1925] Setchell-Gardner : MelanopJiyceae 665 



Key to the Forms 



1. Caecostomata very numerous, 250-450 per square centimeter 2 



1. Caecostomata less than 250 per square centimeter 4 



2. Fronds cartilaginous, much crisped and twisted 5. f. contortus (p. 668) 



2. Fronds tough, coriaceous, plane or nearly so 3 



3. Fronds much branched, 10-18 mm. wide, 20-30 cm. high. ...1. f. tjrpicus (p. 665) 



3. Fronds loose, 10-18 mm. wide, 30-50 cm. high 3. f. elongatus (p. 667) 



3. Fronds much branched, 15-30 mm. wide, up to 90 cm. high 



2. f. luxurians (p. 666) 



4. Receptacles cornute, wholly or in part 5 



4. Receptacles not cornute 6 



5. Segments linear, 5-6 mm. wide 10. f. cornutus fp. 671) 



5. Segments cuneate, 18-24 mm. wide 9. f. nigricans fp. 671) 



6. Young receptacles decidedly reflexed 7. f. reflexus (p. 669) 



6. Young receptacles not reflexed 7 



7. Fronds 8-12 cm. high 11. f. abbreviatus fp. 672) 



7. Fronds over 12 cm. high 8 



8. Fronds 4-12 mm. wide 9 



8. Fronds over 12 mm. wide 10 



9. Fronds 4-7 mm. wide, receptacles acute 13. f. angustus fp. 673) 



9. Fronds 8-12 mm. wide, receptacles blunt 12. f. linearis fp. 672) 



10. Segments increasing in width upward 8. f. latifrons fp. 670) 



10. Segments diminishing in width upward 11 



11. Receptacles covering 3-4 terminal segments, linear 4. f. rigidus fp. 668) 



11. Receptacles covering 1-2 terminal segments, very variable in shape 



6. f. variabilis fp. 669) 



1. Fucus furcatus f. tjrpicus Gardner 



Fronds somewhat caulescent, moderately cartilaginous, 20-30 cm. 

 high, regularly dichotomous, dark olive green, black on drying, seg- 

 ments plane, linear to cuneate, 10-18 mm, wide, midrib distinct, per- 

 current, caecostomata 250-300 per sq. cm., small, inconspicuous, 

 cryptostomata absent or very sparse ; receptacles complanate, mostly 

 broadly linear, 4-6 cm. long, mostly bifid, apices acute ; conceptacles 

 very numerous and relatively small. 



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

 belt. From the Strait of Juan de Fuca to central California. 



Gardner, Genus Fticus, 1922, p. 16, pis. 2, 3. Fucus evanescens f, 

 typicus, Collins, Holden and Setchell, Phyc. Bor.-Amer. (Exsicc), 

 no. 1338. Fucus inflatus f. edentatus, Setchell and Gardner, Alg. 

 N.W. Amer., 1903, p. 280. 



The Fucus furcatus of Tilden's American Algae, no. 234, as to 

 the specimen distributed in Professor Setchell 's copy, is not t.ypical of 

 this species as found on the California coast. The specimen is only a 

 small portion of a plant. It is mature, considerably worn and bat- 

 tered, and has comparatively few caecostomata. The distribution is 



