2. Chromolaena ivifolia (Linnaeus) R. M. King & H. Robinson, Phytologia. 20: 202. 1970.
Ivy-leaf false thoroughwort
Eupatorium ivifolium Linnaeus, Syst. Nat. ed. 10, 2: 1205. 1759 (as ivaefoliu); Osmia ivifolia (Linnaeus) Schultz-Bipontinus
Perennials or subshrubs, 50–150 cm. Stems erect, hispidulous to coarsely short-pilose. Petioles 0 or 0.5–1(–3) mm. Leaf blades linear-lanceolate to elliptic-lanceolate, 1.5–7 × 0.4–1.2 cm, margins denticulate to subentire. Heads usually 5–50+ in (terminal or lateral) corymbiform arrays. Involucres cylindric to campanulate, 5–6 mm. Phyllaries in (3–)4–5 series, apices of the inner ± spreading (pinkish purple, hyaline, petaloid, slightly expanded, truncate). Corollas light blue to purplish or reddish. 2n = 50.
Flowering Aug–Nov. Open woods, edges of fields and woods, roadsides, fencerows, ditches, other disturbed sites, flood plains, bottomlands, along streams; 0–50 m; Fla., La., Miss., Tex.; Mexico; West Indies; Central America; South America.