Kay ex Copeland 1949, Philip. J. Sci. 77:461 (as Athyrium)
| 1a. | Veins free | 2 |
| Veins anastomosing | 35 | |
| 2a. | Frond tripinnatifid or more dissected | 3 |
|
Frond bipinnate, not nearly tripinnate |
18 | |
| 2c. | Pinnae pinnate at base, elsewhere subpinnate | 25 |
| 2d. | Pinnae deeply pinnatifid | 26 |
| 2e. | Pinnae incised or lobed | 30 |
| 2f. | Pinnae serrate | A. pallidum |
| 2g. | Pinnate crenate, sinuate or entire | 33 |
| 3a. | Small ferns, mostly under 20 cm tall | 4 |
| Size moderate or large | 5 | |
| 4a. | Palae and lamina brownish | A. minutum |
| Entire plan blackish | A. squamuligerum | |
| 5a. | Size moderate to 60 cm tall | 6 |
| Large ferns | 8 | |
| 6a. | Axes light brown | 9 |
| Axes dark brown | A. scotinum | |
| 7a. | Pinnae obtus to acute | A. setiferum |
| Pinnae acuminate | A. myerdreesii | |
| 8a. | Fully tripinnate | 9 |
| Tripinnatifid | 12 | |
| 9a. | Secondary pinnules incised | 10 |
| Secondary pinnules entire | 11 | |
| 10a. | Sori enlongate | A. huttonii |
| Sori short, basal | A. decompositum | |
| 11a. | Rachises furfuraceous | A. latilobatum |
| Rachises naked except at nodes | A. pedicellatum | |
| 12a. | Sori short | 13 |
| Sori elongate | 14 | |
| 13a. | Segments 4 mm wide | A. woodwardioides |
| Segments 2-3 mm wide | A. sylvaticum | |
| 14a. | Indusium lacerate | 15 |
| Indusium entire | 17 | |
| 15a. | Veins nearly all simple | A. blumei |
|
Forked veins not rare |
16 | |
| 16a. | Pinnules 25 mm wide | D. nymannii |
| Pinnules 15 mm wide | D. schraderi | |
| 17a. | Segments 12 x 3.6mm | D. schlechteri |
| Segments 10 x 5mm | D. schultzei | |
| 18a. | Lamina think | 19 |
| Lamina firm | 20 | |
| 19a. | Sori short | A. setiferum |
| Sori elongate | A. morobense | |
| 20a. | Small fern, mostly under 20 cm tall | A. squamuligerum |
| Much larger | 21 | |
| 21a. | Pinnules cut 2/3 to costa | D. opacifolium |
| Pinnules cut 1/3 - 1/2 to costa | 22 | |
| 21c. | Pinnules more shallowly toothed | 24 |
| 22a. | Pinnules up to 6 cm long | 23 |
| Pinnules commonly 12 cm long | A. davaoense | |
| 23a. | Lamina over 50 cm long | A. nitens |
| Lamina under 30 cm long | A. morobense | |
| 24a. | Pinnules over 10 cm long | A. maximum |
| Pinnules 3-5 cm long | A. cyatheifolium | |
| 25a. | Palae of stipe elongate, short ciliate | A . uncidens |
| Most palae reduced to tufts of hairs | A. keysseri | |
| 26a. | Stellate palae present | 27 |
| Stellate palae absent | 28 | |
| 27a. | Indusium linear |
A. protensum |
| Indusium wanting | A. asterothrix | |
| 28a. | Stipe and rachis dark | 29 |
| Axes stramineus or greenish | Lunathyrium japonicum | |
| 29a. | Pinnae c.2.5 cm wide | A. sorzogonense |
| Pinnae c. 6 cm wide | A. archboldii | |
| 30a. | Pinnae subcordate |
31 |
| Pinnae truncate or cuneate at base | 32 | |
| 31a. | Lacerate squamules present | A. weinlandii |
| Lacerate squamules wanting | A. crenatoserratum | |
| 32a. | Sori elongate | A. bulbiferum |
| Sori hore-shoe-shaped | A. ledermannii | |
| 33a. | Pinnae c. 1 cm wide | 34 |
| Pinnae much wider | A. fraxinifolium (?=A. bantamense) | |
| 34a. | Stipe and rachis stramineous | A. flavoride |
| Stipe and rachis black, scaly | A. fuliginosum | |
| 35a. | Fronds bipinnate | A. esculentum |
| Fronds pinnate or simple | 36 | |
| 36a. | Base of pinnae cuneate | 37 |
| Frond usually simple, base cordate | A. cordifolium | |
| 37a. | Axes brown, naked | A. fraxinifolium (?=A. bantamense) |
| Axes black, scaly | A. cumingii |
Diplazium merrillii = D. lomariaceum