ANAB.ENA. 285 



Syn. Nostoc irregular e, Wartm. ; N. nivale. Kg. ; N. Peloponne- 

 siacum, Kg.; N. sphwricum, Menegh. ; Tremella verrucosa, 

 Huds. 

 In limestone springs, streams, etc. 



Plate CXCVII, fig. 1, a frond ; fig. 2, filaments from a 

 frond. 



NOSTOC ALPINUM, Kg. 



Growing attached by its margin to rocks in running 

 water, also to dripping rocks. Frond suborbicular, erect, 

 membranaceous, 3-8 lines high, and 1-3 lines thick, very 

 tenacious 5 deep olive green, smooth, often rugosely plicate 

 at the base ; trichomes laxly or somewhat densely inter- 

 woven ; heterocysts spherical. 



Syn. N. Sunderlandi, Dickie : N. cristatum. Bailey ; N. parmeli- 

 oides, Kg. 



From specimens from the rocky bottom of the Susque- 

 hauna, Harrisburg, Pa., and from the Palisades, N. Y. 



Plate CXCVII, figs. 33, 34, fronds in front and in side 

 view. 



NOSTOC ZETTERSTEDTIANA, N.N. 

 A form not recognized here. 



NOSTOC FLAGELLIFORME, Burk. and Curt. 



Fronds dark olive, several inches in length, half a line in 

 diameter, lying prostrate on the surface of the soil, much 

 branched in an irregular dichotomous manner; branches 

 linear compressed ; periderm firm and elastic, cartilaginous, 

 densely filled with moniliform filaments. 



On naked aluminous soil, at San Pedro, Texas. Collected 

 by C. Wright. 



Plate CXCVII, fig. 32, specimen in my herbarium from 

 Texas. 







Genus 94, ANAB^ENA, Bory. 



\ 



Filaments similar to those of Nostocs, moniliform, singly or 

 clustered in gelatinous masses, with rare exceptions with a 

 sheath ; cells globose, or subglobose, some of which change into 

 globose or elongated spores, usually of a brownish color. Heter- 

 ocysts intercalated in the filaments. 



There is considerable vagueness of character in this and three 

 or four allied genera. Different modern authors have modified 



