1917] Gardner: New Pacific Coast Marine Algae I 387 



the main fronds give rise to sterile segments (leaves) alternately 

 arranged and often densely crowded, dendroidally and dichotomously 

 dissected into 15-25 slightly flattened segments, 2-3 cm. long, with 

 midrib ; older branches covered with short, more or less branched, 

 spinose projections ; numerous lateral, terete, secondary branches arise 

 in the axils of the leaves, longer below, shorter above ; these bear 

 reduced leaves similar to those on the main fronds, producing vesicles 

 and the receptacles in their axils ; vesicles usually solitary, smooth, 

 spherical, 3.5-6 mm. diam., on the ends of the pedicels about as long 

 as the diameter of the vesicles ; receptacles in a dense dendroid group 

 in the axils of the sterile segments, often with a vesicle or reduced leaf 

 as a part of the group ; the fruiting fronds often appear nude as the 

 leaves wear away ; conceptacles consj)icuous ; dioeceous ; cryptostomata 

 abundant; plants perennial. 



Growing in the upper sublittoral belt. Abundant at Santa Cata- 

 lina Island, and probably grows in similar habitats along the coast of 

 the mainland of southern California, as it is frequently cast ashore 

 there. Known also from Guadalupe Island, Lower California. 



Sargassnm dissectifolium has been known as S. piluliferum since 

 its distribution in Farlow, Anderson and Eaton's Algae Exsiccatae 

 Americanae-Boreales, no. 102. It was discovered by Dr. E. Palmer 

 in 1875 at Guadalupe Island, Lower California. It seems quite 

 evident from a comparison of the literature that two plants have been 

 confused under this name. The material upon which Turner de- 

 scribed his Fucus pilulifer was from Japan. C. Agardh transferred 

 the species to the genus Sargassnm in 1823, and J. Agardh retained 

 the species in 1848, both referring to the Japanese plant as described 

 by Turner. But when Agardh published his Species Sargassorum 

 Aiistraliae in 1889, the description which he rendered on page 55 is 

 more nearly suited to our plant than to the Japanese plant ; however, 

 he refers to both and evidently considered them to be identical. 

 Yendo (1907, p. 57) has called attention to the dissimilarity between 

 the American and the Japanese species, after a careful comparison 

 of the plant distributed from Guadalupe Island by Farlow, Anderson 

 and Eaton, with the Japanese species. The plant in our waters 

 differs from that in the Japanese waters chiefly in having a prominent 

 terete stipe and terete branches instead of being compressed, or 

 ancipitose and midribbed ; and in having the leaf segments finer, 

 more dissected, flattened sliglitly and midribbed. It also differs in 

 other minor details. Considering all of these differences together, 

 it seems quite desirable and necessary to separate the two and give 

 our plant a new name. 



