Species [var. praelongum]: 
Cell body 380-885 μm long, 11-26 μm, L/W = 22-24;  
slightly curved but straight at the center, tapered at both ends; curveture reversed at both ends, cell wall finely striated.  
[var. brevius Nordstedt ]: 
Cell body shorter than v. praelongum, 
198-360 μm long, 13-24 μm, L/W = 10-22.  
[var. porosum (Gutwinski) Krieger ]: 
Cell body 120-557 μm long, 18-24 μm, L/W = 10-22;  
cellwall finely dotted, 
 (Illustrations of the Japanese Fresh-Water Algae, 1977). 
  
 
 |