| 1 | Body of sporangium lacking setae. |
| 1' | Body of sporangium bearing setae. |
| 2 | Pinnae 4-6 cm wide; edges distinctly serrate throughout |
| 2' | Pinnae 2.5-3.5 cm wide; edges entire or nearly so. |
| 3 | Excurrent veinlets mostly free; sori close to costules |
| 3' | Excurrent veinlets mostly not free; sori not close to costules |
| 4 | Pinnae one pair, a bud at the base of each |
| 4' | Pinnae several pairs on adult plant; no buds present. |
| 5 | Caudex long-creeping; veins very oblique; several acicular hairs on stalk of sporangium |
| 5' | Caudex short-creeping; veins at a broad angle to costules; a hair of 2-3 cells, not acicular on stalk of sporangium |
