Spanish Needles

Bidens bipinnata is probably native in eastern Asia and introduced in South America, Europe, Asia, and Pacific Islands.

Annuals, (15–)30–100(–150+) cm. Leaves: petioles 20–50 mm; blades rounded-deltate to ovate or lanceolate overall, (20–)30–70+ × (20–)30–60+ mm, (1–)2(–3)-pinnatisect, ultimate lobes obovate or lanceolate, 15–45+ × 10–25+ mm, bases truncate to cuneate, ultimate margins entire, sometimes ciliolate, apices rounded to acute or attenuate, faces usually glabrous, sometimes hirtellous. Heads usually borne singly, sometimes in ± corymbiform arrays. Peduncles (10–)20–50(–100) mm. Calyculi of (7–)8(–10) linear bractlets 3–5 mm, ± appressed, margins ciliate, abaxial faces usually glabrous. Involucres ± campanulate, 5–7 × 3–4(–5) mm. Phyllaries 8–12, lanceolate to linear, 4–6 mm. Ray florets 0 or 3–5+; laminae yellowish or whitish, 1–2(–3) mm. Disc florets 10–20(–30+); corollas yellowish to whitish, 2–3 mm. Cypselae red-brown, outer weakly obcompressed, 7–15 mm, inner ± 4-angled, linear to linear-fusiform, 12–18 mm, margins not ciliate, apices ± attenuate, faces 2-grooved, often tuberculate-hispidulous; pappi of (2–)3–4, erect to divergent, retrorsely barbed awns 2–4 mm. 2n = 24, 72.

A cosmopolitan weed.

900-2300 m

Bidens bipinnata var. biternatoides Sherff