Phylum: Charophyta   Family: Desmidiaceae

Cosmarium pseudopyramidatum var. lentiferum W.R. Taylor 1934

Cosmarium pseudopyramidatum is a very variable species and has a number of varieties named after it. The Lewis cells depicted here are a little on the large size for the original concept of var. lentiferum as described by Taylor (1934: 261, pl. L: fig. 7.). However, Bourrelly (1966: 108, pl.18: fig. 2.) widens the size range by including a much larger cell. His measurements are precise suggesting he only found the one larger cell: 70 x 48, with an isthmus of 18 µm. Later, Prescott et al. (1981: 245, pl. CXCIV: figs. 1-3.) enbraced Bourrelly's cells and hence gave a much broader concept for the variety: L: 36-70, B: 26-49, Is: 6-18. My cells agree with Bourerelly's larger find but I'm not sure it should be attached here.

References: 
Taylor, W.R. (1934) The fresh-water algae of Newfoundland Part I.
Bourrelly, P. (1966) Quelques Algues d’eau douce du Canada.