L925J Setchell-Gardner: Melanophyceae 681 



ally it with the edentatus group rather than with the seemingly more 

 imperfectly defined group in flat its. The linear arrangement of the 

 cryptostomata in two rows along the prominent midrib and the 

 relatively small, pointed receptacles distinguish it from all other forms 

 of edentatus. 



5. Fucus edentatus f. divaricatus Gardner 



Plate 104 



Fronds fragile, usually 12-22 cm., but occasionally up to 32 cm. 

 high, regularly dichotomous, with wide angles, stipe and lower 

 branches nearly terete, dark olive brown, receptacles frequently yellow- 

 ish; segments narrowly linear, reduced in width slightly at each 

 forking, terminal, acute, 2-5 mm. wide, midrib highly developed to 

 the apices, alae almost absent, cryptostomata few and unevenly dis- 

 tributed ; receptacles definitely delimited, awl-shaped or slightly 

 flattened. 2.5-4.5 cm. long, mostly simple or deeply furcate; con- 

 ceptacles conspicuous. 



Growing on ledges of sandstone in the lower littoral belt. Belling- 

 ham. AVashington, Comox and Ucluelet, Vancouver Island, British 

 Columbia. 



Gardner, Genus Fucus, 1922, p. 31, pi. 26. Fucus infleitus f. fili- 

 formis, Setchell and Gardner, Alg. N.W. Amer, 1903, p. 281; Collins, 

 Mar. Alg. Vancouver Isl, 1913, p. 111. 



4. Fucus evanescens Ag. 



Fronds moderately robust, sometimes arborescent, usually decid- 

 edly coriaceous, dichotomous or in part subsecund, olive brown, to 

 yellowish above ; segments often quite f oliaceous and crisped, in some, 

 narrow, cuneate to linear, midrib more or less distinct, in some cases 

 vanishing more or less in the terminal segments, cryptostomata few 

 to many, scattered ; receptacles very variable in shape and size, long 

 and narrow to short and blunt, bi- tri-furcate. 



Qrowing in the littoral and upper sublittoral belts. From Bering 

 Sea to Coos Bay, Oregon. 



Agardh, Sp. Alg., vol. 1, part 1, 1820, pp. 92, 93. 



Fucus evanescens was established by C. A. Agardh in 1820 (he. 

 cit.) based upon material collected by Chamisso. The type specimen 

 is in the herbarium of J. G. Agardh under no. 00299, labeled Kam- 

 tschatka with a query. The name was chosen to signify the vanishing 

 of the midrib toward the outer ends of the segments. Much of the 



