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
Site of Ficus superba var. henneana tree a multi-stemmed specimen with stems straddling the site and adjacent properties. The combined trunk diameter exceeds . It is a young and healthy tree, considered against the maximum potential life expectancy for this genus. Based on the synconium being in pairs, the relatively-small size of fruit and presence of a drip tip (to the leaf) there is a reasonable likelihood that the earlier identification (of Ficus superba var.henneana) is now incorrect. Based on the features observed at the two inspections, it would appear that the tree is a white fig, "Ficus virens", probably planted after the first (colonial) settlement in