18 University of California Publications in Botany [Vol. lo 



Fucus furcatus f. angustus f. nov. 



Plate 4 



Frons angusta, caulescens, rigida, subcartilaginosa, 20-35 cm. alta, 

 dichotoma, obscure olivaceo-brunnea, siecata atra; segmentis linearibus 

 vel paululum cuneatis, 4-7 mm. latis, apieibus truncatis, eo.sta evidenter 

 percursa, caecostomatibus 125-175 in quoquo cm. quadrato ; receptaciilis 

 vulgo complanatis, iiiterdum inflatis, distinete definitis, alte ])ifidis, 

 4—7 cm. longis, apieibus acutis vel acuminatis; conceptaculis numerosis 

 confertim dispositis. 



Growing in abundance on rock ledges in the upper third of the 

 littoral belt. San Juan County, Washington, and the central coast of 

 Oregon. 



Type, Gardner, no. 2788 (Herb. Univ. Calif., no. 201188), Sunset 

 Beach, near the mouth of Coos Bay, Oregon, May, 1914. 



The only other definite locality in which this form has been detected 

 is Cattle Point, at the south end of San Juan Island, Washington 

 (Gardner," no. 2352g). This locality is particularly rich in forms of 

 Fucus. There is an intermingling of the waters flowing among the 

 islands to the north and east, which have a varied Fucus flora, with the 

 waters from the Strait of Juan de Fuca and the Straits of Georgia, 

 washing the shores of land to the west and north, which have a some- 

 what different Fucus flora. The shore of the south side of Cattle Point 

 is exposed to a swiftly flowing current and to the action of swells from 

 the Pacific Ocean, through the Strait of Juan de Fuca. Around to the 

 north side of the point the shores are affected but little by the action 

 of the surf and tides. 



Fucus furcatus f. anguMus seems closely related to F. in flat us f. 

 edentatus of Borgesen. I draw my conclusion after having compared 

 our plants with a specimen of Borgesen 's from the Faeroe Islands in 

 the Herbarium of the University of California, no. 99176. I have 

 represented this specimen on plate 20. Borgesen 's specimen lias a 

 more pronounced midrib and the segments are more decidedly cuneate. 

 The color is not so dark as the color of our specimen. The fronds are 

 somewhat roughened and possess a large number of caecostomata. very 

 similar to f. angustus. 



