Loeseliastrum, commonly known as calico, is a small genus of flowering annual herbs in the phlox family (Polemoniaceae), placed in the order Ericales. The genus comprises four accepted species, all native to arid landscapes of the southwestern United States — including Arizona, California, Nevada, Utah, and Texas — and extending into northwestern Mexico.
Plants in this genus are small, hairy annual herbs with alternately arranged leaves up to about 4 centimetres long, whose margins bear distinctive bristle-tipped teeth. The flowers are the genus's most striking feature: the corolla is typically lobed, with three lobes on the upper lip and two on the lower, and the petals are often spotted, streaked, or mottled in intricate calico-like patterns. Colours range from purple-speckled white to orange-speckled yellow in Loeseliastrum schottii (Schott's calico), and from white and lavender streaked with purple and maroon in Loeseliastrum matthewsii (desert calico). The protruding stamens are curved and capped with yellow anthers.
The most widespread species, Loeseliastrum schottii and Loeseliastrum matthewsii, are characteristic wildflowers of the Mojave and Sonoran Desert regions. Loeseliastrum depressum and the less common Loeseliastrum franciscanum round out the genus. The genus name was established by Timbrook (1986), who transferred several species from Linanthus and related phlox genera, based on work published in the journal Madroño.
Etymology
The common name "calico" refers to the spotted or mottled, multicoloured pattern of the flowers, which resemble calico fabric. The species epithet matthewsii honours Washington Matthews, the American ethnologist and army surgeon after whom Loeseliastrum matthewsii (desert calico) was named.
Distribution
The genus is restricted to arid and semi-arid habitats of the southwestern United States (Arizona, California, Nevada, Utah, and Texas) and northwestern Mexico, with Loeseliastrum matthewsii specifically associated with the Mojave and Sonoran Deserts, and Loeseliastrum schottii widespread across desert regions of the southwest and northern Mexico.
Ecology
Species in the genus are characteristic annual herbs of desert scrub, growing in the arid conditions of the Mojave and Sonoran Desert regions. Loeseliastrum schottii is described as common across many parts of the desert region of the southwestern United States and northern Mexico; Loeseliastrum matthewsii is similarly described as relatively common in its Mojave and Sonoran Desert range.
Taxonomy Notes
The genus Loeseliastrum was established by Timbrook in 1986 (Madroño 33(3)), separating several species previously placed in Linanthus and related genera within Polemoniaceae. GBIF places the genus in order Ericales, family Polemoniaceae, with accepted status. Four species are currently recognised; the genus has no accepted infrageneric divisions.
