Acmella uliginosa - Marsh Para Cress

Marsh Para Cress is an annual herb 10–100 cm tall. Stems are erect, scrambling or sometimes creeping, green or reddish, hairless or hairy. Leaves are lanceshaped, narrowly ovate or ovate, 1–8.5 cm long, 0.3–3 cm wide, base flat, margins undulate to toothed, tip pointed to long-pointed, to acuminate, hairless to sparsely hairy. Leaft stalk is 0.2–3.2 cm long, narrowly winged. Flower-heads are yellow, solitary, radiate, 4–6 mm in diameter, 6–8 mm long, on stalks 1–6 cm long. Involucre is 2–4 mm long, of 1 series of green phyllaries. Ray florets only 4–7, pale yellow, 1.8–3.6 mm long, the ray 0.9–2.2 mm long. Disc florets many, yellow to orange- yellow, 1–1.6 mm long. Achenes are 1.2–1.8 mm long, ciliated, producing pappus of 2–4 bristles, 0.1–0.7 mm long. Marsh Para Cress is almost pantropic in distribution.