NO. 10 DAWSON : MARINE ALGAE, GULF OF CALIFORNIA 263 



Plants 1-1.5 cm. high, of slender, erect, and spreading branches 150- 

 300 fx in diameter, subcylindric to compressed; branching mainly dis- 

 tichous, loose, irregular; prostrate parts not extensive, apparently not 

 stoloniferous ; holdfasts of rather small, irregular attachment-disks, not 

 conspicuous in our material; apices acute, somewhat attenuated; cortex 

 and subcortex of about 3 layers of cells surrounding a filament-free me- 

 dulla ; subspherical spores borne in cavities in the subcortex of short, 

 acute terminal branchlets which are not conspicuously swollen and cor- 

 respond in general to typical tetrasporic ramuli of the genus Gelidiella, 

 but spores apparently undivided (monospores) when shed, 20-50 /i, diam., 

 discharged through openings in the cortex. 



Type: D. 237, cast up on beach at north shore of Puerto Refugio, 

 Jan. 28, 1940. Herb. AHF no. 20. 



The observation of what are apparently large monospores rather than 

 tetraspores in these specimens leaves their true nature in doubt. The spe- 

 cies is more or less typically Gelidiella in all other respects and must be 

 placed here to await further investigation. 



Genus WURDEMANNIA Harvey 

 Wurdemannia miniata (Drap.) Feldm. & Hamel 



Feldmann & Hamel, 1936, p. 260, figs. 34-36. Wurdemannia setacea 

 B0rgesen, 1929, p. 268, figs. 360, 361 ; Kiitzing, Tab. Phyc. XIX, 

 tab. 26. Gelidium miniatum Kiitzing, Tab. Phyc. XVHI, tab. 58. 



This species is characterized throughout its wide area of distribution, 

 according to Feldmann and Hamel, by its habit of forming dense mats 

 of slender, branched erect filaments 0.5-2 cm. high. These filaments are 

 cylindrical, irregularly branched, without an apical cell, and with a 

 medullary cone of elongated cells. 



The collections in the Gulf have yielded two sets of specimens which 

 correspond very well to the above concept of this species. A specimen from 

 Carmen Island, Palmer, 1870, matches especially well the description 

 and illustrations quoted above. It forms a dense mat about 2.5 cm. high. 



D. 614 from San Gabriel Bay, Espiritu Santo Island, another warm- 

 water locality, is the same. These plants are 2-2.8 cm. high and form 

 similar mats sometimes as large as 15-20 cm. across. 



The collection of this species in the perennially warm parts of the 

 Gulf corresponds to the habitat of the plant as found in other parts of 

 the world. 



