SPOROCHNACE^. 



i7 



This genus is named in honour of the celebrated 

 French naturalist^ A. G. Desmarest. It does not con- 

 tain many species, but is nevertheless widely distri- 

 buted, and ranges over all the temperate and cold regions 

 to the utmost limits of marine vegetation. The young 

 and mature states of most of the species are very differ- 

 ent, and puzzle those who see them for the first time. 

 All the species not only decay very quickly after being 

 gathered, but also cause any other weeds with which 

 they may come in contact to do the same. They should, 

 therefore, always be kept separate, and laid down as 

 quickly as possible. 



Desmarestia ligulata. Ligulate Desmarestia. 



Prond fiat, with an iDdistinct midrib, repeatedly pinnate ; 

 branches and brauehlets opposite, tapering towards botli 

 ends. 



Ccommon all round our coast. It varies chiefly in 

 the width of the branches, which in some specimens is 

 nearly one-third of an inch, while in others it is scarcely 

 greater than in the filiform fronds of D. viridis, for which 

 it is in consequence sometimes mistaken. 



Desmarestia pinnatinervia. Pinnately-nerved 

 Desmarestia. 



Frond flat, leaf-like, with waved edges, from four inches 

 to a foot or more long, and from an inch to two or even 

 three inches broad, of a pale olive colour, and membranous 

 texture, traversed throughout by a distinct mid-vein, from 

 which spring exactly opposite side-veins. 



This interesting plant is a comparatively recent addi- 

 tion to the British marine flora, and its title to be con- 

 sidered a distinct species is still in doubt. The first 



