1	"Stalks of the ultimate segments attached at the centre of their bases, i.e. segments ± symmetric at base."	2
1	"Stalks of the ultimate segments attached at one corner, i.e. segments asymmetric at base."	3
2	"Scales on rhizomes thin, yellow, transparent, broadly triangular, entire and often spirally curled."	"Adiantum aethiopicum"
2	"Scales on rhizomes triangular, dark brown, ± opaque, with shortly ciliate margins, not spirally curled"	"Adiantum atroviride"
3	"Rhizomes short-creeping or tufted; fronds with lamina simply pinnate or branched palmately or dichotomously."	4
3	"Rhizomes long-creeping; fronds with lamina branched pinnately."	5
4	"Stipes black, slender; stipes and rachises glabrous; ultimate segments of fronds bearing minute, stiff black or brown hairs."	"Adiantum diaphanum"
4	"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."	"Adiantum hispidulum"
5	"Terminal primary pinnae very much shorter than the basal primary pinnae; rhizome deeply buried."	"Adiantum formosum"
5	"Terminal primary pinnae as long as the basal ones; rhizome on the soil surface."	"Adiantum silvaticum"