Family: Colonies consisting of a fixed number of cells (Illustrations of The Japanese Fresh-water Algae, 1977).
Genus: Colony of 8 or 16 cells, exeptionally a single cell state present; cells attached forming a bunch of grapes (consisting of 4 layers of each 2- or 4-celled "chaplet"); cell body ovoid or inverted ovoid, slightly cylindrical to ellipsoidal, posteriorly narrowed and curved; cellwall thin or moderately thick; with two flagella; chloroplast cup-shaped; pyrenoids absent; stigma large, variable in size; nucleus at anterior half of the cell body; two contractile vacuoles apical (Süßwasserflora von Mitteleuropa 9, Chlorophyta I, 1983).
Google Image Search
P. casinoensis
cell μm
Naruto
Chiba, 2003
P. casinoensis
cell μm
river bank
near Doman-green p.
Saitama, 2003
P. casinoensis
cell μm
Japan, 2004
P. rostrata
12-20 x 5-10 μm
Naruto
Chiba, 2003
P. squarrosa
cell 25 x 11 μm
Higashi-sano
Hakuba
Nagano, 2004
