Agnorhiza is a small genus of perennial herbs in the daisy family Asteraceae, comprising five species native to California and adjacent northern Mexico. The genus was formally described in 1998, with its species previously classified within either Wyethia or Balsamorhiza — two closely related genera of western North American composites sometimes collectively called "mule's ears." Plants in Agnorhiza produce large, sunflower-like flower heads 1 to 4 centimeters wide, borne above basal or alternate leaves that are typically broad and often resinous or hairy. The common name "mule's ears" refers to the large, erect leaves characteristic of this group.
The five recognized species — Agnorhiza bolanderi (Bolander's mule's ears), A. elata (Hall's mule's ears), A. invenusta (Coville's mule's ears), A. ovata (southern mule's ears), and A. reticulata (El Dorado mule's ears) — are largely confined to California, with A. ovata extending the group's range marginally into Baja California Norte in northern Mexico.
Distribution
All five species are native to California. Agnorhiza ovata is the only member whose range extends beyond California, reaching into northern Mexico.
Taxonomy Notes
Agnorhiza was erected as a distinct genus in 1998; before that, its species were treated as members of Wyethia or Balsamorhiza, both in tribe Heliantheae of Asteraceae (family Compositae). The segregation reflects morphological and molecular distinctions from those larger genera.
