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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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Tithonia rotundifolia (Miller) Blake
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PlaceOfPublication
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Contr. Gray Herb. 52: 41. 1917.
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Synonym
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Tagetes rotundifolia Miller, Gard. Dict., ed. 8. 1768. TYPE: Chelsea Garden, Miller (BM).
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Description
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Large, shrublike, short-lived herb to 4 m tall; stems drying green or brown, striate, puberulent. Leaves to 35 cm long, ovate or cuneiform, sometimes broadly so, apically and basally acuminate, entire or 3-5-lobed, the lobes ovate with obtuse sinuses, the margins mostly crenate, scabridulous above with short stout hairs and occasional glands, softly pubescent beneath with stout, arching, verrucose hairs; petiole elongate, winged in the upper portion, basally clasping the stem. Inflorescence of solitary or clustered terminal flowers on elongate apically expanded, striate, puberulent peduncles 8-20 cm long with one or more large or small foliaceous bracts along their length. Heads large and showy, radiate; involucral bracts 20-30 mm across, in several subequal series, 10-15 mm long, indurated, many nerved, whitish puberulent, the outermost slightly longer, acute, the innermost obtuse or short acuminate; paleas hyaline, dorsally puberulent, completely enclosing the achene; ray florets several in one series, the ligules yellow or orange, 2-3 cm long, minutely 1-2-notched, puberulent outside, drying with conspicuous veins, staminode sometimes present, the ovary abortive, ca. 3 mm long, flat but faintly 3-angled, glabrous, the pappus of scalelike awns and a ring of short hairs; disc florets numerous, ca. 10 mm long, the corolla tubular, pubescent on the veins outside, the lobes yellow, cuculate with the thickened margins, dorsally papillose-pubescent, the anthers black, 4 mm long, the appendages yellow, expanded and slightly enfolded, the basal auricles connate, the filaments flattened, minutely puberulent, the ovary fertile, the style branches flattened, ventrally puberulent with a tuft of hairs at the base of the short, narrow appendage, the style base slightly expanded, the nectary stipitate, crateriform with irregular margins, enclosing the base of the style. Achene body 5-6 mm long, flat, the endocarp blackish, appearing gray under the weak, white, ascending indumentum; carpopodium inconspicuous; pappus of two sturdy, persistent 3-5 mm long awns and a ring of broad, distinct, 2-3 mm long scales.
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Habit
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shrublike, short-lived herb
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Note
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The acute outer involucral bracts which equal or slightly exceed the inner series are a good feature distinguishing this species from the larger-flowered, longer-lived Tithonia diversifolia.
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Distribution
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native of Central America and the Antilles and has the widest native range of any member of the genus.
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Specimen
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CHIRIQUI: 1 km W of La Repressa, Quebrada Guanabanito, Busey 477 (MO). COCLE: 10 mi E of Nata at Rio Grande, Tyson 5218 (MO). HERRERA: Near Chitre, Allen 1106 (MO). PANAMA: Isla Taboga, Allen 1286 (MO). 3 mi beyond turnoff to Cerro Azul, Croat 13008 (MO). Hills between Capira and Potrero, 80-130 m, Dodge & Hunter 8647 (MO). Cerro Azul, Dwyer 2182 (MO). Road to Cerro Azul, 500 ft, Tyson 6330 (MO).
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Tag
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Project Name
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Tag
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