Leskea rupestris Berggren, Acta Univ. Lund. 3(7): 9, figs. 10-13. 1866; Leskeella nervosa var. sibirica (Arnell) E. Lawton; Pseudoleskeella sibirica (Arnell) P. S. Wilson & D. H. Norris

Plants green, red-green, or orange-green. Stems somewhat loosely appressed to substrate, branches curved to erect. Stem leaves not catenulate when dry, not homomallous, broadly lanceolate to ovate-lanceolate, gradually narrowed to apex, not or weakly concave, not plicate, 0.5-1.5 mm, 3:1; base not flaring or cordate; margins plane or weakly recurved, entire or weakly serrulate distally; apex short-acuminate, not falcate; costa usually single, rarely 2-fid near tip, strong, to mid leaf or into acumen, somewhat flared in acumen; medial laminal cells 2-3:1, walls incrassate. Branch leaves ovate-lanceolate, 0.5-1.2 mm; laminal cell walls thin. Stoloniferous leaves broadly ovate-lanceolate to ovate. [Seta brown or red-brown, 0.1-0.3 cm. Capsule erect, cylindric, symmetric, 2-3 mm. Spores 8-12 µm].

Capsule maturity unknown. Dry shaded calcareous rock; low to high elevations (0-3000 m); Greenland; Alta., B.C., Man., Nfld. and Labr., Nunavut, Ont.; Alaska, Colo., Idaho, Minn., Mont., Utah, Wyo.; w, n Europe.

Pseudoleskeella rupestris is similar to Leskeella nervosa, and should probably be included in that genus. According to W. A. Weber andr. C. Wittmann (2007), plants of P. rupestris from Colorado bear clustered flagelliform branchlets in axils of distal secondary branch leaves, a characteristic trait of L. nervosa. The leaves are irregularly twisted when dry.