Atro means dark, and purpurea means purple. See the description of the stipe.
Rhizome: short-creeping, orange-brown scales.
Frond: 50 cm high by 18 cm wide, evergreen, somewhat dimorphic, sterile shorter and less divided than fertile fronds, blade/stipe ratio: 2:1.
Stipe: dark purple to black, shiny, rounded above, scales uniformly reddish brown (or tan), linear, at base, vascular bundles: 1.
Blade: usually 2-pinnate at the base, but sometimes more or less, elongate-deltate, leathery, rachis hairy, sparsely villous below near midrib of ultimate segments.
Pinnae: 5 to 9 pair, bluish-green, lower pinnae stalked, upper sessile, a terminal pinna like the upper lateral ones; pinnules sessile or nearly so; veins obscure.
Sori: oblong or linearly joined, submarginal, indusium: false, inrolled margins, sporangia: brown, maturity: early to late summer.
Habitat: on calcareous rocks.
Distribution: Guatemala to northeastern North America to Florida.
Hardy to -30°C, USDA Zone 4.
Similar to P. glabella, but differs in being taller, more upright, more divided, and particularly, the hairs on the rachis and costae.
Pteris atropurpurea Linnaeus
Pellaea atropurpurea var. cristata Trelease