| 1 | Sori more or less regularly spaced, in a single row between costa and margin, or in a single, sometimes double, row between the lateral veins, on distinct soral veins or very close to the connective veins |
| 1' | Sori irregularly scattered on the surface of the lamina, mostly on the smallest veinlets |
| 2 | Rhizome not white waxy, without sclerified circumvascular sheaths |
| 2' | Rhizome white waxy, with sclerified circumvascular sheaths |
| 3 | Apical lobe 0.9-1.7 cm wide, scales peltate, sori superficial or slightly immersed. |
| 3' | Apical lobe 2.5-6.5 cm wide, scales pseudopeltate, sori deeply sunken, visible as protrusions on the upper surface |
| 4 | Scales 2-7 mm long, lamina herbaceous |
| 4' | Scales 0.5-1.3 mm long, lamina thin-herbaceous or membranaceous. |
| 5 | Connecting veins forming several more or less equally sized, sometimes irregularly shaped areoles between two adjacent veins, sometimes forming small primary costal areoles, rhizome with scattered sclerenchyma strands |
| 5' | Connecting veins forming one row of large areoles parallel to the costa, bordered by several smaller areoles; costal areole, if present, formed by smaller veins, rhizome without scattered sclerenchyma strands |
| 6 | Rhizome white waxy, without sclerified circumvascular sheaths, sclerenchyma strands 50-100, lamina herbaceous or subcoriaceous |
| 6' | Rhizome not white waxy, with sclerified circumvascular sheaths, sclerenchyma strands 8-15, lamina thin-herbaceous |
| 7 | Rhizome not sclerified at all, lamina thin-herbaceous or membranaceous. |
| 7' | Rhizome with sclerified circumvascular sheaths, lamina herbaceous |
| 8 | Lamina simple, roots densely set, scales 3.5-10 mm long, lamina undersurface without acicular hairs |
| 8' | Lamina pinnatifid, roots sparsely set, scales 0.5-2 mm long, lamina undersurface with acicular hairs |
