Entosthodon rubiginosus

Plants 3-5 mm, pale yellow-green. Leaves slightly contorted when dry, usually broadly ovate, 1.5-2.4 mm; margins entire or nearly so; apices acute to sub-acute, with a subulate tip; costa percurrent to excurrent into subula; basal laminal cells rectangular (75-100 × 30-40 µm), distal cells irregularly hexagonal to oblong rectangular, little differentiated at the margins. Seta 5-6 mm, straight. Capsule reddish brown with age, pyriform from a narrowed neck about half as long as the sporangium, about 2 mm, changing little when dry and empty, sometimes mouth flaring; exothecial cells thickened, narrowly oblong, with orange-brown walls, transversely elongate in 4-6 rows below the mouth; operculum convex-conic; peristome absent or rudimentary, exostome teeth pale brownish yellow, barely extending beyond the capsule rim and terminating in a rather blunt to short-acute point, slightly papillose, 2-3 articulations present, endostome not seen. Calyptra cucullate, long-beaked, inflated around the capsule, large, smooth. Spores 25-35 µm, rough (probably bacculate-insulate).

Sandy or silt-rich soil along river banks, gullies, seepage slopes, alkaline sloughs, and washes; moderate elevations; B. C.; Mont., N.Mex., Tex.

Portions of the above description of Entosthodon rubiginosus are based upon the original one by Williams. This species has been found recently at two new locations in British Columbia (T. T. McIntosh, pers. comm.).