NO. 1 TAYLOR: PACIFIC MARINE ALGAE 115 



9. Leaves subsessile, more narrow, teeth of moderate size . . . 

 S, Skottsbergii 



9. Leaves petiolate, broadly lanceolate or ovate 10 



10. Leaves small, deeply aculeate dentate, the teeth often bifid . 

 S. Brandegeei 



10. Leaves larger, or less deeply dentate 11 



11. Leaves of moderate size, the lower teeth sometimes ciliate . . 

 S. pacificum p.p. 



11. Leaves very large 12 



12. Leaves with rounded asymmetric base, aculeate dentate; stalks 



as long as the vesicles S. pacificum f. megaphyllum 



12. Leaves with tapering base, shallowly and coarsely dentate; 



stalks one half as long as the vesicles . . . . S. ecuadoreanum 

 The genus Sargassum is a difficult one, in this area as in many others. 

 To date so few collections have been made that the limits of variation for 

 the several species on these coasts are as yet quite undefined. From the 

 collections made by the writer there remain a number as yet unidentified 

 which neither fit the descriptions already published nor are sufficiently 

 complete or clear in their differences to describe as new. As will be noted, 

 some of the specimens are only cautiously associated with names accepted 

 by Setchell for plants from this area, and differ a little from his descrip- 

 tions. It is believed that they simply represent variations of these species. 

 Further collections, particularly in quiet shallow water, will substantially 

 add to this list. 



Sargassum setifolium (Grunow) Setchell 

 Plate 24 



Plants to over 8 dm tall, somewhat pyramidal to quite loosely 

 branched, the stem smooth, sparingly to moderately closely leafy above, 

 defoliate below and with branches 8-17 cm long; leaves 2.5-7.5 cm long, 

 simple or more commonly once, less often 2-3 times subdichotomously 

 branched, the narrowly linear segments 0.3-1.2 mm broad, tapering to 

 base and apex, entire, the midrib inconspicuous in the broader leaves and 

 not distinguishable in the more slender ones; cryptostomata absent; 

 vesicles absent or to moderately numerous, broadly to narrowly oval, to 

 3-4 mm diam., the slender stalk 3-10 mm long, the muticous tip generally 

 conspicuous, filiform and often compressed, commonly 5 mm, rarely to 

 more than 15 mm long; receptacles moderately closely clustered but not 

 congested, to commonly loose, simple to 2-3 times unevenly forked, the 

 divisions often spindle shaped, sometimes with vesicles or small leaves 

 intermixed. 



