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:
P. undulatus
43 x 29 μm
Sue-machi
Fukuoka, 2001
P. undulatus
43 x 29 μm
near Yamaguchi Univ.
Yamaguchi, 2004
