KEW GARDENS. 
253 
30,000 tons, worth about six million pounds sterling. The 
value of the manufactured goods made in a single year is 
estimated at fifty million pounds sterling. The quantity of 
unworked rubber imported into the United Kingdom in 1883 
was over 10,000 tons, worth about £3,500,000 ; but in 1885 
it had sunk to less than £2,000,000. 
None of the trees which yield india-rubber have yet been 
brought into cultivation on a large scale, and the time will 
soon come when either this will have to be done, or the 
supply will gradually lessen. There are about sixty distinct 
species in these rubber-yielding genera,* and the botanists 
* List of the india-rubber producing genera , their native countries, 
with the number of species in each , and annual import :— 
Order. 
Genus. 
Number 
of 
Species. 
Native Country. 
Quantity 
Imported 
into 
England 
in 1880, 
in tons. 
Apocynaceae 
Willughbeia 
9 
Tropical Asia .. 
530 
Do. 
Landolpliia, in- 
16 
Africa and Mada- 
eluding Vahea 
gascar.. 
2,200 
Do. 
Hancornia 
1 
Brazil 
Do. 
Urceola .. 
7 
Malay Peninsula 
and Archipelago 
Do. 
Dyera 
3 
Malay Peninsula 
Do. 
Couma (Collo- 
phora) .. 
4 
Guiana and Brazil 
Do. 
Alstonia .. 
3 
Malaya and Fiji 
Do. 
Cameraria 
2 
West Indies 
Artocarpeae 
Castilloa.. 
3 
Central America 
and Cuba 
100 
Do. 
fFicus 
2 
Africa and Tropi- 
cal Asia 
370 
Euphorbia- 
Hevea 
9 
Amazon Region 
3,768 
ceae 
Do. 
Manihot .. 
1 
Brazil 
35 
60 
7,003 
and foresters will have to settle between them which of these 
are best worth cultivating, and where it will pay to grow 
them. Unfortunately at the present time the price of india- 
rubber of all kinds is exceptionally low, the best Para rubber 
being now only worth about 2s. Gd. per lb. in London, against 
4s. in 1884, and the best of the African and Asiatic kinds 
about 2s. per lb. 
f There are altogether over 400 species of Ficus, but only two 
yield india-rubber. 
