Leaves ovate-lanceolate to long-subulate from an ovate or obovate base, serrulate at apex; costa percurrent or ending before the apex. Seta long, 10-30 mm. Capsule inclined, curved; neck 2-3 times as long as urn when dry, long-cylindric, strumose at base; peristome teeth 2-fid or irregularly perforate, not fragile, commonly persistent; annulus compound, revoluble.
The wider definition of this species is adopted here. A capsule neck that is consistently twice as long as the urn, strongly perforated peristome teeth without free filaments, and papillose spores without obvious tetrad scar, separate T. longicollis from the other species. Although gametophytically similar to several other species, identification has not been a problem, as all collections examined have numerous sporophytes.
Plants small to medium, gregarious or in loose tufts, green; terricolous. Stems 1-7 mm high; in section central strand large, cortical cells large, lax, becoming smaller with thicker walls toward margin. Leaves contorted above erect base dry, erect to spreading wet; oval to oblong, abruptly subulate, 2-4 mm long; apex bluntly acute; base sheathing; margin bistratose in subula, with a few projecting cells above, apex frequently toothed. Costa subpercurrent to percurrent; in section flattened, guide cells 6, ventral stereid band small, 3-4 cells in single central row, ventral surface cells smaller than guide cells, covering entire costal surface or restricted to area above ventral stereid band and exposing guide cells laterally, dorsal stereid band 1-3 cells thick, extending across costa, dorsal surface cells smaller than guide cells, occasionally some cells larger, extending upward interrupting stereid band. Laminal cells short-rectangular to quadrate above shoulders; basal cells large, lax, rectangular to oblong-hexagonal. Perichaetial leaves oblong-subulate, 3-4 mm long. Seta 6-15 mm long, yellowish; capsule erect, yellow, urn cylindical, 1.2-1.6 mm long, neck 2.2-3.5 mm long, strumose; peristome reddish, teeth lanceolate, 340-360 µm high, perforated, without free filaments, vertically barred below, upper segments papillose, yellowish, fringe present between teeth, weak, papillose, hyaline; operculum long-beaked, 1.0-1.5 mm high; calyptra cucullate; spores round, 22-25 µm, bluntly papillose.
Plants small to medium-sized, gregarious or in loose tufts. Stems 1-7 mm long. Leaves contorted above erect base when dry, oval to oblong, abruptly subulate, 2-4 mm long; apex bluntly acute; base sheathing; margins bistratose in subula; costa subpercurrent. Laminal cells short-rectangular to quadrate; basal cells large, lax. Capsule erect, urn cylindrical, neck twice as long, strumose; peristome reddish, teeth lanceolate, fringe present between teeth. Spores papillose.