Bidens pilosa
Bidens bigelovii
bident poilu, cobbler's pegs, common beggar-ticks, hairy beggar-ticks, Spanish needle
Bigelow beggarticks, Bigelow's beggarticks, stickseed
petioles 10–30(–70) mm;
blades either ovate to lanceolate, 30–70(–120) × 12–18(–45) mm, or 1-pinnately lobed, primary lobes 3–7, ovate to lanceolate [linear], (10–)25–80+ × (5–)10–40+ mm [blades 2(–3)-pinnatisect], bases truncate to cuneate, ultimate margins serrate or entire, usually ciliate, apices acute to attenuate, faces pilosulous to sparsely hirtellous or glabrate.
petioles 5–25 mm;
blades rounded-deltate overall, 25–90+ × 15–35+ mm, (1–)2(–3)-pinnatisect, ultimate lobes lance-rhombic or ovate to lanceolate, 15–30(–50+) × 5–15(–30+) mm, bases truncate to cuneate, ultimate margins entire or ± serrate to incised, usually ciliolate, apices obtuse to acuminate, faces glabrous.
10–20(–90) mm.
(10–)30–50(–150+) mm.
turbinate to campanulate, 5–6 × (6–)7–8 mm.
± campanulate, 2.5–5+ × 1.5–3(–4) mm.
0 or (3–)5–8+;
laminae whitish to pinkish [yellowish], 2–3 or 7–15+ mm.
0 or 1(–5+);
laminae whitish, 1–3(–7) mm.
20–40(–80+);
corollas yellowish, (2–)3–5 mm.
13–25+;
corollas yellowish, 1–2 mm.
(7–)8–9(–13), lanceolate to oblanceolate, 4–6 mm.
8–13+, lanceolate, (3–)4–6+ mm.
(6–)7–9(–13) ± appressed, spatulate to linear bractlets (3–)4–5 mm, margins ciliate, abaxial faces usually hispidulous to puberulent.
of 8–13 usually spreading, narrowly lanceolate, oblanceolate, or subulate to linear bractlets 2–5 mm, margins entire, usually ciliate, abaxial faces usually glabrous.
usually borne singly, sometimes in open, ± corymbiform arrays.
usually borne singly, sometimes in open, ± corymbiform arrays.
outer red-brown, ± flat, linear to narrowly cuneate, (3–)4–5+ mm, margins antrorsely hispidulous, apices ± truncate or somewhat attenuate, faces obscurely 2-grooved, sometimes tuberculate-hispidulous;
inner blackish, ± equally 4-angled, linear-fusiform, 7–16 mm, margins antrorsely hispidulous, apices ± attenuate, faces 2-grooved, tuberculate-hispidulous to sparsely strigillose;
pappi 0, or of 2–3(–5), erect to divergent, retrorsely barbed awns (0.5–)2–4 mm.
outer red-brown, obcompressed, cuneate, 6–7 mm, margins not ciliate, apices truncate, faces 2-grooved, antrorsely tuberculate-hirtellous;
inner dark brown to blackish, ± equally 4-angled, linear-fusiform, 10–14 mm, margins not ciliate, apices ± attenuate, faces glabrous;
pappi of 2(–3), erect, retrorsely barbed awns (1–)2–4 mm.
= 24, 36, 48, 72.
Bidens pilosa
Bidens bigelovii
R. Ballard (1986) adopted a narrower circumscription of Bidens pilosa than that used here. He used: B. pilosa for plants with outer phyllaries 7–10, ray florets usually 0 (when present, laminae 2–3 mm), disc florets 35–75, pappi of 3(–5) awns 1–3 mm, and 2n = 72; B. alba for plants with outer phyllaries (8–)12(–16), ray florets 5–8 (laminae 5–16 mm), pappi of 2 awns 1–2 mm, and 2n = 48; and B. odorata for plants with outer phyllaries (6–)8(–12), ray florets 5–8 (laminae 3–18 mm), disc florets 12–61, pappi 0, or of 1–2 awns 1–3 mm, and 2n = 24.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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