Bidens leptocephala

Annuals, 10–25(–50) cm. Leaves: petioles 5–40 mm (usually hispido-ciliate); blades rounded-deltate overall, 15–50+ × 12–40+ mm, 1–2-pinnatisect, ultimate lobes ovate or lanceolate to linear, 3–25+ × (1–)2–3(–15) mm, bases ± cuneate, ultimate margins entire, ciliolate, apices acute to attenuate, faces glabrous or hirtellous. Heads usually borne singly, sometimes in open, ± corymbiform arrays. Peduncles (10–)30–80+ mm. Calyculi of 3–4(–6) ± appressed, subulate to filiform bractlets 1–3 mm, margins ciliolate, abaxial faces usually glabrous. Involucres ± cylindric, 2–3(–4+) × 1.5–2+ mm. Phyllaries 4–5(–7), oblong to lanceolate, (2–)3–4+ mm. Ray florets 0 or 2–3; laminae yellowish or whitish, 1–3 mm. Disc florets 5–13; corollas yellowish to whitish, 1.5–2 mm. Cypselae: outer red-brown, flat or unequally 4-angled, linear, 6–8 mm, margins not ciliate, apices somewhat attenuate, faces obscurely 2-grooved, antrorsely hispidulous toward tips; inner similar, blackish (sometimes with pale tips), ± equally 4-angled, linear-fusiform, 9–14 mm, margins not ciliate, apices attenuate, faces 2-grooved, antrorsely hispidulous (at least distally); pappi of 2(–3), erect, retrorsely barbed awns 1–3 mm.

Phenology: Flowering Sep.
Habitat: Along streams
Elevation: 900–1800 m

Distribution

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Ariz., N.Mex., Tex., Mexico (Baja California, Chihuahua).

Discussion

Selected References

None.

Lower Taxa

None.