White Cushion Fleabane

Erigeron disparipilus is similar to E. nanus but less variable. The range of E. disparipilus barely contacts that of E. nanus in southeastern Idaho and they have different ecologies; blue rays of E. disparipilus in Owyhee County may indicate that hybridization occurs.

Perennials, 3–12 cm; taprooted, caudices branched. Stems erect, densely pilose to hirsute or villoso-hirsute (hairs usually slightly ascending, loose, often mixed in orientations, of unequal lengths, relatively thin-based), eglandular. Leaves mostly basal (persistent), (petioles prominently ciliate, hairs thick-based, spreading); blades linear to linear-oblanceolate, 20–40 × 1–2 mm, margins entire, faces finely hirsute, eglandular; cauline reduced, restricted to proximal ¹ / 3 of stems. Heads 1. Involucres 5–7 × 8–16 mm. Phyllaries in 2–3 series, hirsute to hirsuto-strigose, minutely glandular. Ray florets mostly 30–60; corollas usually white, sometimes fading pink, rarely blue, 5–10 mm, laminae loosely coiling. Disc corollas 2.8–4 mm. Cypselae 1.8–2.2 mm, 2-nerved, faces moderately, loosely strigose; pappi: outer of setae, inner of 15–25 bristles.

Erigeron disparipilus is a North American species of flowering plants in the family Asteraceae known by the common name white cushion fleabane. It is found in Oregon, Washington, and Idaho in the northwestern United States.

Erigeron disparipilus is a perennial herb up to 12 cm (4.8 inches) tall. Most of the leaves are generally clustered around the bases of the stems. Each stem generally has only one flower head, with 30–60 white ray florets surrounding numerous yellow disc florets.