1	"Lamina 1-pinnate"	2
1	"Lamina 2–4 (–5)-pinnate"	3
2	"Lowermost pinnae obliquely ovate-flabellate, on stalks to c. 15 mm long; root tubers lacking; rachis often extended beyond the pinnae, with a proliferous bud near its apex"	"Adiantum philippense"
2	"Lowermost pinnae dimidiate on stalks to c. 3 mm long; root tubers present, often proliferous; apex of lamina terminated by a pinnule, never proliferous"	"Adiantum diaphanum"
3	"Pinnules flabellate to ±round, symmetric about their stalks"	4
3	"Pinnules mostly obliquely oblong-obovate to rhomboid, asymmetric about their stalks"	7
4	"Soral flaps broadly attached to lamina, usually occupying most of each lobe apex; notch lacking"	"Adiantum capillus-veneris"
4	"Soral flaps narrowly attached to lamina, notched at the junction with lamina"	5
5	"Scales on rhizome and base of stipe dark brown, ±opaque, with denticulate to finely ciliate margins"	"Adiantum atroviride"
5	"Scales on rhizome and base of stipe golden brown, translucent, with entire margins"	6
6	"Rhizome very short-creeping, horizontal to suberect; stolons never produced"	"Adiantum atroviride"
6	"Rhizome short- to medium-creeping, horizontal; stolons freely produced"	"Adiantum aethiopicum"
7	"Rhizome erect; fronds tufted"	8
7	"Rhizome long-creeping; fronds scattered"	9
8	"Pinnules membranous, with scattered opaque black single-celled setae, these also present on soral flap; all surfaces very rarely glabrous; root tubers present, often proliferous"	"Adiantum diaphanum"
8	"Pinnules herbaceous to coriaceous, with subopaque white multi-celled hairs, similar but usually darker hairs also present on soral flaps; root tubers always absent"	"Adiantum hispidulum"
9	"Primary pinnae progressively reducing in length and degree of branching from base to apex of frond, resulting in a ±triangular lamina outline"	"Adiantum formosum"
9	"Primary pinnae with ±same length and degree of branching, resulting in a ±ovate lamina outline"	"Adiantum silvaticum"