| | 1. Leaf generally 1-pinnate; 1° leaflets generally simple, ± entire to serrate, in P. kruckebergii sometimes 1-lobed |
| |
| | 2. Leaf 10–15(25) cm; 1° leaflets simple or generally lobed at bases of lowest |
| 2 P. kruckebergii |
| | 2' Leaf 10–120(200) cm; 1° leaflets simple |
| |
| | 3. Lowest 1° leaflets ± deltate, ± 1/2 length of longest; petiole 1/6–1/10 blade length |
| P. lonchitis |
| | 3' Lowest 1° leaflets ovate to lanceolate, ± = to ± 2/3 length of longest; petiole generally 1/5–1/2 blade length |
| |
| | 4. Petiole base scales ovate, ± 3(6) mm wide, those above lowest 1° leaflets generally > 1 mm wide, persistent; 1° leaflets generally in 1 plane; indusium ciliate |
| P. munitum |
| | 4' Petiole base scales lanceolate, ± 2–3 mm wide, those above lowest 1° leaflets generally < 1 mm wide, falling early; 1° leaflets in ± 1 plane or not; indusium ± entire to toothed |
| P. imbricans |
| | 5. Leaf 15–80 cm; 1° leaflets in ± 1 plane, longest 3–6(10) cm; sori submarginal |
| subsp. curtum |
| | 5' Leaf 15–50 cm; 1° leaflets often not in ± 1 plane, longest 2–5 cm; sori ± close to midvein |
| subsp. imbricans |
| | 1' Leaf 1–2-pinnate; 1° leaflets deeply pinnately lobed to 1-pinnate, at least at bases of lowest |
| |
| | 6. Leaflet teeth without bristle-like tips; serpentine |
| P. lemmonii |
| | 6' Leaflet teeth with bristle-like tips; serpentine or not |
| |
| | 7. Leaf generally 2- to rarely partly 3-pinnate; 2° leaflets abruptly narrowed to attachment < 0.5 mm wide, often with a lobe on distal side of base; main leaf blade axis with persistent scales |
| P. dudleyi |
| | 7' Leaf generally 1- to partly 2-pinnate; 2° leaflets gradually tapered to attachment < 3 mm wide, lobes 0; main leaf blade axis with deciduous scales |
| |
| | 8. Smallest scales on leaflet lower surface hair-like; blade generally > 5 cm wide |
| P. californicum |
| | 8' Smallest scales on leaflet lower surface linear, few hair-like; blade generally < 5 cm wide |
| |
| | 9. Lowest 1° leaflets ± deltate, longest < 1(–1.5) cm |
| 2 P. kruckebergii |
| | 9' Lowest 1° leaflets ± lanceolate, longest 1.5–3 cm |
| P. scopulinum
|