NO. 2 DAWSON : MARINE RED ALGAE OF PACIFIC MEXICO 249 



July; Dawson, Mar. 11, 1945, La JoUa (Herb. UC). Pacific Baja 

 Calif.— D. 93-45, 161-45, Apr. (Herb. UC), D. 5284, Sept., Punta 

 Descanso; D. 5153, Cabo Colnett, Sept.; D. 9788, Isla Cedros, Apr.; 

 D. 1611, near Punta Maria, Apr.; D. 10349, Punta San Eugenio, Nov. 

 Gulf of Calif. — Johnston 25, Bahia San Francisquito, June (Herb. 

 Calif. Acad. Sci.) ; D. 443-40, Feb., Johnston 53a, Apr., Isla San Este- 

 ban; D. 996, Feb., Johnston 87, July (Herb. Calif. Acad. Sci.), Isla 

 Partida; D. 1035, Isla Rasa, Feb.; D. 777, Isla Patos, Feb.; D. 1840 

 (0), D. 1844 (0), D. 1902 (?), D. 1930 (0), May, D. 10985 

 (0 ^)^ June, D. 3498, Nov., Ensenada San Francisco, near Guaymas; 

 D. 481, D. 530, Feb., D. 1719, D. 1723, May, Ensenada Bocochibampo, 

 near Guaymas ; Drouet & Richards 3407, Punta San Pedro, near Guay- 

 mas, Dec; D. 1657, Bahia Carrizal, near Cabo Arco, May; D. 1786, 

 D. 1797, Punta Colorado, near Guaymas, May. Oaxaca — D. 3808, 

 Jan., D. 10759, May (small and sparse), Salina Cruz. 



This species is another extremely variable Grateloupia in which the 

 type specimen is poorly representative. Kiitzing's habit illustration shows 

 the main axes proportionally broader than they should have been drawn, 

 and the illustration of the transection does not correctly show the net- 

 work of slender filaments of the medulla. The type has been compared as 

 completely as the material warrants with specimens from Salina Cruz, 

 Oaxaca, which appear with little doubt to be the same species as that 

 collected by Liebmann. These show, despite their variability, a char- 

 acteristic pinnate branching which can be recognized in many other 

 collections from more northern stations in Mexico. The extensive series 

 of specimens now at hand shows this species as it may occur under many 

 different conditions. In intertidal situations it is often to be found in 

 rather warm pools. This is especially true of its occurrence along Pacific 

 Baja California. It reaches its most luxuriant development in the central 

 Gulf of California where it commonly occurs in the sublittoral region. 

 In the Guaymas area it matures in summer and often reaches large size. 

 Specimens found in drift along Ensenada San Francisco near Puerto San 

 Carlos are commonly 40-50 cm. tall and with primary blades 2-3 cm. 

 wide. Despite this range in size, it may be recognized by the following 

 combination of characters: the several fronds from a common attach- 

 ment, their substipitate bases, the abundant, rather regular, pinnate 

 branching, often of 3 orders, the frequent production of soft, linear, pro- 

 liferous branchlets from the blade surface, and the rather thick cortex. 



