Plants (10-)60-200 cm. Stems usually simple, sometimes branched proximally. Heads 15-120, in open, diffuse arrays, secund on primary branches longer than peduncles. Involucres (5.2-)6-6.9 mm. Phyllaries 25-45(-62), subulate to lanceolate, narrow, green zones narrowly lanceolate. Ray florets 17-30(-45) in 1 series; laminae lavender to blue, (3.5-)4.5-7 × 0.9-1.3 mm, longer than pappi, drying in 3-5 coils (apices shallowly lobed). Disc florets (20-)33-50; corollas 3.7-4.5(-5) mm. Cypselae (1.3-)1.7-2.5(-2.9) mm; pappi (3-)3.5-4.6 mm. 2n = 10. Flowering Jul-Nov(-Feb). Marshy habitats, often weedy, roadsides, lawns, waste places; 0-1500 m; Ala., Ark., Kans., La., Miss., Nebr., N.Mex., Okla., Tenn., Tex.; Mexico (Chihuahua, Coahuila, Tamaulipas).