154 SEA MOSSES. 



common at San Diego. It is among the most com- 

 mon forms that come to me from my correspondents 

 on the Pacific coast. The color is a full black. It 

 adheres very imperfectly to paper. 



The artist has very excellently represented a frond 

 of this species, in Plate VIII. 



POLYSIPHONIA PARASITICA, GrEV. 



This species in many respects, and especially in 

 general aspect and outline, resembles the last, but 

 differs from it by being smaller, of a much finer 

 and more delicate substance, and lighter color, which 

 is usually a light reddish brown. I have never seen 

 typical forms of this species over two inches high. 

 The figure in Plate VII, excellently well pictures 

 not only the color but every characteristic feature of 

 this very beautiful plant. The stem, branches and 

 branchlets are all flattened and branch from the two 

 edges, primary branches irregularly and very widely, 

 secondary regularly, widely, alternately. The secondary 

 branches are mostly little plumes, or themselves 

 bearers along their edges of little plumes. The 

 branching of all the small parts, even to the 

 minutest, is regularly alternate. This gives the plant 

 a very delicate, feathery appearance, very greatly like 

 the finer fronds of Ptilota plumosa. My correspond- 



