飞机草 fei ji cao

Eupatorium odoratum Linnaeus, Syst. Nat., ed. 10, 2: 1205. 1759.

Herbs, perennial. Rhizomes robust, procumbent. Stems erect, 1-3 m tall, striate; branches robust, often opposite, spreading and horizontal, rarely alternate forming an acute angle with stem; stems and branches densely fulvous tomentose or shortly pubescent. Leaves opposite; petiole 1-2 cm; blade abaxially pale, adaxially green, ovate, triangular, or ovate-triangular, 4-10 × 1.5-5 cm, rather thick, both surfaces scabrid, villous with red-brown glands, abaxially and on veins more densely so, basally 3-veined, lateral veins fine, abaxially slightly raised, base truncate or shallowly cordate, margin sparsely coarsely and irregularly crenate or entire, or serrate on one side, or with one coarse tooth or 3-fid on each side, apex acute; leaves below synflorescence small, often entire. Synflorescence of numerous or few capitula in corymbs or compound corymbs; peduncle thick, densely shortly pubescent. Capitula ca. 20-flowered; involucre cylindric, ca. 10 × 4-5 mm; phyllaries 3- or 4-seriate, imbricate, outer phyllaries ovate, ca. 2 mm, puberulent, apex obtuse, median and inner phyllaries straw-colored, oblong, 7-8 mm, broadly 3-veined, eglandular, apex acuminate; corollas white or pink, ca. 5 mm. Achenes black-brown, ca. 4 mm, 5-ribbed, eglandular, sparsely white adpressed setuliferous along ribs. Fl. and fr. Apr-Dec. 2n = 58, 60.

Forest margins, roadsides, open disturbed land. Introduced in Hainan during World War II; naturalized in Fujian, Hainan, and Yunnan [native to Mexico; widely naturalized in tropical Asia].

Chromolaena odorata is a competitive and pernicious weed.