Northern Prairie Wildlife Research Center
| Lead | Characteristic | Go To |
| 1 | Flowers orange-yellow, usually reddish-brown spotted; spur recurved parallel to the sac and 1/3 to 1/2 its length, the sac conic, longer than wide. | I. capensis |
| 1 | Flowers pale yellow, only faintly spotted if at all; spur recurved at a right angle to the sac and 1/5 to 1/4 its length, the sac broadly obtuse, about as wide or wider than long. | I. pallida |