Species [var. contractum]:
Cell body 28-41 μm long, 18-31 μm wide,
isthmus 5.3-8.7 μm wide, L/W=1.5; semicells broad ellipsoid, laterally circular;
cellwall smooth or finely dotted, a single pyrenoid in each semicell. [var. ellipsoideum (Elfving) W. et G.S. West]: Cell body 31-51 μm long, 24-42 μm wide, isthmus 7-12.5 μm wide, L/W=1.3; apex of semicells slightly flattened; cellwall smooth. [f. jacobsenii (Roy) W. et G.S. West]: Semicells exactly ellipsoid, 28-47.6 μm long, 18-36.4 μm wide, isthmus 4.5-11.3 μm wide. [var. minutum (Delponte) W. et G.S. West]: Cell body 19-28 μm long, 14-22 μm wide, isthmus 4.3-5.6 μm wide; semicells elongated ellipsoid, laterally circular, cellwall dotted. (Illustrations of The Japanese Fresh-water Algae, 1977). |
50 μm
100 μm
150 μm; x 400 :
31 μm
63 μm
94 μm; x 640
