on stones, shells, and other submerged objects. In many there is a 

 definite basal-distal differentiation, with the lower part of the cell 

 narrowed to form an attaching stipe. Although cell division is used 

 by a few forms, the characteristic method of reproduction is by 

 endospores (gonidia), i.e., spore-like bodies cut out simultaneously 

 from the entire protoplast or by successive constrictions at the 

 anterior end of the cell. There is but a single genus represented in 

 our collections. 



CHAMAESIPHON Braun & Grunow in Rabenhorst 1865, p. 148 

 A slender, club-shaped (sometimes ovate or pyriform) sheathed 

 cylinder from a narrow attaching basal portion, growing epiphytic- 

 ally on other algae or larger aquatics; sheath open at the widened 

 apex when the cell is mature to permit the escape of 1-celled gon- 

 idia (endospores) which are cut off successively from the anterior 

 end of the protoplast; cell contents pale to bright blue-green, homo- 

 geneous; sheath thin (usually), hyaline or yellowish; plants nearly 

 always gregarious and often forming extensive patches and showing 

 all stages of development, the germinating endospores sometimes 

 forming a layer more than one cell in thickness on the substrate. Of 

 the many species recognized for this genus, only three are identi- 

 fiable in our collections. 



Key to the Species 

 1. Cells long and strongly curved from a stipe-like base ____ C. curvatus 



1. Cells short, or elongate, straight, not strongly curved ___ 2 



2. Entire content of the cell becoming divided to 



form many gonidia simultaneously __„ C. confervicola 



2. Gonidia cut away from the apex of the protoplast 



by successive constrictions C. incrustans 



Chamaesiphon confervicola A. Braun in Rabenhorst 1865, p. 148 



PI. 108, Fig. 4 



Cylindrical to claviform, usually straight, sometimes curved; 1-2/x 

 in diameter at the base, 3-9ju, at the apex; sheath thin, expanded 

 above; % to % of the protoplast divided to form endospores, which 

 are 2-4/* in diameter and which may occur in double series or in 

 groups of 4; plant either solitary or gregarious. 



Epiphytic on Cladophora and on submerged mosses and other 

 aquatic plants. Wis. 



Chamaesiphon curvatus Nordstedt 1878, p. 4 

 PI. 108, Figs. 5, 6 

 Several-celled, violet in color, solitary or gregarious, cylindrical, 



[476] 



