Genus: Highly flattened; pellicle firm; body form constant (Kudo, 1966).
Chloroplasts small, discoid, pyrenoids usually absent; most species flat and leaf-shaped;
often with ridges or fins running helically or longitudinally (Illustrated Guide, 1985).
Species:
Phacus sp.,
cell body 82 μm long, 46 μm wide, L/W=,
x 640, Lake Biwa near Irie bridge, Maibara city (formerly Maihara town), Shiga Pref., Japan, June 30, 2008, by Y. Tsukii
31 μm
63 μm
94 μm; x 640
Images of collecting locality:
Lake Biwa near Irie bridge, Maibara city (formerly Maihara town), Shiga Pref., Japan, June 30, 2008, by Y. Tsukii