Bot. Gaz. 13: 202. 1888
Plants medium-sized, in dense tufts, light green when young, golden or brownish yellow with age. Stems to 10 cm, densely regularly pinnate, branches 5–7 mm, curved to almost circinate. Stem leaves erect-appressed, triangular-lanceolate, (1–)1.3–2(–2.5) × (0.2–)0.5–0.7(–0.8) mm; base short-rounded, narrowly decurrent; margins plane or often recurved at places, serrulate or subentire; apex acuminate or gradually tapered; costa to 70–95% leaf length, terminal spine present; alar cells ovate, 6–7 µm wide, walls thick, region of 5–10 × 6–10 cells, moderately distinctly delimited, opaque to moderately translucent; laminal cells linear-flexuose, 30–85 × 5–6 µm; basal cells irregularly long-ovate, region in 1–3 rows, indistinctly delimited from distal cells. Branch leaves appressed when dry, spreading when moist, lanceolate, 1–1.7(–2.1) × 0.2–0.4 mm; margins plane or recurved at places, serrulate or serrate proximally and in alar region, entire or minutely serrulate distally; apex narrowly acute to acuminate; costa to 75–95% leaf length, variable within one shoot, terminal spine present; alar cell shape irregular, 5–10 µm wide, walls strongly incrassate, region of 2–10 × 3–8 cells, distinctly delimited; laminal cells linear-flexuose, 25–65 × 4–6 µm; basal cells in 1 (or 2) rows; distal cells smooth. Sexual condition phyllodioicous or dioicous. Seta 0.7–1.5 cm, rough proximally, sometimes slightly so, smooth distally. Capsule erect, narrowly cylindric, straight to slightly curved, 2–2.5 mm; annulus separating by fragments; operculum long-conic to rostrate; peristome hygrocastique; exostome teeth with long transitional zone; endostome basal membrane short, segments as long as exostome teeth, very narrow, cilia absent or less than 1/4 segment length. Spores 9–16 µm.
Habitat: Calcareous rock, quartzite, granite, rotten logs, trunks, soil, forests, open areas
Elevation: low to high elevations (0-3100 m)
Alta., B.C., Calif., Colo., Idaho, Mont., Nev., Oreg., Utah, Wash., Wyo.
Homalothecium nevadense has stem leaf costae that are stout to the end, as does H. aeneum; the branch leaves may be straight, homomallous, or falcate-secund; and the spores are smooth.