 640, No. 2-3, Numa-no-hara marsh (Genseikaen), Madarao highland (Niigata & Nagano Pref.), Myoko village, Niigata Pref., Japan, June 17, 2006 by Y. Tsukii 31 μm
63 μm
94 μm; x 640
Images of collecting locality:
No. 1, 2, Numa-no-hara marsh (Genseikaen), Madarao highland (Niigata & Nagano Pref.), Myoko village, Niigata Pref., Japan, June 17, 2006 by Y. Tsukii