Page:Popular Science Monthly Volume 75.djvu/455

Rh. Two and a quarter millions of dollars' worth of this product came from one district in one year recently and much more is following. Back in the middle of the eighteenth century it was discovered that the source of the rubber in the balls with which the Indians were wont to amuse themselves, was this guayule. As the Indians formerly did, so one now may extract this rubber in the same crude way by chewing the bark and rejecting the fiber until sufficient gum for the purpose has been accumulated.

That this gum is a by-product in the physiological processes of the plant and stored in its tissues in the form of granules, is not the least of its interesting features, for most of the rubber-bearing plants known to the public are trees yielding a milky fluid from which the rubber is obtained by coagulation. But in this case the rubber is not obtained by tapping, but by the immediate destruction of the plant.

Besides the mesquite and the greasewood and other shrubs that clothe the valleys and lower slopes, the steeper acclivities abound in Jatropha, Buddleia, Salvia, Bahia, Ephedra and many other woody plants, members of other genera to the number of a hundred or more, are scattered among the agaves, the palmas and the cacti up and down the mountainside.

One who has not sought these plants where they grow can have little idea of their number and variety, nor of their varied structural and physiological attributes which make for complete fitness in the stern environment of the desert. Here they grow and flourish where it would seem there is no chance for life. But they thrive in these barren wastes—league on league of plain and mountain, where there is neither spring nor pool nor forest shade, blistering heat and glare above and hot dry stones beneath, and find it sufficient.