Shrubby Thoroughwort

Perennials or subshrubs (shrubs), 60–100 cm. Stems mostly sparse­ly puberulent (hairs upcurved or apically bent). Leaves mostly opposite, sometimes subopposite to alternate on distal ¹/3 of stems; petioles 2–8(–12) mm; blades lanceolate, mostly 3–8(–11) × 1–3 cm, bases rounded, margins entire or shallowly crenate, apices acuminate, abaxial faces eglandular, adaxial glabrous. Involucres 4.5–5.5 mm. Phyllaries: outermost narrowly lanceolate, glabrous, margins hyaline on proximal ²/3, eciliate. Corollas usually white, sometimes purple-tinged to yellowish, 2.5–3 mm, lobes glandular. Cypselae 1.8–2.8 mm, sparsely hispidulous. 2n = 20.

Eupatorium solidaginifolium A. Gray, Smithsonian Contr. Knowl. 3(5): 87. 1852