1922] Gardner: The Genus Fucas on the Pacific Coast 27 



Growing on boulders and rock ledges. San Francisco Bay, Cali- 

 fornia. 



Type. Gardner, no. 2165 (Herb. Univ. Calif., no. 201150), 

 Sausalito, California. 



This relatively small group of Fucus plants, although very much 

 circumscribed in its distribution, seems so distinctly marked off in its 

 combination of characters from other species, particularly from those 

 in the southern portion of the range covered in this paper, that it is 

 worthy of specific rank. The combination of characters that dis- 

 tinguish this species consists of the following: relatively long and 

 narrow, smooth and glossy fronds, strict, even overlapping habit of 

 the terminal and subterminal segments, the dark brown color with 

 yellowish receptacles at maturity, absence of caecostomata, and the 

 eryptostomata, when present, are inconspicuous. Its affinities with 

 F. edentatus may possibly be traced, but they seem too remote to merit 

 much serious consideration. The somewhat coriaceous consistency of the 

 fronds suggests relationship in that particular with certain forms of 

 evanescehs, but on the whole it inclines more, in its consistency, to the 

 cartilaginous consistency of F. furcatus, under which I have con- 

 sidered placing it. I have observed this species with considerable care 

 throughout all seasons of the year for the last twenty years. In its 

 typical habitat it seems thoroughly fixed as a distinct entity. 



The chief association of plants extends along the rocky shore from 

 the harbor at Sausalito to Point Cavallo, a distance of about two miles. 

 There are a few smaller groups at other points in the Bay, but in all 

 of these localities the waters are more quiet than along the shores of 

 the Golden Gate out to the Pacific Ocean. In the localities where 

 they are found they are never intermixed with any forms of F. 

 furcatus, the only other known species on the California coast. No 

 plants of F. nitens have ever been found growing on either side of the 

 Golden Gate for some distance inside of the entrance. From Point 

 Cavallo to some distance west of Lime Point, an interesting association 

 exists for which I have no way of accounting, except by hybridization 

 between these two species. A variety of intermediates exist. There 

 are yellowish brown plants with inflated, yellowish, bi-, tri-furcate 

 receptacles like those in the quiet waters of the Bay, but filled with 

 hundreds of small caecostomata characteristic of F. furcatus; and 

 there are plants with flat receptacles and olive green, cartilaginous 

 fronds but which are smooth and glossy and wholly lacking in caeco- 

 stomata, characters belonging to F. nitens. These and other combina- 



