atoll research bulletin no. 392 the flora of - Smithsonian Institution ...

Lake in Anetan. Fosberg (c. 1972) also reports the occurrence of B. gymnorhiza in similar
landlocked ponds, sink-holes and small inland swamps in Palau.
Other species commonly associated with mangroves and present in Nauru include
Derris tnifolia, encountered on limestone outcrops, and Vitex negundo, which is present
in depressions near the base of the escarpment in Menen District.
The swampy areas surrounding Buada lagoon and near the base of the escarpment
on Nauru are dominated by Cyperus javanicus and C. compressus, with one specimen of
Ludwigia octovalvis collected from a coastal depression.
Relict Stands of Inland Forest
In terms of relict stands of primary inland forest on Nauru, there seem to be two
distinct types: 1) plateau forest, which probably covered up to 90 per cent of the island
before the onset of phosphate mining, and 2) escarpment forest, including forest on
unmined limestone outcrops or pinnacles on the plateau.
The former, four-fifths of which has been removed during phosphate mining, is
dominated almost entirely by 16 m-tall Calophyllum inophyllum. Infrequent canopy trees
include Guettarda speciosa, Premna serratifolia and Terminalia catappa, with the
understorey dominated by Scaevola taccada, Morinda citnifolia and Dodonea viscosa, the
parasite Cassythafiliforrnis, Psilotum nudum, and the ferns, Polypodium scolopendria and
Nephrolepis biserrata. Also occasional in open sites is Phyllanthus societatis. Exotic
species dominant in disturbed sites include Psidium guajava, Lantana camara and two
herbaceous species, Euphorbin hirta and Desmodium triflorum (Manner et al. 1984,
1985).
Limestone Escarpment or Pinnacle Vegetation
The dominant species on the limestone cliffs of the escarpment and on emergent
pinnacles on Nauru is Ficus prolixa, with Terminalia catappa, Ochrosia elliptica and
Guettarda speciosa constituting important second stratum species (Manner et al. 1985).
Isolated relict stands of Barringronia asiatica and Pisonia grandis are also found along
the crest of the escarpment above Anibare Bay. The ferns, Nephrolepis biserrata and
Polypodium scolopendria, and the liana, Ipomoea macrantha, are locally abundant, and
the herb, Laportea ruderalis, is found in moist shady habitats at the base of the escarpment.
On the more gradually-sloping colluvial portions of the escarpment almost
impenetrable-thiekets of--HibisewtiZ&e are- found, Uqde~storey- specks include
Colubrina asiatica and Tacca kontopetaloides. In Anetan District, in the north (Figure
I), Clerodendrum inerme festoons limestone outcrops and cliffs. In some areas the exotic