From this plant which Juan holds can be extracted a quantity of real rubber equal to 23 per cent of the weight of the plant. The rubber comes from the roots and branches, only the leaves having no rubber content. This plant is seven years old. At this age it reaches its peak in rubber content. :16

Courtesy of UC Berkeley, Bancroft Library

http://www.oac.cdlib.org/ark:/13030/tf1r29n8xr/?order=1

Title:

From this plant which Juan holds can be extracted a quantity of real rubber equal to 23 per cent of the weight of the plant. The rubber comes from the roots and branches, only the leaves having no rubber content. This plant is seven years old. At this age it reaches its peak in rubber content.

Contributing Institution:

UC Berkeley, Bancroft Library