24 University of California Publications in Botany [Vol. 10 



The consistency of this form is somewhat like that of the evanescens 

 group, the tissues being more delicate and soft than those of the 

 typical furcatus forms. I have placed it in the furcatus group on 

 account of the color, dark olive green to dark olive brown; and the 

 presence of cryptostomata in abundance. 



Many of the terminal segments are very broadly ovate, almost 

 stipitate, on account of the narrowing of their bases, producing broad 

 rounded angles between the segments (plate 12). The growing points 

 differ from those of all other forms observed on our coast, the apices 

 of the segments being rounded and smooth, but with slight incon- 

 spicuous slits to indicate the position of the growing point. 



The receptacles, particularly when young, have the pronounced and 

 distinguishing character of spreading very widely from each other at 

 their bases, in some instances standing at right angles, or even more, 

 to each other. Many segments have the character of reducing their 

 width at each forking, the terminal segments forming the stipelike 

 portion bearing the much wider receptacles. 



Fucus furcatus f. rigidus f. nov. 

 Plate 13 



Frondes robustae, rigidae, cartilaginosae, 30—45 cm. altae, dicho- 

 tomae vel subsecundae, obscure olivaceo- virides, siccatae atrae, costa 

 et receptaculis subtus olivaceo-viridibus, supra olivaceo-brunneae vel 

 luteolis, angulis saepissime rotundatis; segmentis linearibus vel paullo 

 cuneatis, strictis, 1.5-3 cm. latis, apicibus truncatis, costa prominente, 

 caecostomatibus 60-100 in quoquo" cm. quadrato ; receptaculis indis- 

 tincte definitis, complanatis, linearibus, apicibus acuminatis, 2-3- 

 furcatis, 12-20 mm. latis, 5-8 cm. longis ; coneeptaculis magnis partem 

 cuneatem e receptaculo costam decurrentem vestientibus. 



Growing on boulders in the lower littoral belt. Port Townsend 

 and west coast of Whidbey Island, Washington. 



Type, Gardner, no. 1982 (Herb. Univ. Calif., no. 201138), Port 

 Townsend, Washington, July, 1908. Gardner, no. 2352a (Herb. Univ. 

 Calif., no. 201214), from San Juan Island, seems also to belong here. 

 Most of the specimens of this latter collection have shorter receptacles 

 with wider base and with most attenuate and divergent apices. 



According to my conception of this form, its phylogenetic position 

 is between forma latifrons and forma luxurums. From the former it 

 differs in having a more rigid cartilaginous structure, in having nar- 

 rower and more strict segments, and in having longer and narrower 

 receptacles. From the latter it differs in having more strict and more 

 nearly linear segments and longer and narrower receptacles. 



