322 DESCRIPTIONS OF NEW PLANTS FROM NICOBAR ISLANDS. 



etc. Scattered over the area, but more frequent along the many 

 little creeks, we see numerous small crooked trees (as if one had 

 reached the limit of tree-growth) belonging to FagrcBa racemosa^ 

 Aporosa glahrifolia, Antidesma GhcesemliUa, and locally also Casuarina 

 equisetifolia. Pandanus odoratissitmis, here a simple-stemmed, palm-like 

 little tree, with very strong basal aerial roots, finishes the picture. The 

 relationship of these grass-heaths to the tropical forests has remained 

 to me a puzzle, although I have marched for upwards of twelve 

 miles along their abrupt demarcations (not an easy task, as the grass 

 and shrubs in such places are 5-6 feet high). Although I considered 

 every factor of any influence — soil, elevation, winds, drainage, shelter, 

 influence of sea, etc. — I still remain without any clue to a solution 

 of this question. 



The next rocks botanically influential are calcareous sea sand, 

 raised coral banks, limestone and calcareous sandstones, which belong 

 to the so-called Southern group, in which, however, Katchall (an 

 entirely calcareous island) is enumerated. Then come the plutonic 

 rocks and their detritus, which, however, were only little developed 

 in those parts which I visited. All islands consisting of the above 

 rocks are characterised by the absence of grass- heaths, and are covered 

 with forests from the bottom to the top. 



The four principal aspects of vegetation in these islands are — 

 1, mangrove swamps; 2, beach forests; 3, tropical forests, which 

 fall under three groups, those growing on polycistine clay, those on 

 calcareous or coralline strata, and those growing on plutonic for- 

 mations ; 4, grass-heaths. The character of the forests and their 

 relationship to the substratum I must retain for a more complete 

 account of the vegetation of the !Nicobars, and in the meanwhile refer 

 those interested to Dr. Diedrichsen's account of the vegetation of 

 these islands, and especially to the interesting geological reports of 

 Dr. Rink and Dr. Hochstetter, in which many valuable botanical data 

 are given, illustrated by geological botanical sections. In conclusion. 

 I will only indicate a few of the peculiarities in the distribution of 

 Nicobarese plants. 



One of the most conspicuous features of the Nicobarese vegetation 

 is Areca augusta* This palm pushes its head above the highest 

 forest trees, and forms, so to say, a palm forest above the true forest, 

 rendering thus the aspect of the landscape more Brazilian than Indian. 

 This palm is frequent all over the so-called Northern group (Car- 

 nicobar, Theressa, Kamorta, Nankowry, Trinkut, &c.), while it 

 becomes scarcer in the Southern group. But on Katchall, a calcareous 

 island separated from Kamorta and Nankowry only by a channel 

 about eight miles broad, the palm is entirely absent. It is true that 

 there grow two palm-trees on the ridge about two miles north 

 from the southernmost point, and these form rather a good landmark, 

 for they can be seen also from the west side of this island. They 

 were pointed out to me as cocoa-palms, and this is very probable, as 



• By some unexplainable mistake this palm is by Dr. Diedrichsen, as well 

 as by the Austrian expeditioo, invariably called ^/ecaA'iVyum/, a dreadfully armed 

 Bobolifarous palm, which bears not even a remote resemblance to the Nicobar 

 palm. 



