| 1 | Fertile parts strongly contracted |
| 1' | Fertile parts similar to sterile part or narrowed |
| 2 | Rhizome scales with a narrow, subulate, entire acumen |
| 2' | Rhizome scales with acumen not narrow, subulate |
| 3 | Sori slightly or deeply sunken |
| 3' | Sori superficial |
| 4 | Rhizome scales strongly dentate, sori round or longitudinally elongate. |
| 4' | Rhizome scales entire to short-dentate, sori round or forming transverse coenosori |
| 5 | Hydathodes absent, margin of sterile fronds with notches sporadically to regularly present, sori round |
| 5' | Hydathodes frequent, margin of sterile fronds without notches, sori in transverse coenosori |
| 6 | Sori round or elongated, not forming coenosori crossing the veins |
| 6' | Sori forming long, sometimes interrupted coenosori, usually across the veins |
| 7 | Rhizome scales remotely and weakly dentate, hydathodes constantly present, notches in fertile fronds sporadically present |
| 7' | Rhizome scales strongly dentate, hydathodes absent or occasionally present, notches in fertile fronds absent |
| 8 | Rhizome scales pseudopeltate, sclerenchyma strands in the rhizome few, costa only distinct |
| 8' | Rhizome scales peltate, sclerenchyma strands in the rhizome many, veins distinct |
| 9 | Upper surface of lamina not glandular |
| 9' | Upper surfaces of lamina distinctly glandular |
| 10 | Fronds pinnatifid or pinnate |
| 10' | Fronds simple or trilobed |
| 11 | Fronds pinnatifid |
| 11' | Fronds fully pinnate |
| 12 | Calcareous scales persistent, margin of fronds without notches. |
| 12' | Calcareous scales not persistent, notches regularly present |
| 13 | Pinnae inserted more or less transverse to the rachis, rhizome with few, inconspicuous sclerenchyma strands, scales shiny |
| 13' | Pinnae in the same plane with the rachis, rhizome with many sclerenchyma strands, rhizome scales dull |
| 14 | Rhizome scales strongly dentate at least at their base, basal pinnae cut to midrib on basiscopic side |
| 14' | Rhizome scales entire or weakly dentate, basal pinnae with equal base or cut to midrib on acroscopic side |
| 15 | Sori in two or more rows between adjacent veins |
| 15' | Sori in one row between adjacent veins |
| 16 | Hydathodes frequent |
| 16' | Hydathodes absent |
| 17 | Rhizome scales entire, internodes to 2.5 cm long |
| 17' | Rhizome scales short-dentate to strongly dentate, internodes to c. 1 cm long. |
| 18 | Rhizome scales pseudopeltate, rhizome short, phyllopods mostly nearly contiguous |
| 18' | Rhizome scales peltate, rhizome short-creeping, phyllopods distinctly spaced. |
