Polysiphonia in Hawaii — Menez 
211 
Pericentral cells four, ecorticate. Base composed 
of a few rhizoids cut off from the proximal 
ends of the pericentral cells by a cross-wall. 
Rhizoids frequently one per segment, rarely four 
in one segment, in some cases robust and less 
than 1 cm long with disklike terminal ends, in 
other cases slender and more than 1 cm long 
with terminal ends ramified into irregularly 
digitate tips. Rhizoids 25-80 /x in diameter and 
up to 6 80 /x long. Vegetative axes about 100 g 
in diameter near the apex and up to 546 /x in 
the basal portion. Segments about half as long 
as broad. Principal axes dichotomous, angles of 
dichotomy 40-100 degrees, branches 5-10 seg- 
ments apart. Short branchlets slightly torulose 
and recurved. Commonly, some of the exogenous 
branches ^rise cicatrigenously. Trichoblasts occur 
at the branch apices and are 3-5 times forked, 
up to 780 /x long and 21 /x in diameter, with 
a robust basal cell about 47 /x broad. Scar cells 
small, often indistinct, irregularly disposed, one 
to several segments apart and usually arranged 
spirally in a Va divergence. 
Tetrasporangia tetrahedral, 20-35 /x in di- 
ameter when mature, produced in the branch- 
lets, one in each segment, arising in a spiral 
running in a right-hand direction, when the 
branch is viewed from the point where the 
oldest tetrasporangium is found and following 
then toward the branch tip. 
Antheridial clusters subcylindrical, developed 
as primary branches of the trichoblasts, arising 
from a short stalk. The apex consists of one or 
two sterile cells enclosed in a thick cell wall. 
Cystocarps subglobose to ovate, up to 360 n 
in diameter at the widest portion and 470 ft in 
length, with a narrow opening at the distal end; 
produced irregularly on the ultimate branchlets. 
MATERIALS EXAMINED: G. Andrews — 78 
(BISH) & 79 (BISH), from Oahu, and one other 
with no number, in folder "M” (bish), col- 
lected from Waialua, Oahu, 1876; E. Bailey — 
8 (BISH), from Wailuku, Maui; M. Doty — 
8141 (BISH, DUH), on concrete wing dam east 
of Young Women’s Christian Association 
(YWCA) Beach, Waikiki, Oahu, October 7, 
1950; 8753 (BISH, duh), on Sargassum devoid 
of leaves and blackened, collected at Ala Moana 
Park, Oahu, March 19, 1951; 10999 (BISH, 
DUH), afloat near Abbott’s yard at Laie, Oahu, 
January 17, 1954; 12439 (bish, DUH) , on reef 
flat in front of Ala Moana Park, Oahu, April 
12, 1954; 12903 (duh), stiff bristly form afloat 
at Kalama Park, Maui, July 26, 1955; 12982 
(bish, duh), tufts on pavement in less than 6 
ft of water and also on a red alga apparently 
belonging to the family Gigartinaceae outside 
of the breakwater at Maalaea, Maui, August 27, 
1955; 13003 (duh), outside of the breakwater 
at Maalaea, Maui, August 27, 1955; 17373 
(bish, duh), on Sargassum polyphyllum J. 
Agardh near the beach close to the natatorium 
at Sans Souci, Waikiki, Oahu, November 20, 
1955; E. Menez — 713 (bish, duh, m), epiphy- 
tic on Acanthophora spicifera J. Agardh (mixed 
with P. mollis ), collected on a reef flat at Wai- 
kiki, Oahu, February 24, 1961; 740 (bish, 
DUH, M), epiphytic on Acanthophora spicifera 
(mixed with P. mollis ), collected on a sandy reef 
flat with limestone rocks in the Old Sugar Mill 
area, Kaaawa, Oahu, July 7, 1961; J. Rock — no 
numbers (bish), collected from Waikiki, Oahu, 
May 8, 1908, April 1908, March 1908; D. Rogers 
— in envelope "R” (BISH), on Padina sp., Dia- 
mond Head, Oahu, May 21, 1946; B. Stone — 
3137 (duh), afloat at Waikiki, Oahu, January 
10, 1959; /. Tilden — 403 (bish, duh, m), 
from Waikiki, Oahu, May 28, 1900 (labelled 
as being ”P. colensoi Hook. & Harv.”) . 
Polysiphonia suhtilissima Montagne, Ann. des 
Sci. Nat., Bot. 13:199, 1840b 
Figure 6, D-G 
TYPE: Type specimen collected from shores 
of Cayenne, France. 
Thalli tufted with decumbent branches, up 
to 10 cm in height. Pericentral cells four, ecor- 
ticate. Base composed of rhizoids arising as 
protrusions from the central part of the peri- 
central cells, usually one per segment, occasion- 
ally two, with simple and ramified tip, 15-32 /x 
diameter and up to 680 /x long. Vegetative axes 
30-105 /x in diameter. Segments as long as 
broad. Principal branchlets dichotomous, angles 
of dichotomy 20-90 degrees, branches 4-20 
segments apart, with fewer intervening seg- 
ments in the base. Commonly, some of the 
exogenous branches arise cicatrigenously. Oc- 
casionally, trichoblasts may be found at the tips 
and on the vegetative axes, usually one in each 
