Guayule

Aiton's Encyclopedia (1910)

wy-u'le, a rubber plant of recent prominence. It is a bushy shrub of the desert, growing knee high to a horse. The stem does not exceed three inches in diameter. Unlike other rubber-producing plants, it does not yield a milky juice by tapping. The rubber of the guayule is scattered in minute granules throughout the tissues of the branches, stems, and roots, but particularly in the bark. The guayule shrub grows abundantly in Northern Mexico and in adjacent parts of Texas. The natives pluck up the plants by the roots and pack them on burros to baling machines. The bales are transported by pack trains or wagons to a railway station. Pack trains of burros laden with bales of guayule come not infrequently forty miles to a station. The bales are taken in car lots to factories. The guayule is first ground in a mill; the meal thus made is ground to a fine powder by tumbling in a cylinder with heavy stones. The method of extracting the rubber from the dust is guarded carefully. Several million dollars' worth of guayule rubber was shipped from Northern Mexico in 1908. One company operating in the state of Zacatecas has acquired a concession of 25,000,000 acres on which to gather this profitable shrub. A mill requires 100 tons of dried shrub daily, representing the growth possibly of as many acres. The railway stations and sidings in the guayule country are piled with bales awaiting shipment. Inexhaustible as the supply may seem, it can last but a generation. Efforts at growing have not been very successful. The plant does best in limestone foothills. It is difficult to start plants without irrigation; the shrubs grown by irrigation come on rapidly, but are scantily supplied with rubber granules. Shrubs grown without irrigation seemingly require twenty years to reach a size for gathering.