250 
In Dr. Haviland’s collection from Sarawak is a very distinct 
plant labelled ‘ ‘ Jelutong.’ ’ It has stout branches with the 
leaves crowded at the ends oblanceolate obtuse, tapering at the 
base, thickly coriaceous with about 25 pairs of nerves, straight 
and prominent, glaucous on the back with a stout petiole id inch 
long, blade 6 inches long, 2f wide. The panicle is small with a 
few branches on a peduncle 4 .inches or less long. The 
flowers are small, and white, pedicels short and thick. Calyx 
lobes ovate. The corollas are all fallen in my specimen, but the 
style resembles that of D. costulata. 
This is perhaps the plant mentioned under Dyer a costulata in 
the Flora of British India as collected by Beccari and others in 
Sarawak. It was collected at Kuching, December 25th, 1892 
(No. 2170 Haviland), and is probably the source of some at least 
of the Jelutong rubber exported from Borneo to Singapore. 
The Jelutong tree abounds in all parts in a very liquid white 
latex containing a good deal of caoutchouc. The latex pressed 
between the finger and thumb draws out into fine and fairly firm 
threads as do the better class rubbers. Allowed to diy in the or- 
dinary manner it becomes hard and brittle, but for sale it is 
usually coagulated with the aid of kerosine, forming a mealy 
rubber of a white colour, and of but little value. I am inform- 
ed that it is chiefly used for making mouldings of picture frames, 
and for adulterating other local rubbers. 
As the tree is very abundant in the Peninsula and attains a 
very large size, it may be very well worth experimenting with, 
and owing to the liquidity of its latex will perhaps be a subject 
for the centrifugal machine. Till recently the tree has almost 
entirely been neglected both from the point of view of a rubber 
producer, and as a timber tree. Its wood is soft and white, and 
was formerly chiefly used for models and native clogs, lately, 
however, its use for planks for building and boxes has increased, 
and though it is not very durable it can be used for walls and 
partitions of houses. 
A tree in the Botanic Gardens, about 80 feet tall and 2 feet 
through, was tapped for experiment. The bark was noticed to be 
very thick, fully half an inch. The latex flowed freely for a short 
time and then stopped. Two incisions of 6 inches long and 
\ inch wide, one of 12 inches and two of 2 inches were made, 
on two successive days, and if oz. of tolerably dry rubber was 
obtained. The rubber wns white and remained so, hardly elastic 
but easily moulded, insoluble, quite unacted on by ammonia and 
acetic acid, readily softened and made more elastic in boiling 
water. In this state a small piece drawn out to over 5 inches 
when released contracted slowly to about if. On drying it be- 
came very brittle. 
Alstonia scholaris, R. Br. — 44 Pulai ” produces an abundance 
of latex like that of Jelutong. which dries into a rather hard stiff 
sheet. It can hardly be used as rubber, and is very rarely col- 
lected even for adulteration. The tree is very abundant all over 
the Peninsula. 
