Chaetosphaeridium glohosum ( Nordst. ) Klebahn 1893, p. 306 



PI. 14, Figs. 6, 7 



Unicellular, solitary or gregarious, flask-like, the sheath tapering 

 above to form a conical or cylindrical investment of the long fine 

 seta which extends from the cell. Basal interconnecting tubes usually 

 not apparent. Single chloroplast. Cells 12-20)u, in diameter. 



Common; attached to filamentous algae and small aquatic plants; 

 frequently free-floating when old, appearing in the tychoplankton 

 in shallow water of bays and swamps. Mich., Wis. 



Chaetosphaeridium ovalis G. M. Smith 1916, p. 471 



PL 14, Fig. 8 

 Unicellular; solitary or, more often, gregarious in groups of 5-20 

 ovoid individuals. Sheath indistinct about the cell but clearly evident 

 around the base of the seta. Cell with 2 parietal chloroplasts, each 

 with a pyrenoid. Cells 13-15/x in diameter, 20-22/x long; setae ap- 

 proximately 125fx long. 



On submerged aquatics in shallow water. Wis. 



Chaetosphaeridium Pringsheimii Klebahn 1892, p. 276 



PL 14, Fig. 5 

 Unicellular; cells gregarious, but without a common mucilaginous 

 investment. Sheaths present, often forming long basal tubes so 

 that the cells appear in linear series and interconnected. Cells 9-12/i, 

 in diameter; setae up to 300/a long. 

 Mich. 



Chaetosphaeridium Fringsheimii fa. conferta 

 Klebahn 1893, p. 307 

 A form in which the cells are more closely arranged than in the 

 typical; utricles very short. 



In several lakes and in Eagle River, Wis. 



DICRANOCHAETE Hieronymus 1887, p. 293; 1892, p. 370 



A unicellular epiphyte, hemispherical or flattened against the 

 host, bearing a fine, branched seta which arises from the under side 

 of the cell, the seta with a gelatinous sheath. Chloroplast an inverted, 

 parietal cup with 2-3 pyrenoids. Plants solitary or gregarious. 

 Reproduction by zoospores and isogametes. 



The chaetophoraceous character of this genus and its similarity 

 to Chaetosphaeridium necessitate its inclusion in the Chaetophorales. 

 The fact that the plant does not reproduce vegetatively by cell 

 division suggests, of course, strong affinities with the Chlorococcales. 



[131] 



