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(Last Modified On 6/17/2013)
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(Last Modified On 6/17/2013)
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Species
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Bidens pilosa L.
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PlaceOfPublication
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Sp. P1. 832. 1753.
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Note
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TYPE: America, Herb Linn. (LINN 975.8).
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Synonym
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Bidens leucantha Willd., Sp. P1. 3: 1719. 1803.
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Description
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Erect, branched, annual herb to 1.5 m tall; stems angled, green, glabrate. Leaves opposite, 3 (-5) -foliolate, the leaflets to 7 cm long, ovate, apically acute, obtuse or acuminate, basally acuminate to truncate, the margins serrate, pinnately veined, reticulate beneath, puberulent on both sides, the hairs longer beneath; petiole slender, basally expanded and slightly clasping, the basal margins ciliate. Inflorescence mostly of several loosely aggregated, terminal heads; peduncle to 5 cm long, slender, erect, glabrate or puberulent, drying angled. Heads, radiate or discoid; involucre 5-8 mm high, the bracts in 2 dissimilar series, the outer series narrow, herbaceous, expanded basally and apically, only the basal expansion imbricate, 1-nerved, the apex ciliate, obtuse or rounded, the inner series ovate, indurate, obscurely or conspicuously several-nerved, the margins scarious-hyaline; receptacle flat; paleas wanting; ray florets several in 1 series or wanting, the corolla white or yellow, 7-12 mm long, the tube short, dorsiventrally flattened, ciliate on the margins, the limb ovate, sometimes broadly so, 2-notched, drying prominently 5-7 nerved, the style present or not, the ovary sterile, faintly trigonous; disc florets numerous, the corolla yellowish or greenish, 3-4 mm long, sparingly stipitate-glandular, the tube ca. 1 mm long, the limb narrowly obconical, the 5 lobes dorsally pilose, the anthers black, ca. 2 mm long, with ovate, eglandular appendages, the basal auricles indistinct, the style branches flattened, lanceolate, pilose, with a linear apicule, the style base not expanded, immersed in a 0.5 mm long, cylindrical nectary, the ovary compressed, weakly 4-angled, pilose with ascending hairs, glandular-stipitate near the apex, the pappus of two stout retrorse-strigose awns. Achene black, 15-22 mm long, linear, strongly angled, glabrous but with a few stiff, short, ascending hairs near the apex; carpopodium oblique, stramineous, puberulent; pappus of 2-3 stiff, retrorsely strigose awns (aristae ), ca. 3 mm long.
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Habit
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herb
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Distribution
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This species is native to the Caribbean region but is widespread as a weed of tropical and warm temperate lands.
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Note
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It may be recognized by its usually trifoliolate, serrate-margined leaves and by its black, straight, 3-awned, linear achenes. The awns are erect. It is- the only species of Bidens in Panama which sometimes produces white-rayed heads.
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Common
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Spanish Needles
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Note
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A number of varieties and forms have been recognized under this species, T. Melchert has indicated that probably none of these is of taxonomic significance. Panamanian plants which have reduced rays (most collections) may be referred to as f. minor Sherff.
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Specimen
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BOCAS DEL TORO: Above railroad station at mi 7.5, Croat & Porter 16426, 16438 (both MO). Changuinola, Stork C36 (UC). Without definite locality, Wedel 158 (GH, MO). CANAL ZONE: Pedro Miguel, Heriberto 103 (US). Monte Lirio, Maxon 6850 (US). Ancon Hill, Piper 5545 (US). Juan Mina, Piper 5706 (US). Balboa, Standley 27004 (US). Frijoles, Standley 27630 (US). Gamboa, Standley 28473 (US). France Field, Standley 28592 (US). Near Summit, Standley 29995 (US). Darien Station, Standley 31533 (US). Near Salamanca Hydrographic Station, Rio Pequeni, Woodson et al. 1610 (US). Darien Station, MacBryde 2683 (F, US). CHIRIQUI: 19 km W of Puerto Armuelles, 500 m, Busey 608 (MO). El Hato del Volcan, Croat 10404 (MO). Between Boquete and Monte Rey, Croat & Porter 15649 (MO). Cerro Pando, D'Arcy & D'Arcy 6321 (MO). Roadside W of Cerro Pando, ca. 6000 ft, D'Arcy & D'Arcy 6636 (MO). Near Boquete, 3300-4200 ft, Lewis et al. 422 (MO). Valley of the upper Rio Chiriqui Viejo near Monte Lirio, 1300-1900 m, Seibert 233 (MO). Collins Finca, Boquete District, 6000 ft, Ebinger 697 (F). Interam. Hwy. at Concepcion, King 5287 (UC, US). Near Boquete, Maurice 686 (US). Alto Boquete, Partch 69-135 (MO). Cerro Punta, Sawyer, 1 March 1967 (MICH). Upper Rio Chiriqui Viejo near Monte Lirio, Seibert 232 (MO), 233 (CIH, NY). Bambito, 5600 ft. Tyson 5635 (MO). COCLE: El Valle de Anton, D'Arcy & D'Arcy 6716 (MO). PANAMA2: S slopes of Cerro Azul, King 5245 (UC, US). Las Sabanas, Paul 18 (US). Cerro Jefe, Tyson et al. 4299 (MO). VERAGUAS: 15 mi N of Calobre, 644 m, Luteyn 1449 (MO).
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