Key to Genera of Cinchoneae
By C.M. Taylor (MO)
1. Inflorescences terminal (i.e., stem terminates in an inflorescence or flower).
2. Leaves with tertiary and/or quaternary venation lineolate (i.e., parallel or subparallel); corolla lobes often with ellliptic to obovate petaloid appendages......Joosia
2'. Leaves with tertiary and quaternary venation areolate.; corolla lobes without appendages.
3. Corolla funnelform with tube ca. 1 mm long and shorter than lobes; fruits 100+ per inflorescence, 6-12 mm long; petioles at base encircled on lower sides (abaxially) by a low ridge that extends from and connects the bases of the stipules; lowland vegetation.....Cinchonopsis
3'. Corolla salverform with tube 5-75 mm long and longer than lobes; fruits 2-60 per inflorescence, 10-110 mm long; petioles smooth at base, not encircled by ridge; lowland to premontane and montane vegetation.
4. Corolla white or pink, in tube with longitudinal strips of thin tissue extending from sinuses to stamen insertion (i.e., almost fenestrate), lobes villous or ciliate on margins....Cinchona
4'. Corolla white, tube without thin areas, lobes entire and usually papillose on margins.....Ladenbergia
1'. Inflorescences axillary (i.e., stem terminates in a vegetative apex with a stipule).
5. Leaves with secondary and intersecondary veins numerous, similar in form, closely set, and difficult to distinguish.....Stilpnophyllum
5'. Leaves with secondary veins 5-20 pairs, separated and clearlly distinguishable, without intersecondary veins or these visible and markedly shorter than secondary veins.
6. Seeds ciliate to laciniate on margins......Ciliosemina
6'. Seeds entire.
7. Corolla with tube 3-4 mm long; capsules 6-10 mm long; premontane and montane vegetation, central Andes......Pimentelia
7'. Corolla with tube generally 4-35 mm long (unknown in some species); capsules 10-60 mm long; lowland vegetation, and premontane vegetation of Guayana region.
8. Anthers pubescent......Maguireocharis
8'. Anthers glabrous....Remijia