NO. 1 DAWSON : MARINE RED ALGAE OF PACIFIC MEXICO 95 



dichotomously but polystichously branched, provided throughout Nvith 

 many closely set conical or spine-like branchlets which may in turn be 

 minutely spinose; internal structure consisting of densely compacted 

 branching filaments mostly of small, spherical or ovate cells, the lower 

 and inner parts of more and more elongated cells ultimately arising from 

 a prominent central axial filament of elongated cells 35-65 /a in dia- 

 meter; cystocarps borne as subspherical swellings near the ends of 

 branches, 600-800 fx in diameter; carpospores prominently rugose, angu- 

 lar, about 25 /t in diameter ; antheridia about 5 /a in diameter, spherical, 

 cut off terminally from slender, colorless, nemathecial filaments about 

 100 jn long in sori encircling upper branches; tetrasporangia cruciate by 

 oblique walls, elongate or somewhat fusiform, about 18 by 40 /a in dimen- 

 sions, embedded in superficial, encircling nemathecia causing swelling 

 of upper branchlets, the nemathecia 100-125 ix thick, composed of dense- 

 ly compacted, slender, mostly unbranched paraphyses of 8-10 cells. 



Type: Holotype not designated. Syntypes of Kastalsky and of 

 Merk, if extant, are probably in the Herbarium of the Botanical Garden 

 of Leningrad, U.S.S.R. 



Type locality: Two syntype localities indicated : Sitka Island and 

 Unalaska, Alaska. 



Mexican distribution: Pacific Baja Calif. — Hendry 22 (Herb. 

 U.C), Cabo Colnett, May; Cooper 800, Punta Santo Tomas, Mar. (all 

 reproductive phases). 



Although common in California, this species is probably limited along 

 the northwest coast of Baja California by increasing desiccation of its 

 high intertidal habitat. 



Hildenbrandiaceae 



Hildenbrandia prototypus Nardo var. prototypus 



Plate 7, fig. 4 



Nardo, 1834, p. 675; Taylor, 1945, p. 166; Smith, 1944, p. 214; 

 Rosenvinge, 1917, p. 202, figs. 121-124; Kylin, 1944, p. 36, Fig. 30. 

 Hildenbrandia rosea Kiitzing, 1843, p. 384; Setchell & Gardner, 1924, 

 p. 787; Dawson, 1944, p. 265. 



Thallus saxicolous, pale to dark rose red, depending upon the thick- 

 ness of the crust, closely adherent to the substrate, 50-450 ^u. thick, con- 

 sisting of densely packed quadrate or sometimes somewhat anticlinally 

 elongated cells (2.5) 3-4 (5) ju, in diameter, arranged in vertical rows; 

 conceptacles immersed, sub-spherical to compressed, 35-110 jx broad, 



