Plants: shiny light green, yellow-green, or white-green, light brown below. Stems: 0.5–1 cm, somewhat julaceous, strongly branched. Leaves: imbricate when dry, erect to erect-spreading when moist, elliptic to oblong, 0.5–1 mm; margins plane; apex rounded-obtuse to broadly acute, apiculus absent; costa subpercurrent, yellowish; laminal cells 40–80(–100) × 10–20 µm; distal cells at apex irregularly short-rectangular to subquadrate. Seta: red-brown, 0.3–0.7 cm, flexuose. Capsule: horizontal to nutant, short and broadly pyriform, 1.2–2.5 mm; operculum convex, umbonate; peristome absent. Spores: 10–14 µm, ± smooth. Phenology: Capsules mature Aug (summer).
Crevices of volcanic rock in montane areas. high elevations (2200-2600 m). Calif.
Haplodontium tehamense is a distinctive species, with eperistomate capsules and somewhat julaceous stems. The species is known only from a few locations in Lassen Volcanic National Park. of conservation concern.