Pediastrum Boryanum var. undulatum Wille 1879, p. 28 



PI. 48, Fig. 2 

 Similar to the typical plant, but the adjoining cell walls are 

 undulate and irregular rather than straight; surface walls with 

 granules or smooth; the lobes of the peripheral cells narrow and 

 longer than in var. rugulosum, lobes of one cell about the same 

 distance apart as are the lobes of adjoining cells; cells 17— 22jii in 

 diameter. 



Euplankter. Mich., Wis. 



Pediastrum Braunii Wartmann in Wartmann & Schenk 

 1862, Fasc. 1, No. 32 

 PI. 48, Fig. 5 

 Colony circular in outline, nearly entire but with a few interstices, 

 composed of 4-16 quadrate or 5-sided cells (11 peripheral and 5 

 central); peripheral cells with 3 or 4 short, sharp projections which 

 are unevenly spaced; interior cells 4-5-sided, the walls without 

 projections or incisions; cells 9-12/x in diameter. 

 Euplanktei, Wis. 



Pediastrum duplex Meyen 1829, p. 772 

 PI. 48, Fig. 4 



Colony 8-128-celled, the walls smooth, with lens-shaped spaces 

 between the inner cells, which are quadrate, the outer margin 

 concave; peripheral cells quadrate, the outer margin extended into 

 2 tapering, blunt-tipped processes, distance between processes of 

 one cell about one-half the distance between processes of adjacent 

 cells; cells 15.6/,i in diameter; 36-celled colony lOS/x in diameter. 



Common in the eu- and tychoplankton of many lakes and swamps. 

 Mich., Wis. 



Pediastrum duplex var. brachylobum A. Braun 1855, p. 93 

 A variety in which the peripheral cells bear 2 widely separated, 

 very short, truncate processes (about 3/a long); colony composed 

 of 16-128 cells, with granular walls; colony up to 300/x, cells up to 

 40^, in diameter. 

 Mich. 



Pediastrum duplex var. clathratum (A. Braun) Lagerheim 1882, p. 56 



PI. 48, Fig. 6 



Colony with larger perforations than in the typical form; walls 

 with deep emarginations; apices of lobes of peripheral cells truncate; 

 cells 12-20/i in diameter. 



Very common in a large number of lakes of both hard and soft 

 water; generally distributed. Mich., Wis. 



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