124 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 17 



in successive branch-orders above to long-attenuate ultimate branchlets 

 only 50-70 /t in diameter; intergenicula throughout about twice as long 

 as broad, slightly more elongate above; tetrasporangial conceptacles 

 ovoid, about 300 p. in diameter, terminal on upper branchlets, but long- 

 antenniferous and occupying the position of a dichotomy. 



Type: Holotype is Dawson 8355, Dec. 18, 1949, on sheet 54922, 

 including vials 2193-2194 and slide 1453, in HAHF. 



Type locality: Intertidal on outer reef at extreme south tip of 

 Isla Guadalupe, Baja California, Mexico. 



Additional material: Mason 12, Isla Guadalupe, April 1925 

 (a decalcified specimen in the Herbarium of the California Academy 

 of Sciences, sheet 173649). 



The size and habit of this little plant, its partially dichotomous 

 branching and very slender, attenuate, ultimate branches suggests Jania, 

 especially in gross aspect. Its primary pinnate branching, however, places 

 it in Corallina as currently accepted. It is easily the most distinctive 

 species of the Mexican coast. 



Corallina pinnatifolia (Manza) comb. nov. 

 Plate 9, figs. 7-13 



Joculator pinnatif oltus Manza, 1937, p. 47; Manza, 1940, p. 263, 

 pi. 1, figs. 1-2; Taylor, 1945, p. 198, pi. 61. 



Thalli saxicolous, 2.5-5 cm. high, usually more or less densely 

 branched and often forming hemispherical or at least rather compact 

 clumps; branching opposite pinnate-plumose, sometimes tending to be- 

 come whorled below, the pairs of indeterminate branches or the short, 

 determinate, unsegmented pinnae arising from almost every intergenicu- 

 lum; intergenicula variable in shape, those near the base subcylindrical 

 or compressed, those of axis above flattened, usually about as long as 

 broad, usually under 1.5 mm. in greatest diameter, more or less truncate 

 triangular in outline with a distinct midrib, the wings, truncated by the 

 pinnae arising from them, often with a lateral spur arising beneath each 

 such pinna; ultimate, unsegmented pinnae usually irregularly lanceolate 

 or spatulate, often awl-shaped below, and above sometimes tending to be 

 digitate; tetrasporangial conceptacles borne variably, usually more 

 abundant in lower parts of plants, primarily and predominantly ter- 

 minal, often on slender, unsegmented ultimate pinnae which cause them 

 to appear pedicellate, but also terminal on flattened pinnae, and (or) 

 irregularly lateral from the flattened surfaces or margins of the inter- 

 genicula in which case they usually protrude strongly, sometimes the 



