Bighorn fleabane

Perennials, 10–18 cm; taprooted, caudices multicipital or branched. Stems erect to ascending (branched, brittle), hispido-hirsute (hairs brittle), minutely glandular. Leaves basal (often not persistent) and cauline; blades spatulate 15–30 × 1.5–4 mm, cauline gradually reduced distally (reduced to bracts on peduncles), margins usually 3-lobed (lobes linear to oblong-oblanceolate, about as wide as central portion of blades), sometimes 2-ternate or (cauline) entire, faces sparsely hispido-hirsute, minutely glandular. Heads usually 2–4. Involucres 4–5 × 6–9 mm. Phyllaries in 2–3 series, glabrous or sometimes sparsely hispid, densely minutely glandular. Ray florets 20–40; corollas white to bluish, sometimes drying pink, 3–6 mm, laminae not coiling or reflexing. Disc corollas 2.5–3.5 mm. Cypselae 2–2.3 mm, 2-nerved, faces sparsely strigose; pappi: outer of setae, inner of 12–20 bristles.

Flowering May–Aug. Dry, calcareous sites on cliff faces, ledges, talus slopes, ridgetops, rock outcrops, barren redbeds, sometimes with Utah juniper, mountain mahogany, or sagebrush; 1300–2300 m; Mont., Wyo.

The brittle, hispid vestiture, and multiple small heads (more than one per stem) with short rays of Erigeron allocotus are unusual among its putative relatives with 3-parted leaves.