| 1. Petals free; leaves linear to narrowly (ob)lanceolate |
| P. linearis |
| 1' Petal claws adherent below, fused above; leaves lanceolate to widely ovate |
| |
| 2. Leaves petioled, cauline ± equal |
| P. nitidus |
| 2' Leaves sessile, cauline reduced upwards |
| P. thurberi |
| 3. Hairs soft, spreading; stamens 47.5 mm |
| subsp. gilmanii |
| 3' Hairs rough, appressed downward; stamens 610 mm |
| subsp. thurberi
|