| 1 | Leaves of a pair strongly unequal, the larger leaf in a pair ca. 10 times larger than the smaller |
| 1' | Leaves of a pair subequal, the larger leaf in a pair at most 4 times larger than the smaller (C. calotricha) |
| 2 | Leaves with red-purple areas below, sparsely pubescent to pilose above |
| 2' | Leaves (in the Guianas) green below, densely tomentose to hirsute above |
| 3 | Corolla yellow covered with brown or red hairs, subactinomorphic; leaves as long as to much longer than the flowers |
| 3' | Corolla scarlet or red, 2-lipped; leaves usually shorter than the flowers |
| 4 | Pedicels usually as long as the leaves or longer; leaf blade obtuse to acuminate apically, margin entire, subrevolute, glabrous above; calyx lobes sharply serrate, 1.5-3 times longer than wide |
| 4' | Pedicels usually much shorter than the leaves; leaf blade acute or obtuse apically, margin entire to remotely crenate-dentate, strigose to subtomentose above; calyx lobe base entire or with a few teeth, 2.5-10 times longer than wide |
