Herb or weak shrub to 2.5 m tall; stems soft, finely striate, sometimes with conspicuous, elongate lenticels, soon glabrate, unwinged. Leaves alternate, lanceolate or oblanceolate, subentire, the margins sometimes irregularly sinuate, apically acute or acuminate, basally narrowed to the base, darker above and scabridulous, punctate with short white hairs, the lateral venation not prominent, beneath velutinous with small verrucose hairs; petiole wanting, auricles rotund, small but manifest. Inflorescence a many-headed, flat-topped, open panicle to 30 cm across; bracts becoming spatulate upwards, the bractlets linear, variously situated but sometimes subtending the head and resembling involucral bracts; peduncles angled, pubescent. Heads radiate or discoid, to 9 mm long (in Panama); involucral bracts appressed, ciliate, to 6 mm long, indurate and cuculate below, the apex acute or acuminate, sometimes slightly expanded or reflexed; paleas ca. 6 mm long, folded over the disc florets, ciliate on the keel and apex; ray florets few, the corolla white, rectangular, 3 mm long, 3-nerved, truncate, 3-lobed, the tube ca. 2 mm long, pilose, the ovary laterally compressed, pyriform, the narrowed basal portion forming a stipe, ciliate, with two short, strigose awns; disc florets 20-25, 5-6 mm long, the corolla 3-4 mm long, the basal 2/3 pilose, the tube not demarcated from the 5-lobed limb, the anthers black, the appendages dark, the style branches not expanded, apically appendaged, dorsally pubescent, the style base not expanded, subsessile on the ellipsoidal, 0.5 mm long nectary, the ovary laterally compressed, ciliate on the angles, the awns half as long as the corolla, slightly unequal. Achene body (Robinson & Greenman) 5 mm long, tuberculate, especially along the prominent midnerve; pappus awns 2, long, slender, equal.
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