564 University of California Publications in Botany [Vol. 8 



Ruetzing, Tab. Phyc, vol. 9, 1859, p. 40, pi. 95; Collins, Holden 

 and Setchell, Phyc. Bor.-Amer. (Exsicc.), no. 279; Farlow, Anderson 

 and Eaton, Alg. Exsicc. Amer-Bor., no. 121. Spinularia latifrons 

 Kuprecht, Tange, 1851, p. 375. 



The type locality of D. latifrons is, according to Ruprecht (loc. 

 cit.)., Fort Ross, California. We have not seen any specimens from 

 the type locality, although we have both collected algae in that vicinity. 

 The species, as at present known, does not seem to be very abundant, 

 but is scattered sporadically from Coos Bay, Oregon, to Point Sur, 

 Monterey County, California. 



As far as our experience goes, it is one of the most stable, least 

 variable species of the genus, and can readily be told from all other 

 known species. The hairs are relatively long, very abundant and 

 remain on until the plants are nearly maximum growth. These are 

 replaced in part by numerous prominent teeth or aculeae at maturity. 

 The fronds are decidedly rigid and of a dark color. 



Desmarestia latifrons resembles Desmarestia intermedia more than 

 any other of the Acideatae, but is definitely flattened rather than com- 

 pressed, and is not at all either membranaceous or foliaceous. It 

 seems to be a very distinct species of the central Californian coast 

 (extending over into the southern Oregon coast at Coos Bay), but is 

 scarce even in its own territorj^. The species is related to D. aculeata 

 (L.) Lamour., but more closely to D. intermedia P. and R., but is 

 broader and more flattened than either. 



5. Desmarestia intermedia P. & R. 



Fronds subcoriaceous, up to 6 dm. high and 1.5 mm. wide, dark 

 brown in color, almost black on drying, very profusely branched, sub- 

 opposite and fasciculate below, strictly alternate above ; stipe and 

 lower parts cylindrical to subcylindrical ; ramuli decidedly compressed 

 and lanceolate, densely clothed in the juvenile stage with relatively 

 long hairs with alternate or opposite branching ; frequently, especially 

 in the lower parts and in the older plants, two or more branches arising 

 at the same node and on the same side of the frond. 



Growing on rocks in the upper sublittoral belt. Bering Sea to 

 Puget Sound. 



Posters and Ruprecht, Illus. Alg., 1840, p. 13, pi. 26 (Excl. Syn- 

 onymy) ; Desmarestia aeideata Setchell and Gardner, Alg. N.W. Amer., 

 1903, p. 246 (in part); Tilden, Amer. Alg. (Exsicc), no. 352. 

 Possibly, Saunders, Alg. Harriman Exp., 1901, p. 422. 



