VOL. III.] NaUiral History of the Faralloiics. 149 



This little Porphyra I have found growing only on Zostera and 

 Phyllospadix, but it probably grows on other plants, hence the name 

 for the order to which these two plants belong, Naiadaceae. Some 

 small mollusks, in rasping for food on these plants, cause abrasions, 

 in which the spores of this Porphyra find a place to adhere and 

 grow, so that many of the stems and leaves of these Naiads are lit- 

 erally covered with the brownish-purple fronds. It may be found 

 at all seasons, wherever these weeds grow, along the whole length 

 of our California coast. 



Iteretofore it has been distributed as Porphyra zndgaris, but 

 without much more reason than our early botanists had for placing 

 all seaweed in the genus Fucus. 



It adheres closely to paper, and retains its natural color pretty 

 well when mounted. 



P. Nereocystis Anderson, n. sp.* — Fronds 3 to 20 inches long 

 and I to 3 inches broad, very thin and ribbon-like, with nearly even 

 or slightly crinkled edges and a somewhat pointed or oval tip; stipes 

 very short or entirely wanting; frond often divided, sending long sec- 

 tions from either side; color brownish-purple, often changing to a 

 bright carmine-purple, with a soft, glossy surface. Cells smaller, but 

 otherwise hardly difi"erent from P. vulgaris Harv. 



This large and beautiful Porphyra is most frequently found, on 

 this Coast, growing on the long stems of the Nereocystis, although 

 not always confined to that plant. Frequently it is torn loose and 

 comes ashore in the drift, but mostly in fragments. It also has 

 been considered only a form of P. vulgaris. But its structure, color 

 and form surely entitle it to a specific place. 



It adheres well to paper, and is seldom found until past midsum- 

 mer, when the long stems of Nereocystis are well grown. 



Ceramium diaphanum Roth. 



Centroceras clavtdatum Ag. 



Microcladia Coulteri Harv. 



M. borealis Rupr. 



Ptiloia asplenoides Ag. 



P. plumosa Ag.=/'. filicina. 



P. deiisa Ag. 



* This was published — name only — in "List of California Marine Algre," Zoe, 

 ii, 221. 



