Brickellia sonorana (Asteraceae), a new species from Mexico belonging to the subgenus Phanerostylis

A new annual species, Brickellia sonorana B. Turner, is described from Sonora, Mexico.It belongs to the Barroetea complex of Brickellia and has been previously, but incorrectly, referred to as Barroetea laxiflora [-Brickellia laxiflora (T.Brandegee) B. Turner, the type from Puebla, Mexico], The Barroeteoid complex of Brickellia is composed of four closely related species: B. sonorana, B. subuligera (Schauer) B. Turner, B. laxiflora and B. pavonii (A.Gray) B. Turner.A key to these taxa is presented and a map showing their distributions is provided.