Small Limestone Moss

Seligeria calcarea is relatively common in eastern North America from Newfoundland south to Arkansas, and known from a few stations in western Canada and Montana. While its 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. Seligeria calcarea is distinguished from S. pusilla in having a subula filled by an expanded costa, whereas the latter has a slender costa ending in the apex.

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.

Weissia calcarea Hedwig, Sp. Musc. Frond., 66. 1801

Seligeria calcarea (Dicks.) B.S.G. Bryol. Eur
(33-36:) Selig. 4. 1846.
Bryum catcareum Dicks. PI. Crypt. Brit. 2: 3. 1790. Weisia calcarea Hedw. Sp. Muse. 66. 1801.
Plants small, gregarious; stems short, less than 1 mm. high, leafless below, branching by basal buds: leaves crowded at the apex, erect, short, less than 1 mm. long, ovate, abruptly subulate from a broad clear, clasping, sometimes toothed base; costa broadening into and forming the blunt, thick, subulate awn; basal cells clear, rectangular, the upper ones dense, square; perichaetial leaves erect, clasping, longer and broader, 0.5-1 mm. long. Autoicous: antheridia in basal buds, the bracts veinless: seta 2 mm. long, thick, erect, twisted: calyptra cucullate, 0.75 mm. long: capsule ovoid-pyriform, 0.5 mm. long; neck distinct; walls thickened, the cells irregular; stomata absent or imperfect and median; mouth broad, bordered by 3-4 rows of cells; lid conic-rostrate; peristome incurved or recurved, red-brown; teeth fragile, smooth, and thickened at the joints: spores 14-18 ^i in diameter, slightly rough, maturing in summer.
Type locality: Newmarket Heath, England.
Distribution: Very rare, on wet limestone rocks, near Columbus, Ohio; Ontario to Manitoba; also in Europe.