Cinchona L.

Shrubs or usually trees, unarmed; buds flattened with stipules erect and pressed together; bark usually notably bitter. Raphides absent. Leaves opposite, decussate, usually with well-developed domatia; stipules caducous, interpetiolar or shortly united around stem, ligulate to obovate, entire. Inflorescences terminal and often also in axils of uppermost leaves, cymose to paniculiform, many flowered, pedunculate, bracteate. Flowers pedicellate, bisexual, fragrant, usually distylous. Calyx limb 5-lobed. Corolla yellow, pink, purple, red, or occasionally white, salverform or funnelform, inside glabrous or pubescent in throat, with tube often weakly 5-ridged outside; lobes 5, valvate in bud, with margins densely ciliate to villous. Stamens 5, inserted in corolla tube, included to partially exserted; filaments short to developed, glabrous; anthers dorsifixed. Ovary 2-celled, ovules many in each cell on axile placentas; stigma 2-lobed, lobes capitate to linear. Fruit capsular, ovoid to cylindrical or ellipsoid, septicidally dehiscent into 2 valves from base or sometimes from apex with valves then loculicidal through septum, stiffly papery to woody, often lenticellate, with calyx limb persistent; seeds numerous, medium-sized, ellipsoid to fusiform and somewhat flattened with membranous marginal wing and elliptic central seed portion; endosperm fleshy; cotyledons ovate.