﻿1874.] oftlie Burmese Flora. 41 



fluence of elevation modifies and changes vegetation according to well-known 

 laws. 



The leaf-shedding or deciduous forests form the other large class of 

 Indian forests, and cover in these regions a greater area than the former. 

 These grow either on impermeable strata, such as compact calcareous sand- 

 stones, and form then the " dry forests," where catechu trees and several 

 Hindustani trees and arboreous EupJiorhias find their home, while higher up 

 on the crests of the Yomah they become formed almost exclusively of an 

 arboreous Siptage, often accompanied by several rather temperate forms like 

 Heracleum^ Vaccinivmi, Hymenopogon, etc. On laterite and gravelly strata, 

 and also on very stiff plastic clay, grows another variety of forest, called by 

 me the open forests. Those growing on the first named strata are especially 

 interesting and are generally known to the Burmans as the eng or ein-forests, 

 so named after the prevailing tree, Dipterocarpus tuberculatus ; here the 

 botanical rarities of Burma are scattered, and catch the eye the more readily 

 that the surrounding forest is open and the soil-clothing rather scanty ; 

 higher up in the hill-eng forests, (which grow on laterite formed by decom- 

 position of older rocks or on debris of them) the eng-tree is often replaced 

 by other kinds of wood-oil trees (chiefly Dipterocarpics costatus and ohtusi- 

 folius) ; while those open forests that occupy the stiff clay at the base of 

 the hills are characterized by the absence of eng. 



The last variety of deciduous forests are the mixed forests (as they are 

 called by the forester), in which teak is chiefly found almost always accom- 

 panied by pyenkadu {Xylia). The upper ones grow either on permeable silice- 

 ous argillaceous sandstone, as is the case on the Pegu Yomah, and the trees are 

 then usually very lofty, or on metamorphic and other older strata in Mar- 

 taban, and in this case they are richer in species but lower in growth, often 

 accompanied by trees which are very rare in the Yomah, such as Pterocar' 

 pus, Ternstroemiaceae, etc. The lower mixed forests occupy the alluvial 

 lands of the greater rivers and gradually pass into the savannah-forests and 

 the true savannahs. Along the larger choungs in the hills where alluvial 

 deposits spread out to a larger extent, similar savannah-forests recur on a 

 smaller scale, but much better grown, and, especially by favourable exposure, 

 much mixed up with trees that are missed in the plains, such as Erythrina 

 lithosperma, Bischoffia Javanica, etc. 



Such is a bird's-eye view of the Burmese forests, of which I have given a 

 more detailed description in my report on the Pegu-forests, and I hope that 

 these cursory notes may in the mean time aid in the understanding of the 

 habitats of the species given in the following pages. 



The area comprised by me under the general denomination of Burma 

 is not the political one but includes Ava, Chittagong as far as the Fenny 

 G 



