| 1 | Sori exindusiate. |
| 1' | Sori indusiate. |
| 2 | Pinnae not more than 3 cm long. |
| 2' | Pinnae longer on mature plants. |
| 3 | Upper surface short-appressed-hairy; sori elongate |
| 3' | Upper surface glabrous; sori not elongate |
| 4 | Fertile pinnae 2 mm wide |
| 4' | Fertile pinnae to at least 1 cm wide. |
| 5 | Surfaces between veins glabrous. |
| 5' | Surfaces both short-hairy between veins. |
| 6 | Sporangia setiferous |
| 6' | Sporangia not setiferous. |
| 7 | Pinnae 2-3 cm wide |
| 7' | Pinnae not over 1 cm wide |
| 8 | Pinnae c. 15 pairs |
| 8' | Pinnae 2-3 pairs |
| 9 | Fronds simple, 10-20 cm long with cordate base |
| 9' | Fronds pinnate or, if simple, smaller and sterile. |
| 10 | Lower surface between and/or on veins bearing sessile spherical glands. |
| 10' | Lower surface between and on veins lacking sessile spherical glands. |
| 11 | Veins free |
| 11' | Veins anastomosing. |
| 12 | Free pinnae not over 7 pairs, not over 2.0 cm wide. |
| 12' | Free pinnae more numerous or wider. |
| 13 | Hairs on lower surface of costules and on upper surface between veins not appressed |
| 13' | Hairs on lower surface of costules and on upper surface appressed. |
| 14 | Indusium bearing glands |
| 14' | Indusium bearing hairs |
| 15 | Lower pinnae with stalks 1-2 mm long |
| 15' | Lower pinnae sessile. |
| 16 | Hairs on lower surface of costae and costules erect |
| 16' | Hairs on lower surface of costae and costules slender, appressed. |
| 17 | Sterile and fertile pinnae both 8-9 cm long |
| 17' | Sterile and fertile pinnae dimorphous, smaller. |
| 18 | Sterile pinnae c. 4.5 x 1.4 cm; rachis almost glabrous on abaxial surface |
| 18' | Sterile pinnae c. 2.0 x0.8 cm; rachis bearing copious erect hairs on abaxial surface |
| 19 | Glands present on sporangia, in some cases setae also. |
| 19' | Sporangia lacking glands; setae present in most cases. |
| 20 | Fertile pinnae 3-4 mm wide; sterile to 10 mm wide |
| 20' | Fertile pinnae 10 mm or more wide; little dimorphism. |
| 21 | Pinnae 6-10 pairs; sporangia bearing small glands only. |
| 21' | Pinnae 3-4 pairs; sporangia often with both glands and setae. |
| 22 | Pinnae 2-3 cm wide |
| 22' | Pinnae not over 1 cm wide |
| 23 | Fertile pinnae less than 1.5 cm long; sori in 1 row on each side of costa. |
| 23' | Fertile pinnae to at least 2 cm long; sori in several rows. |
| 24 | Pinnae and/or frond-apex on both young and adult plants ± dilated and irregularly lobed distally |
| 24' | Pinnae not thus dilated nor irregularly lobed. |
| 25 | Basal pinnae narrowly cuneate at base both sides, not auricled; fertile pinnae not or little narrower than sterile |
| 25' | Basal pinnae otherwise, usually auricled; fertile pinnae in most cases narrower than sterile. |
| 26 | Indusia not very small, bearing many short hairs. |
| 26' | Indusia small, with dark red cell-walls; marginal hairs few or none. |
| 27 | Upper surface of pinnae bearing short suberect hairs between veins. |
| 27' | Upper surface glabrous between veins. |
| 28 | Pinnae 7 pairs; indusia thin with some superficial hairs. |
| 28' | Pinnae 15 pairs; indusia firm with stiff marginal hairs |
| 29 | Sporangia setiferous. |
| 29' | Sporangia lacking setae. |
| 30 | Sterile pinnae barely 1 cm wide |
| 30' | Sterile pinnae commonly 2 cm or more wide. |
| 31 | Sterile pinnae entire, to 13 x 4 cm |
| 31' | Sterile pinnae crenate, to 11 x 2.5 cm |
| 32 | Indusia firm, almost circular, with hairs in the middle |
| 32' | Indusia thin, shrivelled when dry, hairy throughout. |
| 33 | Sterile pinnae crenate, at least distally |
| 33' | Sterile pinnae entire |
| 34 | Fertile pinnae 1.5 cm or more wide |
| 34' | Fertile pinnae not more than 1 cm wide. |
| 35 | Sterile pinnae not or little more than 1 cm wide, fertile 3-6 mm wide. |
| 35' | Sterile pinnae 1.5 cm or more wide, fertile 5-10 mm wide |
| 36 | Pinnae thick; lower surface glabrous with thick pale prominent veins |
| 36' | Pinnae thin; hairs present on lower surface of costae; veins concolorous, not prominent. |
| 37 | Pinnae to 15 pairs, sterile ones 4-6 cm long, narrowly acuminate. |
| 37' | Pinnae not over 10 pairs, sterile ones shorter, abruptly pointed. |
