322 FRESH-WATER AI.G.E OF THE UNITED STATES. 



Syn. Hpyheoihrix bullosa, Wolle, Bulletin, Tor. Bot. Club, 1877. 



Have been hesitating whether to place this singular plant 

 here or with Microcoleus. Filaments rarely appear divided, 

 and contain two trichomes (internal), but as a whole the 

 plant has most in character with the present genus. 



Plate CCVIII, fig. 19, spherical bodies surrounded by 

 loose wool-like threads, natural size, also three fragments of 

 filaments largely magnified. 



LEPTOTHRIX OCHRACEA, Kg. 



Forming cloud-like, floating, fragile masses of an ochery 

 color. Trichomes very slender, in short, fragmentary parts, 

 scattered. Not articulate. 



Diameter of trichomes, about 2 yw. 



Syn. Lyngbya ochracea, Thur. ; Conferva ochracea, Dillw. ; Oscil- 

 latoria ochracea, G-rev. 



Not infrequent in small pools, produced in rust colored 

 cloud-like masses. The filaments are very slender and 

 usually scattered in broken fragments. A very insignifi- 

 cant form, and of doubtful value. Dillwyn represents the 

 filaments branched ; so are most of our specimens. Sheaths 

 and articulations indistinct. The whole seems more in 

 character with a filamentous lichen, than an algae. Prevails 

 in small pools from Massachusetts to Florida. The position 

 given this plant by Thuret, Kirchner and others, does not 

 appear justifiable, unless the European form is quite distinct. 

 Dried specimens do not appear unlike ours. 



Plate CCII, figs. 32, 33, filaments sometimes decidedly 

 branched ; Plate CCVIII, fig. 14, filaments simple. 



Genus ASTEKOTHRIX, Kg. 



Filaments indistinctly or sometimes distinctly articulate, more 

 or less rigid ; cruciformly branched, nude, ends acute cuspidate 

 or obtuse, somewhat genuflexuous. Propagation unknown. 



ASTEROTHRIX CREGINII, Wolle. 



Filaments short, light bluish green ; branches at right 

 angles, cross-like; articulation usually distinct, somewhat 

 moniliform. 



Diameter of filaments, 2-4 yu. 



Found thickly scattered through a deposit of fine siliceous 

 sand in Norton County, Kansas. Reported by Prof. F. .W 

 Cregin. 



