708 University of California Publications iri Botany [Vol. 8 



nial, dioecious, the two sexes being indistinguishable bj- external 

 morphological characters; color varying from dark brown to olive 

 green. 



Growing in the littoral and sublittoral belts on exposed rocks, or in 

 the sublittoral belt in quiet water. San Pedro, Redondo and at Avalon, 

 Santa Catalina Island, southern California and at least as far south 

 as Ensenada, Lower California. 



Gardner, New Fucaceae, 1913, p. 323, pis. 42-45 ; Collins, Holden 

 and Setchell, Phyc. Bor.-Amer. (Exsicc), nos. CXVI, CXVII. 



72. Cystoseira Ag. 



Frond differentiated into holdfast, stipe and branches of various 

 orders ; holdfast somewhat fibrous and woody, solid or more or less 

 cavernous, conical in general outline ; usually each holdfast giving rise 

 to one main stipe, decidedly angular, with terminal meristem, and 

 giving rise on all sides to a few main divisions having terminal grow- 

 ing points ; the primary branches arising from the main stipe and its 

 divisions and far surpassing them in length, flattened and pinnately 

 lobed at the base, resembling certain fern leaves, but divided above 

 into more or less filiform branches and branchlets bearing the recep- 

 tacles at their termini, and vesicles, usually seriate, in branchlets of 

 different orders ; oosphere single in the oogonium ; plants monoecious 

 or dioecious, perennial. 



Agardh, Sp. I, 1820, p. 50. 



Agardh enumerated fifty-seven species under his newly founded 

 genus. Cystoseira ericoides came first in the list and may be con- 

 sidered the type of the genus. It was founded on Fucus ericaides of 

 Linnaeus (Sp. pi. 1763, p. 1631). Agardh 's combination is still 

 retained and the plant is well illustrated by Harvey in Phycologia 

 Britannica (vol. 3, pi. 265). 



Key to the Species 



1. Fronds robust throughout, 2-4.5 m. long 1. C. osmundacea (p. 709) 



1. Fronds shorter, up to 1.5 m. long, more slender 2 



2. Fructiferous ramuli aggregated into short, dense clusters, vesicles 6-8 



mm. diam 2. C. Setchellii (p. 710) 



2. Fructiferous ramuli not densely aggregated, vesicles 2-3 mm. diam 



3. C. neglecta (p. 710) 



