Leafy herb to 1.5 m, moderately densely pubescent with glandular hairs. Leaves mostly cauline, broadly ovate, the upper ones shorter and narrowly ovate; lamina up to 15 cm (occasionally to 23 cm) long; basal leaves petiolate, the petiole to 6 cm long, broadly to narrowly winged, upper leaves sessile or almost so. Flowers solitary in axils or arising from internodes. Calyx 5–17 mm long; lobes usually spreading or recurved. Corolla-tube 20–60 mm long, to 2.5 mm wide at top of calyx; limb 7–21 mm diam.; lobes usually obtuse or slightly notched. Two of the upper 4 anthers usually slightly above the other 2, the filaments to 2.5 mm long; 5th filament 5–10 mm long, inserted in upper half of corolla-tube. Capsule ovoid to ellipsoid, 6–13 mm long. Seeds reniform; testa usually with wavy-edged honeycomb or wrinkles.
Home