NO. 10 DAWSON : MARINE ALGAE, GULF OF CALIFORNIA 227 



D. 318, sporophytes and gametophytes, rocky shore, Willard's Island, 

 Gonzaga Bay, Jan. ; D. 410, gametophytes, rocky shore, Pond Island, Feb. 



The collections of this plant from the Gulf were first identified as 

 Zanardinia prototypus (Nardo) Nardo (Dawson, 1941, p. 119), a species 

 which they resemble very closely. The discovery and investigation of an 

 "Aglaozonia" among the collections led, however, to the conclusion that 

 the plant belongs to Cutleria, a genus whose sporophyte stage has long 

 been known as A glaozonia. Zanardinia, on the other hand, does not have 

 dissimilar gametophytes and sporophytes. Close correspondence in general 

 aspect was found also with Cutleria adspersa (Roth) De Not. Sauva- 

 geau (1899, p. 298-301) has compared Cutleria adspersa and Zanardinia 

 prototypus (Z. collaris), which differ very little in the nature of the ster- 

 ile gametophytes and has pointed out the slight distinctions. Since, how- 

 ever, the sporophj^te is present also in the Gulf collections, comparison 

 could be made on two bases. Hamel (1931-1939, p. 325) discusses the 

 gametophyte of C. adspersa together with its sporophyte, known as Aglao- 

 zonia melanoidea. The latter plant is characterized by its very dark color 

 and firm attachment to rock surfaces. Its size reaches several (4-8) cm. 

 The A glaozonia stage from the Gulf, which in one case was found grow- 

 ing directly at the base of the Cutleria gametophyte, and which is without 

 question the sporophyte of that plant, is not dark in color, is not firmly at- 

 tached to the substratum, and reaches only 1.5-2 cm. in extent. Though 

 little can be found to distinguish the gametophyte of our species from 

 Cutleria adspersa, except perhaps the thin appearance of the cortical cells 

 in cross section, the presence of a distinctive type of sporophyte seems suf- 

 ficient to establish this plant as a species new to science. 



It is remarkable in being the first member of the order Cutleriales to 

 be positively recorded from the Pacific coast of America. 



Apparently it is an ephemeral plant, and no specimens were found in 

 July, 1940, although special search was made at the precise spot from 

 which examples were taken in January. This fact would indicate a winter 

 annual development. All gametophytes found in January were in excel- 

 lent, fresh, rapidly growing condition, all with fine trichothallic marginal 

 fringes. 



Cutleria adspersa (Roth) De Not has been reported in Japan, but as 

 yet no sporophyte A glaozonia stage has been mentioned. The Japanese 

 plant may perhaps be the same as ours, but evidence is at present incom- 

 plete. 



