2. Pluchea sagittalis (Lamarck) Cabrera, Bol. Soc. Argent. Bot. 3: 36. 1949.
翼茎阔苞菊 yi jing kuo bao ju
Conyza sagittalis Lamarck, Encycl. 2: 94. 1786; Gnaphalium suaveolens Vellozo; Pluchea suaveolens (Vellozo) Kuntze.
Herbs, perennial, erect, aromatic, coarse, 1-1.5 m tall, ca. 1.5 cm in diam. at base, much branched, branches densely tomentose. Stems conspicuously winged by decurrent leaves. Median leaves sessile, lanceolate to broadly lanceolate, 6-12 × 2.5-4 cm, thinly tomentose with viscid glands on surfaces, base attenuate, margin serrate, apex acuminate. Capitula 7-8 mm in diam. when fresh, to ca. 10 mm in diam. when dried, 4-5 mm, in compound terminal and axillary corymbs; peduncle 5-25 mm. Involucre hemispheric; phyllaries greenish brown, 4- or 5-seriate, outer ones widely elliptic to widely obovate, 1-2 × 1-1.5 mm, tomentose abaxially, margins ciliate, apex acuminate, inner lanceolate to linear-lanceolate, 3-4 × 0.4-0.6 mm, grading to glabrous. Receptacle flat, glabrous. Marginal florets numerous; corolla white, 3-3.5 mm, 3-lobed; achenes brown, cylindric, with 5 pale ribs, 0.6-0.8 × ca. 0.2 mm, with viscid glands; pappus white, slightly longer than corolla. Central florets 50-60; corolla white, purplish toward summit, 2.5-3 mm, sparingly glandular hairy at base; anthers acute at apex, shortly tailed at base; anthers and style exserted; achenes vestigial. Fl. and fr. Mar-Oct. 2n = 20.
Exposed flat areas, riverbeds, and swamps, often in large numbers in abandoned rice paddies and grassy fields. Naturalized in Taiwan [native to North and South America].