About Psorothamnus spinosus (A.Gray) Barneby
Psorothamnus spinosus (A.Gray) Barneby, also known by the synonyms Psorodendron spinosum and Dalea spinosa, is a perennial legume tree that grows in North American deserts. Its common names are smokethorn, smoketree, smoke tree, smokethorn dalea, and corona de Cristo. This species is native to desert washes of the Colorado Desert in Southern California, the Sonoran Desert in western Arizona, and most of eastern Baja California state, including several northern islands in the Gulf of California, also called the Sea of Cortez. It is a common tree in Joshua Tree National Park, where it is referred to as smoketree. The range of P. spinosus is centered along a north-south axis through the Lower Colorado River Valley. It extends northwest into the eastern Mojave Desert, west across nearly all of the Colorado Desert, a subsection of the Sonoran Desert, and east of the Colorado River into the Sonoran Desert of southwestern Arizona. In western Baja California, its range reaches the western shore of the Gulf of California, where it grows on Gulf islands including Isla Ángel de la Guarda, but not on Tiburon Island. To the east in Sonora, the species extends into the northwest portion of the large Gran Desierto de Altar, on the northern shore of the Gulf of California. In Arizona, range maps show the species' distribution is centered on the river courses of southwest Arizona: specifically the Bill Williams River to the north, and the Gila River to the south. Its range also extends into extreme southern Nevada, where it occurs mostly in areas adjacent to the Colorado River.
