440 
Fig. 50. Gracilariopsis sp.\ Habit, X 1.1. 
of Gracilaria verrucosa in order to be sure that 
the male plants are of Gracilariopsis rather than 
of Gracilaria. 
Gracilariopsis sp. 
Fig. 50 
A second species of Gracilariopsis is recog- 
nized by a cystocarpic example among speci- 
mens from Sta. 4 (11194, 11217). This species 
is of different habit from Gracilaria verrucosa 
and Gracilariopsis rhodotricha, but in the ab- 
sence of antheridial material it cannot here 
be identified. 
Key to the Species of Gymnogongrus 
1. Thalli under 2 cm. tall G. pygmaeus 
PACIFIC SCIENCE, Vol. VIII, October, 1954 
Thalli 4-9 cm. tall .2 
2. Segments flat 3 
Segments compressed above, terete below 
G. japonicus 
3. Branching divaricate, flabellate 
G. flabelliformis 
Branching rather remote, strict . G. serenei 
Gymnogongrus flabelliformis Harvey 1856 : 
332 (Japan Sea); Okamura 1921, leones 4, 
pi. 181, figs. 7-9, pi. 182, figs. 9-14; Tseng 
1936^/47 ; 
Fig. 51^, b 
LOCAL DISTRIBUTION: Forming dense col- 
onies on the sea wall, Sta. 6 (11234, 11453a). 
My plants are virtually identical with some 
southern Japanese examples of this species in 
size, branching, and vegetative structure. The 
Nha Trang specimens lack the secondary pro- 
liferous pinnae such as are illustrated by 
Okamura, but this feature is not always pres- 
ent in Japanese plants. The only difference 
which may be specifically significant is in the 
form of the cystocarp. In Japanese plants 
examined, the cystocarp ‘is embedded in the 
middle of the thallus and forms a bulge of 
about equal size on either side. In the Viet 
Nam specimens the cystocarps are unilateral, 
the bulge being much more prominent on 
one side than on the other. Tseng speaks of 
this species as "rather variable," and in view 
of its wide known range from Hokkaido and 
Korea to Amoy, China, it seems best to as- 
sign these specimens here, despite this dif- 
ference, awaiting the opportunity for com- 
parison of additional series of plants from the 
southern part of the range. 
Gymnogongrus pygmaeus J. Agardh 1851: 
317 (India); Kiitzing, Tab. Phyc. 19, pk 
64; Bprgesen 1936: 88 
Fig. 51c 
LOCAL DISTRIBUTION: Forming dense col- 
