Hayden’s mountaincrown

Aster haydenii Porter in F. V. Hayden, Prelim. Rep. U.S. Geol. Surv. Montana, 485. 1872; A. alpigenus (Torrey & A. Gray) A. Gray var. haydenii (Porter) Cronquist; Oreostemma alpigenum subsp. haydenii (Porter) Semple; O. haydenii (Porter) Greene

Stems 4–10(–15) cm. Basal leaf blades linear-oblanceolate to narrowly oblanceolate, (30–)40–90(–120) × (1–)2–4(–6) mm, apices acute. Cypselae strigose only distally.

Flowering (Jun–)Jul–Sep. Rocky slopes, talus, ridges, usually in alpine tundra, sometimes in clearings in pine-fir or pine-spruce woods, sometimes around lake edges or near snow banks, usually in drier sites; 2600–3300 m; Idaho, Nev., Oreg., Wyo.