344 Universifi/ of California PHhlirafions . [botany 



waters. He also says that it is a comparatively eoniDioii plant in 

 Pnget Sound, while on the central Californian coast it is rarely 

 found. We have not seen any specimens referable to the genuine 

 A. Fhinnda from any portion of the western coast of North 

 America. 



Antithamnion boreale f. typica Kjellman. 



On rocks and wood in the litoral zone. Port Clarence and 

 St. Lawrence Island, Alaska, Kjellnian (1901, p. 33); Cape Den- 

 bigh, Norton Sound, Alaska, R. C. McGregor, No. 5661! ; Friday 

 Harbor, San Juan Island, Wash., N.L.G., No. 490! 



This form runs into the next and it is often difficult to 

 determine to which form a given plant is to 1>e referred. 



Antithamnion boreale f. corallina Kjellman. 



On rocks in the middle and lower litoral zones. Besboro 

 Island, Norton Sound, Alaska, R. C. McGregor, No. ,5662!; 

 Cormorant Rocks, Uyak Bay, Kadiak Island, Alaska, W.A.8. and 

 A.A.L., No. 5135! ; Sitka and Wrangell, Alaska, i^aiinders (1901, 

 p. 349, wndev Anf if Jiamnio)! horeale) . 



Saunders's specimens are jilaced here because he says that they 

 are very close to this form. All the species of Antithamnion seem 

 to be connected by intermediate forms from the simplest forms 

 of A. horeale up to the most complex forms of A. Pijlaiswi or A. 

 stiiiHlafiiiii. We may well believe with Kjellman (1883, p. 181) 

 that "the genus Antithamnion is a young genus whose species 

 are in course of development, no marked differentiation being as 

 yet established and the transitional forms not having disappeared." 



Plat3rthamnion heteromorphum f. typicum Setchell and 



Gardner com)), no v. 



Cast ashore. West coast of Whidbey Island, Wash., X.L.G., 

 Nos. 164!, 408!; Friday Harbor, San J^^an Island, Wash., 

 Tildeit, No. 310!, under CalHthanniion siihiiJafini/. 



The plants referred here seem to agree well with the descrip- 

 tions of J. G. Agardh (1876, p. 23, and 1892, pp. 22, 23.) The 

 pinnules have branchlets distichous and on both sides below, but 

 secund and on the upper side, above. 



