Amongst arboreous families Leguminosae and Euphorbiaceae are prominent; Hevea belonging to the latter is widely distributed in various species in the Amazon basin, and yields Para and other kinds of rubber.
Successful plantations of Hevea have also been established in Java, Sumatra and Borneo.
In the vast untrodden forests farther east there are timber trees of many kinds, incense trees, a great wealth of rubber trees of the Hevea genus, numerous varieties of beautiful palms, sarsaparilla, vanilla, ipecacuanha and copaiba.
The Hevea product is obtained annually by tapping the trees and coagulating the sap over a smoky fire, but the caucho is procured by felling the tree and collecting the sap in a hollow in the ground where it is coagulated by stirring in a mixture of soap and the juice of a plant called vetilla.
The Hevea is found along the water-courses of the lowlands, which includes the large tributaries of the Maranon, while the caucho species flourish on higher ground, above 900 ft.
Forests: jebe (also written hebe) or seringa, and caucho- the former being collected from the Hevea guayanensis, or H.
Among other forest trees of economic importance are the silk-cotton tree (Bombax ceiba), the Palo de vaca, or cow-tree (Brosimum galactodendron), whose sap resembles milk and is used for that purpose, the Inga saman, the Hevea guayanensis, celebrated in the production of rubber, and the Altalea speciosa, distinguished for the length of its leaves.
So far the Hevea plantations in Ceylon and the East have not been seriously troubled by insect or fungoid pests, and those which have occurred have succumbed to proper treatment.
Ever since plantations of Hevea have been made on an increasing scale in the Straits Settlements, the Federated Malay States and in Ceylon, and at the present time rubber plantations form the principal industry in these colonies.
Africa the Hevea which has been planted promises well, especially in the Gold Coast, where good yields of latex are stated to have been obtained.