YAUPON, THE ONLY NORTH AMERICAN SOURCE OF CAFFEINE.
The yaupon tree (Ilex vomitoria), a member of the holly family, (Aquifoliaceae), is native to Texas and eastern North America. The leaves contain 0.09 percent caffeine and were formerly brewed into a tea by indigenous people native to the Texas area. The Swedish botanist, Linnaeus, upon hearing that the natives of Texas utilized the yaupon leaf tree for ritual purposes, which included ritual vomiting, ascribed the species name "vomitoria." Possibly because of this appellation, some botanists and historians have incorrectly assumed that there is an emetic principle in the leaves. In the nineteenth century, white settlers in Texas made a dark infusion of the leaves called "black drink."
Yaupon is related to the South American yerba maté (I. paraguariensis), the traditional caffeine beverage of Argentina and a popular ingredient in some herbal teas in North America. Although it is the only native plant north of the Rio Grande River to contain caffeine. yaupon leaves have yet to be commercially exploited for their caffeine content, probably due to their relatively low level compared to coffee, tea, maté, cola, and guarana and the relatively high cost of harvesting herbs in the U.S. compared to costs in developing countries.
Article copyright American Botanical Council.