Cinchona boliviana Wedd.

Trees or shrubs up to 15 m tall; branchlets pilosulous, or puberulous or rarely glabrescent. Leaves with blades elliptic, elliptic-oblong, lance-elliptic, or ovate, 6-19 x 2-11 cm, drying chartaceous, pilosulous to puberulous or glabrescent, at base cuneate to acute, at apex rounded to obtuse or shortly acute; secondary veins 7-10 pairs, with domatia in the form of small pits or these sometimes reduced; petioles 0.5-3 cm long, puberulous to hirtellous or often glabrescent; stipules obovate to ligulate, 1.0-2.1 cm long, variously pubescent or rarely glabrescent, at apex subacute to usually broadly rounded. Inflorescences 5-20 x 5-20 cm. Flowers with hypanthium 1.8-3.3 mm long, puberulous to glabrescent; calyx limb 0.8-3 mm long, lobed for up to 1/3 of its length, the lobes triangular, acute to rounded; corolla salverform, white or usually pink to purple, outside pilosulous or strigillose or glabrescent, inside glabrous or pubescent in throat and on lobes, tube 8-13 mm long, lobes triangular, 3.5-6.3 mm long, acute; anthers 2.5-5.3 mm long; stigmas 1.7-4 mm long. Fruits capsular, narrowly ellipsoid to nearly cylindrical or sometimes lanceoloid (i.e., widest below the middle), 5-31 x 3-8 mm, stiffly papery, dehiscent from the base (or sometimes immature capsules opening prematurely also from the apex); seeds 3.3-10 x 1.5-3.5 mm, flattened, small, irregularly elliptic to oblong, marginally winged and often irregularly incised or erose.

High-resolution scans of representative museum specimens for reference are available (along with technical taxonomic information) at TROPICOS: Cinchona calisaya.

This species naturally occurs on eastern slopes of the Andes, from central Peru to Bolivia at elevations of 200-3300 m above sea level; it has also been cultivated and hybridized world wide in warm tropical regions.

Cinchona calisaya has been frequently confused with Cinchona officinalis, and these are quite similar in general. Andersson (1998) separated these based on their leaves, calyx, and fruit: Cinchona calisaya has leaves with the domatia (the tiny pits on the undersurface, at the junction of the midrib and the secondary veins, where tiny mites live) best developed or all in the distal part of the blade (near the apex), the calyx divided for less than half its length into lobes, and capsules with stiffly papery walls; while Cinchona officinalis has leaves with the domatia best developed in the basal or lower half of the blde, the calyx divided for more than half into lobes, and the capsules with thick woody walls. Cinchona officinalis is native in a rather small region, in southern Ecuador, and has been cultivated occasionally outside of South America, while Cinchona calisaya is common and widespread.

The fruits are dry, rather woody capsules that open to release numerous small, papery, flattened seeds that are dispersed by the wind.