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
Latin word order based, and establishing what nuances of meaning or emphasis could be obtained by using different word orders. Two major recent works on Latin word order, based on different approaches, are those of Devine and Stephens (2006) and Olga Spevak (2010). It is generally agreed that pragmatic factors play a major role in Latin word order, that is, factors such as topic and focus, contrast, emphasis, and heaviness. The topic (what is being talked about) often tends to come at the beginning of the sentence, and the focus (what is said about the topic) at the end or in penultimate position.