NO. 1 DAWSON : MARINE RED ALGAE OF PACIFIC MEXICO 71 



densely scattered in the inner medulla depending upon the branch age; 

 secondary pits moderately conspicuous in inner medulla; carposporic 

 plants infrequent; cystocarps 250-400 ju. in diameter, borne singly in the 

 middle of short, simple or compound ultimate branchlets, the branchlet 

 prolonged into a simple or branched apex above the cystocarp, or the 

 cystocarpic branchlet also bearing several of the same short, marginal, 

 determinate branchlets as occur on sterile branches ; antheridia unknown ; 

 tetrasporangial sori variously shaped, on simple, lobed, branched or de- 

 compound, slightly swollen fertile branchlets, these when compound 

 forming densely congested masses on the upper parts of the axes. 



Type: Holotype is a collection of several specimens by Dr. Coulter, 

 in the Harvey Herbarium, Trinity College, Dublin, Ireland. An isotype 

 is on sheet 53929 in HAHF. 



Type locality: Monterey, California. 



Mexican distribution: Pacific Baja Calif. — This species is a 

 common inhabitant of the areas of lower water temperature throughout 

 Pacific Baja California where it has been collected at Punta Descanso, 

 Bahia de Todos Santos, Punta Santo Tomas, Cabo Colnett, outer San 

 Quintin peninsula, Socorro, Punta Baja, Punta Maria, Punta Santa 

 Rosalia, Millers Landing, Islas San Benito, Isla Cedros, Bahia Asuncion, 

 Punta Abreojos and Punta Pequena. Its southern limit appears to coin- 

 cide with the southernmost area of upwelling along Baja California, 

 namely at Isla Magdalena. 



The species is extremely variable in size, in density of branching, in 

 dimension of branches and in degree of branching of fertile branches. 

 Some much reduced fertile plants have been found, in exposed turfs, 

 which are less than 1 cm. high with very reduced lateral branching except 

 at the apex. On the other hand, specimens nearly 20 cm. high have been 

 found in protected pools where luxuriant but less densely tufted growth 

 is characteristic. While some plants may be quite coarse and flattened in 

 lower parts, others may be very slender throughout with main branches 

 never exceeding 0.5 mm. Throughout .all of the collections, the most 

 distinctive and readily recognized feature is the presence, particularly 

 and consistently in lower, sterile parts, of the more or less regular short, 

 determinate, distichous, ascending pinnae. 



Gelidium cartilagineum var. robustum Gardner 



Gardner, 1927a, p. 280, pi. 54; Smith, 1944, p. 196, pi. 43, fig. 4; 

 Taylor, 1945, p. 157. 



