| 1 | Stipe and lower part of rachis bearing numerous stiff spreading scales. |
| 1' | Upper part of stipe and rachis lacking large scales. |
| 2 | Pinnae to 12 cm long. |
| 2' | Pinnae of well-grown plants much longer. |
| 3 | Stipe-scales dark, to 1 mm wide; veins 7-10 pairs |
| 3' | Stipe-scales medium brown, to 2 mm wide; veins 12-17 pairs. |
| 4 | Costae, costules and veins beneath bearing short hairs only; stipe-scales to 6 mm long. |
| 4' | Costae, costules and veins beneath bearing hairs 1 mm or more long, at least on sterile fronds; stipe-scales 10 mm or more long |
| 5 | Lower pinnae not auricled; no glands on lower surface of costules |
| 5' | Lower pinnae strongly auricled; copious glands on lower surface of costules. |
| 6 | Fronds simple |
| 6' | Fronds pinnate or partly bipinnate. |
| 7 | Pinnae not more than 3 cm long. |
| 7' | Pinnae much longer. |
| 8 | Pinnae lobed less than half-way to costa; acroscopic bases of pinnae auricled |
| 8' | Pinnae lobed more than half-way to costa, not auricled |
| 9 | Largest pinnae with several pairs of pinnules |
| 9' | Largest pinnae with at most one free basal lobe. |
| 10 | Sterile pinnae lobed not more than half-way to costa, except sometimes basal pinnae. |
| 10' | Sterile pinnae lobed more than half-way to costa. |
| 11 | Pinnae 6-8(-10) pairs; young fronds red |
| 11' | Pinnae 14-18 pairs; young fronds not red |
| 12 | Pinnae to 6.5 cm wide, lower ones with stalks 3-4 cm long |
| 12' | Pinnae not more than 4 cm wide, lower ones with stalks to 1.5 cm long. |
| 13 | Hairs on lower surface of costae and costules c. 1 mm long. |
| 13' | Hairs on lower surface of costae and costules not over 0.3 mm long. |
| 14 | All pinnae distinctly stalked; copious short hairs and glands between veins on lower surface |
| 14' | Pinnae sessile; sparse erect hairs 0.5 mm long and no glands between veins on lower surface |
| 15 | Indusia firm, glabrous, covering the sorus almost to maturity; fertile pinnae lobed to 1-1½ mm from costa |
| 15' | Indusia small, not covering developing sori, or ± hairy; fertile pinnae lobed less deeply. |
| 16 | Fertile pinnae lobed to 2 mm from costa; indusia small, firm, glabrous. |
| 16' | Fertile pinnae lobed less deeply; indusia usually with some hairs, thin and almost obscured by sporangia if small. |
| 17 | Fronds rarely dimorphic; pinnae thin, rarely more than 2 cm wide; indusia always conspicuous, firm, bearing a variable number of short hairs |
| 17' | Fronds usually dimorphic; pinnae rigid, fertile to 3 cm, sterile to 4 cm wide; indusia varied in size, thin and shrivelling when dried |
