Entosthodon tucsonii

Plants 2-5 mm, pale yellow-green. Leaves variously contorted when dry, oblong-lanceolate to narrowly obovate, imbricate, somewhat concave, mostly 2.5-4 mm; margins serrulate to serrate by projecting ends of thin-walled cells; apices gradually narrowed to an acumen bearing a filiform tip of 3-4 cells; costa ending 4-7 cells before the awn; basal laminal cells rectangular (85-110 × 32-40 µm), distal cells irregularly rectangular to oblong-rectangular, or polygonal, somewhat rhomboid near the margins. Seta brownish, 6-10 mm, straight, not hygroscopic. Capsule ovoid-pyriform from a long neck approximating half the total length, 2-3 mm, sulcate especially in the neck when dry and empty; exothecial cells scarcely thickened, oblong (2-3:1) and transversely elongate in 5-7 rows proximal to the mouth; operculum rounded-conic; peristome rudimentary or absent, exostome teeth brownish, irregularly blunt tipped, striate-papillose, endostome segments shortly rounded triangular, extending to about the tooth middle, smooth. Calyptra cucullate, long-beaked, inflated around the capsule, large, smooth. Spores 32-40 µm, papillose.

Sandy soils, along intermittent desert streams; moderate to high elevations; Ariz., Calif., Colo., Tex.