THE MARINE BOTANIST. 119 



scribes it as follows : — ^^ Substance stiff and little. 

 Colour reddish. Stems set with spines which hold 

 the plant together so that it is difficult to dis- 

 entangle." 



P. iiigrescens. A very common species on rocks 

 and stones between tide-marks ^ it dries of a black 

 colour, and scarcely adheres to paper excepting in 

 specimens collected in the summer, when the ramuli 

 are tender and then adhere better. In autumn 

 and winter this species looks coarse and bushy, from 

 the loss of the more slender branchlets, which 

 disappear at the end of the season. It is a vari- 

 able species, putting on many different aspects ; 

 microscopically it may be known from other 

 species by the very large number of tubes in the 

 stem. 



P. affinis. On rocks, &c., in the sea. Carn- 

 lough, near Glenarm. Cushendall. Not unlike 

 the preceding, but more flaccid, and with an ovate 

 outline. 



P. subulifera. Usually grows in deep water, 

 very local. Annual. Summer. Torquay. Wey- 



