Plants to 1.5 cm high, in hoary green to gray-green cushions, opaque-green to nearly black below. Leaves loosely imbricate when dry, loosely erect-spreading when moist, somewhat concave but not at all keeled, to 3 mm long with the awn constituting nearly 1/2 of that length, ovate-lanceolate from a loosely sheathing somewhat expanded base, 2.5–3.5: 1. Median leaf cells in regular longitudinal rows, unistratose in the expanded base but uniformly bistratose in the limb, smooth, to 7 µm wide, isodiametric with lumens irregular but without corner thickenings. Marginal cells not differentiated. Basal juxtacostal cells elliptical, to 3: 1, to 15 µm wide, with irregularly thickened lateral walls. Basal marginal cells transversely elongate, 0.5–0.7: 1, to 15 µm wide. Costa flared at the base and filling 1/3–1/4 of immediate leaf base, narrowed and obscure above, percurrent in the somewhat acuminate awn. Costa cross-section at leaf middle broad and flattened, less than 1.5 times as thick as the adjacent leaf, with a weak abaxial band of stereids or substereids and with a single layer of larger cells on the adaxial face. Margin of leaf limb plane to incurved, entire below. Awn strongly decurrent with its margin somewht serrulate, and with its surface spinose-prorate. Axillary hairs to 100 µm long, with 6–8 nearly isodiametric and thick- walled cells, without a basal brown cell. Rhizoids red brown, to 15 µm wide at base, smooth. Stem cross-section rounded-triangular with a large and well-defined central strand, and with leptodermous, hyaline and large inner cortical cells, and with the 1–2 cell-thick outer stereome composed of much smaller, thick-walled cells strongly pigment with yellow to yellow-brown.
Dioicous with male and female plants similar. Perichaetial leaves loosely sheathing base of seta, somewhat larger and with a relatively longer, less decurrent awn than the adjacent vegetative leaves. Seta to 2.5 mm long, yellow to pale brown, straight and smooth. Urn erect, symmetrical, smooth to lightly wrinkled when dry, to 1.2 mm long, 1.5–2: 1, not strumose. Operculum short rostrate, about 1/3 as long as urn. Annulus formed of 2–3 rows of relatively more thin-walled cells. Calyptra mitrate, covering about 1/2 of urn. Peristome red-brown, to 200 µm long, cribrose along median line near the apex, papillose to vertically striate-papillose. Exothecial cells to 25 µm wide, not in regular vertical rows, quite irregular in size and shape, rectangular 2–4: 1, rather thick walled. Stomata phaneroporous, restricted to base of urn. Spores smooth, to 12 µm.
|Literature||See Muñoz and Pando 2001. As Dryptodon patens Crum and Anderson 1981; Showers 1982; Vitt and Belland 1991. As Racomitrium patens Holmberg 1969; Koch 1950a; Koch and Ikenberry 1954; Lawton 1971; McGrew 1976; Spjut 1971.|
|Illustrations||Malcolm et al. 2009 p. 68; Crum and Anderson 1981; Greven 2003; Ignatov and Ignatova 2003; Lawton 1971; Smith 1978.|
|Bioregions||CaR, MP, NW, SN.|
|Vouchers||Del Norte Co.: Whiskey Lake, Six Rivers National Forest, Norris 83362; Lake Co.: Stony Creek, Snow Mountain Wilderness, Mendocino National Forest, Toren & Dearing 5344 (CAS); Modoc Co.: road to Beeler Reservoir about 16 miles east of Medicine Lake, Modoc National Forest, Norris 22506; Nevada Co.: Fall Creek between Bowman Lake and Highway 20, Tahoe National Forest, Shevock, Ertter, & Morosco 15708 (determined by Muñoz); Placer Co.: North Fork Campground southeast of Emigrant Gap, Norris 88042 & 88043; Shasta Co.: Coffee Creek at East Fork of Coffee Creek, Norris & Hermann 22578; Siskiyou Co.: Etna-Sawyers Bar Road about 18 miles from Etna, Norris & Hermann 22745 and Baldy Mountain above Happy Camp, Klamath National Forest, Branscomb 22739 (MO) [determined by Muñoz]; Tehama Co.: Doll Basin Research Natural Area, Mendocino National Forest, Toren & Bourell 6792 (CAS, MO).|