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.

It is a tropical plant. It grows in regions with an average temperature of 26°C. The rainfall is 2,700 mm per year. The relative humidity is 85%. It is damaged by frost.

The leaves are eaten raw or steamed and eaten. The raw leaves are used to flavour salads. The spicy taste is destroyed with cooking. The flowers are also used as a vegetable. They are eaten boiled green or in dried forms. Caution: The leaves when chewed can cause numbing of the mouth. (The chemical is called spilanthol)

It can be grown from seed. It can also be grown from shoots or cuttings. For seed germination a temperature above 21°C is needed.