Description: Perennial herbs, glabrous or pubescent with simple glandular hairs.
Leaves alternate, rarely paired, mostly simple, margins entire, sessile or petiolate.
Flowers solitary, terminal or in upper leaf axils, bisexual, slightly zygomorphic. Calyx tubular to obconical, 5-lobed. Corolla white or violet; tube slender, elongate; limb expanded, campanulate to funnel-shaped, 5-lobed. Stamens 5, inserted at summit of corolla tube, 4 in two pairs, exserted and surrounding style; anthers 2-locular, joined ventrally to filaments, dehiscing by longitudinal slits. Ovary 2-locular; stigma expanded, 2-lobed.
Fruit a capsule, the valves deeply 2-fid at dehiscence, enclosed by persistent calyx.
Distribution and occurrence: World: c. 30 species, mostly South America, 1 species North America. Australia: 1 species (naturalized).
Text by B. J. Conn