70 
PACIFIC SCIENCE, VoL XXII, January 1968 
water along with the typical form of the spe- 
cies. Also representative of this variety is H. 
65-79=5 (D. 22567) from muddy bottom in 
shallow water of an ancient fish trap, southeast 
Molokai, Apr. 22, 1965. 
Polysiphonia poko sp. nov. 
Fig. 3 A 
Plants to 4 mm high, assurgent from pros- 
trate branches attached by unicellular rhizoids 
which are cut off from pericentral cells by a 
cross-wall, mostly from the proximal end ; pros- 
trate branches and larger erect branches 90- 
l40-(190)|i in diameter; pericentral cells 4, 
ecorticate with segments mostly about 0.5 di- 
ameter long; erect branches mostly unbranched; 
all branches cicatrigenous, not narrowed at the 
base; trichoblasts not well developed or up 
to 500fi or more long and 2 Op in diameter at 
the base with 3-4 dichotomies, arising one per 
segment in J spiral sequence ; scar-cells on pros- 
trate and erect branches ; wall-scars often prom- 
inent; tetrasporangia spirally arranged in the 
branches, slightly distending the segments ; 
cystocarps globular-ovoid, to 360p in diameter 
with cells of the ostiolar rim not enlarged; 
spermatangial branches cylindrical, without a 
sterile tip; comprising a primary branch of a 
trichoblast. 
Plantae ad 4 mm alt., assurgentes e ramis prostratis, 
per rhizoidea unicellularia, a cellulis pericentralibus 
per dissepimentum plemmque ab extreme proximali 
separata, affixis; rami prostrati et rami maiores erecti 
90-1 40- (190)1^ diam.; cellulae pericentrales 4, escor- 
ticatae, segmentis plemmque ca. 0.5 plo brevioribus 
quam lata; rami erecti vulgo non ramosi; omnis ramus 
cicatrigenus, ad basim non attenuatus; trichoblastae 
non bene evolutae aut usque ad 500p vel plus long, 
et 20p, diam. ad basim. 3-4 dichotomias habentes, una 
in unoquoque segment© in \ spira enascente; cellula- 
cicatrices in ramis prostratis erectisque; membranae- 
cicatrices saepe manifestae; tetrasporangia in ramis 
spiraliter ordinata, segmenta paululum distendentes; 
cystocarpi globoso-ovoidei, ad 360p, diam., cellulis 
orae ostioli non dilatitis; rami spermatangiales cyiin- 
drici, sine cacumine sterili, ramum primarium tricho- 
blastae comprehendentes. 
type: FI. 65-113=1, cystocarpic and sperma- 
tangial, on dead coral, at a depth of 1-2 m, 
20 m shoreward from the outer reef margin, 
north of North I., Johnston L, legit R. S. Jones, 
Apr. 22, 1965. 
The Hawaiian name, meaning short, refers 
to the short segments. This species is close to 
P. herpa, from which it differs chiefly in the 
undivided scar-cells. It also lacks the multi- 
cellular tips of rhizoids common in F. herpa. 
It is in some respects similar to P. sphaero - 
carpa , differing in the mostly shorter segments 
in P. poko and in the unbranched erect branches 
of the latter. 
This species also resembles F. coacta Tseng 
(1944), from which it differs in that: (1) the 
erect branches are mostly unbranched and seem- 
ingly exclusively cicatrigenous in F. poko , except 
for the assurgent origin of some of the erect 
branches from prostrate branches; (2) there is 
little or no evidence of coherence of erect 
branches by means of tentacular rhizoids as 
described for F. coacta. 
P . poko var. poko var. nov. 
Figs. 3 A, 15 
ADDITIONAL COLLECTIONS EXAMINED (those 
marked * are more slender, attenuate forms) : 
Hawaiian islands — D. 10361.1, on other 
algae, Poipu Beach Park, Kauai, Feb. 6, 1952; 
D. 19710C, a poor specimen from the inter- 
tidal flow of the reef flat, Kumimi, Molokai, 
Dec. 29, 1953; D. 22410.2, a very delicate 
form, Papawai Point, Maui, legit H., T., and B., 
Apr. 19, 1965; johnston island — H. 65- 
106.7, spermatangial, on dead coral at the type 
locality, legit R. S. Jones, Apr. 22, 1965 ; line 
islands — L. 2720.3*, in crevices of reef flat, 
Jarvis L, Nov. 17, 1964; L. 2782.2*, on wave- 
swept reef near the airport, Christmas I., Nov. 
23, 1964; tuamotu archipelago (all legit 
M. S. Doty and Jan Newhouse, 1952) ; D. 
11518.1*, on Microdictyon sp., outer reef edge, 
Akau, Raroia Atoll, Aug. 5; D. IH6OB3, on 
reef near ship pass, Takeke, Raroia Atoll, 
July 9; D. 11189.4, on other algae, lagoon 
transect, Ngarumaoa, Raroia Atoll, July 12; 
D. 11509.1*, on dead coral, near Pakokota, 
Oneroa, Raroia Atoll, Aug. 5; D. 11533=1, on 
Caulerpa. sp. under coral overhang of reef in 
front of Oneroa Village, Raroia Atoll, Aug. 5; 
D. 11858.1*, on dead coral, sea reef near Otetou, 
Raroia Atoll, Aug. 21; phoenix islands — L. 
2416.5, on Halimeda sp., western reef of Mc- 
Kean L, Oct. 18, 1964; L 2444.4*, on Hali- 
meda sp. in sandy pool, northeastern reef of 
McKean L, Oct 20, 1964; L. 2451.10*, on 
