Poly sip honia in Hawaii— -ME&EZ 
221 
Tanaka). Specimen presumed to be in Dr. 
Yukio Yamada’s herbarium at Hokkaido Uni- 
versity, Sapporo, Japan. 
Thaili up to 2 cm in height, forming densely 
erect branches arising from a prostrate system. 
Pericentral ceils 10-12, each with one to several 
secondary pit connections, ecorticate. Base com- 
posed of rhizoids cut off by a cross-wall from the 
proximal ends of the pericentral cells, occasion- 
ally branched. Terminal ends disklike when in 
contact with other filaments or branches of 
Poly sip honia and other algae and simple when 
free; diameter about 22 /x and up to 575 /x long. 
Vegetative axes more or less equal in diameter 
from the base to the segment near the apex. 
Branches 2-10 segments apart, rarely with as 
many as 20 intervening segments. Ultimate 
branc h lets slightly recurved. Principal axes ir- 
regularly dichotomous, angle of branching 40- 
80 degrees. Cicatrigenous branches common, 
particularly on the creeping portion and occa- 
sionally on the erect axes. Trichoblasts devel- 
oped on the axes and apices, 2-5 times forked, 
10-32 /x in diameter and 625 /x long. The first 
two segments of the base shorter than the rest, 
swollen in appearance in comparison to the 
upper segments, the cells of which have parallel 
walls. Scar cells small, occurring irregularly at 
intervals of two or three segments, with to 
14 of a spiral turn in a right-hand direction 
between them. 
Tetrasporangia, antheridia, and cystocarps 
were not found in the materials at hand. 
MATERIALS EXAMINED: M. Doty — 10816 
(bish, duh), collected just below the upper 
edge of a nip, forming dense turf patches 3 X 
2 X 5 inches, Kapoho Point, Kailua, Oahu, 
October 10, 1953; /. Tilden—508 (bish, duh), 
collected at Laie Point, Koolauloa, Oahu, June 
16, 1900 (labelled P. calothrix ); 602 (duh), 
collected at Laie Point, Koolauloa, Oahu, June 
1900 (labelled P. calothrix). 
DISCUSSION 
Of the six species of Poly sip honia previously 
recorded as occurring in the Hawaiian Islands, 
I examined exsiccate materials of P. aquamara, 
P. mollis , P. calothrix, and P. femlacea deposited 
in the herbarium of the B. P. Bishop Museum. 
I was not able to find specimens of the other 
two species reported from Hawaii: P. polyphysa 
and P. tongatensis. 
A specimen in Tildens collection labelled 
” Polysiphonia colens oi Hook. & Harv.,” depos- 
ited at the Bishop Museum, seems to agree well 
with the description of P. femlacea and there- 
fore is cited here as such. It was used as basis 
for Tildens report of P. colens oi for Hawaii. 
Though unable to locate the type of Poly- 
siphonia aquamara Abbott, and basing my ob- 
servations entirely on the materials of this spe- 
cies sent to me by Dr. I. A. Abbott and on two 
other specimens deposited by her in the Bishop 
Museum, I conclude that these three collections 
of P. aquamara are not specifically distinct from 
the species I am calling here P. mollis. They 
agree well with the description of P. mollis in 
this paper and are therefore cited here as such. 
A personal communication (Abbott, December 
15, 1961) indicated her records show that she 
deposited the type specimen (her Mo. 1535) of 
P. aquamara in the Bishop Museum. According 
to Miss M. Neal, curator of the herbarium, and 
Mr. E. H. Bryan, curator of collections at the 
Museum, no record exists of this specimen hav- 
ing been received. 
Re-examination of Tildens collections of P. 
calothrix (Nos. 508, 602) revealed that they are 
not distinct from P. yonakuniensis as this species 
is described in this paper. Comparisons of the 
descriptions for P. calothrix and P. yonakunien- 
sis led the author to regard Tildens collection of 
P. calothrix from Hawaii as a form of P. yona- 
kuniensis. The only satisfactory disposition, 
therefore, seems to be the citing of these collec- 
tions (Tilden Nos. 508, 602) as P. yonakuni- 
ensis. 
The seven species of Polysiphonia described 
in this work were recognized primarily by their 
morphological features using Hollenberg’s 
(1942) criteria for distinguishing specific enti- 
ties in Polysiphonia. In addition, two other char- 
acteristics of Polysiphonia, which have not been 
previously used by monographers but which 
appear to be important criteria for delimiting 
the Hawaiian species of Polysiphonia, have been 
utilized. One is the presence of more than one 
secondary pit connection between adjacent peri- 
central cells, a condition present in P. rhizoidea 
and P. yonakuniensis but not in the other species 
