20 University of California Puhlications 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 cm. altae, regulariter dichotomae, 

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

 segmentis divergentibus, linearibus vel iis angustioribus paullo cuneatis 

 vel iis latioribus raanifeste cuneatis, 5-6 mm. latis, apicibus acuminatis. 

 truncatis, costa distincte exposita, prominente, superne paululum 

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

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

 complanatis vel inflatis, vulgo quam segmentis multo latioribus. 

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

 vulgo a laterale reflexis ; conceptaculis non numerosis, inconspicuis. 



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

 Yakutat Bay, Alaska, to Victoria, British Columbia. 



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

 Alaska, July, 1917. 



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

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

 Collins, Holdeu 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 qiioted 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 an>- 

 which I have seen. 



The narrow fronds with prominent midribs and the very dark color 

 make this form clase to certain narrow forms of cdentatiis, 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. 



