Herposiphonia of Tropical Pacific — Hollenberg 
545 
branches, but frequently at alternate nodes, 
with indeterminate branches on the intervening 
nodes ; trichoblasts mostly much shorter than in 
var. dendroidea; cystocarps terminal, promi- 
nently urceolate, 200p in diameter, 300p long; 
spermatangial branches unknown. 
Algae epiphyticae proprietates speciei, praecipue 
trichoblastis, habentes, multo minores, autem, ramis 
determinatis plerumque 80-1 75, p alt., 25-35p diam., 
cellulis pericentralibus 6-7; rami determinati plerum- 
que in nodis alternatis orientes, ramis indeterminatis 
in nodis interjacentibus, aut interdum, tres rami deter- 
minati inter ramos indeterminatos successivos siti. 
type collection: D. 11533-2, tetrasporic, 
cystocarpic, on Caulerpa sp., under reef ledge, 
in front of Oneroa Village, Akau, Raroia Atoll, 
Tuamotu Archipelago, legit M. S. Doty and Jan 
Newhouse, Aug. 5, 1952. This collection is 
represented by a glucose slide mount and fluid- 
preserved material. 
ADDITIONAL COLLECTIONS EXAMINED: TUA- 
MOTU archipelago — all legit M. S. Doty and 
Jan Newhouse, 1952; D. 11368B1, D. 11477B, 
on Microdictyon sp., lagoon reef, Mataiva, 
Raroia Atoll, July 29; D. 11514, on Liagora sp., 
in channels, just north of Oneroa, Raroia Atoll, 
Aug. 5; D. 11538.1, on dead coral, and D. 
11542B, on Microdictyon sp., along with the 
type collection; marshall islands — H. 48- 
0914.6, outer reef, Uku I., Bikini Atoll, July 9, 
1948; H. 48-1091 A, on Pocockiella sp., outer 
reef, Arji I., Bikini Atoll, July 12, 1948; H. 
48-1213.168, Amen I., Bikini Atoll, July 7, 
1948; H. 48-1 609 A, on reef several miles 
north of Bikini I., Bikini Atoll, July 5, 1948; 
Caroline islands — all legit Ernani Menez, 
I960; D. 23032. 3A, on Microdictyon sp., reef 
between Ifalik and Falalap islands (7° 14' N, 
144° 27' E), Aug. 10; D. 23112.6, abundant 
on Microdictyon sp., reef, eastern side of Ifalik 
and Falalap islands, Aug. 10; D. 23207.2, 
abundant in algal turf on other algae, southern 
tip of Sorol I., Aug. 13; D. 23756.3, in algal 
turf on reef, Quoi I., Truk group, Aug. 2; 
maldive islands — Ha. 30-2Q-17B, probably 
to be referred to this variety, was collected on 
Bushy I., Addu Atoll, May 10, 1964. 
This variety is most commonly found grow- 
ing on species of Microdictyon. 
Herposiphonia dubia sp. nov. 
Fig. 15 
Saxicolous algae forming extensive mats to 
12 mm high; indeterminate prostrate branches 
to 15 Oja in diameter, of segments 0. 6-1.0 diame- 
ters long, with about 12 pericentral cells, and 
with 1-2 unicellular rhizoids per segment ; apex 
of indeterminate branches and young deter- 
minate branches strongly inrolled; each deter- 
minate branch followed distally by an indeter- 
minate branch and the latter followed by 1-2 
bare nodes; determinate branches 100-120p in 
diameter, composed of 45-75 segments 1.0-1. 5 
diameters long, with 12-16 pericentral cells and 
a central cell distinctly larger to twice the diame- 
ter of the pericentral cells; apex of determinate 
branches blunt or rounded, often remaining in- 
rolled or arched at or near maturity; secondary 
indeterminate branches frequently developing 
from the apical parts of determinate branches; 
walls relatively thick and brownish; chromato- 
phores not zonate; trichoblasts mostly lacking 
but 1-2 very rudimentary ones occasionally 
present; tetrasporangia 40-5 Oji in diameter in 
straight series of 15-25 in the upper parts of the 
determinate branches ; sexual reproductive struc- 
tures not observed. 
Algae saxicolae, tegetes amplas usque ad 12 mm 
alt. formantes; rami indeterminati prostrati ad 15 Op, 
diam., e segmentis 0. 6-1.0 longioribus quam latis, 
c. 12 cellulas pericentrales atque 1-2 rhizoidea in 
omni segmento habentibus, compositi; 1-2 nodi nudi 
inter ramos indeterminatos successivos unum ramum 
distaliter consequentes; rami determinati 100-120p 
diam., e 45-75 segmentis 1.0-1. 5 plo longioribus 
quam latis, 12-16 cellulas pericentrales habentibus, 
compositi; cellula centralis multo maior quam cellulae 
pericentrales; parietes crassiores; chromatophora non 
zonata; trichoblastae plerumque nullae, 1-2, autem, 
maxime rudimentariae interdum visae; tetrasporangia 
40-5 Op diam., 15-25 in serie recta in partibus super- 
ioribus ramorum determinatorum; structurae repro- 
ductivae sexuales non observatae. 
TYPE COLLECTION: D. 22472.1, tetrasporic, 
reef flat, Kahana, Maui, Hawaii, legit H., T., 
and B., Apr. 20, 1965. This collection is repre- 
sented by several glucose slide mounts and fluid- 
preserved material. 
ONE ADDITIONAL COLLECTION, D. 22349.1 
was from rocks, mid-littoral, interidal basalt 
east of Maalaea, Maui, legit H., T., and B., 
Apr. 19, 1965. 
