Erigeron allocotus is a species of flowering plant in the daisy family known by the common name Bighorn fleabane . It has been found only in the Bighorn Mountains of north-central Wyoming and southern Montana. Erigeron allocotus is a short, branching shrub rarely more than 18 cm (7 inches) tall. Leaves are 3-lobed. The inflorescence generally consists of 2 or 3 flower heads per stem, each head with sometimes as many as 40 small yellow disc florets and surrounded by a ring of up to 40 white or blue ray florets.