NO. 1 DAWSON : MARINE RED ALGAE OF PACIFIC MEXICO 65 



Gelidium crinale var. luxurlans Collins 

 Plate 4, figs. 4-5 



Collins, 1903, in Collins, Holden & Setchell, P.B.A. No. 1138; 

 Gardner, 1927a, p. 277, pi. 46, fig. 1, pi. 47, fig. 3. 



Thalli saxicolous, 2.0-7.0 cm. high, rather densely tufted or con- 

 gested, consisting of a loose mass of primary rhizomatous branches, 

 attached by small discs and semi-penetrating tips, from which arise 

 numerous erect branches; erect fronds 150-250 /* in diameter, compressed 

 to flattened and of rather uniform diameter throughout, pinnately 

 branched in 2-3 orders, the branches alternate or opposite, of irregular 

 spacing and length; transection broadly oval, showing a prominent sub- 

 cortex, a very limited medulla, often of a single row of thick-walled 

 cells, and a moderate to small number of rhizoidal filaments aggregated 

 along the central medullary line; tetrasporangial sori borne on sub- 

 terminal, slightly swollen areas of acute fertile branches, sometimes ex- 

 tending continuously back into 2-3 orders of branches; cystocarps and 

 antheridia not seen in Mexican material. 



Type: Holotype not designated. Syntypes are number 1139 in 

 Phycotheca Boreali-Americana. 



Type locality: Pacific Beach, San Diego County, California. 



Mexican distribution: Pacific Baja Calif. — D. 265, 8 km. south 

 of Punta Descanso, Jan. ; D. 174, 180, shore at Rio San Telmo, Jan. ; D. 

 8774, outer shore, San Quintin peninsula, Jan.; D. 8697, Punta Baja, 

 Jan. 



The size, habit and tetrasporangial characters, and particularly the 

 structure of this plant are quite unlike those of the other variants of 

 Gelidium crinale along this coast, but apparently the same degree of 

 variation is to be found in other parts of the world inhabited by this 

 widespread species. 



Gelidium nudifrons Gardner 



Gardner, 1927a, p. 274, pi. 43, pi. 37, fig. 2; Dawson, 1949, p. 227. 



Thalli saxicolous, to 25 cm. high, consisting of much-branched erect 

 parts from a small holdfast of branched, adherent stolons; erect fronds 

 compressed throughout, 300-500 (730) jm in diameter, without percurrent 

 axes, repeatedly, irregularly, alternately and rather distantly branched, 

 mostly at intervals of 1-2 cm., subdistichous but not apparently so, all of 

 the vegetative branches indeterminate, without short branchlets, or with 

 only a few; transection oval, showing rhizoidal filaments massed in the 



