| 1 | Veins free. |
| 1' | Veins anastomosing. |
| 2 | Groove of rachis open to admit grooves of branch rachises and midribs of leaflets. |
| 2' | Groove of rachis not open to admit grooves of branches |
| 3 | At least some sori elongate along veins. |
| 3' | Sori not elongate along veins |
| 4 | Sori not indusiate; fleshy outgrowths present at bases of pinnae on upper surface. |
| 4' | Sori indusiate; no such outgrowths. |
| 5 | Double sori (on both sides of a vein) not connected at their distal ends. |
| 5' | Double sori (at least some of them) connected at their distal ends; usually some reniform and J-shaped sori present |
| 6 | Sori almost circular, indusium reniform |
| 6' | Sori elongate along veins. |
| 7 | Veins anastomosing regularly, about as in Cyclosorus; sori on nearly all veins of fertile frond. |
| 7' | Veins anastomosing less regularly, the areoles adjacent to costae large; sori never so abundant. |
| 8 | Indusium rather firm, its edge reflexed at maturity |
| 8' | Indusium thin, sausage-shaped, breaking at maturity, its edge not reflexed. |
