20 University of California Publications in Botany [Vol. 10 



limit of 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 caeco- 

 stomata making the fronds rough, particularly prominent on drying. 



Fucus furcatus f. cornutus f. nov. 



Plate 7 



Frondes subcoriaceae, 20-30 em. altae, regulariter dichotomae, 

 obscure olivaceo-virides vel obscure olivaceo-brunneae siccatae atrae ; 

 segmentis divergentibus, linearibus vel iis angustioribus paullo cuneatis 

 vel iis latioribus manifeste cuneatis, 5-6 mm. latis, apieibus acuminatis, 

 truncatis, costa distincte exposita, prominente, superne paululum 

 evanida, alis angustis, caeeostomatibus sparsissimis, parvis, 10-20 in 

 quoquo cm. quadrato ; receptaeulis distincte definitis, valde variabilibus, 

 complanatis vel inflatis, vulgo quam segmentis multo latioribus. 

 integris, vel .bifurcatis, 2-4 cm. longis, obtusis vel acuminatus, apieibus 

 vulgo a laterale reflexis ; conceptaculis non numerosis, inconspicuis. 



Growing on rocks in the middle and lower littoral belts. Prom 

 Yakutat Bay, Alaska, to Victoria, British Columbia. 



Type, Gardner, no. 3993a (Herb. Univ. Calif., no. 201193), Sitka, 

 Alaska, July, 1917. 



Fucus evanescem f. cornutus, Saunders, Alg. Harriman Exp., 1901, 

 p. 432, pi. 62, fig. 2; Collins, Mar. Alg. Vancouver Isl., 1913, p. Ill ; 

 Collins, Holden and Setchell, Phyc. Bor.-Amer.- (Exsicc), no. 927. 



I have not seen the Saunders' specimen, but have based my judg- 

 ment upon his description and figure quoted above, which seem to 

 agree very well with my specimen from Sitka. He states that some 

 of the receptacles are up to 7 cm. long, being much longer than any 

 which I have seen. 



The narrow fronds with prominent midribs and the very dark color 

 make this form close to certain narrow forms of edentatus, but the 

 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 I am familiar, certain specimens being nearly free 

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

 edentatus group. 



