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|
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|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|
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|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|
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|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|
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|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|
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