Erect rarely prostrate herb to subshrub, up to 2.7 m high, sparsely branched to branched. Stems and branches up to 0.5 cm in diam., terete, slightly 4-angled to 4-angled to 4-winged, wings 0.1-0.4(-1) mm wide; internodes 0.5-15.1 cm long. Leaves sessile to shortly petiolate, cauline, evenly distributed; petiole 2-20 mm long; blade membranaceous to rarely coriaceous, elliptic, ovate to lanceolate, rarely ellipticly orbicular to ovately orbicular, 1-13.3 x 0.4-5.1 cm, margin not thickened, flat, apex acute, acuminate to rarely obtuse, base attenuate, acute to obtuse, lower leaves attenuate. Inflorescence 1-39-flowered; bracts ovate with acute apex or oblong with obtuse apex, 0.1-3.2(-5.7) mm long; pedicel 4-20 mm long. Flowers horizontal to nodding; calyx green, 4-10 x 3-6 mm, lobes ovate to circular, 2-5 x 2-3 mm, margin membranaceous, apex acute to obtuse; corolla blue, purple, lavender, inner side of throat sometimes white, funnel-shaped to tubular, sometimes nearly campanulate, 18-72(-87) mm long, 9-36 mm wide at mouth, lobes ovate to circular, 5-17 x 3-14 mm, apex obtuse; stamens not exserted, sometimes longest exceeds corolla slightly, filaments 16-45 mm long, strongly curved close to anther, anthers white, yellow to orange, oblong, 2.6-6.7 mm long, recurved; pollen exine differentially reticulated with polar loops (see Maguire & Boom, 1989; Nilsson, 1970, 2002); pistil 27-44 mm long, ovary 4-5.4 x 1.2-1.3 mm, style 20-50 mm long, stigma lobe elliptic, 1.9-5.4 x 0.7-2.1 mm. Fruit horizontal to nodding, brown, ellipsoid, 6-20 x 3-9 mm; seeds brown, 0.1-0.4 mm in diam.
Guianas present present, Southern America: Bolivia (Bolivia present); Colombia (Colombia present); Ecuador (Ecuador present); Peru (Peru present); Venezuela (Venezuela present)
Colombia, Venezuela, the Guianas, Ecuador, Peru, Bolivia and Brazil; 362 collections studied, of which 239 from the Guianas (GU: 117; SU: 47; FG: 75).
In Guyana an infusion of the leaves was used by the Arawaks for smallpox (according to Harrison 1345), and has been used against fungal infections (according to Hoffman & Patterson 878).
In the same publication, Grisebach also described
In 1845, Grisebach classified the purple-flowered