Gemmae absent.

Capsules mature fall. Soil, sandstone, calcareous rock, bluffs, boulders, under overhanging ledges, seepage areas, logs; 0--2300 m; B.C., N.B., N.W.T., Ont.; Ala., Alaska, Ariz., Ark., Calif., Colo., Iowa, Ky., Mass., Maine, Md., Mich., Mo., Mont., N.H., N.Y., N.C., Ohio, Penn., Tenn., Tex., Vt., Va., Wash., W.Va.; Mexico; West Indies; Central America; South America; Eurasia; Africa; Indian Ocean Islands; Pacific Islands (Hawaii, New Zealand); Australia; Arctic.

H. A. Crum and L. E. Anderson (1958) detailed the abundant variation between specimens with very narrow, often fragile (W. C. Steere 1978) leaves and those with comparatively broad leaves, the latter commonly identified in herbaria as var. holtii (Braithwaite) Dixon. The species often has a thin line of hyaline cells running up each leaf margin from the differentiated proximal cells, but this is largely of a single row of cells rather than a distinctly tapering broad wing of a V. Although the Mexican type of Trichostomum mollissimum (Brotherus) H. A. Crum is Pseudosymblepharis schimperiana (Paris) H. A. Crum with typical bushy, crowded linear-lanceolate leaves, specimens from the range of the flora previously identified under the former name are T. tenuirostre. Trichostomum tenuirostre, T. spirale¸and T. recurvifolium share a similar areolation by the leaves with a band of rather thick-walled rectangular cells between the thinner walled basal cells and the distal medial cells.