NO. 10 DAWSON : MARINE ALGAE, GULF OF CALIFORNIA 253 



Genus PORPHYRA J. Agardh 

 Porphyra perforata J. Ag. 



J. Agardh, 1883, p. 69; Hus, 1902, pi. XX, figs. 4a-10; Phyc. Bor. 

 Amer., no. 682. 

 Specimens agreeing very well with certain forms of this species as 

 they occur on the coast of California and the outer coast of Lower Cali- 

 fornia were collected from an abundance of material on the upper littoral 

 rocks at Agua Verde Bay, D. 539, February. The plants are greenish rose 

 colored when dry, up to 16 cm. high and with lanceolate fronds. The 

 habitat is also typical of the species. Our material is probably nearest to 

 what Setchell and Hus called Porphyra perforata f. segregata (loc. cit.). 



Porphyra Thuretii Setchell & Dawson nom. nov. 



Porphyra leucosticta Hus (not of Thuret) 1902, p. 199, pi. XX, figs, la- 

 3b; Howe, 1911, p. 499; Phyc. Bor. Amer., no. 376. 



Fronds from a small, distinct disk, bearing a short but distinct stipe 

 with cordate base expanding into a broader or narrower oblong mem- 

 brane, 7-70 cm. long, 2-25 cm. broad, margins somewhat undulate, mono- 

 stromatic, cells once and a half to twice as broad as high (in transverse 

 section), surface jelly and jelly between cells thin, very readily soluble in 

 dried plants; monoecious, spermatangia forming small elongated patches 

 among the dark-colored cystocarps, the fruit at first marginal, gradually 

 developing over the whole frond, compact, no vegetative cells mixed with 

 the reproductive cells; vegetative frond 25-50 fx thick, cystocarpic 25-50 

 yu, thick, spermatangial 30-50 fx thick; each cystocarp (simple) forming 8 

 spores (in two tiers) ; spermatangia (simple) forming 64 spermatia ar- 

 ranged in two spherical groups in each spermatangium ; color pinkish. 



Type: W. A. Setchell 5161 (Univ. Calif., Flerb.), Pacific Grove, 

 California. 



Specimens are also known in California from Santa Cruz and from 

 Monterey Bay, on rocks or sometimes epiphytic, March to May. 



Hus has already called attention to the fact that the Pacific coast 

 specimens referred by him to Porphyra leucosticta Thuret differed from 

 the European and N. E. Atlantic coast specimens in being more definitely 

 stipitate, in being a much lighter shade of red, and in the arrangement of 

 the spermatia within the spermatangium. Although the type specimen of 

 Thuret has not been studied, in view of these differences and the wide dis- 

 continuity in distribution it seems best to bestow upon the California 



