Ulvacece.'] porphyra. 323 



gives now in the ' Phycologia ' liis decided opinion tliat it is 

 only a narrow-fronded variety of P. vulgaris in a young 

 state; that though in November they appear distinct 

 enough, by the end of spring it will be difficult to trace in 

 them the slender ribbons of winter. He admits that there 

 are localities near high-water mark where the frond never 

 attains any great length or breadth, and therefore remains 

 more true to the name linearis , but the stunted growth is 

 clearly referable to deficient nourishment. All this may be 

 correct, but I am not thoroughly convinced ; and I am 

 unwilling to give up the pretty little linearis. It appears 

 to me more distinct as a species than P. laciniata ; and 

 this, perhaps, is not saying much, for with us P. vulgaris 

 and P. laciniata run very close into each other. With us 

 they are of the same colour, and this cannot be said of P. 

 linearis, which is always diff'erent from both the others; 

 these two are never reddish here, and linearis always is. 

 P. linearis, for many miles on the coast of Ayrshire, is got 

 only on one little patch of rock in early spring, painting it 

 red when the tide is out; P. vulgaris is found at the 

 same season quite near it, as near high- water mark, almost 

 as narrow as linearis, but nearly a foot long, which is more 

 than the length of linearis ; and while linearis is always red. 



