1925] SetcheJl-Gardner : MeJanophyceae 655 



5. Dictyota crenulata J. Ag. 



Frond attached by a stupose base, decompositely dichotomous, with 

 wide sinuses; segments linear, margins crenulate-dentate, narrow 

 below, tongue-shaped above, areolae rectangular ; sori sparingly scat- 

 tered over the whole surface of the segments. 



Keported from St. August in, on the west coast of Mexico, and from 

 La Paz, on the peninsula of Lower California. 



J. Agardh, Nya Alg., 1847, p. 7 ; Setchell and Gardner, Mar. Alg. 

 Gulf Calif., 1924, p. 730, pi. 18, figs. 50, 51. Dictyota Bartayresiana 

 var. dcuticulata Kuetzing, Tab. Phyc, 1859, p. 8 (as to synonym only). 



The type locality for Dictyota crenulata is St. Augustin, Mexico. 

 We referred a plant to this species {loc. cit.) collected at La Paz, which, 

 although sparse, seems to belong to J. G. Agardh 's species from 

 St. Augustin, 



'»" 



6. Dictyota hesperia S. and G. 



Fronds linear, repeatedly branched, 8-10 cm. high, 2-4 mm. wide, 

 80-120jU, thick, more or less finely stupose at the base, dichotomously, 

 or at times subdistichously branched, antheridia and oogonia distri- 

 buted over both surfaces on the same frond, oogonia single and 

 antheridia in small, circular groups ; tetrasporangia single or in small, 

 irregular groups. 



Growing on rocks in the lower littoral and upper sublittoral belts. 

 San Marcos Island, Gulf of California. 



Setchell and Gardner, Mar. Alg. Gulf. Calif., 1924, p. 731, pi. 18, 

 figs. 52, 53. 



Dictyota hesperia' seems to belong to the subgenus or section of 

 the group designated as Pleiadophora by J. G. Agardh (1894, p. 69) 

 with close af^nity with D. sandvicensis Sond. 



60. Neurocarpus Web. and Mohr 



Fronds smooth, fairly firm, with distinct, percurrent midrib, 

 repeatedly dichotomo-flabellate, attached by a stupose base, composed 

 of two distinct tissues, a medulla of cuboidal to angular cells, many 

 layers deep at the midrib, diminishing to few at the margin, and a 

 single layer of small, color bearing cells on the surface; aplanospores 

 arranged in sori along: either side of the midrib ; oogonia and antheridia 

 scattered. 



