| 1 | Fertile fronds trilobed, pinnatifid or fully pinnate |
| 1' | Fertile fronds simple |
| 2 | Rhizome scales pseudopeltate |
| 2' | Rhizome scales peltate |
| 3 | Rhizome scales strongly dentate, or long-ciliate, hydathodes with persistent calcareous scales, margin of the sterile fronds without notches. |
| 3' | Rhizome scales entire to short-dentate, hydathodes, if present, without persistent calcareous scales, margin of all fronds notched |
| 4 | Fertile fronds pinnatifid, glaucous, fertile parts similar to sterile part, rhizome scales dark, shiny, evenly coloured |
| 4' | Fertile fronds fully pinnate, not glaucous, fertile parts strongly contracted, rhizome scales with a lighter margin |
| 5 | Sterile fronds normally absent, most fronds with narrowed apical fertile parts, pinnae ovate, narrowed at the base, sori superficial |
| 5' | Sterile fronds regularly present, fertile fronds with narrowed lamina, pinnae linear, not narrowed at the base, sori deeply sunken |
| 6 | Hydathodes absent |
| 6' | Hydathodes frequent |
| 7 | Fertile parts strongly contracted, sori deeply sunken |
| 7' | Fertile parts narrowed, sori superficial or shallowly sunken |
| 8 | Sori in two rows between adjacent veins, notches in fertile fronds regularly present |
| 8' | Sori in one row between adjacent veins, notches in fertile fronds absent or sporadically present |
| 9 | Sori sunken, rhizome scales spreading or squarrose, contracted to a narrow subulate acumen, margin of sterile fronds without notches |
| 9' | Sori superficial, rhizome scales appressed, acute, margin of sterile fronds with notches regularly present |
| 10 | Sclerenchyma strands many |
| 10' | Sclerenchyma strands absent or few |
| 11 | Sori sunken, rhizome without sclerified sheaths around the vascular strands.. |
| 11' | Sori superficial, rhizome with distinct sclerified sheaths around the vascular strands |
| 12 | Fertile parts similar to sterile part |
| 12' | Fertile parts narrowed or strongly contracted |
| 13 | Fertile parts strongly contracted, costa only distinct |
| 13' | Fertile parts narrowed, veins distinct |
| 14 | Sori in 5 or more rows between midrib and margin, margin of all fronds without notches or notches sporadically present |
| 14' | Sori in one row between midrib and margin, margin of sterile fronds with notches regularly present |
