66 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 17 



subcortical area and scattered in the medulla, not strictly longitudinal; 

 cystocarps (not seen in Mexican material) single, on short simple ulti- 

 mate ramuli ; antheridia unknown ; tetrasporangia in elliptical sori in the 

 swollen tips of sparse, short, simple (or branched) ultimate branchlets. 



Type: Holotype is Gardner 4994b, on sheet 264686 in the Her- 

 barium of the University of California, Berkeley. 



Type locality: Ensenada, Baja California, Mexico. 



Mexican distribution: Pacific Baja Calif. — Hubbs, Feb. 9, 

 1951, Bahia de Todos Santos; American Agar Co., Nov. 1932, south of 

 Ensenada; D. 1502, Punta Santa Rosalia, Apr.; D. 1377, Millers Land- 

 ing, Apr. 



No specimens approaching the coarseness of the more northern Gelid- 

 ium arborescens have been taken thus far in Mexico. Our plants seem 

 to be quite identical with the Japanese plant known as G. linoides Kiitz. 

 It is necessary to review the type of this Hawaiian alga whose tropical 

 habitat suggests that it is probably distinct from the Japanese and Pacific 

 American plants, both of which inhabit waters of appreciably lower 

 temperature. 



Gelidium polystichum Gardner 



Gardner, 1927a, p. 276, pi. 41 ; Dawson, 1949a, p. 24. 



Thalli to 15 cm. high, consisting of several erect axes from a small 

 loose group of prostrate or arcuate, semi-penetrating stolons attached to 

 aggregated rock-covering crustose corallines, worm tubes, sponges, etc. ; 

 erect axes subterete or compressed at the base, flattened above to about 

 1 mm. wide, more or less denuded in lower parts, with 2-3 orders of 

 closely spaced, alternate or subopposite branches of which usually the 

 greater number are distichous from the margins, but of which many arise 

 polystichously without order from the flattened surfaces of the branches, 

 each order progressively smaller, giving the main branches a narrow- 

 pyramidal aspect at the tips, and an irregularly congested aspect in the 

 prominently polystichous regions ; rhizoidal filaments straight, concen- 

 trated in the subcortical area, scattered in the medulla; tetrasporangia 

 borne in small sori on the somewhat expanded tips of ultimate branchlets ; 

 cystocarps and antheridia not seen in Mexican material. 



Type: Holotype is Gardner 1927 on sheet 284088 in the Her- 

 barium of the University of California, Berkeley. 



Type locality: In drift at Whites Point, near San Pedro, Cali- 

 fornia. 



