332 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 3 



bearing many lateral ramifications of limited growth, these several times 

 subdichotomously, multifariously branched with very short internodes, 

 giving a strongly excurrent, arborescent appearance; fronds with four 

 large pericentral cells per segment, becoming corticated in thicker parts 

 toward base ; cortication beginning by appearance of small cells in longi- 

 tudinal rows between the pericentral cells, becoming complete only in 

 lowermost parts; segments equilateral or more often shorter than broad; 

 apices provided with abundant, long, much-branched trichoblasts arising 

 exogenously, in % right-hand spiral divergence toward tip, early de- 

 ciduous and not present except in growing specimens; branches arising 

 independently, replacing trichoblasts ; scar-cells left by deciduous tricho- 

 blasts; tetrasporangia in single, spiral rows in somewhat swollen ultimate 

 branchlets. 



Type : D. 629c, epiphytic on Sargassum leaves, cast up, San Jose 

 del Cabo, Feb. 16, 1940. Herb. AHF no. 61. 



H. 610a, San Jose del Cabo, August, 1932 (hairs not present; an 

 old, sterile specimen). 



The habit of this species is especially striking because of the strongly 

 excurrent development and the short rigid nature of the lateral branches. 



Polyslphonia californica Harv. 



Kylin, 1941, p. 36; Collins, Holden & Setchell, Phyc. Bor. Amer. no. 

 1142. 



The nomenclature of these plants has been well reviewed and clari- 

 fied by Kylin. This may be distinguished from other Polyslphonia species 

 in the Gulf by its large number of pericentral cells, 9-10, or more. 



It is not a common plant in the Gulf region, to judge from the two 

 known collections, both brought up in the dredge. 



D. 52, growing epiphytically on membranous reds, dredged in 4-6 

 meters, Guaymas Bay, Jan.; D. 361, in 6-20 meters at high water, 

 Punta Pefiasco, Feb. 



Genus LOPHOSIPHONIA Falkenb. 



Lophosiphonia villum (J. Ag.) S. & G. 



Plate 48, Figs. 1-6 



Kylin, 1941, p. 40. Polyslphonia villum J. Agardh, 1863, p. 941 (not 

 P. villum Snyder in Collins, Holden & Setchell, Phyc. Bor. Amer. 

 no. 246). 

 Kylin has reinvestigated the type specimen of this species which was 



