Key for Mendoncia Vand.

1Corolla bright red or purplish
1'Corolla white, cream white or cream white and tinged yellow distally, sometimes light lilac, or white with purple spots or lilac streaks
2Bracteoles narrowly oblong, 30-40 mm long
2'Bracteoles oblong-lanceolate to ovate-lanceolate, 20-25 mm long
3Corolla 20-30 mm long
3'Corolla 50-65 mm long
4Bracteoles glabrous, ovate, 14-20 mm long; leaf blade glabrous or nearly glabrous.
4'Bracteoles hirsute, oblong-elliptic to ovate, 20-30 mm long; leaf blade hirsute
5Bracteoles ovate, 20-30 mm x 14-20 mm; leaf blade margin distinctly crenate
5'Bracteoles oblong, 30-40 x 9-13 mm; leaf blade margin entire or undulate, not crenate