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(Last Modified On 6/17/2013)
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(Last Modified On 6/17/2013)
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Subspecific
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Bidens bipinnata var. cynapiifolia (H.B.K.) Maza
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PlaceOfPublication
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Anales Soc. Esp. Hist. Nat. 19: 275. 1890.
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Synonym
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Bidens cynapiifolia H.B.K., Nov. Gen. Sp. PI. 4: 235. 1820. TYPE: Cuba, Guanavaca, Bonpland 1562 (P).
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Description
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Erect, branched annual herb to 1.5 m tall; stems glabrate, drying conspicuously many-ribbed. Leaves opposite, pinnate or bipinnate, to 15 cm long (including petiole), leaflets apically acuminate or acute, basally cuneate to truncate, the margins mostly saliently toothed, ciliate in part, puberulent above and beneath with short hairs, venation pinnate; petiole slender, glabrate. Inflorescences solitary heads or a paniculate aggregation of heads involving upper portions of the plant; peduncle slender, to 12 cm long, glabrate; bracts small, compound; bracteoles when present solitary on the peduncle, linear. Heads radiate, sometimes inconspicuously so; involucral bracts in 2 dissimilar series, the outermost ca. 8, linear, expanded apically and basally, apically obtuse or rounded, glabrate, drying 1- or 3-nerved, ca. 5 mm long, the innermost lanceolate, glabrous, conspicuously dark-striate, the margins hyaline; receptacle pilose; paleas resembling the inner- most series of involucral bracts but narrower; ray florets several or wanting, the corollas yellow, the limb broad, drying strongly 5-7-nerved, apically entire or minutely emarginate, the tube flat, 1.5 mm long, glabrous; disc florets numerous, 5-6 mm long, the corolla tube 1 mm long, ?angled, the limb cylindrical, conspicuously dark-nerved, the 5 lobes glabrous with dark nerves, the anthers ca. 1.5 mm long, dark, the appendages dark, the basal auricles small or wanting; style branches flattened, lanceolate, dorsally pilose, with a slender apicule, the style base not expanded, immersed in the 1 mm tall, cylindrical nectary, the ovary compressed, the margins sparingly pubescent near the apex, the pappus of ca. 6 awns, each with a dark costa. Achene dark, ca. 12 mm long, slightly curved, angled, glabrous, with ca. 6 stout, erect, retrorsely barbed awns, those of the margin shorter, ascending-tomentose.
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Habit
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herb
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Note
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This erect species may be recognized by the usually bipinnate leaves which are not divided into narrow segments as in B. ostruthioides. The achenes are dimorphic; the majority of the innermost are glabrous but a few at the margin are densely tomentose.
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Distribution
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Variety cynapiifolia ranges through the Antilles and Central America. It is reported from South America and is adventive in Hawaii and in the Old World.
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Note
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It is a weedy species of lowlands. Bidens bipinnata L. var. bipinnata of the southeastern United States differs from var. cynapiifolia in having usually straight achenes with less differentiation between those of the margin and those of the center.
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Specimen
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CANAL ZONE: Mount Hope Cemetery, Standley 28804 (US). Farfan Beach area, Tyson & Blum 2610 (MO). cOCLE: Aguadulce, Pittier 4839 (US). PANAMA: Pefia Prieta, Heriberto 251 (US). E of Rio Tocumen, Standley 26646 (US). Near Juan Franco race track, Standley 27799 (US). Nuevo San Francisco, Standley 30741 (US). 2. Bidens ostruthioides (DC.) Schultz-Bip. in Seem., Bot. Voy. Herald 308. 1856.
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