NO. 1 DAWSON: MARINE RED ALGAE OF PACIFIC MEXICO 55 



Type locality: "West Coast" of U.S., but not specifically 

 indicated. De Toni's indication would suggest that it is Oregon. 



Mexican distribution: Pacific Baja Calif. — D. 77-45, Punta 

 Descanso; D. 13-45, Cabo Colnett; Taylor, 34-648, Ma Cedros; D. 1142, 

 1298. 8702, 8883, Punta Baja; D. 1379, Desembarcadero de Miller; 

 D. 1426, 1513, 2918, Punta Santa Rosalia; D. 7267, 13418, Isla Mag- 

 dalena. 



Ceramium equisetoides Daws. 

 PI. 19, fig. 4 

 Dawson 1944, p. 320, pi. 51, fig. 1; Dawson 1950, p. 128. 



Thalli 8-15 mm. high, 80-100 jx in diam., primarily dichotomously 

 branched, the young sterile apices usually forcipate, with frequent 

 secondary monopodial branches, corticated only at the nodes; cortical 

 bands 0.5-0.75 times as long as wide, non-tumid, truncate above and 

 below, composed of a row of larger, median sub-surface cells and a 

 surface layer of irregularly arranged angular cells mostly under 10 /x 

 in maximum diameter; internodes very short above, reaching 200 /x in 

 the lowermost parts; tetrasporangia immersed in swollen terminal por- 

 tions of the main or lateral branches which are non-forcipate, usually 

 a single whorl at each node; shorter lateral tetrasporangial branches 

 resembling the strobili of Equisetum; spermatangia completely covering 

 terminal ramuli, or, if internodes are early elongate, in verticillate tufts; 

 cystocarps unknown. 



Type: E. Y. Dawson 479-40, January 1940, in Herb. A. Hancock 

 Foundation (56). 



Type locality: Puerto San Carlos, near Guayrnas, Sonora, 

 Mexico. 



Mexican distribution: Gulf of Calif. — D. 7206, 7238, Bahia 

 San Francisco, near Guayrnas; D. 21697, Bahia Empalme; D. 6931, 

 near La Paz. 



In the absence of adequate material of C. templetonii S. & G. from 

 the Galapagos Islands it is not clear how these two species differ. The 

 tetrasporangial axes in C. templetonii appear to become swollen well 

 below the forcipate tips, while those of C. equisetoides are terminally 

 swollen to acute tips. However, a specimen from Bahia Agua Dulce, 

 D. 911, appears to agree with C. templetonii in its tetrasporangial 

 branches, but otherwise with C. equisetoides. Further collections in both 

 the Gulf of California and the Galapagos Islands are needed. 

 Ceramium evermannii Setch. & Gard. 

 PI. 21, fig. 3-4 

 Setchell & Gardner 1930, p. 169, pi. 8, fig. 28-29; Dawson 1950, p. 123. 



Thalli 4-6 cm. high, flaccid, 390-410 /x in diam. in the basal re- 

 gion; main branches dichotomous, arising by longitudinal splitting 

 of the apical cell, with numerous proliferous branches of limited growth 



