VOL. 5 | West-Coast Porphyras. 67 
cells of the layer adjacent to the surface of the blade of the host- 
plant produce rhizoid-like projections which enter, to a very slight 
extent, the cuticula of the host-plant. 
This parenchymatous base enables us to distinguish easily 
between this species and 7. adyssicola, though there also exists a 
difference in the reproductive bodies, ?. xaiadum being apparently 
dicecious, each sporocarp containing 8 carpospores. 
flabitat. P. naiadum occurs exclusively on Phyllospadix and 
Zostera. In sheltered places we find it.all through the winter, 
but where the eel-grass is exposed to the violence of the waves the 
Porphyra disappears about August, to reappear in the Semaren 
form in the latter part of January. | 
Distribution. This plant appears to be limited to the Pacific 
Coast, cectoag from Washington to Southern California 
(48° 10’—32° 20’ N. lat). 
Localities. Coupeville, Washington, N. dis Gardaveis Ballard 
Beach, Seaftle, Washington, A/ss /. &. Tilden’; Cresent City, 
_ Del Norte Co., Calif., WH. Hus’; Fort Ross, Sonoma Co., Calif., 
W. A. Setchell No. 1789!/; Duxbury Reef, Marin Co., Calif., 
» W. A. Seichell No. 1037! H. Hus!; Farallone Isl., Calif., 7: 
W. Blankinship,;, Wand’s End, San Francisco, Calif., W. A. - 
Setchell! H. Hus!; Monterey, Calif., W. A. Setchell! C. P. Nott! 
R. E. Gibbs! H. Hus!; Santa Cruz, Calif. C. Z. Anderson’; 
‘San Pedro, Calif., 4. J. McClatchie,; San Diego, ne , Wiss Reed 
No. ro7/ 
- PORPHYRA AMPLISSIMA (Kjellm.). Setchell et Hus MS. 
. Diploderma amplissimum (Kjellm.).- The Algee of the Arctic 
Sea, p- 188, 1883. 
This species can be distinguished from other Maicchiaee species 
by the number of reproductive bodies, each sporocarp containing 
4-8 carpospores, each antheridium containing 16 antherozoids. 
ffabitat. On rocks in the sublitoral zone. Also found float- 
ing. v 
Distribution. From Alaska southward to Washington (60°- 
48° 10’ N. lat.). 
Localities. Orca, Alaska, W. A. Setchell and A. A. Lawson 
