4. Erigeron oreophilus Greenman, Proc. Amer. Acad. Arts. 41: 257. 1905.
Achaetogeron pringlei Larsen; Erigeron delphiniifolius Willdenow var. oreophilus (Greenman) Cronquist
Perennials, (8–)25–90 cm; taprooted, caudices woody. Stems erect, sparsely hirsuto-villous (hairs 0.6–2 mm) or glabrous, densely stipitate-glandular (at least on distal 1 / 2 , glands relatively large, capitate). Leaves basal (sometimes withering by flowering) and cauline; basal blades 15–60 × 8–37 mm, cauline gradually reduced distally, margins deeply pinnatifid, lobes 2–4(–5) pairs, faces usually glabrous, stipitate-glandular. Heads (1–)5–25(–50) in loosely corymbiform arrays. Involucres 4.5–5.5 × 8–12 mm. Phyllaries in 3–4 series, glabrous or sparsely hirsute, densely stipitate-glandular. Ray florets 75–130; corollas white, 8–14 mm, laminae reflexing. Disc corollas 2.8–3.5 mm. Cypselae 1–1.2 mm, 2-nerved, faces sparsely strigose; pappi: outer of setae, inner (readily falling) of (8–)10–12 bristles. 2n = 18.
Flowering Jul–Oct(–Nov). Open, rocky habitats, cliff ledges or crevices, grassland, chaparral, oak, pine, pine-fir; 1100–2800(–3100) m; Ariz., N.Mex.; Mexico (Chihuahua, Durango, Sonora).
Erigeron oreophilus is similar to E. neomexicanus in its perennial habit, typically pinnatifid leaves, white, reflexing rays, and 10–12 readily falling pappus bristles; it has a vestiture of dense, viscid, stipitate glands and sparse, spreading, nonglandular hairs.