| 1 | Sori marginal or submarginal, more or less elongate, protected by a reflexed indusium. |
| 1' | Sori acrostichoid. |
| 2 | Rhizome scandent |
| 2' | Rhizome not scandent. |
| 3 | Sorus along one edge of ultimate lobes of lamina |
| 3' | Sorus along both edges of ultimate lobes. |
| 4 | Sori joining many veins, usually one sorus along each edge of a lobe of the lamina. |
| 4' | Sori short, often more than one on each edge of a lobe; fertile margin thickened |
| 5 | Stock stout, erect; veins reticulate throughout; only distal pinnae fertile. |
| 5' | Rhizome slender, long-creeping or climbing; veins forming one series of narrow areoles by costa (seen near apex of leaflet); fertile fronds normally wholly fertile. |
