1Fronds usually bipinnatifid apart from basal pinnae; pinnules, if present, mostly adnate to pinna-rachis; many additional areoles always present below sinuses between lobes; sinus-teeth only evident in larger sinuses
1'Fronds amply bipinnate on mature plants, most pinnules not adnate; areoles few be low sinuses; sinus-teeth always evident
2Fronds normally bipinnatifid, the largest sometimes bipinnate near the base; sori scat tered irregularly, very abundant
2'Fronds, at least in basal parts, bipinnate with lobed pinnules; sori all, or almost all, arranged in one row on each side of costules of pinnule-lobes
3Sori midway between costules and margins of pinnule-lobes and also some on basal veins
3'Sori close to margins of pinnule-lobes, lacking on basal veins
4Pinnules of suprabasal pinnae acuminate, to 12 cm long and 2 cm wide at their broadly cuneate bases, not adnate to pinna-rachis
4'Pinnules of suprabasal pinnae to 4 × 0.8 cm with blunt apices, adnate to pinna-rachis
5Sori present on all vein-branches, in more than 1 row on each side of costules, sev eral sori irregularly arranged on veins below sinuses
5'Sori almost always in a single row on each side of the costules (sometimes on both branches of a vein), additional ones below sinuses few
6Sori indusiate
6'Sori exindusiate
7Pinnules of middle pinnae lobed c. 2/5 towards costules, lobes distinctly falcate; sinus-teeth narrow
7'Pinnules more deeply lobed; sinus-teeth triangular
8Pinnules short-acuminate, lobes obtuse
8'Pinnules long- acuminate, lobes acute
9Pinnule-lobes subentire (small teeth distally)
9'Pinnule-lobes crenate to lobulate
10Stipe dark, glossy; pinnules to 25 × 5 cm, pinnate for half their length
10'Stipe not dark and glossy; largest pinnules not thus pinnate
11Pinnules to 15 × 3 cm, their lobes lobulate, drying brown-olivaceous
11'Pinnules commonly 8 × 1.8 cm, their lobes crenate, drying greenish
12Pinnules lobed about 2/3 towards costa; lobes entire or at most minutely crenate-dentate
12'Pinnules lobed more deeply or not; lobes distinctly crenate
13Costules 4-4.5 mm apart; several costular areoles present; basal scales to 5 cm long, 3 mm wide at base
13'Costules to 6 mm apart; few costular areoles present; basal scales shorter and narrower
14Sinus-teeth narrow, short, in base of sinus
14'Sinus-teeth broadly triangular, on basiscopic side of base of sinus
15Pinnules of suprabasal pinnae to 4.5 cm wide, their lobes acute
15'Pinnules of suprabasal pinnae to 2.5 cm wide, their lobes obtuse
16Pinnules all lobed to c. 1 mm from costa, to 2.5 cm wide, spores not spinulose
16'Pinnules lobed less deeply, narrower; spores spinulose