| | 1. Annual; stem < 1 dm; leaf < 15 mm; flower < 2 cm (sect. Chondrophyllae) |
| |
| | 2. Leaves dissimilar, upper cauline strongly ascending, much narrower than basal, margins of all conspicuously white; corolla lobes white to pale blue, exterior often dark blue |
| G. fremontii |
| | 2' Leaves all ± similar, ± spreading, margins not or obscurely white; corolla medium to deep blue on both sides |
| G. prostrata |
| | 1' Perennial; stem generally > 1 dm; leaf > 15 mm; flower > 2 cm (sect. Pneumonanthe) |
| |
| | 3. Stems arising laterally from caudex, below a rosette |
| |
| | 4. Stems > 1 dm; leaves of middle to upper stem < internodes; corolla ± uniformly blue |
| G. setigera |
| | 4' Stems generally < 1 dm; leaves of stem generally > internodes; corolla white to deep blue, except exterior on and below lobes sometimes dark brownish purple |
| G. newberryi |
| | 5. Corolla medium to deep blue |
| var. newberryi |
| | 5' Corolla white to pale blue except exterior on and below lobes sometimes dark brownish purple |
| var. tiogana |
| | 3' Stems arising terminally from caudex, rosettes 0 |
| |
| | 6. Sinuses between corolla lobes ± truncate |
| G. sceptrum |
| | 6' Sinuses between corolla lobes with a conspicuous, toothed or fringed appendage |
| |
| | 7. Corolla sinus appendages divided ± to base into several thread-like parts; leaf base sheaths at mid-stem generally > 5 mm |
| G. plurisetosa |
| | 7' Corolla sinus appendages divided ± to base or < 1/2 way to base into often 2 parts, each thread-like only toward tip; leaf base sheaths at mid-stem < 5 mm |
| |
| | 8. Leaf, calyx lobe margins minutely ciliate; calyx lobes generally <1.5 mm wide; corolla lobes generally < 7 mm; inflorescences terminal and at 1–6 upper nodes, flowers 1–several per inflorescence |
| G. affinis var. ovata |
| | 8' Leaf, calyx lobe margins generally obscurely, minutely dentate, not ciliate; calyx lobes generally > 2 mm wide; corolla lobes generally > 7 mm; inflorescences generally terminal (sometimes also at 1–3 upper nodes), flowers 1–few |
| G. calycosa
|