540 
PACIFIC SCIENCE, Vol. XXII, October 1968 
algal turf on boulders, Honokohau, northern 
Maui, legit H., T., and B., Apr. 20, 1965; Ha. 
30-2Q-17A, on Dictyota sp., Bushy Island, 
Addu Atoll, Maidive Islands, May 10, 1964. 
This species is close to H. pare a, from which 
it differs chiefly in being much coarser, with 
more numerous pericentral cells, mostly shorter 
segments, tapering determinate branches, and 
coarser trichoblasts. It is also characteristically 
saxicolous, whereas H. parca is usually epiphy- 
tic. 
Herposiphonia delicatula sp. nov. 
Figs. 1 A, IB, 2 H, 3 
Epiphytic algae, with indeterminate prostrate 
branches mostly 35-40p in diameter, composed 
of segments 1-2 diameters long, with 7-8 peri- 
central cells, attached by rhizoids with digitate 
and frequently multicellular tips; determinate 
branches erect, in alternating series of three be- 
tween successive alternating, indeterminate 
branches, which mostly remain short; erect 
branches 30-40ix in diameter, composed of 12- 
14- (30) segments 1.0-1. 5 diameters long or 
occasionally longer, with 6-8 pericentral cells; 
chromatophores commonly zonate; trichoblasts 
3-4, terminal, with 1-3 dichotomies, mostly 
poorly represented, but occasionally as much as 
700|i long, with a basal cell up to 2 5 Op long and 
20p in diameter; tetrasporangia in series of 5-8 
in the lower or middle part of the branches; 
procarps arising on the 4th to 6th segment from 
the base of the branches; cystocarps not ob- 
served; spermatangial stichidia lanceolate, about 
80p long, and 25p in diameter, arising on the 
convex side of the branches 3-5 segments from 
the base or sometimes nearer the apex, without 
a sterile tip. 
Algae epiphyticae ramos prostratos plerumque 
35-40p, diam. habentes, cellulis pericentralibus 7-8; 
rami determinati erecti, tribus in positionibus alter- 
nantibus inter ramos indeterminatos successivos sitis, 
30-40p, diam., e plerumque 12-14 segmentis 1.0- 
1.5 plo longioribus quam latis compositis, cellulis 
pericentralibus 6-8; trichoblastae 3-4, terminates, 
1-3 dichotomias habentes, plerumque parum evolutae, 
interdum, autem, usque ad 700 jll long., cellula basali 
usque ad 2 5 Op, long.; tetrasporangia 5-8 continua, in 
partibus inferioribus mediisve ramorum nata; pro- 
carpi in segmento quarto vel sexto a basi ramorum 
orientes; cystocarpi non observati; stichidia sperma- 
tangialia lanceolata, 80 X 25p, uno vel duobus in 
latere convexo ramorum in segmento tertio ad quinto 
a basi natis, sine cacumine sterile. 
TYPE collection: D. 21876.1, tetrasporic, 
cystocarpic, spermatangial, on Amphiroa sp., on 
a reef at Falas Island, Truk group (7° 32' N, 
151° 45' E), Caroline Islands, legit E. Menez, 
Aug. I960. This collection is represented by 
three glucose slide mounts. 
ADDITIONAL COLLECTIONS EXAMINED: HA- 
WAIIAN islands — D. 19135Z3, tetrasporic, 
dredged at 26 fa in front of the river mouth, 
Waialua, Oahu, Aug. 2, 1959; marshall 
islands — H. 48-1213.71, Amen I., Bikini Atoll, 
July 7, 1948; Caroline islands — all legit E. 
Menez, D. 15126.1, on Amphiroa sp., on a 
reef at Tafansak Village, Kusaie I., July 16, 
I960; D. 23261.2, on Halimeda sp., Falas I., 
D. 23438.2, tetrasporic, cystocarpic, on Am- 
phiroa sp., Moen I., D. 23444.1, tetrasporic, on 
Amphiroa sp., from a reef at Falas I., July, 
I960 ; D. 23471.2, tetrasporic, on a jointed 
coralline, on a reef at Yap I., Aug. 18, I960; 
Philippine islands — D. 18099C, tetrasporic, 
on Sargassum sp., Davao, Mindanao, June 22, 
1958; MARIANA ISLANDS — D. 20129, sperma- 
tangial, 20130, on Sargassum sp., Guam, legit 
E. Menez, Oct. 12, I960; Malaysia — D. 18179, 
on Thalassia, floating in a channel between Tand- 
jung, Penang and Singapore, Oct. 29, 1957; 
MALDIVE islands — Ha. 9-2E-1 2 1-33B, on 
Dictyota sp., is doubtfully referred to this spe- 
cies. It was collected from the channel between 
Maro and Mafilefuri, Fadiffolu Atoll, Mar. 24, 
1964; western Atlantic ocean — a collec- 
tion by Louis G. Williams, No. 247, on Codium 
sp., from Shark Shoal Jetty, Beaufort, North 
Carolina, July 25, 1949, identifies readily with 
H. delicatula, differing chiefly in the number of 
segments in the determinate branches, as many 
as 40 segments being counted. The material is 
cystocarpic, with procarps arising in the lower 
center of the branches, and with mature cysto- 
carps ovoid and about 200p in diameter. The 
number and position of the trichoblasts could 
not be determined with the material at hand. 
This species is closest to H. tenella, and like 
that species exhibits considerable variability of 
branching pattern, some specimens having no 
