Bidens heterosperma

A. Gray

Smithsonian Contr. Knowl. 5(6): 90. 1853.

Treatment appears in FNA Volume 21. Treatment on page 209. Mentioned on page 207.

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.

Phenology: Flowering Sep–Oct.
Habitat: Seeps on rocky slopes
Elevation: 1500–2800 m



Ariz., Colo., N.Mex., Mexico (Baja California, Chihuahua, Sinaloa, Sonora).


Selected References


Lower Taxa