Marine Plants of Nha Trang — Dawson 
417 
Fig. 28. a, Liagora ceranoides: An assimilatory filament bearing antheridia, X 400. b, Actinotrichia fragilis: An 
upper portion of a plant, X 7.5. r, <7, Galaxaura vietnamensh: c, A small portion of the cortex from the flattened 
face of a blade, X 225; d, a small portion of the cortex from the margin, cut through a fascicle of extended 
assimilatory filaments with their associated spinulose cells, X 250. 
Galaxaura vietnamensh sp. nov. 
Figs. 28c, d, 29a 
Thallo typi sexualis, ad 9 cm. alto, e stipite 
brevi, gracili, velutino, laminas complanatas 
cuneate edente; ramificatione in una planitie 
angulis angustis, intervallis 8-19 mm.; lam- 
inis 3. 5-4. 5 mm. latis, tenuibus, marginibus 
ad 350-400 fx, integris, baud constrictis, plene 
calcificatis, plus minusve nitentibus, apici- 
bus obtusis, rotundis; cortice plerumque 
distromatico; cellulis subepidermalibus ro- 
tundis hemisphaericalibusque, 23-35 /i dia- 
metro; cellulis epidermalibus angularibus in 
aspectu superficiali, circiter 18 n diametro; 
cellulis spinulosis solum ad margines, pler- 
umque in fasciculis parvis filamentorum as- 
similativorum extensorum aggregatis. 
Thallus of sexual type, to 9 cm. high, con- 
sisting of a simple or forked, terete, velvety 
stipe about 1.2 mm. in diameter and 2 mm. 
long giving rise cuneately to the complanate 
blades; branching in one plane at narrovy 
angles, at intervals of 8-19 mm.; blades 3.5- 
4.5 mm. wide, thin, the margins thickened to 
350-400 fjL, entire, unconstricted, fully cal- 
cified and + — nitent, not striate, the apices 
blunt and rounded, scarcely tapered; cortical 
tissue mostly distromatic, partly tristromatic 
at the margins; subepidermal cells rotund- 
hemispherical, 23-35 M in diameter; epidermal 
cells angular in surface view, about 18 ju in 
diameter; spinulose cells only at the margins, 
usually aggregated among small groups of 
extended assimilatory filaments; reproduction 
not seen. 
TYPE: Holotype is a collection by Raoul 
Serene, April, 1950, in the U. S. National 
Herbarium. 
Type locality: Dredged from 33 meters off 
the north side of "Black Rocks,” Sta. 8. 
This is one of the broadest of Galaxaura 
species, being most similar in this respect to 
G. magna Kjellm. from Cape Agulhas, South 
Africa. It differs from that species in its some- 
what more flabellate branching at shorter in- 
tervals, its distinctly thickened margins, its 
usually distromatic cortical tissue, and the 
presence of groups of spinulose cells mixed 
