70 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 17 



wide, often unbranched in its lower parts, this giving rise to 3-4 orders 

 of progressively more slender distichous, alternate or subopposite 

 branches, in part closely spaced and congested, the ultimate ones sub- 

 cylindrical and only 100-130 /x in diameter; transection of older parts 

 showing a medulla of more or less uniform cells of distinctly granular 

 content ; rhizoidal filaments congested in a subcortical zone, sparsely 

 scattered through the medulla; cystocarps and antheridia not seen in 

 Mexican material ; tetrasporangia in relatively small, terminal sori in 

 swollen, blunt tips of slender, long-stipitate, fertile branchlets of the 

 ultimate and subultimate orders. 



Type: Holotype not designated, but represented by one or more 

 specimens under Loomis 5291, June 30, 1930, in the private collection 

 of Mrs. Nina Loomis, 1324 North Ogden Avenue, Hollywood, Cali- 

 fornia. Isotype preparations are on slides 1104-1105 in HAHF. 



Type locality: In beach drift, Palisades, Santa Monica, Cali- 

 fornia. 



Mexican distribution: Pacific Baja Calif. — D. 1162, Punta 

 Baja, Apr. ; D. 2915, near Punta Santa Rosalia, Oct. 



Although some other sterile examples may be referable here, at least 

 the two tetrasporangial collections cited above seem unquestionably 

 identical with this species. The long, slender, subcylindrical tetrasporang- 

 ial branchlets with rather small terminal sori distinguish this species 

 from Gelidium pulchrum and G. purpurascens. 



Gelidium coulteri Harvey 



Harvey, 1853, p. 117; Smith, 1944, p. 196, pi. 44, fig. 5; Dawson, 

 1945b, p. 65; Dawson, 1949, p. 222, 227; Doty, 1947, p. 163. Gelidium 

 densum Gardner, as interpreted by Taylor, 1945, p. 156. 



Thalli densely tufted, dark reddish-brown to blackish in color, 2-7 

 cm. high, or sometimes to 18 cm. high depending upon the degree of 

 exposure in the intertidal zone, saxicolous or partially epiphytic on coral- 

 line turfs, attached by a complex of branched stolons ; erect primary axes 

 usually unbranched below, irregularly distichously and rather sparsely 

 branched above, compressed to flattened in lower parts, subcylindrical 

 above, 0.4-0.8 mm. in diameter, all the main branches provided with 

 more or less uniform short, subcylindrical, ascending, determinate, dis- 

 tichous branchlets 0.6-2.0 mm. long ; medulla of thick-walled cells about 

 13-15 [X. in diameter; rhizoidal filaments strictly longitudinal, densely 

 packed in a broad subcortical and outer medullary zone and more or less 



