Plants tiny, olive-green. Leaves linear-lanceolate to ovate-lanceolate, stoutly subulate from oblong-ovate base, narrowly obtuse; costae ending in apex, filling subula; margins entire; leaf cells (1--)2:1; perichaetial leaves somewhat larger but similar to vegetative leaves, not much differentiated. Seta 1--1.5 mm, straight. Capsule ovate to hemispheric, as wide as long, widest at mouth only when old; peristome of 16 well-developed teeth; columella immersed. Spores 14--16 µm.

Calcareous substrates; Alta., Man., N.W.T., Nfld., Ont., Que.; Ark., Ind., Iowa, Ky., Mich., Minn., Mo., Mont., N.Y., Ohio, Pa., Tenn., Vt., Wis.; Europe.

Seligeria calcarea is relatively common in e North America from Newfoundland s to Arkansas, and known from a few stations in western Canada and Montana. While the long, stoutly subulate leaves are quite similar to those of S. donniana; the leaf margins of S. calcarea are entire and those of S. donniana are denticulate. The sporophytes of S. calcarea are generally distinctive: the capsules gradually contract to the seta though a shriveled neck, a well-developed peristome is present, and the length of the capsule equals or slightly exceeds the width. It is distinguished from S. pusilla in having a subula filled by an expanded costa, whereas S. pusilla has a slender costa ending in the apex.