NO. 1 DAWSON: MARINE RED ALGAE OF PACIFIC MEXICO 61 



4-5 /x diam., trichoblasts ; tetrasporangia beginning to form near the 

 base of the main filament and extending throughout the entire system 

 of branches to the ultimate ramuli, scattered more or less all the way 

 around the filament at the nodes, but mostly in two groups on opposite 

 sides of the filament, naked, projecting upward from the upper half 

 of the band, not subtended by bracteate filaments, 60-65 ll wide, 80-90 

 [x long; cystocarps and antheridia unknown." (after Setchell & Gardner) 



Type: H. L. Mason 191, April, in Herb. California Academy 

 of Sciences, (173632). An isotype slide is in Herb. A. Hancock Founda- 

 tion. 



Type locality: Growing on Eel Grass cast ashore at Isla 

 Guadalupe, Baja California, Mexico. 



"A much more robust plant than either C. caudatum S. & G. from 

 the Gulf of California or C. personatum . . . The cortical bands are 

 much more complex . . ." 



Ceramium pacificum (Collins) Kylin 

 PL 23, fig. 3; PL 24, fig. 1 

 Kylin 1925, p. 61; Dawson 1945, p. 67; Dawson 1950, p. 120, pi. 4, fig. 

 30; Dawson, Neushul & Wildman 1960, p. 50, pi. 37, fig. 1-2. Ceramium 

 rubrum var. pacificum Collins, in Collins, Holden & Setchell, Phyc. Bor. 

 Amer. no. 893, 1747. 



Thalli 5-7 (up to 18) cm. tall, deep red, the branching dichtomous 

 and with a divergence of 50-80°, the ultimate dichotomies less widely 

 divergent and forcipate, completely corticated throughout; branches 

 beset with numerous simple of forked proliferous branchlets most of 

 which are less than 5 mm. in length; differentiation of nodal and 

 internodal portions of corticating tissue indistinct; tetrasporangia im- 

 mersed, irregularly distributed ; cystocarps borne at the last two or three 

 forkings of branches, surrounded by involucral branchlets (modified 

 from Smith) . 



Type: Not specifically designated, but represented by syntypes 

 distributed as no. 893 in Phycotheca Boreali Americana. 



Type locality: Monterey, California. 



Mexican distribution: Pacific Baja Calif. — D. 1509, 1610, 

 1557, just south of Punta Maria, in drift. 



Ceramium paniculatum Okam. 

 PL 23, fig. 5-7 

 Okamura 1921, p. 114, pi. 179, fig. 8-16; Dawson 1944, p. 319; Dawson 

 1950, p. 122; Dawson 1959, p. 10. 



Thalli 8-12 mm. high, the filaments about 150 jx in diam., little 

 reduced except at the very tips, regularly dichotomously branched 

 with few proliferous branchlets, corticated only at the nodes; cortical 

 bands truncate above and below, mostly 1.5 times as wide as high, of 

 angular cells, the larger ones in the center; internodes very short 



