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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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Rumfordia DC.
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PlaceOfPublication
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Prodr. 5: 549. 1836.
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Note
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TYPE: R. floribunda DC.
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Description
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Large branching herbs or weak shrubs to 3 m tall; stems glabrescent, drying striate. Leaves opposite, simple, apically acuminate, basally acute, obtuse, rounded or hastate, often contracted into wings on the petiole, the margins serrate or crenate, sometimes with one or two prominent lobes or angles, the niidvein dividing into 3 principal veins well above the base, the minor venation mostly pinnate, puberulent with weak, multicellular, uniseriate hairs; petioles mostly distinct, broadly winged apically or for the full length, the wings sometimes produced into basal auricles. Inflorescences mostly well differentiated open panicles; foliaceous bracts subtending the lowermost two or three branches; minute leaflike or scalelike bractlets present at the base of minor branches and pedicels. Heads radiate, sometimes showy; involucral bracts in two dissimilar series, the outer herbaceous, ca. 5, the innermost smaller, narrow, only slightly enfolding the outer achenes; ray florets numerous in one series, the ligules yellow, broad or narrow, entire or 1-3-notched, sometimes glandular or pubescent, the tube elongate, the ovary fertile; disc florets much more numerous than the rays, the corolla limb tubular, 5-lobed, basally expanded, pubescent or glandular, the tube slender, sometimes as long as the limb, the anthers light or dark, long-exserted, apically appendaged, basally subauriculate, the style branches slender, glabrate, the ovary fertile. Achenes obovoid, glabrous, slightly compressed; pappus wanting.
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Habit
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herbs or weak shrubs
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Distribution
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A genus of about a dozen species ranging from Mexico to Panama
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Note
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Rumfordia is distinguished by its large outer involucral bracts and by the elongate tubes of the corollas. Only one species occurs in Panama. Rumfordia is closely related to Tetragonotheca of the southern United States which differs in having more strongly, angled achenes, relatively shorter corolla tubes, and the fixed number of 4 outer involucral bracts. Both Tetragonotheca and Rumfordia are closely related to Polymnia, differing mainly in having both ray and disc florets with fertile ovaries. The elongate corolla tubes of Rumfordia are unusual but such tubes are also found in Sclerocarpus. Rumfordia and Sigesbeckia lack verrucose hairs and it is likely that these genera are best placed in association with Polymnia and other Melampodiinae.
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