Pediastrum duplex var. cohaerens Bohlin 1897, p. 31 



PI. 48, Fig. 11 



Colony with large clathrations; cell walls granular; cells 15-20/i, 

 in diameter. 



Common in tychoplankton. Mich., Wis. 



Pediastrum duplex var. gracilimum West & West 1895a, p. 52 



PI. 48, Fig. 12 

 Colony with large perforations; body of cells narrow, equal in 

 width to the processes of the peripheral cells, which are relatively 

 larger than described for the typical plant. 



This is undoubtedly a growth form of the typical plant. 

 Euplankter. Mich., Wis. 



Pediastrum duplex var. reticulatum Lagerheim 1882, p. 56 



PI. 49, Fig. 1 



Outer margins of the peripheral cells having lobes with subparallel 

 sides; inner cells nearly H-shaped. 



This form, like the preceding one, should be interpreted as a 

 growth form of P. duplex. 



Widely distributed; euplanktonic. Mich., Wis. 



Pediastrum duplex var. rotundatum Lucks 1907, p. 31 



PL 48, Fig. 8 



Marginal cells with stout lobes which have convex rather than 

 parallel margins; apices of lobes closer together than in the typical 

 plant. 



Euplankter; common. Mich., Wis. 



Pediastrum duplex var. rugulosum Raciborski 1889, p. 24 



PI. 49, Fig. 3 

 Colony ovoid, entire except for small lens-shaped openings be- 

 tween peripheral and inner cells; walls irregularly crenate and 

 wrinkled, granular; cells 15-22/i, in diameter. 

 Euplankter. Wis. 



Pediastrum glanduliferum Bennett 1892, p. 7 



PI. 49, Fig. 4 



Colony elliptical, entire or nearly so; peripheral cells 5- or 6-angled 



with a concave incision between 2 long, capitate projections which 



are tipped with a globular swelling; cells about 10/a in diameter, 12/a 



long. 



Euplankter. Wis. 



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