Dicranum crispum Hedwig, Sp. Musc. Frond., 132. 1801; Anisothecium crispum (Hedwig) Lindberg; A. vaginale (Withering) Loeske; Bryum vaginale Dickson

Plants to about 5 mm, yellow-green. Leaves 0.6-2 mm, the distal leaves squarrose and linear-subulate from a sheathing base, the proximal spreading-flexuose and lanceolate; margins plane, usually serrulate at the apex; costa percurrent (nearly filling the slender apex); distal cells 2-stratose, long and narrow (6-8:1). Sexual condition dioicous (also reported to be autoicous). Perichaetial leaves 2-3 mm, plainly squarrose. Seta red, 5-18 mm. Capsule erect or nearly so, tapered to the base and ribbed when dry, 0.7-0.9 mm; annulus of 2 rows of cells, deciduous or persistent; operculum rostrate, sometimes curved; peristome teeth 300-350 µm, divided ¹/2 of the length distally. Spores 17-20 µm, papillose to smooth.

Capsules mature spring and summer. Moist, often sandy or silty soil; medium to high elevations; Greenland; Alta., B.C., Man., Nfld. and Labr. (Nfld.), N.W.T., Nunavut, Ont., Que., Yukon; Alaska, Calif., Colo., Idaho, Mont., Oreg., Wash., Wyo.; n, c Europe.

The leaves of Dicranella crispa, particularly the distal, are wide-spreading from a clasping base, while the slender capsules are erect, tapered to the base, and distinctly striate. According to R. S. Williams (1913), the male inflorescence may be on a separate branch or separate plant. The distribution above includes reports by E. Lawton (1971) and D. H. Norris and J. R. Shevock (2004).