672 University of California Publications in Botany L VoL -8 



absence of cryptostomata and the small caecostomata relate it to the 

 furcatus group. It has the least number of caecostomata of all the 

 forms with which we are familiar, certain specimens being nearly 

 free from them. In this character the form approaches very closely 

 to the edentatus group. 



11. Fucus furcatus f. abbreviatus Gardner 



Plate 98 



Fronds cartilaginous, rigid, rough, 8-12 cm. high, regularly 

 dichotomous, varying from olive green to olive brown or light yellow- 

 ish ; segments cuneate to linear, 8-16 mm. wide, apices truncate, mid- 

 rib narrow but distinct, caecostomata comparatively large, prominent 

 on drying, 60-80 per sq. cm. ; receptacles distinctly delimited, much 

 wider than the segments, 2-3.5 cm. long, complanate or swollen with 

 mucilage, 1-2 furcate, apices acuminate; conceptacles numerous and 

 very prominent. 



Growing on boulders in the middle littoral belt. Islands of San 

 Juan County and vicinity, Washington. 



Gardner, Genus Fucus, 1922, p. 19, pi. 6. 



This form is fairly abundant in the moderately quiet waters among 

 the islands of San Juan County, Washington, and extends into the 

 upper Sound region. It varies considerably in size, both in length and 

 in width of the fronds. Specimens 3 to 4 cm. in height have been taken 

 in full fruit, but these were depauperate forms, in the upper limit on 

 the belt in which they grow. The striking features of this form are 

 the short bunchy habit, the abundance of well developed receptacles 

 appearing simultaneously, and the numerous large caecostomata 

 making the fronds rough, particularly prominent on drying. 



12. Fucus furcatus f. linearis Gardner 



Fronds somewhat caulescent, cartilaginous, 30-35 cm. high, pro- 

 fusely branching, dichotomous, dark olive green, black on drying; 

 segments strict, linear, 8-12 mm. wide, caecostomata 40-70 per sq. cm., 

 inconspicuous on drying; receptacles very numerous, definitely 

 delimited, wider than the fronds, entire or bifid, mostly ovate, 1.5-2 cm. 

 long; conceptacles numerous, large. 



Growing in quiet w r ater on boulders in the low r er littoral belt. 

 Tracyton, Kitsap County, Washington. 



Gardner, Genus Fucus, 1922, p. 19, pi. 5. 



