A small shrub from the thistle family (Compositae) native to the deserts of northern Mexico and southwestern United States. The guayule produces a natural resin along with a rubber hydrocarbon, also called guayule, that is similar to polyisoprene. Crude guayule rubber is soft and tacky and is often used as an adhesive. For commercial use, it is steam cleaned, then washed with acetone to remove the natural resin. Guayule rubber was used as a substitute for hevea rubber during World War II.