Arctoa 19: 30. 2011.
Plants moderately small to medium-sized, in loose or moderately dense tufts, green to yellowish. Stems to 5 cm, creeping, terete-foliate, not julaceous, irregularly to regularly pinnate, branches to 10 (–15) mm, terete or subcomplanate-foliate. Stem-leaves erect at base, densely to loosely arranged, often loosely arranged at shoot ends, falcate-secund, ovate or ovatelanceolate, slightly to moderately plicate, rarely not plicate, 1.4–2.5 × 0.3–0.5 (–0.7) mm; margins plane or recurved in places (more commonly proximally), serrulate to base, rarely subentire; apex gradually or abruptly long-acuminate, acumen often falcate or flexuose; costa to 50–75% leaf length, terminal abaxial spine small; alar cells subquadrate, 10–25 × 8–15 µm, region extensive, triangular, of 8–10 × 5–8 cells, fairly distinctly delimited; laminal cells linear, 50–90 × 45–10 µm; basal juxtacostal cells shorter, to 8–10 µm wide, indistinctly delimited. Seta reddish, 1–1.5 cm, smooth or slightly rough distally. Capsule inclined, sometimes slightly erect, reddish, ovate, 1–2 mm; endostome basal membrane 1/5–1/3 endostome length, cilia short to absent. Spores 10–15 µm.
Habitat: Soil, damp to dry rock, shaded places, under overhanging rock and exposed tree roots
Elevation: moderate to high elevations (1500-1900 m)
Brachytheciastrum delicatulum is characterized by narrow leaves, many of them more than five times longer than wide, rather numerous alar cells, and, usually, an almost erect capsule with a reduced peristome. The branch leaves are lanceolate to linear. The species is known only from Millard County.
"long" is not a number."broad" is not a number.