Rocky Mountain Beggarticks

Annuals, (5–)10–30(–60+) cm. Leaves: petioles 3–20 mm; blades usually rounded-deltate overall, 10–30+ × 5–20+ mm, 1–2-pinnatisect, ultimate lobes linear to filiform, 2–25 × 0.5–1(–2) mm, bases obscurely cuneate, ultimate margins minutely, if at all, ciliate, apices obtuse to acute (sometimes apiculate), faces glabrous or sparsely hirtellous. Heads usually borne singly. Peduncles 10–50(–100) mm. Calyculi of (1–)3(–5), appressed to spreading, linear bractlets (1–)3(–4) mm, margins minutely, if at all, ciliate, abaxial faces usually glabrous, sometimes sparsely hispidulous. Involucres ± cylindric, 3.5–5 × (1–)2–3 mm. Phyllaries 5–6, lance-elliptic to lanceolate, 2.5–4(–5) mm. Ray florets 0 or 1–3+; laminae yellowish, 1–4 mm. Disc florets 5–9(–13); corollas yellowish, 1–1.5 mm. Cypselae red-brown to blackish (sometimes with lighter blotches), outer ± obcompressed and linear, 3–5 mm, margins not ciliate, apices ± truncate, faces 2-grooved, usually glabrous; inner similar, ± equally 4-angled, linear-fusiform, (6–)7–12 mm, apices ± attenuate; pappi 0, or of 2(–3) spreading to divergent, retrorsely barbed awns 1–2 mm.

Bidens heterosperma, the Rocky Mountain beggarticks, is a North American species of flowering plant in the family Asteraceae. It is native to northwestern and north-central Mexico (Baja California, Chihuahua, Sinaloa, Sonora) and the southeastern United States (Colorado, New Mexico, Arizona).

Bidens heterosperma is an annual herb up to 60 cm (2 feet) tall. It usually produces flower heads one at a time, each containing both yellow disc florets and yellow ray florets. The species usually grows in wet seeps on mountain slopes.