Bidens pilosa
Bidens tripartita
bident poilu, cobbler's pegs, common beggar-ticks, hairy beggar-ticks, Spanish needle
bident à trois divisions, three-lobed beggar-ticks, three-lobed beggars-ticks, three-part beggarticks, threelobe beggarticks, tickseed
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.
sessile or petioles 5–15(–35+) mm (± winged);
blades ± elliptic to ovate or lanceolate, 40–80(–150+) × 15–40(–60+) mm, sometimes laciniately 1-pinnatisect with 1–4+ lobes near bases, bases cuneate, margins entire or dentate to serrate, usually ciliate, apices acute to acuminate, faces glabrous or hirtellous.
10–20(–90) mm.
10–40(–80) mm.
turbinate to campanulate, 5–6 × (6–)7–8 mm.
campanulate to hemispheric or broader, (4–)5–7(–12) × (3–)6–12(–15+) mm.
0 or (3–)5–8+;
laminae whitish to pinkish [yellowish], 2–3 or 7–15+ mm.
usually 0, sometimes 1–5;
laminae orange yellowish, 4–8 mm.
20–40(–80+);
corollas yellowish, (2–)3–5 mm.
(5–)20–60(–150+);
corollas pale yellow to orange, (2–)3–4 mm (gradually ampliate, anthers usually pale).
(7–)8–9(–13), lanceolate to oblanceolate, 4–6 mm.
(6–)7–8(–13), elliptic-ovate to lance-ovate, (4–)6–9(–12) mm.
(6–)7–9(–13) ± appressed, spatulate to linear bractlets (3–)4–5 mm, margins ciliate, abaxial faces usually hispidulous to puberulent.
of (2–)6–7(–10) ± spreading, oblanceolate or lanceolate to linear, ± foliaceous bractlets or bracts 7–35(–60) mm, margins (entire or serrate) sometimes sparsely ciliate, abaxial faces hispidulous near bases, distally glabrous.
usually borne singly, sometimes in open, ± corymbiform arrays.
borne singly or in 2s or 3s.
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.
blackish to purplish or brown, ± flattened, sometimes weakly 3(–4)-angled, usually cuneate to linear, outer (3–)6–7(–10) mm, inner (4–)6–9(–11) mm, margins proximally antrorsely to patently, distally retrorsely, barbed, apices ± truncate to concave, faces ± 1-nerved, usually smooth, seldom notably tuberculate, glabrous or sparsely strigillose;
pappi 0, or of (1–)3–3(–4+) ± erect to spreading, retrorsely barbed awns (0.2–)2–3(–6) mm.
= 24, 36, 48, 72.
= 48.
Bidens pilosa
Bidens tripartita
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.)
Plants with cypsela mid-nerves strongly developed (cypselae more or less strongly 4-angled and, often, tuberculate) that are treated below as Bidens connata have been included in B. tripartita, perhaps rightly so. And some botanists have included (or advocated inclusion of) B. eatonii, B. heterodoxa, and/or B. infirma in B. tripartita, as well, perhaps rightly so.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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