Polysiphonia of the Tropical Pacific, 1 — Hollenberg 
77 
naturally arises as to whether they are distinct 
species. However, the growth habit is very dif- 
ferent: P. saccorkiza is chiefly prostrate with 
relatively short unbranched laterals, whereas P. 
ruhrorhiza has few or no prostrate branches 
and is primarily erect, with much higher erect 
branches with several laterals. 
P. saccorhiza was reported from southeastern 
Queensland by Cribb (1954). Later Cribb 
(1956) decided his plant was P. platycarpa. 
Since the Queensland plant lacked the tricho- 
blasts and scar-cells, it can hardly be identified 
with the Midway specimens. 
Howe (in Britton, 1918) states that L. sac - 
corhiza* occasionally grows somewhat free from 
the substratum. In the Midway specimens the 
prostrate branches may similarly grow free from 
the substratum, but their identity as prostrate 
branches is not lost. Howe states, furthermore, 
that the development of free branches suggests 
the genus Polysiphonia rather than Lophosi- 
phonia . This indicates that he considered the 
prostrate habit as the chief distinguishing fea- 
ture of Lophosiphonia , a view difficult to main- 
tain. 
It should be noted here that Doty and Menez 
(I960) reported the occurrence of pigmented 
rhizoids on a species of Tiffaniella . This alga 
was likewise epiphytic on a species of C odium. 
Polysiphonia savatieri Hariot (1891:226) 
Figs. 37, 38 
Epiphytic algae, mostly 1 cm high or less, 
from a basal attachment or a briefly prostrate 
or assurgent base attached by unicellular rhizoids 
cut off by a cross-wall from the proximal end 
of the pericentral cell ; pericentral cells 4, ecorti- 
cate, with segments in the median parts of erect 
branches, mostly about 1 diameter long ; median 
parts of erect branches mostly 80-1 40p in di- 
ameter ; all branches arising independent of 
trichoblasts mostly at intervals of 7-10 seg- 
ments; trichoblasts one per segment in J spiral 
sequence, with mostly 2-3 dichotomies, to l40\x 
long, soon deciduous, leaving persistent scar- 
cells; tetrasporangia 53-60|a in diameter in spiral 
series in the terminal branches which are usually 
considerably distended; cystocarps globular 130- 
145— (220) |x in diameter, to somewhat urceo- 
late, with pericarp cells more or less isodia- 
metric in surface view, and with ostiolar cells 
sometimes prominently enlarged; spermatangial 
branches 130-1 70ji X 45-5 6\i arising as a pri- 
mary branch of a trichoblast with or without 
a sterile tip. 
COLLECTIONS STUDIED: MIDWAY ISLAND — 
D 18727, sterile, on Codtum , awash, legit C. 
H. Lamoureux, Dec. 16, 1962; Hawaiian is- 
lands — H. 65-15, on Centro ceras in shallow 
water near Coconut L, Kaneohe Bay, Oahu, 
Mar. 20, 1965; H. 65-49-5, cystocarpic, on a 
small seagrass, Waikiki Beach, Oahu, Apr. 26, 
1965; H. 65-86.1, tetrasporic, on Pocockiella, 
legit M. Kajimura, Diamond Head Beach, 
Oahu, May 1965; H. 65-50, tetrasporic, male, 
with very delicate trichoblasts, on Codtum, on 
the bottom of a 2 ft pool at low tide, Wawa- 
malu Beach, Oahu, May 1, 1965; D. 20144, on 
Sargassum, in tidepools, Kamoamoa, Puna, Is- 
land of Hawaii, Mar. 21, 1961; tuamotu 
islands — D. 11858.3, male, 11860B, tetra- 
sporic, transect area, Otetou, Raroia Atoll, legit 
M. S. Doty and Jan Newhouse, Aug. 21, 1952; 
American SAMOA — T. 262A, male, at high 
water line 20 m from shore, Nuuli Village, 
Tutuila L, Sept. 8, 1963; marshall islands — 
D. 9603A, cystocarpic, male, on Galaxaura, 
awash at Ine Village, Ine L, Amo Atoll, legit 
Leonard Horwitz, Aug. 8, 1951; Caroline is- 
lands — D. 15 586. 3 A, cystocarpic, male, on 
Padina , on the reef at Koror L, Palau Group, 
legit E. Menez, Sept. 5, I960; D. 15654.8, tetra- 
sporic, and D. 15656.1, male, cystocarpic, on 
Sargassum, on the reef at Pulo Anna L, legit E. 
Menez, Sept. 3, I960; D. 23423, cystocarpic, on 
seagrass, on the reef near Utwa Village, Kusiae 
L, legit E. Menez, July 17, I960; Philippine 
islands — D. 18173.1, tetrasporic, cystocarpic, 
male, Mangagoy, Bislig, Surigao, legit E. Menez, 
June 29, 1958. Also several unnumbered collec- 
tions by D. P. Abbott, 1957, as follows: on 
Chaetomorpha, tetrasporic, male, northeast coast 
of Siasi L, Sulu Sea, Jan. 28; on Dictyota sp., 
tetrasporic, cystocarpic, male, on sand flats, 
Laminusa, Siasi L, Sulu Sea, Jan. 29; on turtle 
grass east of Laminusa, Jan. 30; on other algae, 
tetrasporic, on reef west of Cagayan Sulu, Sulu 
Sea, Feb. 28; on other algae, tetrasporic, on reef, 
Pasig Bay, Balabac L, Mar. 1 ; on T h alias ia and 
Acanthophora, tetrasporic,' cystocarpic, ‘Gnat 
Reef, Balabac L, Mar. 4. 
