| 1 | Pinnae of sterile acrophylls sessile or nearly so. |
| 1' | Pinnae of sterile acrophylls, at least lower ones, stalked. |
| 2 | Sterile pinnae 2-2½ cm wide |
| 2' | Sterile pinnae 1-1½ cm wide |
| 3 | Bases of some sterile pinnae conspicuously asymmetric. |
| 3' | Bases of sterile acrophyll pinnae symmetric or nearly so. |
| 4 | Stalks of sterile pinnae 3-5 mm long. |
| 4' | Stalks of sterile pinnae 5-10 mm long |
| 5 | Basal pinnae with almost symmetric base, base of others strongly asymmetric; fertile pinnae 4.5-5.5 cm by 5-7 mm |
| 5' | Basal pinnae strongly asymmetric at base, bases of upper pinnae less so; fertile pinnae 20-24 cm by 2.5-3 mm |
| 6 | Pinnae of sterile acrophylls to 20 by 2 cm. |
| 6' | Pinnae of sterile acrophylls not over 16 cm long, proportionately wider. |
| 7 | Stalks of sterile pinnae to 5 mm long |
| 7' | Stalks of sterile pinnae to at least 10 mm long. |
| 8 | Sides of sterile pinnae parallel except in distal ⅓; fertile pinnae 3 mm wide. |
| 8' | Sides of sterile pinnae not parallel; fertile pinnae c. 10 mm wide. |
