Species: Cell body broad ellipsoidal or nearly spherical, 18-35 μm in diam.; papilla broad with flattened apex; chloroplast cup-shaped; a pyrenoid horseshoe-shaped, located beneath equatorial line or slightly posterior; stigma longitudinally elongated, thin, located at equator or slightly anterior; nucleus at anterior half of the cell body. [ var. globulifera (Korschikoff) Korschikoff 1938]: Papilla narrower and more protruded; cellwall thick; with several pyrenoids irregular in shape. [ var. perforata Vlk 1940]: Pyrenoid ring-form. [ var. longirubra Ettl 1976]: Stigma large, elongated, stick-like in shape, longitudinally located at anterior half of the cell; papilla more broad and short; a pyrenoid elongated, curved as half-ring (Süßwasserflora von Mitteleuropa 9, Chlorophyta I, 1983).

31 μm 63 μm 94 μm; x 640

An algal parasite, Rhyzophydium sp. (Chytridiales, Chytridiomycota, Eumycota) attached Chlamydomonas monadina, C. monadina cell body 17 μm long, 16 μm wide, Rhyzophydium cell body spherical 2 μm in diam., x 640, Akigase Park, Saitama city, Saitama Pref., Japan, March 2002 by Y. Tsukii
31 μm 63 μm 94 μm; x 640