NO. 10 DAWSON : MARINE ALGAE, GULF OF CALIFORNIA 293 



Family Gracllariaceae 



Genus GRAGILARIA Greville 

 Gracilaria Vivesii Howe 



Howe, 1911, p. 503, pis. 30, 33, figs. 1-5 ; Setch. & Gard., 1924, p. 750. 



This species has not appeared in any of the recent collections and is 

 known only from cast-up specimens, the type from La Paz, Vives 20e, and 

 M. 20 from Guaymas. It may be identified by its large, broad, dichoto- 

 mous-flabellate fronds. Excellent figures of both specimens have been 

 given. 



Gracilaria Johnstonii S. & G. 



Setch. & Gard., 1924, p. 752, pi. 22, figs. 11-14, pi. 60. Gracilaria sini- 

 cola, S. & G., 1924, p. 752, pi. 62. Gracilaria vivipara S. & G., 

 1924, p. 750, pi. 24, figs. 28, 29, pi. 63. 



This species, which is closely related to Gracilaria Vivesii, has un- 

 doubtedly been misinterpreted, owing to lack of information regarding 

 the habitat of the plants. All of the type specimens concerned in the above 

 synonymy have been examined, and there appears to the author no reason 

 for segregating them specifically^ The name G. Johnstonii is chosen to 

 represent this entity because the type specimen is the most normal and 

 characteristic-appearing plant of the three, though the other names pre- 

 cede it in the paging of the original publication. The type of G. vivipara 

 is clearly only a proliferating example of this species ; that of G. sinicola 

 is merely a somewhat old, ragged, and curled cystocarpic specimen. Other 

 examples of the latter from the same station are proliferating much as 

 G. vivipara and are partly covered with epiphytes. Considerable variation 

 in the width of the fronds is shown in the several specimens, ranging from 

 1 cm. at the forks to as much as 5 cm. The heavy, coreaceous texture is 

 the same in all of them, and in this particular they differ from all Gulf 

 Gracilarias except G. Vivesii. 



No mature plants which can be referred to this species with certainty 

 occur in the winter collections. From the evidence at hand it would ap- 

 pear to be a summer annual of sublittoral habitat. 



Specimens are known from Smith Island, J. 61 (AHF no. 79), June; 

 J. 108 (AHF no. 78), San Esteban Island, April; J. 62 (AHF no! 77), 

 Isla Partida, July; J. 36, 36x, Los Angeles Bay, June. 



Gracilaria lacerata S. & G. 



Setch. k Gard., 1924, p. 755, pi. 51c. 



Several plants of this species were collected at Guaymas, growing on 

 rocks in the intertidal zone, D. & R. 3353, December. They are up to 10 



