Fissidens rigidulus Hook.f. & Wilson

Plants 5–80(–120) mm, yellow-green to dark green, black below, tufted or forming dense mats. Stems sparingly branched, with rhizoids in leaf axils and at base of branches. Leaves in 10–80 pairs, slightly overlapping to distant at mid stem, spreading to erect-spreading (in var. pseudostrictus), plane to decurved when moist, apex acute, laminae unistratose to partially and variably pluristratose; vaginant laminae ⅔–¾ leaf length, ⅔ closed to closed; dorsal lamina ending at leaf insertion, or shortly decurrent; margins entire to very weakly crenulate, bordered or unbordered (in var. pseudostrictus); cells of apical and dorsal laminae quadrate to irregularly hexagonal, smooth, non-bulging, firm-walled to incrassate. Costa sub-percurrent, bryoides-type in cross-section.

Dioicous. Perichaetia and sporophytes terminal or unknown (in var. pseudostrictus); perichaetial leaves longer than vegetative; Perigonia terminal. Setae orange-brown, wiry, 4–7 mm; capsules inclined, slightly asymmetric, 0.7–1.0 mm; operculum rostrate from a conic base, ½–⅔ the length of theca. Peristome bryoides-type; teeth with long-columnar papillae on the adaxial trabeculae below the bifurcation, 42–72 µm wide at base. Calyptra smooth, cucullate. Spores 17–20 µm.