548 
PACIFIC SCIENCE, Vol. XXII, October 1968 
Numerous tetrasporangia arise in series near the 
branch tips and the tips of older branches tend 
to become frayed. 
H. filifera resembles H. caespitosa , described 
by Tseng (1944) from Hong Kong, in the 
branching pattern, in the numerous well de- 
veloped, spirally disposed, branched trichoblasts, 
in the terminal cystocarps on shortened branches, 
and the numerous, terminal, spermatangial 
stichidia. From the description given by Tseng, 
H. filifera differs in being considerably more 
slender, in having nearly twice as many seg- 
ments in the determinate branches, in the taper- 
ing rather than "obtuse-rounded” apices of the 
determinate branches, in tetrasporangia more 
numerous and more terminal in position, and in 
considerably smaller and arcuate spermatangial 
stichidia without the large sterile terminal cell 
described for H. caespitosa. Efforts to obtain 
specimens of H. caespitosa for comparison have 
been unsuccessful. 
In the number of pericentral cells and the 
number of segments in the erect branches, as 
well as in the numerous tetrasporangia in the 
upper parts of the determinate branches, H. 
filifera resembles H. pacifica. It differs from H. 
pacifica in the lack of bare nodes on the indeter- 
minate branches, in the more or less simulta- 
neous elongation of the numerous segments of 
young determinate branches, and in the rela- 
tively persistent trichoblasts, which likewise 
develop more or less simultaneously, 8 or more 
being commonly present at one time, rather than 
mostly 1-2 being present at a given time as in H. 
pacifica. Furthermore, scar-cells are relatively 
small in H. filifera , but large in H. pacifica. 
Herposiphonia nuda sp. nov. 
Figs. 2 E, 2 F, 21, 8 
Epiphytic algae, with prostrate, indeterminate 
axes attached to the host by frequent unicellular 
rhizoids, with a branch on every node, and with 
3 erect determinate branches in alternate posi- 
tions on either flank between successive indeter- 
minate branches, as is characteristic of the genus 
in general; prostrate branches 80-105ji in di- 
ameter, with mostly 7-8 pericentral cells and 
slightly smaller central cells, and with segments 
1-2 diameters long; determinate branches very 
slender, 2 — 3 — (3.5) mm high, 40-60 ( 80 )p in 
diameter, composed of 2 5-30- (44) segments 
1.5-3. 5 diameters long, with 4-5 pericentral 
cells slightly flattened periclinally and a much 
more slender central cell, the branches termina- 
ting in a conical or rounded cell, and occasionally 
bearing a lateral branch; chromatophores seem- 
ingly not zonate ; trichoblasts and scar-cells 
totally lacking in vegetative branches; sperma- 
tangial stichidia 2-3 per ramulus, arising from 
the entire trichoblast primordium on the con- 
cave side of the young branches well above the 
median point, lanceolate, about 27 5 p long and 
70p in diameter at maturity and bearing a sterile 
tip of 2-3 cells; procarps arising in similar 
positions; mature cystocarps and tetrasporangia 
not observed. 
Algae epiphyticae, rami prostrati tres ramos deter- 
minates erectos inter ramos indeterminatos successivos 
ferentes; rami prostrati 80-10 5 p diam., cellulis peri- 
centralibus plerumque 7-8; rami determinati 2-3- 
(3.5) mm alt., 40-60-(80)p diam., e 25-30-(44) 
segmentis 1.5-3. 5 plo longioribus quam latis com- 
posite cellulae pericentrales segmentorum 4-5, cellula 
centrali multo tenuiore; rami in cellulam conicam 
rotundatamve desinentes, ramum lateralem interdum 
ferentes; chromatophora non zonata; trichoblastae et 
cellulae-cicatrices in ramis vegetativis nullae; stichidia 
spermatangialia 2-3 in omni ramulo, e primordio 
trichoblastae toto in latere concavo ramorum iuvenum 
longe supra partem mediam orientia, lanceolata, ma- 
tura c. 275 X 70p, cacumen sterile e 2-3 cellulis con- 
stans ferentia; procarpi similiter positi; cystocarpi 
maturi atque tetrasporangia non observata. 
type collection: D. 19137J1, cystocarpic 
and spermatangial, on Padina sp., dredged at 
15-20 fa, Ilio Point, Molokai, Hawaii, Sept. 7, 
1959. This collection is represented by one glu- 
cose slide mount and fluid-preserved material. 
ADDITIONAL COLLECTIONS EXAMINED: HA- 
WAIIAN islands — D. 19135J1, spermatangial, 
D. 19135K2, cystocarpic, and D. 19135Z2, on 
Hypnea sp., all epiphytic and dredged at 26 fa, 
in front of the river mouth, Waialua, Oahu, 
Aug. 2, 1959; D. 19137N1, sterile, dredged 
along with the type; marshall islands — G. 
760.3, on Halimeda sp. in the lagoon at a depth 
of 9 m, Eniwetok Atoll, Sept. 7, 1955; mal- 
dive islands — Ha. 1 5-1 F-l 24-26, on a foliose 
red alga, dredged at 36 fa, in the lagoon near 
Bomasdu I., Miladummadula Atoll, Mar. 29, 
1964; Ha. 26-2N-23A, at a depth of 2 ft, 
Wilingili, Addu Atoll, Apr. 30, 1964. 
