Bidens pilosa |
Bidens amplissima |
|
---|---|---|
bident poilu, cobbler's pegs, common beggar-ticks, hairy beggar-ticks, Spanish needle |
Vancouver Island beggar-ticks |
|
Habit | Annuals [perennials], (10–)30–60(–180+)[–250] cm. | Annuals, (30–)50–120 cm. |
Leaves | 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 10–50 mm (winged); blades lance-elliptic to lance-oblong, 80–120(–250) × 30–100 mm (proximal usually with 1–2 lobes near bases), bases cuneate, margins laciniate to serrate, ciliate, apices acuminate, faces glabrous. |
Peduncles | 10–20(–90) mm. |
(10–)30–70+ mm. |
Involucres | turbinate to campanulate, 5–6 × (6–)7–8 mm. |
± hemispheric or broader, 6–10 × 18–25 mm. |
Ray florets | 0 or (3–)5–8+; laminae whitish to pinkish [yellowish], 2–3 or 7–15+ mm. |
6–11; laminae yellow, 4–8 mm. |
Disc florets | 20–40(–80+); corollas yellowish, (2–)3–5 mm. |
50–100+; corollas yellow, 2.5–3.5 mm. |
Phyllaries | (7–)8–9(–13), lanceolate to oblanceolate, 4–6 mm. |
13–16+, oblong to lance-ovate, 6–10 mm. |
Calyculi | (6–)7–9(–13) ± appressed, spatulate to linear bractlets (3–)4–5 mm, margins ciliate, abaxial faces usually hispidulous to puberulent. |
of 8–10 usually spreading, lance-linear to lanceolate, sometimes ± foliaceous bractlets or bracts 10–20(–75) mm, margins entire or incised, ciliate, abaxial faces ± hispid at bases. |
Heads | usually borne singly, sometimes in open, ± corymbiform arrays. |
in ± corymbiform arrays. |
Cypselae | 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. |
olivaceous green, ± flattened, unequally 3–4-angled, cuneate, outer 5–6 mm, inner 6–7 mm, margins antrorsely to retrorsely barbed, apices truncate to concave, faces weakly striate, glabrous or sparsely puberulent; pappi 0, or of (1–)3(–4) suberect, retrorsely barbed awns 2–4 mm. |
2n | = 24, 36, 48, 72. |
|
Bidens pilosa |
Bidens amplissima |
|
Phenology | Flowering year round. | Flowering Aug–Oct. |
Habitat | Disturbed, wettish sites | Seasonal wetlands, borders of ponds, lakes, streams, estuaries |
Elevation | 10–1900 m (0–6200 ft) | 0–100 m (0–300 ft) |
Distribution |
AL; AZ; CA; CT; FL; GA; KY; LA; MA; MD; MO; MS; NC; NM; PA; SC; TX; ON; QC; Mexico; Central America [Introduced, Europe]
|
WA; BC
|
Discussion | 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.) |
Of conservation concern. For decades, Bidens amplissima was known only from Vancouver Island; it is now known from southwestern British Columbia and northwestern Washington (F. R. Ganders et al. 2003). Occurrences in southern Manitoba and northwestern Nebraska may represent ephemeral introductions. The restricted natural range of B. amplissima has stimulated interest in it, the addition of it to rare plant lists, and the consideration of need for protected sites where it grows. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 21, p. 211. | FNA vol. 21, p. 216. |
Parent taxa | Asteraceae > tribe Heliantheae > subtribe Coreopsidinae > Bidens | Asteraceae > tribe Heliantheae > subtribe Coreopsidinae > Bidens |
Sibling taxa | ||
Synonyms | B. alba, B. alba var. radiata, B. odorata, B. pilosa var. radiata | B. cernua var. elata, B. elata |
Name authority | Linnaeus: Sp. Pl. 2: 832. (1753) | Greene: Pittonia 4: 268. (1901) |
Web links |