Chlorella vulgaris Beyerinck 1890, p. 758 

 PI. 53, Fig. 13 

 Cells spherical, scattered among other algae or sometimes occur- 

 ring in almost pure growths; chloroplast a parietal cup, sometimes 

 without a pyrenoid; cells 5-8.5-(10);a in diameter. 



In small lakes and pools, especially where there is a concentration 

 of organic matter. Mich., Wis 



WESTELLA de Wildemann 1897, p. 532 

 A free-floating, globose colony of 30-100 spherical cells without 

 a gelatinous investment; members in groups of 4 and bound together 

 by the persistent remains of old mother cell walls; 1 parietal, cup- 

 shaped chloroplast, often with a pyrenoid. 



Key to the Species 

 Colonies of 40 cells or fewer; cells arranged in 



linear series, 3-6/^ in diameter W. linearis 



Colonies of 40-80 cells; cells arranged to form 



quadrate or pyramidate clusters. — __ W. botryoides 



Westella botryoides ( W. West) de Wildemann 1897, p. 532 



PI. 53, Fig. 14 

 Colony composed of 40-80 spherical cells, quadrately arranged 

 in groups of 4, the groups loosely connected by the persistent 

 remains of old mother cell walls; cells with 1 parietal, cup-shaped 

 chloroplast; pyrenoid sometimes present; cells 3-9/a in diameter. 



Rare but widely distributed, in a large number of lakes, especially 

 in the plankton of soft water. Mich., Wis. 



Westella botryoides var. major G. M. Smith 1918, p. 628 



A variety differing from the typical by having larger cells, 8-lSfj. 

 in diameter. 



Rare in euplankton. Mich., Wis. 



Westella linearis G. M. Smith 1920, p. 107 



PL 53, Figs. 15, 16 



An irregularly shaped colony of about 40 spherical cells arranged 



in a linear series of 4; groups of cells held together by inconspicuous 



remains of old mother cell wall fragments; cells 3-6/a in diameter. 



Rare in euplankton. Wis. 



DICTYOSPHAERIUM NaegeU 1849, p. 72 

 Colony globular or ovoid, composed of spherical or ovoid cells 

 attached by fine, branching strands which radiate from a common 



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