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
Liquid Acrobat as Regards the Air instead. Gerry Conway, a drummer of Fairport Convention appears on the album. The most ambitious track is also its lengthiest. "Darling Belle", the track Williamson said "came to me in a dream", is composed of three-way vocals and spoken-word. Heron would vocalize and McKechnie would mimic his words with her high-pitch vocals. It tells the story of a woman from childhood to old age. "Tree" is a remake of the song "The Tree" from the band's first album. Liquid Acrobat as Regards the Air Liquid Acrobat as Regards the Air is the ninth album by the Incredible String Band. It