to a long hair, 16/x in diameter; sheaths thick, lamellate, discolored 

 in age; heterocysts basal, hemispherical, 12/x in diameter; cells 

 11-14/i in diameter, very short, V^-^i as long as wide, contents 

 blue-green. 



Attached to larger filamentous algae. Wis. 



Calothrix epiphytica West & West 1897, p. 240 

 PL 132, Figs. 2, 3 

 Filaments either single or in small clusters, gradually tapering 

 from base to apex, ending in a long hair; 5-7.5- (7.8) /a in diameter; 

 sheaths wide, not lamellate; heterocysts basal, 4-5/x in diameter; 

 cells 4-5/i, in diameter at the base of the trichome, about as wide 

 as long. 



On filamentous algae and submerged aquatics. Mich., Wis. 



Calothrix fusca (Kuetz. ) Bornet & Flahault 1886, p. 364 



PI. 132, Figs. 4, 5 

 Filaments strongly curved from short horizontal basal portions, 

 attached in the mucilage of other algae, bulbous at the base, 11-14/* 

 in diameter, tapering to a long hair; vegetative cells 7-1 1/x in 

 diameter, % as long as wide; heterocysts basal, hemispherical, 9-10/x 

 in diameter. 



Attached in the mucilage of Coleochaete, Batrachospermum, and 

 other algae inclosed in mucilage. Wis. 



Calothrix parietana ( Naeg. ) Thuret 1875, p. 381 

 PI. 132, Fig. 6 



Trichomes solitary or gregarious, forming dark brown patches on 

 submerged substrates or in aerial habitats, tapering from the base, 

 much twisted and contorted, with the basal portion of the trichome 

 appressed on the substrate; vegetative cells very short, 5-10/x in 

 diameter, 2.5-3/* long; heterocysts 6-10/* in diameter, usually basal, 

 quadrate-globose to hemispherical; sheaths firm, relatively thick 

 and close, not lamellated, becoming yellowish-brown with age; 

 filaments 10-12/* wide. 



Attached to old logs and stones in running water; tychoplankton. 

 Mich., Wis. 



Calothrix stagnalis Gomont 1895a, p. 197 



PI. 132, Fig. 7 



Filaments usually gregarious in stellate clusters or tufts, rarely 



soHtary, appressed to the substrate in the basal region but bent 



sharply or twisted to form an erect apical portion; trichomes tapering 



[553] 



