92 Journal of the Asiatic Society of Bengal. [N.S., XIX, 
issued by the Forest Service' , almost the only botanical study 
is a paper on the Flora of the Minbu District by Colonel Gage. 
LM.S2. The numerous references to the vegetation of Burma 
which appear in standards works both on Ecology —such as 
Schimper’s monumental ‘ Pflanzengeographie ’—and on 
otany—such as Brandis’ “Indian Trees ’’—are largely derived 
from Kurz’ earlier studies. 
he present note is, therefore. an attempt to classify the 
natural vegetation of a part of Burma and _ to analyse its 
connexion with the controlling factors of climate and soil. 
Il. Tae EcotogicaL Factors. 
It is unnecessary to remind the reader that Burma !s 
essentially a monsoon country but that the area under 
consideration is profoundly affected by the general topography 
of the country. The rain-bearing south- westerly monsoon- 
winds are intercepted by the lofty and uninterrupted range of 
the Arakan Yoma which separates the central tract of Burma 
from the sea. The result is that the centre of Burma is 
oceupied by the “ Dry Belt’ with a rainfall as low as 2] 
inches in the middle (Salé). In the area under consideration 
the rainfall decreases steadily from 47°25 inches at Prome 
along the riverine stations to 25°52 inches at Yenangyaung. 
Westward from the River Irrawaddy there is a rapid increase 
as one approaches the foot-hills of the Arakan Yoma. Eas 
wards there is also a slight increase towards the Pegu Yoma 
(compare Minhla, 32°85 inches and Taungdwingyi, 40° 
e low ranges of hills which border the Trrawaddy 
from Prome to Minbu enjoy a slightly higher rainfall than the 
neighbouring lowlands, especially from pees ma: at the 
commencement and towards the end of the monsoons. In the 
drier regions, the rain falls mainly on a few days of the “ rainy 
season’ and owing to the hardened. baked surface of the soil 
by far the greater portion runs off and is lost so far as the soil 
and the vegetation is concerned. There is thus a greater 
contrast between the Teak-Forests of Prome and the Semi- 
Desert of Yenangyaung than the mere difference in rainfall 
would suggest. 
eat would not seem to be a very important factor in the 
present area. The extremes both diurnal and annual are 
greater in the drier regions. At Minbu, the only station in 
this area for which complete records exist, the montaly mean 
varies from 71:1° in January to 90°2° in April. In 192% the 

1A. rng 8 A Handbook of the Forest Products of Bowne (ee 
J. oA Lace, A er of Trees, Shrubs, ete. recorded from Burma (191 2) 
C. B. Smales, A Simple Key stn = Hundred Common Pts ees of Burma 
wase's Civenrataeet Press, Ran 
Records Botanical prin - taste, Vol. IIT, (1904). 
