Bidens radiata

Annual herb.

10–60 cm high.

The stem is often heavily branched, typically tawny or maroon and glabrate.

The leaves are opposite, short-petiolate and light (yellowish) green. The lamina is three-to-five-lobed or rarely simple. The lobes are lanceolate and coarsely serrate.

The capitula are solitary, erect, long-pedunculate and 1–2 cm wide. The phyllaries are in two rows. There are 7–14 outer phyllaries, which are foliaceous and 2–5 cm long, of varying lengths. The inner phyllaries are hyaline and mostly brown. There are only bisexual disc-flowers with yellow corolla in a capitulum.

The achene including its awns is 5–7 mm long, attenuate, compressed, with a retrorse-ciliate margin, lustrous and brownish purple. The pappus forms two retrorse-glochidiate 2–3 mm long awns.