Erigeron rydbergii

Perennials, 2.5-6 cm; taprooted, caudex branches relatively short, thick. Stems erect, finely hirsutulous to villosulous, eglandular. Leaves mostly basal (persistent); blades linear-oblanceolate to narrowly spatulate, 10-50 × 1-3 mm, cauline mostly on proximal ¹ / 2 of stems, reduced distally, margins entire (apices obtuse to rounded), abaxial faces glabrous, adaxial glabrous or sparsely villous, eglandular. Heads 1. Involucres 5-6 × 7-12 mm. Phyllaries in 2-3 series, densely and finely hirsuto-villous (hairs without colored cross walls), minutely and inconspicuously glandular. Ray florets 15-35; corollas usually bluish to purplish, rarely white, 6-9 mm, laminae coiling. Disc corollas 3.7-5 mm. Cypselae 1.8-2 mm, 2-nerved, faces sparsely strigose; pappi: outer of setae, inner of 15-20 bristles.

Flowering Jun-Aug. Open subalpine to alpine slopes; 2000-3200 m; Idaho, Mont., Wyo.