Boltonia diffusa Elliott

Plants 30–200 cm; basal offshoots and stolons present or absent. Stems erect (slender). Leaf blades linear to narrowly lanceolate; cauline 25–115 × 3–17 mm, bases not decurrent. Heads 30–100+ in paniculiform arrays, primary branches mostly spreading; only proximal bracts leaflike, others reduced, linear to linear-oblanceolate or subulate, 8–55 × 1–6 mm. Peduncles 5–185 mm; bracts 3–10, linear to linear-oblanceolate or subulate, 2–10(–15) mm. Involucres 2.5–3 × 2.5–6 mm. Phyllaries in 4–6 series, subulate or linear-oblong, unequal, 6–8 merging down peduncles; outer 1–1.8 × 0.3–0.6 mm; inner 1.8–3 × 0.3–0.7 mm. Ray florets 20–40; corolla white to lilac, laminae 3–6.3 mm, tubes 0.6–1.35 mm. Disc florets 50–135; corollas 1.2–2.5 mm. Cypselae obovoid, 1.6–2.5 × 1–1.6 mm, wings 0.2–0.4 mm wide; pappus awns 0.3–0.7 mm.