Ageratina aromatica (L.) Spach

Intergrades (probable hybrids) between Ageratina aromatica and A. altissima were identified by A. F. Clewell and J. W. Wooten (1971) over a broad area of their sympatry. They also found intergrades between A. aromatica and A. jucunda where their ranges meet.

Perennials, 30–80(–100) cm. Stems erect, villous-puberulent. Leaves opposite; petioles 1–8(–12) mm; blades narrowly to broadly deltate to nearly ovate or lanceolate, 2–7(–9) × 1.5–4 cm, (usually subcoriaceous) bases rounded or truncate to barely cuneate or subcordate, margins usually crenate, sometimes crenate-serrate to dentate or subentire, apices acute to obtuse, faces minutely pilose. Heads clustered. Peduncles 2–9 mm, densely and closely puberulent. Involucres 3.5–5 mm. Phyllaries: apices acute, abaxial faces puberulent to villous-puberulent. Corollas white, lobes sparsely villous. Cypselae usually glabrous or sparsely puberulent (near apices), rarely hirtellous on angles. 2n = 34.

Eupatorium aromaticum Linnaeus, Sp. Pl. 2: 839. 1753; E. latidens Small