The bark of guayule plants is a source of rubber or latex. ... Products that can be made from the resins in guayule include wood preservatives, pesticides, and plasticizers.
Except where the context otherwise requires, throughout the nomenclature the expression `rubber' means the following products, whether or not vulcanized or hard: natural rubber, balata, gutta-percha, guayule, chicle and similar natural gums, synthetic rubber, factice derived from oils, and such substances reclaimed ...