An identification key of Macroscepis in México.

1. Apex of the gynostegial corona exerted from the corolla tube ..........................................................................................................2

- Apex of the gynostegial corona included in the corolla tube .............................................................................................................3

2. Corolla greenish-brown to brown, rarely orange; gynostegial corona apex straight, rectangular. Fruit wings with margin entire to slightly lobulated. Plants distributed from México (Jalisco to Chiapas) to Nicaragua ................................. Macroscepis diademata

- Corolla orange, gynostegial corona apex inflexed, sub-quadrangular. Fruit wings with margin irregularly crenate to slightly dentate. Plants endemic to Sinaloa, México ........................................................................................................... Macroscepis sinalobolana

3. Inflorescences usually with 8 or more flowers.............................................................................................. Macroscepis pleistantha

- Inflorescences usually with 2–5 flowers ............................................................................................................................................4

4. Corolla greenish-brown to green; gynostegial corona pinkish to purple, apex concave............................ Macroscepis yucatanensis

- Corolla orange; gynostegial corona yellowish to brown, apex plane................................................................ Macroscepis stevensii