Scenedesmus acuminatus (Lag.) Chodat 1902, p. 211 



PI. 62, Fig. 16 

 Cells arranged in a curved series of 4 (rarely 8) cells strongly 

 lunate, with sharply pointed apices, the convex walls adjoined in- 

 wardly, the concave faces directed outward; cells S-7 fj. in diameter, 

 30-40/x long. 



Plankter; rare. Mich., Wis. 



Scenedesmus acuminatus var. minor G. M. Smith 1916a, p. 436 



A small variety; cells 3.5-6/x in diameter, 18-28/x between the 



apices. 



Wis. 



Scenedesmus acuminatus var, tetradesmoides 



G. M. Smith 1916a, p. 439 

 A variety with cells less strongly curved than in the typical; 

 2.5-4^ in diameter, 11-15/x long; curvature of colony varying from 

 slight to acute. 

 Wis. 



Scenedesmus acutiformis Schroeder 1897a, p. 45 

 PL 62, Figs. 6, 7 

 Cells arranged in a single series of 4 (2 to 8), fusiform-elliptic, 

 with poles sharply pointed; inner cells with a single facial longitu- 

 dinal ridge; outer cells with 2-4 longitudinal ridges; cells 7-8/x in 

 diameter, (16)-22.5/a long. 



Plankter; found in several lakes and bogs; fairly common. Mich., 

 Wis. 



Scenedesmus arcuatus Lemmermann 1899a, p. 112 



PI. 62, Fig. 8 

 Cells arranged to form a curved (usually double) series of 4-16 

 oblong-ovate individuals with lateral walls in contact along V^to % 

 their length; cell wall without spines or teeth; poles of the cell 

 broadly rounded; cells 4-8-(9)/a in diameter, 10-15- ( 17 )/x long. 

 Swamps, lakes. Mich., Wis. 



Scenedesmus arcuatus var. capitatus G. M. Smith 1918, p. 637 



PI. 62, Fig. 9 

 Similar to the typical form but with a short, blunt-pointed pro- 

 jection at each pole of the cells; cells 5-11/a in diameter, 11-23^ long. 

 Wis. 



Scenedesmus arcuatus var. platijdisca G. M. Smith 1916a, p. 451 



PI. 62, Figs. 10-12 

 Plant composed of 8 cells arranged in a flat, rather than a curved, 

 double series; cells oblong-elliptic, 4.5-7.5/x in diameter, S-ll/x long. 

 Mich., Wis. 



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