| | 1. Fruit tightly coiled; petals fused |
| |
| | 2. Inflorescence a spike-like raceme; leaf hairy |
| P. pubescens |
| | 2' Inflorescence a head; leaf glabrous or short-hairy |
| P. strombulifera |
| | 1' Fruit not coiled; petals free |
| |
| | 3. Plant ± glabrous; 2° leaflets generally > 15 mm, length 7–9 × width |
| P. glandulosa var. torreyana |
| | 3' Plant with short, dense hairs; 2° leaflets generally < 15 mm, length 3–4 × width |
| P. velutina
|