Polysiphonia of the Tropical Pacific, I — Hollenberg 
93 
enousiy at frequent intervals; pericentral cells 
4, ecorticate; tridioblasts to 800|i long with 
2-4 dichotomies and with basal cells to 260p 
long and 3 Op in diameter, and with very delicate 
tips, arising one per segment in terminal parts 
of erect branches but at intervals of 2-3 seg- 
ments in lower parts; tetrasporangia in short 
spiral series near branch tips; cystocarps urceo- 
late, 140-1 3 Op broad and 190-220p long, on 
the middle and upper parts of erect branches; 
spermatangial branches 100-1 3 Op X 3 3-3 Op, 
without sterile apices, arising from the entire 
trichoblast primordium. 
Algae minutae ramos repemtes 30-3 5p diam., 
composites e segmentis ca. aequae longis ac lactis, 
habentes, per rhizoidea unicellularia, ut cedillas dis- 
cretes a celiulis pericentralibus separata, affixae; sine 
cellulis-cicatricibus in ramis prostratis; rami erecti ad 
2 mm alt., non ramosi, 28-3 5p diam., segmentis 1.5- 
(2.0) longioribus quam lata, intervallis frequentibus 
endogene nascentes; cellulae pericentrales 4, ecorti- 
catae, trichoblastae ad 300p long., 2-4 dichotomias 
habentes, celiulis basalibus ad 260p long, atque 2 Op 
diam., una in unoquoque segmento in partibus ter- 
minalibus, intervallis, autem, 2-3 segmentorum in 
partibus inferioribus; tetrasporangia in serie spiral! 
brevi; cystocarpi urceolati, l40-150p lat. atque 190- 
220m. long.; rami spermatangiales 100-1 30p X 35- 
5 Op, sine cacuminibus sterilibus, e primordio toto 
trichoblastae enascentes. 
type: H. 65-105.1 is the only collection. It 
is represented by 6 glucose mounts and some 
fluid-preserved material. It was growing on 
dead coral and was collected by R. S. Jones at 
a depth of 1-2 m and 20 m shoreward from 
the outer reef margin north of North L, Johns- 
ton Island, Apr. 22, 1965. 
This is another minute plant resembling P, 
scopulorum in habit, in endogenous origin of 
erect branches, and spermatangial branches 
arising from the entire trichoblast primordium. 
From P. scopulorum it differs in the rhizoids 
which are cut off as separate cells and in the 
occurrence of tetrasporangia in spiral series. 
From P. pseudovillum it differs in the endog- 
enous origin of branches and in the sperma- 
tangial branches. 
Polysiphonia tuber osa sp. nov. 
Figs. 3 D, 3 E\ 39 
Minute epiphytes with limited to extensive 
prostrate branches 45-8Q-(100)|x in diameter, 
frequently with local portions of prostrate 
branches conspicuously swollen and filled with 
what appears to be food reserves; attached by 
unicellular rhizoids cut off from the peri- 
central cells as separate cells; erect branches 
assurgent or endogenous, to 12 mm high and 
5 0-6 5|,i in diameter with segments 1. 5-2.0 
diameters long, mostly with infrequent lateral 
branches, at intervals of 7-20- (30) segments; 
pericentral cells 4, ecorticate; tridioblasts few 
and not well developed or frequently long (to 
500u) and with 2-3 dichotomies and a basal 
cell up to 1 40 ix long; scar-cells at intervals of 
1-2 segments on erect branches, mostly lacking 
on prostrate branches; erect branches mostly or 
all endogenous, lateral branches cicatrigenous, 
sometimes appearing to arise in connection 
with a trichoblast, when in fact the branch 
arises from the potential scar-cell bearing the 
still persistent trichoblast; tetrasporangia to 58|i 
in diameter, in short straight series, much dis- 
tending the segments; spermatangial branches 
arising as a primary branch of a trichoblast. 
Algae epiphyticae minutae, ramis prostratis prae- 
finitis ad late patentes, 48-80- ( 100 )p diam., horum 
partibus localibus manifeste tumidis et, ut videtur, 
mutrimento reservato plenis; plantae per rhizoidea 
unicellularia, a celiulis pericentralibus et cellulas dis- 
cretas separata, affixae; rami erecti assurgentes aut 
endogeni, ad 12 mm alt, 5 0-6 5 p diam., segmentis 
1. 5-2.0 plo longioribus quam lata, plerumque rarios 
ramos laterales, interdum, autem, aliquot ramos lat- 
erals intervallis 7-20- (30) segmentorum habentes; 
cellulae pericentrales 4, ecorticata; trichoblastae paucae 
necnon male evolutae, aut saepe longae (ad 50 Op) 
et 2-3 divisiones atque cellulam basalem usque ad 
l40p long, praebentes; cellulae-cicatrices intervallis 
1-2 segmentorum in ramis erectis, in ramis pros- 
tratis maxime ex parte carentes; rami erecti plerique 
omnesve endogeni, rami laterales cicatrigeni, interdum 
in associante cum trichoblasta ut videtur enascentes, 
cum enim rami e cellula-cicatrici potentiali tricho- 
blastam etiam persistentem ferente, enascent; tetra- 
sporangia ad 58p diam., in serie brevi rectaque, seg- 
ments. mu Iturn distendentia; rami spermatangiales ut 
ramus primarius trichoblastae enascentes. 
type: D. 19137N1, sterile, dredged 15-20 
fa, off Ilio Pt, Molokai, Hawaii, Sept. 7, 1959. 
Represented by a glucose slide mount. 
additional collections (all from Ha- 
waii): D. 19134AC2, on Sargassum; D. 
19134H1, on Amansta , all from 25 fa near a 
channel buoy, Kaneohe Bay, Oahu, July 15, 
