1	"Sori borne only on a reflexed modified flap of lamina (soral flap)."	Adiantum
1	"Sori superficial, marginal or submarginal, sometimes covered by a reflexed flap of lamina but not borne on that flap, or protected by a marginal indusium."	2
2	"Sori superficial, borne along the length of the veins, exindusiate."	3
2	"Sori marginal or submarginal, continuous or interupted."	4
3	"Lamina herbaceous to thinly coriaceous; abaxial surface usually with a white or golden yellow waxy coating."	Pityrogramma
3	"Lamina membraneous to thinly herbaceous; abaxial surface lacking a coloured waxy coating."	Anogramma
4	"Ultimate segments usually more than 10 mm long; if less then fronds only once pinnate."	Pellaea
4	"Ultimate segments 8 mm or less long; fronds at least pinnate-pinnatifid"	Cheilanthes