Symphyotrichum frondosum

Annuals or sometimes perennials, 5-140 cm. Stems 1-6+, decum­bent to erect (straight), glabrous. Leaves thin, margins entire (basal sometimes serrulate), sometimes ciliate or remotely scabrous, acute to ± obtuse, faces glabrous; basal withering by flowering, petiolate, blades oblanceolate to spatulate, 20-115 × 2-15 mm [cult.], bases attenuate; proximal cauline withering by flowering; cauline subpetiolate or sessile (distal), blades oblanceolate to linear, 10-80 × 1.5-10 mm, reduced distally, bases cuneate. Heads (radiate) in narrow, paniculiform to spiciform arrays, branches often in axils of nearly every leaf, ascending. Peduncles glabrous, bracts linear. Involucres narrowly campanulate, 5-9 mm. Phyllaries in 3-4 series, ± spreading, oblong-oblanceolate or -lanceolate to obovate, subequal to ± unequal, linear-lanceolate or linear (innermost), bases scarious, margins narrowly scarious, hyaline, erose, ciliolate, green zones (outer) foliaceous, (inner) lanceolate, apices obtuse to rounded, inner acute, mucronulate, faces glabrous. Ray florets 90-110 in 4-5+ series; corollas pink to pinkish white, laminae 1.5-2 × 0.1-0.2 mm (surpassing style branches, barely surpassing disc corollas; tubes ± 3 mm). Disc florets ± 37; corollas yellow, 4.4-5.2 mm, barely ampliate, tubes much longer than cylindric limbs, lobes lanceolate, ± 0.3 mm. Cypselae tan, obovoid, ± compressed, 2 mm, 2-3-nerved, faces strigillose; pappi white to yellowish, 6.3-7.5 mm. 2n = 14.

Flowering Aug-Oct. Moist, usually saline soils, summer-receding shores of lakes or ponds, vernally moist, alkaline bottoms, marshes, often in steppes; 10-2200 m; B.C.; Ariz., Calif., Colo., Idaho, Nev., N.Mex., Oreg., Utah, Wash., Wyo.; Mexico (Baja California).