Rafinesquia, commonly known as plumeseed or desert chicory, is a small genus of flowering plants in the daisy family (Asteraceae), placed in the order Asterales. The genus comprises just two species, both annual wildflowers native to arid and semi-arid landscapes of the western United States and northwestern Mexico, including Baja California and Sonora.
Plants in this genus produce characteristic white or pale lavender ray florets and are adapted to the desert and dry-scrub habitats of the Sonoran and Mojave deserts. Like other members of the chicory tribe (Cichorieae), they bear ligulate (strap-shaped) flower heads — all florets are ray florets — and the milky sap typical of the tribe.
The two species are Rafinesquia californica Nutt. (California plumeseed or California chicory), found across California, Oregon, Nevada, Arizona, Utah, and into Baja California and Sonora; and Rafinesquia neomexicana A.Gray (New Mexico plumeseed or desert chicory), with a somewhat broader eastern range extending into New Mexico and Texas. Both are spring-blooming annuals that often grow in the shelter of desert shrubs.
The genus was described by Thomas Nuttall in 1841 and named in honour of Constantine Samuel Rafinesque, the prolific and eccentric nineteenth-century polymath and naturalist.
Etymology
The genus name Rafinesquia honours Constantine Samuel Rafinesque (1783–1840), a prolific polymath and self-taught naturalist known for describing thousands of North American plant and animal species. The name was assigned by botanist Thomas Nuttall when he formally described the genus in 1841.
Distribution
Rafinesquia is native to the western United States and northwestern Mexico. R. californica occurs in California, Oregon, Nevada, Arizona, and Utah, as well as Baja California and Sonora. R. neomexicana shares much of this range and extends further east into New Mexico and Texas.
Ecology
Both species are spring-blooming desert annuals, typically found in sandy washes, dry slopes, and open desert scrub of the Sonoran and Mojave deserts. They commonly grow in the partial shade cast by larger desert shrubs, a strategy that reduces moisture loss in arid conditions.
