Guayule

A desert shrub (Parthenium argentatum) native to the Chihuahuan Desert of northern Mexico and the southwestern United States, cultivated as an alternative source of natural rubber extracted from its stems and roots, distinct from the tropical rubber tree that supplies the great majority of the world's natural rubber. Interest in guayule has risen and fallen with rubber supply crises, including a large wartime cultivation push in the United States during the 1940s when Southeast Asian rubber tree supplies were cut off, followed by renewed research interest in recent decades tied to concerns over rubber tree disease risk and interest in hypoallergenic latex. The crop remains a minor, developing alternative rubber source rather than a major world commodity, grown mainly in small commercial and research plantings in the American Southwest.