| 1 | Rhizome covered with peltate scales (Subg. Myrmecopteris) |
| 1' | Rhizome not covered with peltate scales (Subg. Lecanopteris) |
| 2 | Rhizome massive, strongly flattened, arched, scales sparse, not completely covering the surface |
| 2' | Rhizome hollow, thick, scales dense, covering the surface |
| 3 | Fronds simple, rhizome little-branched |
| 3' | Fronds pinnatifid, rhizome frequently branched |
| 4 | Rhizome a uniform structure, all branches hollow, scales mostly with a brown centre |
| 4' | Rhizome consisting of solid, frond-bearing main branches and hollow, ovate or irregularly shaped, frondless lateral branches, the scales mostly with a blackish centre |
| 5 | Rhizome and fronds glaucous, naked |
| 5' | Rhizome green, with spines, coralloid outgrowths or dense glandular indumentum (lens!), or stipe and rachis with hairs below |
| 6 | Rhizome with spines or coralloid outgrowths in two rows, replacing fronds; a single internal gallery system; and hollow, protruding phyllopods |
| 6' | Rhizome with irregular, dense cover of spines or coralloid outgrowths not replacing fronds; two internal gallery systems; and solid phyllopods |
| 7 | Rhizome with hollow spines; fronds entire to pinnatifid |
| 7' | Rhizome with solid spines or coralloid outgrowths; fronds pinnatifid |
| 8 | Rhizome with coralloid outgrowths 1-3 cm long |
| 8' | Rhizome with spines |
| 9 | Large plants; rhizome 2.5-3.5 cm thick, with abundant spines; fronds up to 1 m long |
| 9' | Smaller plants; rhizome to 2.5 cm thick, with few spines; fronds up to 45 cm long |
| 10 | Rhizome covered with short hairs and scattered scales, stipe and rachis glabrous, sori round |
| 10' | Rhizome glabrous except near apex, stipe and rachis with persistent hairs below, sori laterally flattened |
| 11 | Fronds simple, sori deeply immersed on lamina |
| 11' | Fronds pinnatifid, sori on marginal lobes |
| 12 | Veins not sclerified, green, sori on stalked, unreflexed lobes |
| 12' | Veins sclerified, appearing black; sori on unstalked, reflexed lobes. |
