32 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 26 



multifarious; tetrasporangia adaxial on the ramuli, elliptical, 45-55 [i in 

 diam., solitary, sessile; spermatangia in tufts along the adaxial side of 

 ultimate branchlets ; cystocarps essentially terminal near the tips of main 

 axes, binate, the halves almost spherical, about 130 /x in diam. 



Type: A collection by Carl Skottsberg, probably in the Botanical 

 Museum, Copenhagen, Denmark. 



Type locality: Easter Island. 



Mexican distribution: Gulf of Calif.— D. 195-40, Puerto Refugio 

 (intertidal) ; D. 381f-40, Bahia Tepoca (22m.) ; D. 849, 851-2 (with 

 some corticating filaments) Isla Jorge (intertidal) ; D. 46-798, Isla 

 Patos (intertidal) ; D. 1004, D. 1029, Isla Partida (intertidal) ; D. 511, 

 Bahia Bocochibampo (intertidal); D. 18803, Isla Monserrate (-1 to 

 —5 feet) ; D. 7072, Punta Frailes (40 m.) 



Yamada's (1944) Callithamnion minutissima seems to be closely 

 related here, if not identical. Described from the warmer, southern part 

 of Japan, but never illustrated, it seems to have little to separate it from 

 C. paschale. Yamada says, however, that it is "dichotomously branched 

 in general, in the lower and middle parts of the frond dichotomously or 

 somewhat alternate-pinnately." It is not clear how these terms should be 

 interpreted, but if the main branching is dichotomous this would provide 

 a ready distinction. 



Callithamnion ramosissimum Gard. 



PL 10, fig. 6-7 

 Gardner 1927b, p. 404, pi. 86 



Thalli epiphytic, 8-12 mm. high, attached by loose, descending 

 rhizoidal filaments; principal axes 170-300 fj. in diam. at the base, of 

 cells about as long as broad, ecorticate or with a few descending, 

 appressed filaments, giving off several orders of branches gradually 

 reduced to 10 p or less in the ultimate ones; branching alternate, 

 spiral, polystichous, upwardly curved, the ultimate ones of 6-10 cells 

 2-5 diameters long, slightly attenuated, incurved, very abundant, termi- 

 nally blunt; gland cells described as "sparse" in the type, not observed 

 in the Mexican material; tetrasporangia 2-4 seriate, sometimes 2 from 

 a single cell, sessile, adaxial on upper branchlets, broadly ellipsoidal, 

 50-65 fx long including the thick envelope; spermatangia densely 

 crowded on the adaxial side of the ultimate ramuli ; cystocarps unknown 

 (modified after Gardner). 



Type: N. L. Gardner 5034, June, in Herb. University of 

 California, Berkeley (296618). 



Type locality: Epiphytic on Hypnea, La Jolla, California. 



Mexican distribution: Pacific Baja Calif. — D. 8566, Isla Gua- 

 dalupe, lowermost intertidal. 



