RHIZOMES: 4-8 mm in diameter, short- to more commonly long-creeping, usually unbranched, the scales 3-7 mm long, lanceolate, acuminate at the tip, monomorphic, brown, the margins ciliate, the surface minutely hairy.

LEAVES: closely to relatively widely spaced, 50-130 cm long.

PETIOLES: longitudinally grooved adaxially, straw-colored, sparsely scaly toward the base, at least when young, the scales similar to those of the rhizome, sparsely to moderately pubescent distally with minute spreading needle-like hairs.

RACHISES: similar to petioles, moderately to densely hairy.

BLADES: 15-45 cm wide, triangular-ovate, with numerous lateral pinnae, the basal 1 or 2 pairs of pinnae slightly reduced, the pinnae evenly or more commonly abruptly reduced toward the elongate pinnatifid tip.

PINNAE: mostly 7-22 cm long, 10-22 mm wide, lobed 1/2-4/5 of the way to the costa, the acroscopic basal lobe of proximal pinnae often slightly longer than the adjacent lobes, the basiscopic basal lobe of distal pinnae often fused to the rachis, the costae and costules minutely hairy and with sparse minute scales abaxially (Fig. 2).

LOBES: with the margins often somewhat curled under, minutely hairy on both surfaces or the surface glabrous adaxially.

SORI: more or less medial.

INDUSIA: withering prior to soral maturity, densely pubescent with minute needle-like hairs.

PARAPHYSES: absent.

SPORANGIA: glabrous.

SPORES: 35-55 mm long, the surface rugose, dark brown. 2n = 144.

NOTES: 2 vars., 1 in AZ. This taxon has been treated variously as one of ca. 900 spp. of a broadly circumscribed Thelypteris, among the ca. 580 species of a broadly circumscribed Cyclosorus Link (but no combination is available there) when an intermediate number of genera are recognized, or one of 60 or more mostly Old World species of Christella Lév. in the most finely dissected classification.

REFERENCES: Yatskievych, G. and M.D. Windham. Vascular Plants of Arizona: Thelypteridaceae. CANOTIA 5 (1): 49-52, 2009.