| 1 | Rhizome long-creeping, fronds scattered at intervals of up to 7 cm. |
| 1' | Rhizome short-creeping, fronds tufted or spaced at intervals of at most 2 cm |
| 2 | Paraphyses peltate only (often completely absent in old sori), usually opaque with lumina of central cells almost entirely filled with wall material, lamina usually asymmetrically truncate below the spike |
| 2' | Paraphyses with laterally affixed blades nearly always present, usually translucent, lamina usually gradually and symmetrically narrowed below the spike |
| 3 | Rhizome scales with dentate to ciliate margin, all cells thick-walled |
| 3' | Rhizome scales entire or almost so, central cells thick-walled, marginal cells thin-walled |
| 4 | Sori completely covering the spike, the latter usually narrow, linear, 0.1-0.2 (rarely 1) cm wide |
| 4' | Sori leaving a clear marginal and sometimes also a narrow costal zone free, spike relatively wide, to 2 cm wide |
| 5 | Rhizome short, fronds tufted, scales dull with a dark brown centre and a lighter margin, lamina generally 1-2 cm wide |
| 5' | Rhizome more widely creeping, fronds scattered at intervals of up to 2 cm, scales uniformly light brown, glossy or iridescent, lamina generally 3 or 4, sometimes 6 cm wide |
