Ctenitis (C.Chr.) C.Chr.

Caudex short, erect or suberect or rarely prostrate, its apex and the bases of stipes densely covered with thin flat scales which are not more than 1 mm wide at their bases, stipes scaly throughout, with a ± abrupt change from the long basal scales to shorter ones of two different types, distinctive for each species; lamina always bipinnate at the base, the basiscopic pinnules of basal pinnae always longer than the acroscopic ones, the basal ones usually longest and very deeply lobed, in some species pinnate to bipinnate near their bases; distal pinnae or pinnules ± adnate to the rachis and ± decurrent at their bases but their basal basiscopic veins almost always arising from the pinna-or pinnule-midrib; texture of lamina mostly thin with veins distinct on both sides but in some species opaque with the smaller veins indistinct; veins all free, those in each pinna-lobe all arising from the costule of the lobe (not from the costa of the pinna); lower surface of pinna-rachis or pinna-midrib always bearing scales which are progressively smaller distally, similar scales also present on costae of pinnules, some ctenitoid hairs also present and often appressed cylindric unicellular glands, such glands also often present between veins, sometimes with the addition of short hairs of various kinds; upper surface of pinna-rachis or pinna-midrib and of costae of pinnules prominent, always covered with ctenitoid hairs which are thicker than those on the lower surface, similar hairs scattered on veins but not between veins where appressed cylindric glands or short non-ctenitoid hairs may occur; sori usually medial on the veins, not terminal; indusia usually present, sometimes very small and hidden by the mature sporangia, always unpigmented, thin and fragile, usually bearing marginal cylindric glands when young; spores of two distinct kinds.