Small Limestone Moss

Seligeria tristichoides is relatively frequent in Alaska and western Canada, and is disjunct in Colorado, and in the east ranges from Newfoundland south to Vermont. This tiny gregarious species has a persistent columella and well-developed peristome. These features, along with the turbinate capsules and subulate vegetative leaves with costa filling the apex, are diagnostic. As the epithet attests, the leaves are often somewhat three-ranked.

Plants tiny, olive green to light green. Leaves lanceolate, to ovate-lanceolate, often stoutly subulate from broader base, narrowly obtuse to broadly acute; costa ending in apex or filling it; margins entire to crenulate; leaf cells (1-)2:1; perichaetial leaves larger and longer than vegetative leaves, somewhat differentiated. Seta 1-1.5 mm, slightly curved, stout. Capsule hemispheric to obovate-turbinate, flaring at mouth when old; peristome of 16, broad, well-developed teeth; columella exserted. Spores (15-)18-24 µm.

Seligeria tristichoides Kindb. Rev. Bryol. 23: 20. 1896
Seligeria trifaria palula Lindb. Oefv. Sv. Vet.-Akad. Forh. 21: 189. 1864. Seligeria tris'.icha laxa Holz. Bryologist 5: 9. 1902. Seligeria tristichoides laxa Holz. Bryologist 5; 63. 1902.
Plants in bright-green cushions, mixed with lime; stems 3-5 mm. high, crowded and branching, with numerous short sterile, triquetrous innovations: leaves bright-green, spreading or refle.xed, tristichous, 1-1.5 mm. long, lanceolate-subulate from a pale hyaline base; costa percurrent into a rough thick point, not quite filling the awn, ending in a short apical cell; lower cells linear, the upper cells shorter with thick projecting walls; perichaetial leaves longer, erect or spreading, the point scabrous and broader, almost reaching the base of the capsule. Autoicous: antheridia few, in clustered axillary or basal buds: seta erect, or slightly curved, 1-1.5 mm. long, stout: calyptra cucullate, 1 mm. long: capsule ovoid, becoming hemispheric when empty; lid rostrate, 0.5 mm. long; columella more or less persistent and exserted; mouth broad, bordered by darker denser cells; neck lacking; stomata imperfect, around the middle of the capsule; walls with thick irregular hexagonal cells, pustulose when dry; peristome red, inserted below the mouth; teeth incurved, smooth, occasionally perforate, with 10-12 narrow joints: spores yellow, minutely roughened, 18-24 ^ in diameter, maturing in June.
Type locality: Northern Norway.
Distribution: Cliff at Willoughby Lake, Vermont; also in France, on the slopes of the Pyrenees, and Norway.
Illustratio.v: Bryologist 5: 8./. 2-5.