Eupatorium cannabinum Linnaeus var. heterophyllum (Candolle) Kitamura; E. mairei H. Léveillé; E. wallichii Candolle var. heterophyllum (Candolle) Diels.

Herbs perennial, 1-2 m tall, or subshrublike, woody in median-lower part. Stems erect, brownish or purple-red, 1-2 cm in diam. at base, branched, and with corymbose synflorescence branches, white or sordid-white puberulent, more densely hairy on synflorescence branches and peduncles, glabrescent or sparsely hairy in middle-lower part by anthesis. Leaves opposite; median stem leaves large, 3-sect, -partite, or -lobate; petiole 0.5-1 cm; central lobe large, elliptic or lanceolate, 7-10 × 2-3.5 cm, base cuneate, apex acuminate; lateral lobes homomorphic with central lobe, smaller, or all stem leaves simple, oblong, elliptic-lanceolate, or ovate, abaxially densely gray-white tomentose, adaxially scabrid, white puberulent, both surfaces with dense yellow glands, pinnately veined, lateral veins 3-7-paired, abaxially prominent, margin rather regularly and deeply incised-crenate, not undulate; basal leaves withered by anthesis. Capitula numerous in terminal compound corymb; synflorescence to 25 cm in diam. Involucre campanulate, 7-9 cm; phyllaries 3-seriate, imbricate; outer phyllaries short, ovate or broadly ovate, ca. 2 mm, outside sparsely white puberulent; median and inner phyllaries elliptic, 8-9 mm; all phyllaries purple-red or purplish rose, apex obtuse. Florets white or reddish tinged; corolla ca. 5 mm, with sparse yellow glands. Achenes black-brown, elliptic, ca. 3.5 mm, 5-angled, with yellow glands, glabrous. Pappus white, ca. 5 mm. Fl. and fr. Apr-Oct.

One of us (Hind) follows King and Robinson (Monogr. Syst. Bot. 22: 1-581. 1987) in treating Eupatorium heterophyllum as a synonym of E. cannabinum. However, the others of us (Chen and Kawahara) prefer to treat E. heterophyllum as a distinct species. Whereas the leaves of E. cannabinum are irregularly lobed, with the margin serrate and undulate, those of E. heterophyllum are 3-sect, with the margin rather regularly and deeply incised-crenate and not undulate.

The stems or whole plant of Eupatorium heterophyllum are used medicinally for treating injuries and trauma.

Forests, forest margins, grasslands on slopes and in valleys; 1700-3000 m. Anhui, Gansu, Guizhou, Hubei, Shaanxi, Sichuan, ?Taiwan, Xizang, Yunnan [Nepal].