290 NOSTOCHINE^E. 



Ulva pisiformis Hudson. Conf. pisum, Flor. Dan.; 

 Harv. in Hook. Brit. Flor. p. 400. ; Harv. in Manual, 

 p. 185. ; Meneghini, Monographia Nostochinearum, 

 p. 110. 



Hob. In rivulets and fountains, attached to stones, &c. 

 Appin : Captain Carmichael. Pools near Barmouth and 

 Llyn Coron, near Anglesea : Mr. Ralfs. Co. Wick- 

 low : Mr. Moore. 



" Fronds from half a line to two lines in diameter, globular, 

 firm, smooth, solid, heaped on each other like a parcel of small 

 shells. Internal filaments rather thinly scattered through the 

 mass." Carm. 



ee This species dried and again moistened sometimes emit a 

 most grateful violet odour, as though it were a species of 

 Chroolepis, and such as no other Alga of the family of Nos- 

 tochinece presents." Menegh. 



The filaments are moniliform, and exactly correspond with 

 those of Nostoc foliaceum in size, the young state of which 

 species, as it agrees with it also in habit, it may eventually 

 prove to be. 



5. NOSTOC VESICAKIUM D. C. 



Char. (f Frond globose, plicated., greenish yellow., the internal 

 viscid mucus escaped, vesic&form, cartilaginous. Filaments 

 curved, slender, with cells twice as large, thickly interspersed 

 and terminal." Menegh. 



D. C. Flor. Fr. vol. iii. ; Harv. in Hook. Br. Flor. p. 399. ; 

 Harv. in Manual, p. 184.; Ag. Syst. p. 19. ; Meneghini, 

 Monographia Nostochinearum, p. 108. 



Hob. Road-side, near Perth : G. A. W. Arnott, Esq. 



" The diameter of the frond varies from a millimetre to an 

 inch. The colour in the smaller fronds obscurely green, verges 

 in the larger to a yellowish brown. Substance firm, cartilagin- 

 ous, including a fluid viscous juice : afterwards, the gelatinous 

 substance having escaped, empty, vesicasform, membranaceous ; 



