Marine Plants of Nha Trang — Dawson 
Cua Be 
The sand and mud flats of Cua Be support 
a distinctive flora entirely unlike that of the 
coral shore in the vicinity of Cau Da. The 
marine phanerogams, particularly Diplanthera, 
are dominant here. The shallow pools in the 
flats exposed at low tide yield many algae, 
some epiphytic on the phanerogams, others 
attached to shell and debris or growing di- 
rectly in the sand. The more conspicuous of 
these are Hypnea, Spyridia, Acanthophora, Pa- 
dina, Gracilaria, Rosenvingea, Avrainvillea, 
Lyngbya. 
A small rocky area along the shore midway 
between Cau Da and Truong Dong yields the 
only intertidal Sargassum near the Institut. 
The best material of Halimeda may be found 
in this rocky area. 
The Sea Wall 
Just beyond Rue de la Poste at Nha Trang 
is a short sea wall and a small adjoining area 
of rocks. This locality, opposite the main 
channel into Nha Trang Bay, is subjected to 
the most violent surf of any section of the 
inner shore of the bay. The rocks and sea 
wall are covered with a dense association of 
algae in which the species are almost without 
exception different from those found in the 
vicinity of Cau Da. The genera and some of 
the species are like those which the writer has 
observed in similar wave-dashed habitats on 
the east side of the Pacific along southern 
Mexico. Several of the dominant species are 
characteristic of southern Japan and reflect 
the effect of violent agitation in counteracting 
the lowered solubility of gases in the warmer 
waters of lower latitudes. Most conspicuous 
are the genera Grateloupia, Gymnogongrus, Chae- 
tomorpha, Cladophora, Pterocladia, Porphyra, 
and Polysiphonia. 
Cu Lao 
The shore just east of Cu Lao varies from 
sand to rock and supports a number of plants 
which are not to be found abundantly else- 
where in the bay. Enteromorpha is common in 
375 
the upper intertidal zone, reflecting the in- 
fluence of the fresh water from the Nha Trang 
river mouth. Various forms of Colpomenia are 
prevalent in the muddy area. A dense bed of 
Sargassum occurs on a slightly submerged 
rocky strip leading to an islet. On the seaward 
side Gelidiella acerosa is abundant enough to 
be collected for food, while Anadyomene is 
common about the base of large rocks of the 
islet. 
Infratidal Coral 
A number of species of the smaller, in- 
conspicuous algae may best be obtained by 
searching coral masses pulled up from depths 
of 2-3 meters. Those obtainable off the In- 
stitut yield such genera as Valonia, Bornetella, 
Udotea, Struvea, Acetabularia, Pseudobryopsis, 
Lithoporella, Hypoglossum, Gelidiella, Ceramium, 
Callith amnion, Halicystis, Actinotrichia, etc., as 
well as diverse Rhodomelaceae. Such coral 
heads taken from the lagoon at Hon Mieu 
yielded a number of species not found at Cau 
Da, including several crustose corallines, 
Ceramium huysmansii, and Gracilaria eucheum- 
oides. 
Black Rocks {Roches Noires) 
These low rocks, which are entirely awash 
at high tide, support a marine flora adapted 
to conditions of high oxygenation provided 
by the constant wash and surge and the semi- 
exposure of this habitat. They lack, however, 
the violent pounding of surf such as obtains 
at the sea wall locality, and, with only two 
or three exceptions, the species differ from 
those found in any other habitats known to 
the writer in Nha Trang Bay. The dominant 
vegetation consists of Chnoospora pacifica, Ect- 
ocarpus breviarticulatus , and Dermonema frappi- 
erii, with lesser components of Chaetomorpha 
antennina, Ceramium taylorii, Laurencia, Chon- 
dria, etc. 
Binh Cang Bay 
The rocky shore along the south side of 
Binh Cang Bay is readily accessible by Route 
