Polypodiaceae

Abstract

Usually terrestrial or epiphytic, sometimes epilithic, usually small to medium-sized, sometimes large ferns with short- to long-creeping stem bearing basifixed, pseudopeltate or peltate, clathrate, opaque or hyaline scales that are marginally entire, toothed, ciliate, or lacerate, and provided with at least a terminal glandular cell; stele dorsiventral, dictyostelic. Leaves close to remote, usually articulate to phyllopodia, mono- or sometimes dimorphic. Petiole variously developed, sometimes winged, variously scaly or glabrous, with several vascular bundles in a U-arrangement, the adaxial ones larger and with hooked xylem strands; adaxial face of petiole usually terete or with a median groove. Lamina simple, lobed to pinnatifid and costate, or simply pinnate, rarely bipinnate, pedate, or dichotomously compound; pinnae costate, often articulate at base; terminal segment, if present, conform to pinnae or the lamina terminally with gradually reduced and confluent divisions; laminal hairs glandular, usually 2- or 3-celled, sometimes otherwise; scales often present, variously shaped; veins free, simple or forked, or variously anastomosing with or without included free veins. Fertile leaves sometimes with contracted laminai parts. Sori usually rounded, sometimes elongate, linear, or sporangia acrostichoid, sori often diplodesmic; sporangia short- to rather long-stalked, the stalk mostly 3-seriate; capsule with vertical, interrupted annulus; stomium 2-celled, not continuous with the bow; receptacular trichomes and/or scales of varying shape often present; sporangial appendages and sporangiasters sometimes present. Spores usually 64 per sporangium, rarely 8 (Platycerium ridleyi) or 16 (Lecanopteris p. p.), monolete, usually ± bean-shaped, rarely fusiform, very rarely trilete, white, yellow or brown, with or without a prominent, variously shaped perispore (Fig. 106).