Etymology Glabella describes being rather smooth.

Description Rhizome: short-creeping or erect, orange-brown scales.
Frond: 35 cm high by 8 cm wide, evergreen, monomorphic, blade/stipe ratio: 1:1.
Stipe: dark purple to black, shiny, rounded above, croziers sparsely hairy at emergence, then glabrous, vascular bundles: 1.
Blade: usually 2-pinnate at the base, less above, linear, leathery, rachis glabrous or very sparsely hairy in some subtaxa.
Pinnae: 4 to 9 pair, bluish-green, lower pinnae stalked, upper sessile, a terminal pinna like the upper lateral ones; pinnules sessile or nearly so; margins entire; veins obscure.
Sori: oblong or linearly joined, submarginal, indusium: false, inrolled margins, sporangia: pale brown, maturity: early to late summer.

Culture Habitat: limestone substrates. Distribution: eastern North America, disjunct north-central North America and the Rocky Mountains. Hardy to -35°C, USDA Zone 3.

Distinctive Characteristics Similar to P. atropurpurea, but differing in monomorphism, smaller size, and particularly the glabrous stipe and rachis.

Synonyms
Pellaea glabella subsp. glabella Mettenius ex Kuhn
Pellaea atropurpurea (Linnaeus) Link var. bushii Mackenzie
Pellaea atropurpurea (Linnaeus) Link var. occidentalis E. E. Nelson
Pellaea glabella subsp. occidentalis (E. E. Nelson) Windham
Pellaea glabella var. nana (Richardson) Cody
Pellaea glabella var. occidentalis (E. E. Nelson) Butters
Pellaea occidentalis (E. E. Nelson) Rydberg
Pellaea pumila Rydberg
Pellaea glabella subsp. missouriensis (G. J. Gastony) Windham
Pellaea glabella subsp. simplex (Butters) A. Löve & D. Löve
Pellaea glabella var. simplex Butters, Amer. Fern J. 7: 84. 1917
Pellaea atropurpurea (Linnaeus) Link var. simplex (Butters) C. V. Morton
Pellaea occidentalis (E. E. Nelson) Rydberg subsp. simplex (Butters) Gastony
Pellaea suksdorfiana Butters