1. Homalotheciella subcapillata (Hedwig) Brotherus in H. G. A. Engler and K. Prantl, Nat. Pflanzenfam. 232/233[I,3]: 1133. 1908.
Pterigynandrum subcapillatum Hedwig, Sp. Musc. Frond., 83, plate 16, figs. 7-12. 1801; Burnettia fabrofolia Grout; Homalotheciella fabrofolia (Grout) Brotherus; Homalothecium subcapillatum (Hedwig) Sullivant; P. brachycladon P. Beauvois ex Bridel; Pterogonium decumbens Schwagrichen
Plants glossy. Stems 0.2 cm, branches short, ascending-erect, straight or often curved. Leaves 0.7-1.3 × 0.3-0.5 mm; margins plane; alar cells in 2-5 vertical rows; laminal cells 40-60 × 5 µm, smooth. Perigonia gemmiform, axillary on stem. Seta 0.5-1 cm, straight. Capsule exserted, 1-1.5 mm, smooth or wrinkled-plicate when dry; exothecial cells oblong-rectangular; stomata few, proximal on capsule; peristome pale; exostome teeth pale yellow-orange, 300 µm, external surface finely cross striolate, internal surface transversely ridged, fimbriate-bordered, papillose at apices. Calyptra 2 mm.
Capsules mature Sep-Feb. Trunks of soft-barked trees, logs, roots, stumps, rock, mesic to wet forests; low to high elevations (0-2000 m); Ala., Ark., Conn., Del., D.C., Fla., Ga., Ill., Ind., Ky., La., Maine, Md., Miss., Mo., N.J., N.Y., N.C., Ohio, Pa., S.C., Tenn., Tex., Va., W. Va.
Homalotheciella subcapillata is distinguished as small, glossy, creeping, pinnate plants bearing leaves with long, slender tips crowded on short branches. The species is easy to recognize under the microscope by its leaves with denticulate margins, weak costa, and quadrate alar cells. The delicately haired calyptra also is distinctive among Brachytheciaceae, as most species of the family have naked calyptrae. Pylaisiella selwynii (Hypnaceae) can be very similar to H. subcapillata, but differs in its more regularly curved branches and ecostate entire-margined leaves.