CHAPTER XIII 



THE CENTRAL AMERICAN RUBBER TREE, 

 GASTILLOA ELASTICA, CERV. 



Species of Castilloa. — The rubber trees which occur wild 

 in Central America belong to the genus Castilloa of the 

 natural order Urticaceae, and until recently it was 

 customary to regard the majority of the trees as Castilloa 

 elastica, the original species described by Cervantes in 

 1794. It was known, however, that the trees showed 

 some variations in characters, for in 1885 Hooker, in 

 a paper " On the Castilloa elastica of Cervantes and some 

 allied rubber-yielding plants," * had drawn attention 

 to the existence of tliree well-marked varieties of Castilloa 

 from Central America which differed in certain respects 

 from the typical C. elastica, but he did not assign new 

 specific names to these forms. Subsequently Koschny 

 studied the Castilloa trees of Costa Rica and came to 

 the conclusion that there were four distmct varieties, 

 which he named C. alba, C. nigra, C. rubra, and C. Tanu, 

 the first three of these bemg rubber-yielding trees. These 

 views as to the existence of different forms of Castilloa 

 have since been fully confirmed, and it is now recognised 

 that the CastiUoa trees growmg in different districts of 

 Central America vary not only in botanical characters, 

 but also in the yield of rubber which they furnish. It 

 has been stated that nine fairly distinct forms of Castilloa 

 can be distinguished in Mexico alone, some of which 

 are specially suited to certain climatic conditions, so 

 that plants raised from seed obtained from the Castilloa 

 trees growing on the Atlantic Coast, where there is an 

 almost continuous rainfall, will not succeed on the Pacific 

 coast, where there is a distinct dry season of about six 

 months. 



* Transactions of Linnean Society, vol. ii. pt. 9, p. 209. 

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