Oocystis novae-semliae var. maxima West & West 1894, p. 13 

 A variety dififering from the typical plant by its much greater 



size, 12-15/A in diameter, 19-23/* long; colony 23-42/x in diameter, 



40-52/* long. 



Plankter; in several lakes. Wis. 



Oocystis panduriformis West & West 1894, p. 15 



A family of 4 oblong-ovate cells with emarginate, concave lateral 



walls; cells broadly rounded at the poles and furnished with a 



conspicuous nodular thickening; chloroplasts numerous, parietal 



discs, each with a pyrenoid; cells 23-25/i in diameter, 50-61. 5/i long. 



Typical plant not represented in our collections. 



Oocystis panduriformis var. minor G. M. Smith 1916, p. 471 



PL 54, Fig. 11 



A variety differing from the typical plant by its smaller size, 

 12-20/A in diameter, 30-41/* long; colony of 4 cells up to 59/* in 

 diameter, 103/* long. 



Euplankter. Wis. 



Oocystis parva West & West 1898, Jour. Bot., 36, p. 335 



PI. 54, Fig. 3 



One-celled or in families of 2-8 individuals, inclosed by the 

 enlarged mother cell wall of the previous generation; 2-4 generations 

 sometimes involved; cells ellipsoid or fusiform with pointed poles 

 which are not furnished with definite polar nodules; chloroplasts 

 1 to 3 parietal discs, pyrenoids sometimes present; cells 4-7.5/* in 

 diameter, 6-15.6/* long; colony up to 43.9/* in diameter. 



Common in the tycho- and euplankton of several lakes and bogs. 

 Mich.,Wis. 



Oocystis pusilla Hansgirg 1890, p. 9 

 PI. 51, Fig. 15; PI. 54, Figs. 4, 5 



A colony of 4 ovate cells inclosed by the enlarged mother cell 

 wall; poles of the cells broadly rounded, without nodular thicken- 

 ings; chloroplasts 1 or 2 parietal plates, pyrenoids sometimes present; 

 cells 3.8-7.5/* in diameter, 6-12/* long. 



Plankter. Uncommon but found in several lakes. Mich., Wis. 



Oocystis pyriformis Prescott 1944, p. 357 

 PI. 54, Figs. 8, 9 

 Cells broadly pyriform-ovoid, with a prominent apiculation at 

 one pole, the other end broadly rounded; united in families of 2 



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