Polysiphonia of the Tropical Pacific, I — Hollenberg 
61 
carps arising on very short pedicels on the 
creeping branches. 
It should be noted here that a very similar 
alga was collected by E. Y. Dawson, number 
7472, tetrasporic, from Lake Surprise, Key 
Largo, Florida, May 28, 1949. The Florida alga 
corresponds closely with the Pacific species as 
far as known, with certain exceptions, namely: 
(1) the Florida specimens are seemingly less 
firmly attached to the substratum; (2) tricho- 
blast primordia or scar-cells do not occur regu- 
larly one per segment on the prostrate branches 
as they do in P. anomala, but at irregular and 
less frequent intervals; (3) the indeterminate 
(prostrate) branches are somewhat larger in the 
case of the Florida specimens ; (4) tetrasporan- 
gia often occur in the indeterminate branches 
in series of 10-12 somewhat back of the apex. 
In spite of these differences it seems best for 
the present to identify the Florida plant with 
P. anomala on account of the general features, 
and especially the short and more or less deter- 
minate erect branches arising from much more 
extensive creeping branches, the very large and 
much branched trichoblasts, and the rhizoids, 
which are cut off as separate cells from the 
pericentral cells. 
Polysiphonia apiculata sp. nov. 
Figs. ID, 8, 9 
Plants mostly sublittoral, epiphytic, up to 
2.0 cm high, with a limited basal attachment by 
a number of unicellular rhizoids, which are 
cut off as separate cells from the basal end or 
middle of the pericentral cells; main branches 
150-250-(320)|x in diameter, composed of 
segments mostly 0. 5-1.0 diameter long; branch- 
ing pseudodichotomous, replacing trichoblasts 
at intervals of 7-l4-(20) segments; ultimate 
branches non -tapering for most of their length, 
but abruptly narrowed and more or less apicu- 
late terminally; pericentral cells 4, ecorticate, 
trichoblasts mostly very rudimentary, occasion- 
ally 260-740p long and 17p in diameter at 
the base, with 3-4 dichotomies, arising one per 
segment in J spiral sequence, soon deciduous 
leaving very small scar-cells; tetrasporangia up 
to 60p in diameter in slightly spiral series in the 
ultimate branches, whose segments are scarcely 
or not at all distended ; pericarp globular, 240- 
320p in diameter, composed of relatively large 
cells, with the cells of the ostiolar rim not much 
enlarged; spermatangial branches (immature) 
arising as a primary fork of a trichoblast. 
Plantae epiphyticae, ad 2 cm alt., affixionem 
basalem praefinitam per rhizoidea, ut cellulas dis- 
cretas separata, habentes; rami principales plerumque 
150-250|n diam., segmentis 0. 5-1.0 plo breviora quam 
lata habentes; rami pseudodichotomi, intervallis 7-14- 
(20) segmentorum, pro trichoblastis substitutui; rami 
ultimi abrupte angustati, ad apicem plus minusve 
apiculati; cellulae pericentrales 4, ecorticatae; tricho- 
blastae plerumque elementariae, 3-4 furcas habentes, 
una in unoquoque segmento in \ spira enascente, 
mox decidua; cellulae-cicatrices minutae; tetraspor- 
angia in serie paululum spirali, non protuberantia; 
cystocarpi globosi, cellulis orae ostiolaris vix ampli- 
ficatis; stichidia spermatangialia ut furca primaria 
trichoblastae enascentia. 
type: D. 19127p, tetrasporic, dredged 10-14 
fa, Pokai Bay, Oahu, Hawaii, July 30, 1959; 
represented by a glucose mount. 
ADDITIONAL COLLECTIONS: HAWAIIAN IS- 
LANDS— D. 19144AE1, on Amansia, D. 
19144AV2, tetrasporic, cystocarpic, D. 19144C2, 
tetrasporic, cystocarpic, on Galaxaura sp., D. 
19144M1, on Lauren cia sp., D. 19144Q2, sper- 
matangial, D. 19145 Jl, tetrasporic, cystocarpic, 
on Laurencia, all dredged 6-13 fa, Port Allen, 
Kauai, Sept. 12, 1959; D. 19136K1, sperma- 
tangial, washed ashore north of Koloa Stream, 
Oahu, Apr. 15, 1956; D. 191150, dredged 
20 fa, east of Explosive Ammunition Area, 
Oahu, Sept. 15, 1959; D. 191180, on Amansia 
sp., dredged 16-25 fa, Pokai Bay, Oahu, July 
30, 1959; D. 19122D1 and D. 19124R, dredged 
15—25 fa, Pokai Bay, Oahu, July 30, 1959; D. 
1912 6 J 1 , dredged 20-25 fa, Pokai Bay, Oahu, 
July 29, 1959; H. 65-14, cystocarpic, dredged 
2-3 fa, Kaneohe Bay, Oahu, Mar. 20, 1965; 
LINE ISLANDS — Da. 20016 (as P. mollis Hooker 
and Harvey), immature spermatangial, adrift 
northeast side of Clipperton I., Aug. 1958; 
MARSHALL ISLANDS — H. 48-0290.3, On 
Laurencia sp., inner reef, lagoon side of Eric I., 
Bikini Atoll, July 13, 1948; Caroline islands 
— D. 21857.1, tetrasporic, cystocarpic, on other 
algae, on reef flat, Yap I., legit E. Menez, 
Aug. 18, I960; Philippine islands — collec- 
tion by D. P. Abbott, on Halimeda sp., cysto- 
carpic, Pasig Bay, Balabac I., Mar. 3, 1957. 
