Sargassum herporhizum

Sargassum herporhizum Setchell et N. L. Gardner

Sargassum herporhizum Setchell et N. L. Gardner, 1924a:739, pl. 20: figs. 69–71; Setchell and Gardner, 1925:720; Dawson, 1944:249, pl. 40: figs. 1–12; Dawson, 1961b:400; Dawson, 1966a:13; Norris, 1973:7; Huerta-Múzquiz, 1978:337; McCourt, 1984b:141;

Rocha-Ramírez and Siqueiros-Beltrones, 1990:19; De Lara Isassi, 1992:22; Espinoza-Ávalos, 1993:333; Phillips, 1995:118; González-González et al., 1996:160; Pacheco-Ruíz and Zertuche-González, 1996b:171; Cruz-Ayala et al., 2001:190; Mateo-Cid et al., 2006:50, 58; Pacheco-Ruíz et al., 2008:205; Pedroche et al., 2008:93.

Algae up to 30 cm long, with several erect terete, smooth axes, alternately to irregularly branched, often

whorled, above entangled rhizomes. Primary axis initially arising from a small discoid base that develops numerous, branching, narrow in diameter (less than 3 mm), repent cylindrical rhizomes that are attached at various points by small haptera; several erect secondary axes arise along horizontal rhizomes as they lengthen. Leaf-like blades, long and narrow, 15–25 mm long and 2–5 mm wide, with a midrib (sometimes less distinct or faint on uppermost blades); cryptostomata absent or few and inconspicuous; margins vary, uneven or slightly to

irregularly dentate. Vesicles spherical to ovoid, mostly smooth, up to 3 mm in diameter; on pedicels; occasionally apiculate.

Dioecious; receptacle branchlets scattered among vesicles, narrow, subcylindrical, up to 10 mm long, branched, on short pedicel, with conspicuous conceptacles.

HABITAT. On rocks and tidal platforms and in tide pools; mid intertidal to shallow subtidal, down to 6 m depths.

DISTRIBUTION. Gulf of California: Puerto Peñasco to Bahía de La Paz. Pacific coast: Jalisco; Galápagos Islands.

TYPE LOCALITY. Isla San Jorge (George’s Island), off Sonora, Gulf of California.