Acmella oleracea (L.) R.K.Jansen

Herbs, annual. Stems decumbent to usually erect, not rooting at nodes, green to red, glabrous. Petiole 2-6.4 cm, glabrous to very sparsely pilose, narrowly winged; leaf blade broadly ovate to deltate, 5-10 × 4-8 cm, usually glabrous on both surfaces, base truncate to shortly attenuate, margin dentate, apex shortly acuminate to usually acute. Capitula discoid, 10.5-23.5 × 11-17 mm; peduncles 3.5-12.5 cm, glabrous to very sparsely pilose; phyllaries 15-18, 3-seriate, herbaceous, entire to sinuate, sparsely ciliate, those of outer series 5 or 6, 5.8-7.3 × 2.1-2.8 mm, usually narrowly ovate to lanceolate or sometimes ovate, acute; receptacle 8.3-21.5 × 3.5-8.5 mm. Florets 400-600; corollas 2.7-3.3 mm, yellow, 5-lobed; tube 0.5-0.7 × 0.2-0.4 mm; lobes 0.3-0.6 × 0.2-0.4 mm; stamens 1.4-1.7 mm. Achenes 2-2.5 × 0.9-1.1 mm, moderately to densely ciliate with straight-tipped hairs; pappus of 2 subequal bristles, longer one 0.5-1.5 mm, shorter one 0.3-1.3 mm. Fl. Apr-Jul. 2n = 52, 60, 78.