1876.] S-. Kurz — A Sketch of the Vegetation of the Nicobar Islands. 109 



(i). Coral-reef Forests. — These forests occupy, as the name indicates, 

 the raised coral-reefs which usually stretch out behind the dunes, and are 

 sometimes of comparatively large extent. The substratum being calcareous 

 and of a very permeable nature, these differ greatly in their constituents 

 from the true tropical forests. They form masses of pretty low ever- 

 green trees overshadowed only by a few species of lofty trees up to 120 feet 

 high, which, however, are pretty numerous in individuals. Such big trees are 

 Eugenia occlnsa, Alstonia spectabilis, Ficus Inclica and F. retusa, Artocar- 

 pus pomiformis, Saccopetalum Sorsfieldii, Carcinia speciosa, and a few 

 others not recognised by me. The smaller trees comprise chiefly Orophea 

 Katschallica in abundance, Glycosmis insularis, Aglaia argentea and A. 

 Andamanica, Amoora ganggo, Cupania Jackiana, Olax imbricata, Apodytes 

 Andamanica, Ixora Favetta, I. webereefolia in abundance, and J. brimnescens, 

 Webera densifora, Fetunga Foxburghii, Morinda bracteata, Alchomea, 

 Alsophila albo-setacea here and there (usually clothed with mosses and 

 Trichomanes Filicula and T. muscoides), Mallotus acuminatus and 3£. mu- 

 ricatus in abundance, and several others. Of the shrubs are especially 

 conspicuous Psychotria Nicobarica, P. tylophora, and P. Andamanica, Ixora 

 Kurziana. Areca Catechu is here so plentiful as to appear wild, but is, I 

 believe, only planted or self-sown. Pandanus Leram usually accompanies 

 the betel-nut palm. Of climbers, I observed chiefly Griffithia curvata, 

 Dinochloa Andamanica, Antitaxis calocarpa, Vitis lanceolaria and other 

 species, Alangium Sundanum, Stenochlcena scandens, Freycinetia in abun- 

 dance, often acconvpanied by the fleshy Pellionia procridifolia. The soil- 

 cover is scanty and chiefly consists of Adenostema viscoswn, Aglaonema 

 simplex, Cyperus moestus ; and a number of ferns, such as Davallia speluncae, 

 Vittaria elongata, Antrophium callaefolmm, Aspleniwn macrophyllum, and 

 Nephrolepis acuta are observed as epiphytes, together with a number of 

 orchids, especially Saccolabium obliquum. The coral-rocks are densely 

 covered with a tamariscine Sypnum, and long garlands of Nechera Lepi- 

 neana and of Hepaticae depend from the branches and trunks where 

 the jungle is not too dark. 



Where depressions occur in these upheaved coral-lands, fresh water 

 collects and forms pools and swamps,* which dry up more or less during 

 the driest months on these islands (March and April). These are filled 

 then to several feet in depth with black vegetable mould, which is so soft 

 that one sinks into it up to the knees. They cause a sort of swamp-forest 



* Dr. Rink has proposed a theory to explain the origin of these swamps in the 

 raised coral-reefs. Similar jungle-swamps, often of large extent, occur in all Malay- 

 tropical forests on metamorphic as well as on alluvial formations, and are in my opinion 

 only the result of rains, which drain into the depressions and carry quantities of vegeta- 

 ble mould into them until they silt up. 



