Trixis is a genus of shrubs belonging to the family Asteraceae (the daisy family), within the order Asterales. The genus is native to the Americas, with its range spanning North America, Central America, South America, and the West Indies. Species within Trixis are commonly referred to as "threefolds," a name that alludes to the distinctive three-lobed outer lip of the corolla — the same feature that inspired the genus name itself.
The genus encompasses around 40 described species distributed across a wide latitudinal range, from the southwestern United States and Mexico through the Caribbean and Central America to the southern cone of South America, including Paraguay, Uruguay, Brazil, and Argentina. Notable members include Trixis californica (American threefold), found in the arid southwestern USA and northern Mexico, and Trixis inula (Tropical threefold), which ranges from Texas through Mexico, Central America, and the West Indies into northern South America.
Trixis was historically broader in circumference; numerous species formerly placed here have been reassigned to other genera including Acourtia, Clibadium, Dolichlasium, Holocheilus, Perezia, and Riencourtia.
Etymology
The genus name Trixis is derived from the Greek τριχος (trixos), meaning "threefold." This name refers to the distinctive outer lip of the corolla, which is divided into three lobes — a defining morphological character of the genus.
Distribution
Trixis is native to the Americas, ranging from the southwestern United States (California, Arizona, New Mexico, Texas) and Mexico southward through Central America and the West Indies into South America, with species recorded in Colombia, Venezuela, Peru, Bolivia, Brazil, Paraguay, Uruguay, and Argentina.
Taxonomy Notes
Several species formerly placed in Trixis have been moved to other genera, including Acourtia, Clibadium, Dolichlasium, Holocheilus, Perezia, and Riencourtia. GBIF recognises Trixis in the family Asteraceae, order Asterales.
