Bidens pilosa

Erect annual herb to 1 m high; stems glabrous to densely hairy. Leaves ovate to broad-ovate in outline, mostly 6–12 cm long and 1–4 cm wide, usually trifoliate or pinnate, sometimes simple, terminal leaflet largest, more or less glabrous to appressed-pubescent, margins toothed; petiole to c. 4 cm long, slightly winged. Capitula 5–15 mm diam.; outer involucral bracts herbaceous, linear, 4–8 mm long; inner bracts lanceolate, 5–10 mm long. Ray florets present, (2–)4–8 mm long, ephemeral, white or pale yellow, or absent. Cypselas linear, 6–12 mm long, curved, 4-angled, antrorsely barbed all over or only on ribs; pappus of 2 or 3 awns, 2–4 mm long, erect or spreading.