3 
CHARACTER OF THE VEGETATION. 
I propose to limit my remarks chiefly to the vegetation of 
Doi Sootep as most of my collecting has been done on that 
mountain. : 
Chiengmai itself is surrounded by rice fields, but here and there 
occur patches, which have either gone out of cultivation, or are not | 
considered worth cultivating. These patches are usually covered 
with a scrub jungle, consisting for the most part of a small thorny 
bamboo, bushes of Capparis tenera and Zizyphus Jujuba, with 
season preventing any further development; such are Brucea 
sumatrana, Desmodium longipes, Clerodendron serratum and Hibiscus 
cancellatus. iganosma marginata, Celastrus paniculata, Acacia 
pennata, Calycopteris floribunda and Hurrisonia Bennettii are the 
chief woody climbers. A plentiful growth of herbaceous plants 
comes up in the rains, including several ground orchids, Habenaria 
Helferi, Peristylus constrictus and two or three species of Pogonia, 
and many other plants such as Zingiber Zerumbet, Clerodendron 
diversifolia and Inula polygonata. 
This jungle extends to the foot of the first steep slope, where it 
gives place to the deciduous jungle knuwn in this country as 
“Pah Paa” and in Burma as “Eng Jungle.” The pah paa 
extends up the mountain to an altitude of about 2000 ft.; its 
characteristic trees belong to the Dipterocarpaceae, the prevailing 
species varying with the nature of the soil, and the slope of the 
ound, ere are certain features common to the different forms 
of pah paa. The jungle is open, the ground being either bare and 
stony, or covered with a tufty growth of grass; epiphytes abound, 
but there are few or no woody climbers. Where the ground is very 
stony the jungle is composed chiefly of stunted trees of Pentacme 
siamensis—75 per cent. of all the trees present may belong to this 
ecies. These trees are much infested by such parasites as 
ranthus and Viscum. Occasionally, on somewhat similar ground, 
Shorea obtusa is found as the predominant tree, but intermixed with 
Pentacme siamensis. 
18391 | A2 
