Marine Plants of Nha Trang — Dawson 
379 
to bullate, gelatinous colony 7 
Filaments relatively free, forming tufts or 
velvet-like colonies 6 
6. Plants forming velvet-like areas on rocks; 
filaments about 25 m in diameter . 
. Calothrix pilosa 
Plants epiphytic, forming tiny tufts; fil- 
aments 9-12 jjL in diameter 
Calothrix aeruginea 
7. Colonies crustaceous, smooth 8 
Colonies plicate-expanded to bullate. . . 
Brachytrichia quoyi 
8. Forming a film about 250 fx thick on ex- 
posed rocks; heterocysts intercalary; cells 
irregularly shaped. 
Brachytrichia maculans 
Forming greenish patches on mangrove 
roots; heterocysts basal; cells regularly 
shaped Calothrix contarenii 
9. Sheaths not present, or very thin and 
hyaline, or diffluent. 10 
Sheaths present, conspicuous 12 
10. Filaments about 6.5-8 /x in diameter. . 1 1 
Filaments about 18 ix in diameter 
........... Oscillatoria margaritifera 
11. Trichomes not constricted at the septa; 
filaments epiphytic, adnate, curved 
Hydrocoleum lyngbyaceum 
Trichomes constricted at the septa; often 
on limpets . . . Oscillatoria nigroviridis 
12. Filaments agglutinated, forming thin, 
crustaceous patches on mangrove roots 
Phormidium corium 
Filaments fasciculate, entangled or more 
or less agglutinated, forming an erect 
spongy tuft to 4 cm. high 
Symploca hydnoides 
Filaments free 13 
13. Plants entangled, commonly epiphytic. . 
14 
Plants forming silky colonies on rock 
surfaces; trichomes about 15 jx in dia- 
meter Lyngbya confervoides 
14. Trichomes about 30-35 /x in diameter; 
apices not tapered, broadly rounded . . . 
. Lyngbya majuscula 
Trichomes about 20-24 /x in diameter 
with slightly tapered, capitate apices . . . 
.Lyngbya aestuarii 
Entophysalis conferta (Kiitz.) Drouet and 
Daily 1948: 79- Palmella conferta Kiitzing 
1845: 149 (Cuxhaven, Germany) 
Fig. 3r 
LOCAL DISTRIBUTION: Growing as small 
gelatinous masses on Lyngbya confervoides from 
rocks at end of Cau Da wharf (11300a). 
Hormothamnion solutum Bornet and Fla- 
hault 1888: 260 (Tongatabu, Polynesia) 
Fig. 
LOCAL DISTRIBUTION: Entangled on other 
algae and marine phanerogams, Sta. 4 (11199). 
Hormothamnion enteromorphoides Bor- 
net and Flahault 1888: 260 (Tongatabu, 
Polynesia) 3^ 
LOCAL DISTRIBUTION: Growing in mixture 
with Lyngbya majuscula, Sta. 4 (R. Serene No. 
1161, Aug. 22, 1949) 
Calothrix pilosa Bornet and Flahault 1886: 
363 (Key West, Florida) 
Fig. 3^ 
LOCAL DISTRIBUTION: Forming velvet areas 
on upper intertidal rocks, Sta. 1 (11065). 
Calothrix aeruginea Bornet and Flahault 
1886: 358 (Cherbourg, France) 
Fig. 3J- 
LOCAL DISTRIBUTION: Growing epiphytical- 
ly in tiny tufts on small red algae, Sta. 2 
(11085). 
