Ageratina altissima
Phytologia 19: 212. 1970.
Perennials, (30–)50–80(–120) cm (bases usually fibrous-rooted crowns, sometimes rhizomatous). Stems ascending to erect, sometimes semiscandent, puberulent (hairs minute, crisped). Leaves opposite; petioles (5–)10–30(–50) mm; blades usually deltate-ovate to ovate or broadly lanceolate, sometimes ovate-lanceolate, 4–11(–13) × 2.5–8(–9) cm, bases usually rounded to truncate or obtuse, sometimes cordate, margins coarsely and doubly incised-serrate, apices usually acuminate. Heads clustered. Peduncles 1–5 mm, puberulent. Involucres 4–5 mm. Phyllaries: apices acute, abaxial faces glabrous or sparsely and finely villous. Corollas white, lobes sparsely short-villous. Cypselae glabrous.
Distribution
North America.
Discussion
Varieties 2 (2 in the flora).
Selected References
None.
Key
| 1 | Phyllaries 3–5 mm, apices not cuspidate | Ageratina altissima var. altissima |
| 1 | Phyllaries 4–7 mm, apices cuspidate to acuminate | Ageratina altissima var. roanensis |