Pellaea atropurpurea is a fern, from a densely short-branched, wooly rhizome.
Leaves tufted, evergreen 20-40 cm long; leaf stalk 1-23 cm long, shorter than blade, wiry, stiff, dark purplish, finely hairy; blade once or twice pinnate, pinnae 5-11 pairs, short-stalked, with 3-11 leaflets 1-7.5 cm long, 0.5-1 cm wide, axis and leaflet stalks dark, wiry, fertile leaflets narrower than sterile, linear, margins rolled under, eventually opening out.
Spore cases continuous along margins of leaflet undersides.
Wetland status: UPL.
Frequency in NYC: Very infrequent.
Origin: Native to NYC.
Habitat: Scattered individuals on the cliff-like stone part of the Metro North RR trestle. Normally on limestone cliffs or walls.