Plants in dense turfs, to 25 mm high, branched only by innovations below the perichaetia, red-brown in younger portions but black in older portions. Stems dark red to black even in young material. Leaves, when dry, appressed in younger portions of the stems, spreading below; when moist, erect spreading from a somewhat sheathing base. Leaves to 1.5 mm long, about 3: 1, lanceolate to ovate lanceolate but somewhat constricted at the top of the sheathing base, acuminate to the blunt or acute apex, concave below. Median cells arranged in very regular rows, to 10 µm wide, 1–1.5: 1, isodiametric to elliptic with very irregular lumens due to the strongly trigonous thickenings, incrassate with lumen/wall ratio about 1: 1. Papillae present on the dorsal face of most of the distal 2/3 of leaf, arising from over the thick walls instead of over the lumen, solid and unbranched. Marginal cells of leaf base quadrate to short rectangular, 1–3: 1. Upper cells of leaf margin, to 8 µm wide, mostly transversely elongate. Cells of median leaf base so incrassate as to obscure the lumen, to 10: 1 with sinuose lateral walls. Costa absent. Margins ascending and entire to crenulate throughout, not at all decurrent. Stem nearly homogeneous, of thick-walled cells without a central strand. Axillary hairs to 75 µm long, 2-celled, not offset, one isodiametric and concolorous, the other elongate and clavate, so thick-walled as to obscure the lumen.
Plant autoicous, perigonia below the terminal perichaetia. Perichaetial leaves undifferentiated prior to fertilization, becoming much larger and elliptic ovate after fertilization, to 2.0 mm long, loosely sheathing most of the pseudopodium. Pseudopodia to 4 mm long, straight. Capsule dark brown except for a pale apex, elliptic, 2: 1, to 1.2 mm long before dehiscence, opening by four longitudinal slits. Median exothecial cells to 30 µm wide, 1.5–3: 1, with thick and pitted walls. Exothecial cells along lines of eventual capsule dehiscence much more elongate and narrow in 1–2 irregular rows. Exothecial cells at capsule apex isodiametric and thick walled, somewhat smaller than median cells. Stomates absent. Spores to 30 µm, smooth, with trilete mark.
|Literature||Jessup 2000; Koch 1950a; Showers 1982; Toren 1977.|
|Illustrations||Malcolm et al. 2009 p. 30; Abramov and Volkova 1998; Crum and Anderson 1981; Ignatov and Ignatova 2003; Ireland 1982; Lawton 1971; Murray 1988; Sharp et al. 1994.|
|Bioregions||CaR, MP, NW, SN, SNE.|
|Vouchers||Amador Co.: above Kirkwood Lake east of Kirkwood, Eldorado National Forest, Norris 82728; Fresno Co.: slopes above Lower Twin Lake, Kaiser Wilderness, Sierra National Forest, Shevock, Ertter, & Laeger 22857 (confirmed by Murray); Humboldt Co.: headwaters of Oregon Creek north of Trinity Summit Guard Station, Six Rivers National Forest, Norris & Creek 50092; Inyo Co.: above Treasure Lake west of Big Pine, John Muir Wilderness, Inyo National Forest, Norris 46979; Modoc Co.: Alcohol Crater Rim, Modoc National Forest, Harpel 16324 (pers. herb.); Shasta Co.: Hot Springs Creek above Devil's Kitchen, Lassen Volcanic National Park, Showers 2398 (UC); Siskiyou Co.: Long Gulch Lake southwest of Callahan, Klamath National Forest, Norris 57500 & 57534 (confirmed by Murray).|