
i 
ts Fe EEE 
eet aias eue a aa eaa 
13 
has been cleared up by the observations of Mr. Barrington Brown 
F.G.S., in British Guiana. Briefly stated, the process is as follows :—* In 
ég 

XXVIII.—CASTILLOA RUBBER OF CENTRAL 
AMERICA. 
(Castilloa elastica, Cerv.) 
This is one of the earliest described of rubber-yielding plants, but 
according to Sir Joseph Hooker (Trans. Lin. Society, Vol. IL, pt. 9, 
p. 209), it is probable that more than one rubber-bearing species exists 
The Ule of British Honduras and Nicaragua is no doubt Castilloa 
elastica of Cervantes, but what is known locally as Tunu and said to 
ield a “ gutta-percha,” is so far undetermined owing to the absence of 
good specimens of the leaves and flowers. e species named Castilloa 
Markhamiana (Collins, Report on the Caoutchoue of Commerce, 1872, 
p. 12, t. 3) has been shown to belong to another genus, viz., Perebea 
{Genera Plantarum, Vol. III., p. 372). 
Plants of Castilloa have been widely distributed from Kew to various 
tropical colonies, and seed-bearing trees are now found in Ceylon, 
Singapore, Mauritius, Jamaica, Trinidad, and the west and east coasts 
of tropical Africa, 
The original stock of Kew plants was obtained by Mr. R. Cross in 
1875 for the India Office from the Isthmus of Panama, under the name . 
“ tomentose.” 
above brief statement respecting the determination of the rubber- 
yielding plants of Centra erica will serve to show the present 
position of our knowledge of the subject. 
he plants distributed from Kew, and now under cultivation in various 
tropical colonies, would be more correctly termed according to the place 
of origin Darien Castilloa. This would distinguish them from the Ule 
of Mexico, British Honduras, and Nicaragua, and sufficiently indicate 
their history. As regards the quality of rubber yielded by the Darien 
