112 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 12 



Fucaceae 



Plants moderate to very large, often massive, forming cushion-shaped 

 or fibrous holdfasts from which arise cylindrical to flattened axes, sub- 

 simple or branched, often with a broad membranous margin, dichotomous 

 or in some genera pinnate, or divided into axis and lateral foliar organs; 

 inflated vesicles often present in the branchlets, or lateral ; reproduction 

 by the formation of fertile crypts distributed generally over the plant 

 body, or in special receptacular branchlets ; heterosporous, eventually pro- 

 ducing gametes by continuing the division in the sporogenous organs. 



KEY TO GENERA 



1. Special foliar organs absent, the minor divisions of the vegetative 

 portions fiUform ; vesicles absent Blossevillea 



1. Lateral organs foliaceous or, if filiform, clearly flat ... 2 



2. Vesicles seriate, somewhat moniliform, in regular branchlets . 

 Cystoseira 



2. Vesicles solitary, in regular branchlets, several chambered . . 



Halidrys 



2. Vesicles generally present, always solitary, lateral, unilocular . 



Sargassum 



BLOSSEVILLEA Setchell & Gardner, 1913 



Blossevillea galapagensis (Piccone&Grunow) n. comb. 



Plate 23 



Plants gregarious, olivaceous, firm in texture, black and brittle when 

 dried, exceeding 4 dm in height, the basal holdfasts small, irregularly 

 lobed ; branching close to the base into several main axes which are about 

 1.0-1.5 mm diam., and which branch irregularly into smaller divisions, 

 especially above bearing scattered lateral determinate aculeate to filiform 

 branchlets 1-3 cm long; above irregularly dichotomously branched, the 

 sterile divisions slender, near the top somewhat fastigiate ; fertile branches 

 dichotomously or sometimes laterally branched, the divisions nodulose, to 

 2.5 mm diam., tapering, the conceptacles hermaphrodite, the oval spo- 

 rangia 133-200 fj, long, 46-80 [x diam., each producing one egg. 



Piccone & Grunow in Piccone 1886, p. 40, pi. 1, fig. 1, pi. 2, fig. 3 

 (as Fucodium galapagense) ; De Toni 1895, p. 215 (as Pelvetia ? gala- 

 pagensis) ; Farlow 1902, p. 90 (as F. galapagense). 



Preserved material was available for study and enabled a close exami- 

 nation of the conceptacles to be made. They are clearly hermaphrodite, 



