Chroococcus varius A. Braun in Rabenhorst 



1861-1878, Nos. 246, 248, 252 



PI. 100, Fig. 15 



An irregularly shaped colony of 2-8 spherical cells inclosed by a 



hyaline, sometimes colored, gelatinous envelope, forming dark-green 



or brownish masses on moist aerial substrates, or among other algae 



in shallow water; colonial envelope lightly lamellate, individual cell 



sheaths not distinctly evident; cell contents blue-green or olive, not 



granular; cells 2-4/u in diameter. 



Most of the records of this species in North America are from 

 moist substrates near geysers and hot springs, or from sulphur water. 

 Not infrequent in the tychoplankton of a variety of both hard and 

 soft water lakes. Wis. 



GLOEOCAPSA Kuetzing 1843, p. 174 



Essentially unicellular but with many individuals aggregated to 

 form amorphous gelatinous masses of spherical cells, or as associa- 

 tions of families of irregularly arranged cells, each individual in- 

 closed by a lamellate, mucilaginous, and usually thick sheath; plant 

 mass blue-green, reddish, yellowish, or brown; cell contents blue- 

 green or yellowish to olive-green, homogeneous or (more often) 

 granular, without pseudo vacuoles. 



This genus should be compared with those attached or sedentary 

 species of Chroococcus in which the colonial envelopes of the 

 families are persistent and do not become confluent with the general 

 investing mucilage. In general, Gloeocapsa masses contain many 

 more cells than Chroococcus, and the lamellate, thicker sheaths are 

 more conspicuous, whereas in some (especially planktonic) species 

 of the latter genus they tend to become confluent. 



Key to the Species 



1. Sheaths yellowish or brownish to orange G. rupestris 



1 . Sheaths colorless — - - 2 



2. Cells 6-9m in diameter without sheaths, 11-12/t 



in diameter with sheaths __ G. calcarca 



2. Cells smaller 3 



3. Plants encrusting on moist substrates; cells 2-4^ in diameter .__- G. aeruginosa 

 3. Plants free-floating ( tychoplankton ) ; cells 



0.7-2.3/x in diameter'. G. punctata 



Gloeocapsa aeruginosa ( Carm. ) Kuetzing 



1845-1849, Tab. Phyc, PI. 21, Fig. 2 



PI. 101, Fig. 6 



Plant mass with firm or leathery mucilage, blue-green; cells 



spherical, with blue-green, homogeneous contents, arranged in small 



[451] 



