78 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 17 



branches to 15 mm. long, complanate except at the very base, 300-500 /x 

 wide, 1-2 times pinnate, the ultimate pinnae of irregular length, often 

 rather closely spaced at irregular intervals in groups, usually with acute 

 tips; transection showing numerous rhizoidal filaments aggregated with- 

 in a narrow medullary zone ; cystocarps unilocular, borne near the ends 

 of free branchlets ; antheridia and tetrasporangia unknown. 



Type: Holotype is Dawson 425, Feb. 7, 1946, on sheet 4181, in- 

 cluding slides 1178-1181, in HAHF. 



Type locality: On precipitous shore rocks at the village of San 

 Felipe, northern Gulf coast of Baja California. 



Additional material: D. 410, on intertidal rocks just north 

 of Punta San Felipe, Baja Calif., Feb. 



This species shows several features in common with Pterocladia 

 musciformis Taylor from which it differs in its larger size, its extensive 

 free parts, and the groups of closely spaced pinnate branchlets. Unfor- 

 tunately the tetrasporic phase which one would expect to yield diagnostic 

 characters does not occur in the present collections. 



Smith's illustration (1945, pi. 44) of a plant from Monterey, Cali- 

 fornia which he identifies as Gelidium caloglossoides Howe suggests a 

 closer affinity with the present plant than with Howe's species. 



Pterocladia complanata Loomis 



Loomis, 1949, p. 4, pi. 6, figs. 1-2, pi. 7, figs. 1-4, pi. 9. 



Thalli saxicolous, to 12 cm. high, consisting of many erect fronds 

 arising from a holdfast of entangled, branched, adherent stolons; erect 

 parts flattened throughout, 0.6-1.2 mm. broad, 100-250 /x thick, repeat- 

 edly pinnately branched, the branches either opposite or alternate, the 

 ultimate ones more or less spatulate, constricted at the base, 300-400 jx 

 wide; transection showing a moderate abundance of rhizoidal filaments 

 mainly confined and concentrated in the middle of the medulla; sexual 

 reproductive plants approximately as plentiful as the asexual ones; tet- 

 rasporangia borne in linear sori occupying the middle of the surfaces of 

 ultimate branchlets; sori much elongated and often extending far down 

 from the tips of branchlets, or even into the order of branches below the 

 last; cystocarps frequent, usually borne singly near the bases of ultimate 

 branchlets or of branches of lesser orders, or sometimes more than one 

 cystocarp on a branch ; antheridia in elongated or linear superficial sori 

 on either side of ultimate or subultimate branches. 



