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(Last Modified On 6/17/2013)
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(Last Modified On 6/17/2013)
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Genus
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Verbesina L.
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PlaceOfPublication
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Sp. P1. 90. 1753
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Note
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TYPE: V. alata L.
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Description
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Herbs, shrubs or trees, rarely prostrate; stems glabrous or pubescent, in some species 2-6-winged by concaulescence of the petiole bases. Leaves alternate (in Panama) or opposite, dentate or lobed, rarely entire, mostly pubescent, sometimes scabrous; petioles sometimes winged or auricled, sometimes fused in part with the stem and forming wings. Inflorescences mostly several-many-headed, mostly open panicles; bractlets mostly minute, situated along the length or subtending
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Habit
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Herbs, shrubs or trees
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Description
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the heads and resembling involucral bracts. Heads large or small, mostly radiate, of various shapes; involucral bracts narrow in 2-6 graduated, more or less similar series, mostly much shorter than the paleas, the outermost bracts rarely the longest; paleas mostly resembling the involucral bracts but narrower and longer, the apices various, enfolding the disc florets; ray florets mostly yellow or white, the limb broad, denticulate, the tube relatively long, often pubescent, the ovary mostly fertile, laterally compressed; disc florets numerous, the corolla tubular, 5-merous, the tube short and mostly poorly demarcated from the limb, the anthers append- aged, basally obtuse or auriculate, the style branches dorsally pubescent, some- times apically penicillate with a short or long, deltoid, pubescent apical appendage, the two stigmatic lines often evident, the style base sometimes expanded, sessile on the cylindrical nectary, the ovary mostly fertile, ciliate, pubescent or glabrous, laterally compressed, lenticular, the pappus mostly of two, sometimes unequal, strigose awns. Achenes mostly black and broadly winged with two apical, strigose awns, the body or wings sometimes pubescent, the body sometimes tuberculate, the outermost achenes sometimes distinctive.
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Note
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A commonly represented but poorly understood American genus of more than 100 species, Verbesina is distinguished by its compressed, winged achenes with their two apical awns. The ovary is usually stipitate. Several attempts have been made to segregate various elements into distinct genera, but these have not been accepted, and in the current century, little has been done to clarify the taxonomy of the group as a whole. In Panama, all species are shrubs or trees with alternate leaves, and the involucral bracts are short and narrow in 2-3 series.
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Key
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a. Leaves mostly lobed. b. Stems glabrate ...... 2. V. gigantea bb. Stems copiously pubescent. c. Stems in inflorescence area winged by concaulescent petiole bases; leaves scabridulous above ...... 7. V. turbacensis cc. Stems not winged, or if so, only below the inflorescence area; leaves strongly scabrous above ...... 6. V. sublobata aa. Leaves denticulate or entire, not lobed. d. Leaves scabrous above ...... 6. V. sublobata dd. Leaves glabrate above. e. Heads more than 10 mm across; leaves large, more than 20 cm long and 5 cm wide ...... 1. V. fuscasiccans ee. Heads less than 10 mm across (excluding rays); leaves smaller, narrower. f. Involucral bracts acute; leaf midvein glabrous beneath ...... 3. V. guatemalensis ff. Involucral bracts obtuse or rounded; leaf midvein puberulent beneath. g. Involucral bracts less than 3 mm long; disc corollas glabrous; pubescence of young stems all appressed ...... 5. V. oerstediana gg. Some involucral bracts more than 3 mm long; disc corollas basally pilose; young stems with some loose, spreading hairs ...... 4. V. lanata
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Description
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Shrub to 2.5 m tall; stems stout, soft, finely striate, tomentose, glabrescent, light brown or yellowish. Leaves alternate, oblanceolate or obovate, to 30 cm long, 10 cm wide, apically short acuminate, basally acuminate into the winged petiole, the margins entire or denticulate, slightly revolute, veins ca. 9 on each side of the midvein, excurrent --and contrasting beneath, less prominent above, glabrate, sparingly pubescent on the veins beneath, shining above, drying dark brown or green and contrasting with the stem; petioles 5-6 cm long, broadly winged, abruptly contracted at the very base. Inflorescence a condensed, cymose panicle to 15 cm across, foliose bracts distributed through the branches; pedicels short or long (to 9 cm long), tomentulose with short, weak hairs. Heads ca. 2 cm across, globose; involucral bracts numerous, of two distinct forms, the outer series in 2-3 whorls, oblong, costate, ciliolate, with slightly expanded, green, rotund tips, the inner series in about 1 whorl, slightly longer, narrower, apically acute; paleas ca. 10 mm long, folded around the floret, the costa extended in a thin, ciliate wing, apically dark and the acute tip slightly outcurving; ray florets several, the corolla ca. 10 mm long, the tube tomentose, curved, the ligule narrow, apically entire or cuculate, the style branches linear, pubescent, the ovary fertile, laterally flattened, the margins corneous-ciliate, in part narrowly winged; disc florets numerous, ca. 11 mm long, the corolla shallowly lobed, ca. 7 mm long, the tube narrow, the base of the limb abruptly expanded, the anthers black, ca. 3 mm long, the appendages black, the basal auricles crumpled, the style branches fusiform, pubescent, the base expanded into a cylinder emersed in the urceolate nectary, the ovary fertile, flattened, ciliate but otherwise glabrous. Achene black, 5 mm long, flat, apically recessed, the margins ciliate and narrowly winged; carpopodium not evident; pappus of two short, stout strigose awns.
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Habit
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Shrub
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Note
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This species is distinctive in its large leaves which dry dark, contrasting with the light colored stems, in the nectary on the ovary which is large and urceolate, and in the ciliate margins of the achenes. The achene (immature in all material seen) resembles achenes of Spilanthes. It is likely that these margins expand and become broad wings with maturity. Verbesina fuscasiccans is known only from two collections taken on Cerro Jefe, a hill northeast of Panama City.
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Specimen
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PANAMA: E slope of Cerro Jefe, 2700 ft, Blum & Dwyer 2189a (MO). Campo Tres beyond Cerro Jefe, 700 m, Gioat 27091 (MO).
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