18 WRIGHT : THE GENUS DIOSPYROS 
and the remainder sub-opposite. D. oppositifolia resembles 
D. Melanoxylon in the opposite and sub-opposite arrange¬ 
ment of the leaves. In the former species, however, many 
twigs have their leaves crowded together to form large 
rosettes. 
Form and Size of Leaves .—The leaves conform to the 
usual tropical type in that they are simple, entire, and 
petiolate. The shape may be ovate (D. ovalifolia), lanceolate 
(D. hirsuta), or lanceolate oblong, with a tapering or abrupt 
apex, and a rounded or tapering base. 
The size varies considerably, being smallest (30 to 70 mm.) 
in D. oocarpa and D. pruriens, and largest (190 to 350 mm. 
long) in D. Moonii, D. insignis, and D. Embryopteris. 
Within the same species there is often a considerable 
variation in size, the young leaves arising on offshoots from 
the main stem being many times the size of those occurring 
on the normal twigs. A case in point is in the large 
leaves of D. Melanoxylon, these occurring on the young 
shoots arising from the base of small trees and measuring 
100 to 240 mm., whereas the normal dimensions for this 
species are 50 to 100 mm. Heterophylly occurs to a 
marked degree in D. Gardneri, D. oppositifolia, and D. 
sylvatica. 
Venation .—The vascular bundles in the leaf form a 
central stout midrib with several smaller lateral factors 
connected alternately along its length, these in their turn 
being made up by the coalescence of the very small bundles 
scattered between them. Sometimes the vascular bundles 
project strongly on the upper surface (D. Embryopteris), 
sometimes on the lower surface (D. insignis), but are often 
relatively inconspicuous (D. affinis, D. montana, and D. 
oocarpa). 
The midrib may be very conspicuous, as in D. Moonii and 
D. acuta, or it may be insignificant as in D. oocarpa and D. 
attenuata. 
