1. Calyptocarpus vialis Lessing, Syn. Gen. Compos. 221. 1832.
金腰箭舅 jin yao jian jiu
Herbs, perennial. Stems prostrate, branched, rooting at nodes, densely appressed strigillose. Petiole 3-8 mm, narrowly winged toward blade, margin ciliate; leaf blade ovate to broadly ovate, to 35 × 25 mm, both surfaces densely appressed strigillose, base attenuate, margin crenate-serrate, apex acute, apiculate. Capitula axillary, solitary, subsessile; peduncle to 15 mm; involucre narrowly oblong-oblanceolate, 6-7 × 2.5-3.5 mm; phyllaries 4, 2-seriate, concave, lanceolate, 6-7 × 3-3.5 mm, apex acuminate and apiculate; paleae hyaline, narrowly elliptic, 3.5-4.8 × 0.8-1 mm. Ray florets 3-8, yellow; corolla 4.5-6.2 × 1.4-1.8 mm, 3-toothed; achenes oblanceolate, 3.5-4 × 1.7-2 mm; pappus of 2 ascending divergent awns, 1.2-2.4 mm. Disk florets 3-8; corolla 2.6-3.6 mm, apex 2- or 3-toothed or entire, densely papillose within; achenes similar to those of ray florets but slightly narrower and thicker, sometimes 3-angled, 1.1-1.7 mm wide, evidently muricate. 2n = 24.
Naturalized weed of roadsides. Taiwan [native to Cuba, Mexico, and United States].