(including genus Fagara) is a genus of about 250 species of deciduous and evergreen trees and shrubs in the citrus or rue family, Rutaceae, native to warm temperate and subtropical areas worldwide. Several of the species have yellow heartwood, to which their generic name alludes.
The generic name is derived from Ancient Greek words ξανθός (xanthos), meaning “yellow,” and ξύλον (xylon), meaning “wood.” It refers to a yellow dye made from the roots of some species. The Takhtajan system places the genus in the subfamily Rutoideae, tribe Zanthoxyleae, while Germplasm Resources Information Network places it in the subfamily Toddalioideae and does not assign it to a tribe. The once separate genus Fagara is now included in Zanthoxylum.
Many Zanthoxylum species make excellent bonsai and in temperate climates they can be grown quite well indoors. Zanthoxylum beecheyanum and Zanthoxylum piperitum are two species commonly grown as bonsai. The fruit of several species is used to make the spice, Sichuan pepper. They are also used as bonsai trees. Common names include “prickly ash” and “Hercules club”.