64 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 26 



angia 20-25 [x in diam., maturing within 300 ll of apex of terminal 

 branches, borne in whorls of 3-5 (mostly 4) within the cortical band 

 which is modified by their expansion to form an involucre; cystocarps 

 and spermatangia unknown. 



Type: E. Y. Dawson 1769, May 16, 1946, in Herb. A. Hancock 

 Foundation (48795). 



Type locality: Growing on Coeloseira pacifica, Bahia Bocochi- 

 bampo, near Guaymas, Sonora, Mexico. 



Mexican distribution: Gulf of Calif. — D. 501, 509, 455a, 1706, 

 1749, 1772, 3566, Bahia Bocochibampo, Sonora, on various hosts; D. 

 3667, Mazatlan, Sinaloa. 



Ceramium serpens Setch. & Gard. 

 PL 25, fig. 6 

 Setchell & Gardner 1924, p. 775, pi. 27, fig. 58; Dawson 1944, p. 318, 

 Dawson 1949, p. 244; Dawson 1950, p. 129. 



Thallus microscopic, epiphytic, the lower filaments creeping, 30-40 ll 

 in diam. at the nodes, attached by short rhizoids arising singly at the 

 nodes, sparsely forking, giving rise to a few sparsely branched erect 

 axes 3-4 mm. (up to 10 mm.) high; cortication only at the nodes, the 

 internodes naked and equal to or up to 4 times as long as the nodes; 

 tetrasporangia usually solitary at the nodes, spherical, 20-25 (to 40) ll 

 in diam., extruding through the cortex; sexual plants unknown. 



Type: Marchant 67c, May, in Herb. University of California. 

 Berkeley. 



Type locality: Epiphytic on Laurencia, La Paz, Baja California. 



Mexican distribution: Southern Baja Calif. — D. 3132, La Paz; 

 D. 3264, Punta Palmilla. 



This species is also reported from the Marshall Islands. 



Ceramium sinicola Setch. & Gard. var. sinicola 



PI. 25, fig. 4-5; PL 27, fig. 6-7 



Setchell & Gardner 1924, p. 773, pi. 25, fig. 40-41, pi. 75; Dawson 1944, 

 p. 315; Dawson 1950, p. 118, pi. 1, fig. 4-5; Dawson 1957, p. 5, 8; Dawson 

 1959, p. 30. Ceramium bicorne Setchell & Gardner 1924, p. 773, pi. 28, fig. 

 64, pi. 74. Ceramium codicola, as interpreted by Dawson 1944, p. 318 (in 

 part); Dawson 1945, p. 67; Dawson 1949, p. 26. 



Thalli epiphytic, 1-3 cm. high, attached by slender, branched, non- 

 bulbous rhizoids of various lengths and depths of penetration depending 

 upon the texture of the host; erect parts dichotomously branched, the 

 forcipate apices long and blunt, completely corticated in upper parts, 

 the more slender basal parts of axes showing prominent internodal 

 spaces; corticating cells irregularly arranged, angular, 8-11 ll in diam.; 

 mature apices commonly with 1-several short, straight, pluricellular 

 spines, tetrasporangia completely immersed, whorled at the nodes, oc- 

 cupying several forks of the somewhat swollen terminal ramuli. 



