BOT.— Vol. II.] 



HUS—rORPIIVRA . 175 



Collins (1882) reported P. Jaciniata from the east coast, and 

 later (1884) P. leticostida and P. miniata. 



J. Agardh (1882) reports P. coccinca (P. naiadumf ) and 

 P. perforata from the Pacific Coast. Since then Dr. Ander- 

 son (1892) has added two new species to the number, 

 P. naiadum and P. nereocystis. 



Miss Tilden in Century III of "Alg£e of North America" 

 has distributed four species of Porphyra from the Pacific 

 Coast under the names P. miniata, P. naiadum, P. lenco- 

 sticta, and P. laciniata. 



Up to 1898, however, there had been reported from the 

 west coast of North America but four distinct species. 



In the winter of 1897 Professor Setchell suggested that 

 the writer investigate the peculiar base of P. naiadum 

 And., but specimens of Porfhyra gathered on collecting 

 trips, and a consideration of those in the herbarium, showed 

 such a variety of morphological and anatomical characters 

 that the desirability of a collection and investigation of the 

 species of Porfhyra occurring on this coast became appar- 

 ent; it is the results of these investigations which are set 

 forth in the following paper. 



II. Morphology. 



The shape of the fronds of the various species of Porphyra 

 is exceedingly variable, but that of most of them can be 

 reduced to the elongated type of frond. The variation is 

 between linear and oblanceolate, and nearly all the species 

 mentioned in this paper exhibit both characters at various 

 periods of their existence. A striking exception to this rule 

 is Porphyra perforata f. lanceolata, which, as a rule, is 

 constantly linear; yet there are specimens in our herbarium 

 which are decidedly lanceolate. On the other hand, I 

 beheve there are but few mature specimens oiP. temtissima, 

 if any, which ever exhibit a Hnear form. The nearest 

 approach the plant makes to the linear form is when young; 

 it then-possesses an oblong outline. 



Closely connected with the shape of the fronds are their 

 length and width. These three characters seem to be 



