KEY TO THE SPECIES of Pronephrium Subg. Menisciopsis Sect. Grypothrix

1Caudex long-creeping with well-spaced fronds.
1'Caudex short-creeping, fronds close together.
2Pinnae one pair, opposite, always asymmetric
2'Pinnae 2-6 pairs, distal ones small and adnate, rest with variable asymmetry
3Pinnae all narrowly cuneate at base, fertile ones commonly 1 cm wide; hooked hairs lacking on lamina and sporangia
3'Pinnae not all narrowly cuneate at base, fertile ones always much more than 1 cm wide; hooked hairs present on some parts of lamina and usually on sporangia.
4Pinnae 1-3 pairs; no buds at their bases.
4'Pinnae of well-grown plants more than 3 pairs; a bud always present at base of uppermost pinna.
5Pinnae always opposite; fertile pinnae with undulate margins; hooked hairs present on basal scales and on sporangia
5'Pinnae not always opposite; fertile pinnae sharply serrate-crenate distally; no hooked hairs on scales nor on sporangia
6Bud confined to base of uppermost pinna; pinnae widest in basal half; hydathodes on upper surface conspicuous
6'Buds present at bases of several pinnae; pinnae usually widest above middle; hydathodes not conspicuous 57. P. ramosii
7Hooked hairs present on sporangia
7'Hooked hairs lacking on sporangia