1922] Gardner: The Genus Fucus on the Pacific Coast 45 



side, through its widest specimens, it seems not unlike certain narrow 

 specimens of F. evanescens f. pergrandis. It differs from the former 

 in having wider segments not perceptibly reduced in width, as in 

 f. costatus, above the forkings, and in having wider, much more robust 

 and blunt receptacles. From the latter it differs in being much less 

 robust throughout, in having fewer cryptostomata and in having much 

 more delicate and membranaceous alae. 



Fucus evanescens f. macrocephalus Kjellm. 



Plate 46 



' ' f . fronde caulescente ; segmentis linearibus, subcoriaceis, 5-6 mm. 

 latis. costa parum prominente ; receptaculis sublimitatis, magnis, 2.5- 

 3.5 cm. longis, 1.5-2 cm. crassis plus minus turgidis. vel simplicibus 

 ellipsoideis vel semel furcatis, cuneatis, ramis subcylindricis, apice 

 rotundatis; scaphidiis magnis." 



"Beringon, ymnig; siilskaplig inom litoralregionem tillsamman med 

 foregaende ; med receptakler. ' 



Kjellman. Om Beringh. Algflora, 1889, p. 34. 



Fronds subcaulescent, 12-18 cm. high, subcoriaceous, dark brown 



below varying to light brown or yellowish above; segments linear to 



slightly cuneate, 5-12 mm. wide, midrib well developed, percurrent, 



alae rather thin, cryptostomata absent or sparce ; receptacles distinctly 



delimited, complanate in part, but mostly very tumid and mucilaginous, 



light yellow. 2-3.5 cm. long. 1-2 cm. wide, simple, retuse, or bifid; 



conceptacles conspicuous. 



Plate 45 



Growing in the middle of the littoral region. Bering Sea to Juneau, 

 Alaska. 



Newhall and Rhodes, nos. 5791, 5792 (Herb. Univ. Calif., nos. 

 99112, 99113), Cape Dyer, Alaska; McGregor, no. 5689 (Herb. Univ. 

 Calif., no. 99114), Dutch Harbor, Alaska; Setchell and Lawson, no. 

 4077 (Herb. Univ. Calif., no. 99120), Amaknak Island, Alaska; 

 Setchell and Lawson, no. 5152 (Herb. Univ. Calif., nos. 99116, 99119), 

 Orca, Alaska; Gardner, no. 2230fir (Herb. Univ. Calif., no. 201134), 

 Juneau, Alaska. 



Kjellman, loc. cit.; De-Toni, Syll. Alg., 1895, p. 202; Saunders, 

 Alg. Harriman Exp., 1901, p. 432, pi. 62, fig. 1; Setchell and Gardner. 

 Alg. N.W. Amer., 1903, p. 282. 



Saunders (1901, p. 432) reports this form as growing at Puget 

 Sound, Annette Island, Wrangell, Juneau, Sitka, Glacier Bay, Prince 

 William Sound, Cook Inlet, Kukak Bay, and Shumagin Islands, and 

 states: "This is the most abundant seaweed on the northwest coast." 

 I have not been able to examine any of the specimens of Saunders' 



