Polysiphonia in Hawaii — Menez 
217 
Antheridia and cystocarps were not found 
in the materials at hand. 
MATERIALS EXAMINED: M. Doty — 8882 
(BISH, duh), collected on exposed shoulder of 
lava, Halona, Oahu, May 21, 1951; 12384 (DUH), 
washed in at Beach Laboratory, Waikiki, Oahu, 
February 6, 1954; 13349 (duh), on boulders 
in sand between low-tide riffle on beach flat 
and the exposed rock to the east, Kumimi, Molo- 
kai, December 29, 1953; 17222 (bish, duh), 
collected at Punaluu Bay, Hawaii, January 29, 
1953 ; E. Menez — 741 (bish, duh, m), collected 
on limestone rocks in sandy bottom, Mokuleia, 
Oahu, August 7, 1961. 
Polysiphonia rhizoidea sp. nov. 
Figure 5, A-H 
TYPE: Doty 19236 , on top of prehistoric lava 
flow dike 6-8 m above high-tide line, about 50 
ft east of the 1955 lava flow at Keekee, Puna, 
Hawaii, December 23, 1959. This number in- 
cludes antheridial and cystocarpic thalli, of 
which I designate the antheridial material as the 
type specimen. 
Thalli parvi dense intricati in massos usque 
ad 1 cm alto, cellulae pericentrales 8-10 cellulis 
singulis ecorticatis cum 1-3 connectivis aper- 
turalis; basis rhizoidalis rhizoideis 15-55 g di- 
ametro et usque ad 550 g longis cum partitionis 
in latere proximale celluli pericentrali; apicibus 
simplicibus vel disciformibus; ramificationibus 
nullis vel raribus. Segmentis singulis thallorum 
unicum rhizoideam emittens; segmentis alteris 
non rhizoidiferis. Axes vegetativi 52-115 g di- 
ametro, ramis primariis prostratis inconspicuis, 
ramis secundariis dichotomis vel pseudo-dicho- 
tomis (angulis ramificationii 45°-90° ) ; ramulis 
attenuatis, fere paulo curvatis vel raro recurvatis; 
segmentis in longitudine quam latitudine 1.5-2 
X excedens; ramulis 2-18 segmentis inter- 
venantibus. Trichoblastis subapicalis 2-3 fur- 
catis, 21 g diametro et 625 g longis, segmentis 
apicalis fere quam segmentis basalibus longioris, 
pedicellis unicellulatis 36 g diametro. Tetra- 
sporangiis tetrahedralis, globosis, irregulariter 
dispositis, pseudo-spiraliter vel lineariter seriatis, 
usque 66 g diametro; antheriae aggregatis, api- 
calis, elongatis vel cylindricis, 52 g diametro, 
usque 280 g longis, fere solitariis rare binis in 
pedicellum unicum. Cystocarpiis globosis vel 
spheroidalis, breve-pedicellatis, 234 g diametro 
et 286 g aids, aperturis anterioris 57 g latis; 
carposporiis clavatis, 68 g longis et 26 g dia- 
metro. 
Thalli forming low, densely matted cushions 
and not more than 1 cm in height. Pericentral 
cells 8-10, each with 1-3 secondary pit connec- 
tions, ecorticate. Base composed of multicellular 
rhizoids cut off by a cross-wall from the proxi- 
mal ends of the pericentral cells with simple 
terminal ends or forming disklike structures, 
rarely ramified with several short cells, occurring 
no more than one per segment and several 
segments apart, 15-55 g in diameter and up to 
550 g long. Vegetative axes 52-115 g in diam- 
eter, branchlets attenuated, slightly curved, in 
rare occasions hooked, arising from an incon- 
spicuous primary prostrate branch. Principal 
axes dichotomous or pseudodichotomous, angle 
of branching 45-90 degrees, rarely more. Seg- 
ments about as long as broad, branches 2-18 
segments apart. Trichoblasts developed near the 
apex, rare, 2 or 3 times forked, 2 1 g in diameter 
and 625 g long, with a short, robust one-celled 
stalk 36 g in diameter. Basal trichoblast seg- 
ments generally shorter than those near the 
apices. Scar cells rare or wanting. 
Tetrasporangia 52-78 g, tetrahedral, globose, 
arranged irregularly in the axes, sometimes ap- 
pearing spiralled in a right-hand direction and 
in other cases in straight series, up to 66 g in 
diameter. 
Elongate or cylindrical antheridial clusters, 
52 g in diameter and up to 280 g long, occurring 
near the apices of the branches. Some seem to 
arise as primary branches of the trichoblasts 
but generally are independent of the latter. 
Cystocarps globose or almost spherical, shortly 
pedicellate, 234 g in diameter and 286 g high. 
Opening at the anterior end narrow, 57 g. 
Carpospores clavate, 68 g long and 26 g in 
diameter. 
MATERIALS EXAMINED: M. Doty — 13076 
(bish, duh, m), red-brown to maroon, velvety 
cushions of an extended sort around high-tide 
edge of a brackish fishpond at Anaehoomalu, 
Kona, Hawaii, November 15, 1952; 19236 
(BISH, duh), on top of prehistoric lava flow 
dike 6-8 m above high-tide line, about 50 ft east 
of the 1955 lava flow at Keekee, Puna, Hawaii, 
