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.
23 x 20 μm
Uruguay, 1999
Phacus sp.
26-28 x 19 μm
Hazama marsh
Ashikaga
Tochigi, 2003
