| 1 | Sori 2 or more pairs on each pinnule-lobe of larger fronds. Largest pinnules 20-35 mm wide; pinnules on the two sides of a pinna not greatly different in length. Hairs on lower surface of costae and costules almost always thin and flaccid, never spreading |
| 1' | Sori never more than 2 pairs on each pinnule-lobe. Largest pinnules 15-25 mm wide; pinnules on basiscopic side of lower pinnae much shorter than those on acroscopic side. Some rigid hairs usually present with flaccid ones on lower surface of costae, the rigid hairs sometimes spreading. |
| 2 | Always one pair of sori. Spreading hairs usually present on lower surface of costae; hairs normally absent on lower surface of lamina between veins |
| 2' | Always two pairs of sori on large fronds. Spreading hairs lacking, but rigid (often red) appressed hairs always present and sometimes abundant; small flaccid hairs present on lower surface of lamina between veins |
