NO. 10 DAWSON : MARINE ALGAE, GULF OF CALIFORNIA 219 



Thallus 8-10 cm. high, essentially cylindrical, attached by a disk 

 about 1 cm. broad; one to several erect axes arising from the holdfast; 

 branches irregularly forked, narrow below and constricted at the junc- 

 tions, broadest in midportions above, swollen to as much as 11-13 mm.; 

 utricles long, slender, about 1100 /x long in upper swollen parts, mostly 

 125-200 fi diam., shorter and narrower below but of same proportions; 

 end-wall very thick, 50-75 /x, laminate, smooth, dome shaped ; gametangia 

 mostly narrow fusiform, 250-300 fi long, 70-90 fi broad. 



Type: MacDougal, Port Libertad, Sonora, May 4, 1923. Isotype, 

 Herb. AHF no. 6. 



This is one of the most outstanding species of the Gulf of California, 

 distinct at once from any of the other Pacific coast species, and one of the 

 few known in which the branches are swollen above. The utricles are 

 notably long and narrow, and the end-walls very thick. In Setchell's study 

 notes there is a statement that he has considered this plant near to Codium 

 contractum Kjellm. of northeast Asia, another species with swollen upper 

 branches. 



An additional collection of this plant was recently made by Dr. Poin- 

 dexter at Punta Pefiasco, near the type locality, March, 1941. His speci- 

 mens are largely immature, but some show very well the broad, swollen 

 upper portions of the branches. 



