NOSTOC. 287 



the course of the filaments, from which finally they become 

 separated. 



<( This name is unexplained : it was first used by Paracel- 

 sus, and adopted by Yaucher for the present group, which 

 before that time was included in Tremella" Harv. 



1. NOSTOC VARIEGATUM Moore. 



Plate LXXIV. Fig. 3. 



Char. Frond terrestrial) expanded, gelatinous, livid, variable 

 in shape. Filaments rather distant. Cells oval, and 

 variable in size. 



Harv. in Manual, p. 183. 



Hob. Ireland : Mr. Moore. 



" This singular plant I first collected in 1836, growing on 

 the face of a moist bank over which water trickled. When 

 recent it formed a soft gelatinous mass, of a livid colour, 

 bearing the closest resemblance, both in substance and co- 

 lour, to those gelatinous Medusas which are cast ashore along 

 the coast, and called by the country people f fallen stars.' I 

 again collected it on the same spot in 1838, when I sent Dr. 

 Greville specimens, who thinks it different from any thing 

 he knows, and coming nearest to Nostoc commune" 

 Moore's MS. 



If I had acted on my own convictions in reference to this 

 species, I should have removed it to the genus Anabaina, to 

 which it seems more properly to belong than to Nostoc. In 

 the genus Nostoc there is an exact similarity in all the fila- 

 ments ; in the species under consideration, a considerable 

 want of uniformity is observed, some being composed of cells 

 larger than those of others, as may be seen by the figure, in 

 which particular it resembles Anabaina, as it does also in the 

 diffused or unlimited mucous matrix, in which the threads 

 are imbedded, and in the oval form of the enlarged or repro- 

 ductive cells. 



