352 Ridley. — On the Dispersal of Seeds by Wind . 
unknown. The wind usually persists in one direction, according to the 
time of year ; but at present, though from the south-east, it veers round 
occasionally to the west. 
Shorea leprosula , Miq., is a very common tree in most parts of the 
peninsula, occupying a very large area and occurring also in Sumatra and 
Borneo. It attains a great height, ioo to 150 feet, with a straight tall 
stem and a big head of foliage. It usually fruits about once in live years, 
and then produces a vast amount of fruit. As in most of these trees, a very 
large proportion of the fruit is barren, and this falls first. Then after 
a time the ripe fruit falls. The fruit is about half an inch long, with three 
equal wings (modified calyx-lobes) 2f inches long, half an inch broad, 
linear, oblong, blunt ; when the fruit falls it rotates rapidly, descending 
with the ovary downwards. 
It appears to have no other modification for dispersal, and is apparently 
not disseminated in any way by animals ; but the fruits of these Diptero- 
carpeae are often eaten apparently by rats, in which case the fallen fruits 
attacked by them are quite destroyed on the spot. 
A big tree in the Botanic Gardens, 100 feet tall, stands in an open 
spot, but about 20 yards away on one side is the jungle, through which 
wide paths run, so that the plant has exceptional advantages for dispersing 
its seeds. 
I surmise that the tree is about 100 years old, perhaps more. These 
Dipterocarpeae are of slow growth, and the Shoreas at least do not fruit 
till they are fully thirty years old, when they are about 30 feet tall. Fruits 
from small trees do not fly so far as those from large trees, as the 
surrounding foliage of the forests being much taller prevents their receiving 
the full force of the wind. I have been in high forests in a gale, when, 
though the wind was tearing through the upper branches of the trees 100 
feet high and upwards, and throwing down large boughs, there was no wind 
below, where I was standing. 
The furthest limit I have found the fruit from this Shorea was a single 
one 98 yards from the tree-base, on a grass plot. The greatest number 
fell within 20 yards of the tree, and continued abundant up to 40 yards. 
I saw none beyond this distance in the jungle ; on paths and grass they 
naturally get drifted a little further after alighting, pushed along by wind, 
or the gardeners’ brushing, or some such accident not possible in the forest. 
The distance may therefore be for purposes of estimation calculated at 
ico yards at the outside, though practically it must be rare for them to go 
50 yards. 
The furthest young tree descended from this big Shorea leprosula is 
40 yards away from the parent tree, and though many thousands of seeds 
must have been blown into the neighbouring jungle, there are only about 
a dozen young plants in the neighbourhood. Fruits dropped from my 
