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
The Book of the New Sun a boat: Two examples of the arcane words Wolfe uses are "Ascian" and "Hydrargyrum". Ascian, despite its similarity to the word "Asian" is derived from a Latin word meaning "without shadow", as the Ascians are tropic dwellers who have no shadow at noon. Hydrargyrum, the fluid contained in Severian's sword Terminus Est, is derived from the Latin "hydr", meaning water, and "arguers", meaning silver, as hydrargyrum is liquid mercury. The Ascian language further expounds on the idea that word choice alters the thinking of people, as the Ascian language is simply a set of quotations from government propaganda called "Correct