1Fronds simple and linear, or dichotomously branched with linear branches (which in some non- Malaysian species are joined laterally), the sorophores borne laterally near the apex of the frond or of its branches; no indusia. Spores monolete
1'Fronds of young plants dichotomously branched, of older plants of indefinite growth with twining rachis, the rachis-branches variously branched and bearing leaflets which have sorophores at the ends of their veins; each sporangium protected by a separate indusium. Spores trilete