15. Operculina Silva Manso, Enum. Subst. Braz. 16, 49. 1836.
[Latin operculum, cover, alluding to distal portion of fruit separating as a lid]
Daniel F. Austin†
Perennials. Stems usually twining-climbing, sometimes procumbent, glabrous [hairy]. Leaves petiolate; blade ± ovate or palmately to pinnately lobed, 20–120 mm, surfaces sparsely hairy [glabrous]. Inflorescences 2–3-flowered cymes or flowers solitary, usually bracteate, bracts foliaceous. Flowers: sepals obovate, orbiculate, or ovate, 11–16 mm, equal or unequal, larger and leathery in fruit, margins sometimes dentate, glabrous; corolla white [yellow or reddish to salmon], campanulate [funnelform or salverform], 34–53 mm, limb ± entire [weakly 5-lobed]; anthers twisted after dehiscence; pollen 3-colpate, not echinate; styles 1; stigmas 2, globose. Fruits capsular, cuboid to globose, dehiscence circumscissile. Seeds 1–4, ellipsoid [ovoid], glabrous [hairy]. x = 15.
Species ca. 18 (1 in the flora): Texas, Mexico, worldwide in tropics and subtropics, most in Old World.
