net-work covering only part of the wall, containing 1 pyrenoid; 

 both starch and oil present as food reserves; reproduction by frag- 

 mentation and by autospores. 



Key to the Species 

 1. Cells inclosed by a tough, rubbery, often darkly colored mucilage 2 



1. Cells invested by a thin, colorless mucilage B. sudeticm 



2. Colonial envelope completely covering the cells; mucilage darkly 



colored, especially in the older colonies B. Braunii 



2. Colonial envelope leaving the outer face of the cells free B. protuberans 



Botryococcus Braunii Kuetzing 1849, p. 892 

 PI. 52, Figs. 1, 2, 11 



Cells ellipsoid, radiately arranged at the periphery of irregularly 

 shaped, usually dark-colored masses of mucilage; free floating; 

 colonial mucilage much folded and extended into tough, foamy 

 strands, often forming colonial complexes by interconnecting strands 

 of mucilage; chloroplast a thin, or dense, parietal net with 1 pyrenoid, 

 covering only a portion of the wall (often masked by the dark 

 color of the mucilage); starch and oil droplets present; individual 

 cells invested by a layer of fatty substance and an outer layer of 

 pectin; cells 3-6/x in diameter, 6-12/a long. 



Common, and often abundant, especially in semi-hard water 

 lakes where it frequently is the dominant component of water-bloom 

 associations. 



Mich., Wis. 



Botryococcus protuberans var. minor G. M, Smith 1918, p. 652 



PI. 52, Figs. 4, 5 



Cells ovoid, arranged in few-celled clusters which are connected 

 by long tough, fibrous strands, 4-16 such clusters involved to form 

 multiple colonies; cells embedded in but not entirely surrounded 

 by mucilage, one end protruding at the periphery; cells 5-6.5^ in 

 diameter, 8-9.5yu, long. 



Rare to common in the euplankton of several lakes, Mich., Wis. 



Botryococcus sudeticus Lemmermann 1896a, p. Ill 



PL 52, Fig. 3 

 Cells spherical, clustered and embedded in a hyaline mucilaginous 

 envelope, forming irregularly shaped or somewhat spherical masses 

 which may be joined together by gelatinous strands to form com- 

 plexes; cells 6-13;u, in diameter. 



Rare in the euplankton of several lakes. Mich., Wis. 



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