674 University of California Publications in Botany [Vol. 8 



mostly in the terminal and subterminal segments, relatively small but 

 papillate on drying ; receptacles mostly complanate, in part inflated, 

 bifid and acuminate. 



Growing in the littoral belt. From the Bering Sea to Puget Sound, 

 "Washington. 



Gardner, Genus Fucus, 1922, p. 32. 



Key to the Forms 



1. Cryptostomata sparse and inconspicuous 3. f. limitatus (p. 674) 



1. Cryptostomata up to 60 per square centimeter 2 



2. Fronds 8-14 cm. high, 5-9 mm. wide, receptacles wider and blunt 



4. f. abbreviatus (p. 676) 



2. Fronds over 14 cm. high 3 



3. Fronds 12-20 cm. high, 4-9 mm. wide, receptacles sharply acuminate 



6. f. aciiminatus (p. 677) 



3. Fronds over 10 mm. wide 4 



4. Fronds up to 6 cm. wide, cryptostomata 15-20 per square centimeter... 



2. f. latissimus (p. 675) 



4. Fronds less than 3 cm. wide 5 



5. Cryptostomata 20-25 per square centimeter, receptacles acuminate or acute... 



1. f. typicus (p. 674) 



5. Cryptostomata 30-40 per square centimeter, receptacles blunt 



5. f. obtusus (p. 676n 



1. Fucus membranaceus f. typicus Gardner 



Fronds caulescent, 28-40 cm. high, flaccid, membranaceous, dicho- 

 tomous, alae wearing away below, leaving the relatively small, thick- 

 ened, cylindrical midrib, light yellowish brown ; segments narrowly 

 cuneate to linear, 10-18 mm. wide, growing point in a slight, crescent 

 shaped depression, midrib moderately developed, alae thin, cryptosto- 

 mata small, 20-25 per sq. cm., conspicuous on drying, mostly in the 

 terminal and subterminal segments; receptacles relatively large, dis- 

 tinctly delimited, mostly inflated, bifid, apices long attenuate ; con- 

 ceptacles moderately abundant, relatively small, but conspicuous 

 because of their dark color. 



Growing on rock ledges and boulders in the middle of the littoral 

 belt. Sitka, Alaska. 



Gardner, Genus Fucus, 1922, p. 34, pis. 30, 31. 



This form was sparsely interspersed in groups among the multi- 

 plicity of forms growing in the vicinity of Sitka. It may readily be 

 recognized by its light yellowish color, its mostly inflated receptacles, 

 and by its moderately narrow, long, membranaceous fronds. 



