Key to the species of Prepusa

1. Inflorescence simple; calyx reddish, winged from the base to the apex of the calyx tube or not winged; corolla white (Rio de Janeiro) ............................................................................................................................................................................. 2.

- Inflorescence simple or compound; calyx yellowish-green or greenish-brown, winged from the base, but not reaching the apex of the calyx tube; corolla green to wine-brown ........................................................................................................... 4.

2. Calyx winged from the base to the apex of the calyx tube; calyx lobes transversely elliptic, widely elliptic or depressed ovate, with caudate to mucronate apex; corolla campanulate, longer than calyx ........................................................ P. alata

- Calyx not winged ................................................................................................................................................................. 3.

3. Bracts 34–61 × 18–32 mm, connate at the base, forming a bilabiate sheath; calyx lobes caudate; filaments twisted when dry ........................................................................................................................................................................... P. connata

- Bracts 19–27 × 5–9 mm, sub-connate at the base; calyx lobes apiculate to mucronate; filaments not twisted when dry....... ........................................................................................................................................................................... P. hookeriana

4. Stems woody, shrub or small tree; leaf apex obtuse and emarginate; calyx yellowish-green, lobes cuspidate; corolla greenish (Bahia) ............................................................................................................................................................. P. montana

- Stems not woody (herbaceous) or woody only at the base (subshrub); calyx greenish-brown, lobes acuminate; corolla green or wine-brown (Espírito Santo) .................................................................................................................................. 5.

5. Leaf apices obtuse or rounded; inflorescence compound; corolla wine-brown, usually longer than the calyx; stigma villous ............................................................................................................................... ................................................. P. dibotrya

- Leaf apices acuminate or acute; simple inflorescence; corolla green, usually the same size as the calyx; stigma verrucose. .............................................................................................................................................................................. P. viridiflora