1925] SetcheU-Gardner: Mchniophyceae 701 



Pelvetia fastigiata (J. Ag.) De-Toni 



Mature fronds terete below, compressed above, narrowly linear, 

 profusely branched, branching often beginning just above the base, 

 dichotomous, fastigiate, 2-4 dm. (up to 10 dm.) high, 5-10 mm. diam. 

 below, tapering above ; color yellowish brown to dark olive green ; the 

 central portion of the fronds consisting of long, branched, colorless 

 filaments with thick gelatinous walls, surrounded by a layer of large 

 parenchymatous cells, becoming smaller toward the surface consisting 

 of a single layer of small, compact cells ; oogonia on one-celled stalks, 

 broadly elliptical, dividing longitudinally or occasionally obliquely 

 into two (very rarely into three) oospheres; antheridia very numerous, 

 on short branches in the basal portion of the conceptacles, paraphyses 

 not at all, or only slightly, extruded; receptacles moderately swollen, 

 occasionally forked, variable in shape, some conical, others fusiform. 



Always growing on rocks, in the middle of the littoral belt. 

 Extending from Coos Bay, Oregon, to the west coast of Lower Cali- 

 fornia (Ensenada). 



De-Toni, Syll. Alg., vol. 3, 1895, p. 215 ; Gardner, Nuclear Extru- 

 sion, 1910, p. 130, pi. 17, figs. 11-16; Collins, Holden and Setchell, 

 Phyc. Bor.-Amer. (Exsicc), nos. 176 and CXIII. Funis (Pelvetia) 

 fastigiata Farlow, Anderson and Eaton, Alg. Exsicc. Amer.-Bor., 

 no. 110. Fucus fastigiatus J. Ag., Symb. I, 1841, p. 3 ; Harvey, Ner. 

 Bor.-Amer., 1851, p. 68, pi. 3 A. 



The plants of Pelvetia fastigiata vary considerably in size. So 

 far as has been observed, they reach their greatest length in southern 

 California, where at San Pedro plants 10 dm. long have been observed. 

 Usually when the plants are growing where they are subjected to a 

 heavy surf, the fronds become much thicker and much more rigid and 

 less branched than those growing in more sheltered situations. This 

 is the typical condition of plants on the west end of the Monterey 

 peninsula, the type locality. Here the branches are widespreading 

 and the angles much rounded, and some of the fronds measure 2 cm. 

 wide near the base. 



