Polysiphonia of the Tropical Pacific, I — Hollenberg 
79 
are abundant epiphytes 13-2.0 cm high, each 
basally attached by a tuft of rhizoids with little 
or no prostrate portion. In most details the 
plants identified with P. savatieri in this paper 
agree with the type. They differ from the type 
in minor respects: (1) they are smaller and 
more delicate; (2) the segments are somewhat 
longer; (3) there are occasional prostrate 
branches; (4) branching is mostly more lax, 
with basal unbranched axis occasionally up to 
33 segments long. 
The similarities between P. savatieri, P. sphae- 
rocarpa, P. mollis, P. simplex (cf. Hollenberg, 
1942^:782), and several other species in the 
genus are such as to raise questions concerning 
their distinctness. However, it seems best to 
continue to recognize them as distinct species 
for the present at least. A study of the early 
developmental stages of P. sphaerocarpa and 
P. mollis might be helpful in determining 
whether or not P. savatieri is merely a fruiting 
developmental stage or an ecological form of 
one or more of these species. D. 19143T3, 
cystocarpic, is identified with P. savatieri even 
though it is only 2 mm high. It was growing 
on a species of Galaxaura and was dredged 
from 15 fa, at Ilio Pt., Molokai, Hawaii, 
Sept. 7, 1959. This specimen may be merely a 
young but fruiting plant, or its minute size 
may be related to the habitat. 
Polysiphonia s copul ovum Harvey (1854:540) 
Lophosiphonia scopulorum (Harvey) Wom- 
ersley (1950:188) 
Plants mostly 0. 5-1.0 cm high from pros- 
trate branches 5 0-8 5 p in diameter and with 
segments mostly about 1 diameter long, at- 
tached by frequent unicellular rhizoids with 
digitate tips, which remain in open connection 
with the pericentral cells bearing them; erect 
branches similar to prostrate branches, mostly 
40-60p in diameter, with segments mostly 1 
diameter long but often shorter or longer, aris- 
ing endogenously mostly at intervals of 2-3 
segments, simple or with occasional lateral cica- 
trigenous branches ; 4 pericentral cells, ecorti- 
cate; trichoblasts and scar-cells infrequent and 
limited mostly to the tips of erect branches, 
often short but commonly 2 00-40 Op long or 
longer; scar-cells not occurring in prostrate 
branches; tetrasporangia 40-45 p in diameter, 
in straight series, sometimes greatly distending 
the segments; spermatangial branches arising 
from the entire trichoblast primordium or in 
pairs from the primary branches. 
type locality: Fremantle, Western Aus- 
tralia. 
P. scopulorum var. scopulorum (Harvey) 
comb. nov. 
Figs. 6F, 30, 31, 33, 36 
Mostly 5-8 mm high and with segments 
mostly shorter than broad ; erect branches arising 
mostly at intervals of 2-3 segments from the 
prostrate branches and usually distinctly nar- 
rowed at the base (Figs. 30, 31). The rhizoids 
of this variety are sometimes finely and repeat- 
edly branched (Fig. 31) or ornately discoid 
(Fig. 30) in the case of epiphytic specimens. 
Examination of the type material kindly 
loaned from the herbarium at Trinity College, 
Dublin, leaves little doubt that numerous speci- 
mens from the tropical Pacific Ocean are to be 
identified with P. scopulorum var. scopulorum. 
From var. villum it differs in the coarser erect 
branches with consistently shorter segments and 
narrowed base. Also the erect branches are more 
key to the varieties OF Polysiphonia scopulorum 
1. Erect branches mostly less than 1 mm high 2 
1. Erect branches 5 or more mm high at maturity 3 
2. Epiphytic algae with erect branches mostly less than 500p high, unbranched, and bearing relatively huge 
trichoblasts var. macrotrichia 
2. Saxicolous algae with erect branches mostly more than 500p high, frequently branched, and bearing tricho- 
blasts of more moderate size var. minima 
3. Erect branches commonly arising at intervals of 2 segments, with segments in median parts mostly 
shorter than broad var. scopulorum 
3. Erect branches mostly at more distant intervals, with segments in median parts mostly longer than 
broad var. villum 
