Description: Terrestrial ferns with rhizomes short and tufted to long-creeping and freely branching, bearing narrow, dark brown to black, entire or toothed scales.
Fronds 1–4-pinnate, vernation circinate; stipe stiff, polished dark red-brown or black, scaly at the base, sometimes hairy above; segments of the lamina membranous to herbaceous, ± fan-shaped but often asymmetric at the base.
Sori ± reniform, borne on and covered by the strongly recurved marginal lobes forming false indusia, lobing often associated with notches or grooves in the margin of the segment.
Distribution and occurrence: World: 150–200 species, cosmopolitan. Australia: 8 species, all States.
Text by Peter G. Wilson, updated by Matt A.M. Renner (6 May 2020).
Taxon concept: Flora of NSW 1 (1990)
| | Key to the species | |
| 1 | Stalks of the ultimate segments attached at the centre of their bases, i.e. segments ± symmetric at base | 5 |
| Stalks of the ultimate segments attached at one corner, i.e. segments asymmetric at base | 2 |
| 2 | Rhizomes short-creeping or tufted; fronds with lamina simply pinnate or branched palmately or dichotomously | 3 |
| Rhizomes long-creeping; fronds with lamina branched pinnately
Back to 1 | 4 |
| 3 | Stipes black, slender; stipes and rachises glabrous; ultimate segments of fronds bearing minute, stiff black or brown hairs | Adiantum diaphanum |
| Stipes black, stout, slightly rough to scabrous; ultimate segments of fronds bearing minute, soft white hairs; stipes and rachises sparingly hairy with fine white hairs
Back to 2 | Adiantum hispidulum |
| 4 | Terminal primary pinnae very much shorter than the basal primary pinnae; rhizome deeply buried | Adiantum formosum |
| Terminal primary pinnae as long as the basal ones; rhizome on the soil surface
Back to 2 | Adiantum silvaticum |
| 5 | Soral flaps oblong, broadly attached to lamina, attachment usually occupying most of each lobe apex; soral flap sinus broad and shallow, notch lacking | Adiantum capillus-veneris |
| Soral flaps reniform, narrowly attached to lamina, attachment occupying central part of lobe apex only; soral flap sinus narrow, forming a notch at the junction with lamina
Back to 1 | 6 |
| 6 | Scales on rhizomes thin, yellow, transparent, broadly triangular, entire and often spirally curled | Adiantum aethiopicum |
| Scales on rhizomes triangular, dark brown, ± opaque, with shortly ciliate margins, not spirally curled
Back to 5 | Adiantum atroviride |
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