Natural rubber at least showed promise as rubber sources, include the rubber fig ("Ficus elastica"), Panama rubber tree ("Castilla elastica"), various spurges ("Euphorbia" spp.), lettuce ("Lactuca" species), the related "Scorzonera tau-saghyz", various "Taraxacum" species, including common dandelion ("Taraxacum officinale") and Russian dandelion ("Taraxacum kok-saghyz"), and perhaps most importantly for its hypoallergenic properties, guayule ("Parthenium argentatum"). The term gum rubber is sometimes applied to the tree-obtained version of natural rubber in order to distinguish it from the synthetic version. The first use of rubber was by the indigenous cultures of Mesoamerica. The earliest archeological evidence of the use of natural latex from the
Ficus pumila milky sap of "Ficus pumila" can cause phytophotodermatitis, a potentially serious skin inflammation. Although the plant is not poisonous per se, "F. pumila" is listed in the FDA Database of Poisonous Plants. Ficus pumila Ficus pumila (creeping fig or climbing fig) is a species of flowering plant in the mulberry family, native to East Asia (China, Japan, Vietnam) and naturalized in parts of the southeastern and south-central United States. It is also found in cultivation as a houseplant. The etymology of the species name corresponds to the Latin word "pumilus" meaning "dwarf", and refers to the very small leaves of