Bidens heterosperma
Smithsonian Contr. Knowl. 5(6): 90. 1853.
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 redbrown 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
Distribution
Ariz., Colo., N.Mex., Mexico (Baja California), Mexico (Chihuahua), Mexico (Sinaloa), Mexico (Sonora)
Discussion
Selected References
None.