Symphyotrichum welshii

Perennials, 30-100 cm colonial; rhizomes shallow and long, often relatively thick (those of the season each producing a distal rosette near the parent plant). Stems 1-2, ascending to erect (sometimes lax, sometimes reddish), glabrous or sparsely strigoso-villosulous distally (arrays). Leaves (adaxially green, abaxially pale green, sometimes glaucous) thin (proximal) to stiff (distal), margins serrulate (proximal) or entire or nearly so, ± revolute, scabrous, apices mucronulate or sometimes callous-pointed, faces glabrous; basal withering by flowering, petiolate (petioles narrowly winged, sheathing), blades oblanceolate to spatulate, 10-40+ × 4-9+ mm, bases attenuate, margins entire, apices obtuse; proximal cauline withering by flowering, sessile or winged-petiolate, blades lanceolate to oblanceolate, 50-150 × 8-11 mm, bases slightly clasping, margins sparsely serrulate, apices acute; distal sessile, blades linear to linear-lanceolate, 50-130 × 4-6 mm, gradually reduced distally, bases ± clasping, apices acute. Heads in open, slender, leafy, paniculiform or racemiform arrays, branches ascending. Peduncles 0.5-2 cm, scabro-villosulous, bracts linear, scabro-ciliolate. Involucres cylindro-campanulate, 4-7 mm. Phyllaries in 3-4 series, lanceolate (outer) to linear (inner), ± unequal, bases indurate, margins hyaline, erose, distally scabro-ciliolate to ciliolate, green zones ± foliaceous (outer) or lanceolate, apices acute to acuminate, sometimes purplish, faces glabrous. Ray florets 18-25; corollas pink to white, laminae 9-12 × 0.8-1.5 mm. Disc florets 23-60; corollas pale yellow, 3.8-6.4 mm, tubes shorter than funnelform throats, lobes narrowly triangular, 0.4-0.8 mm. Cypselae pinkish tan (nerves stramineous), obovoid, ± compressed, 0.8-1.6 mm, 3-5-nerved, faces sparsely strigillose; pappi white, 2.8-5.3 mm. 2n = 16.

Flowering Aug-Oct. Wet soils in dry areas, hanging gardens, seeps, wet ledges, stream banks; of conservation concern; 1300-2300 m; Ariz., Idaho, Mont., Utah, Wyo.