Brachythecium rutabulum

   Plants closely matted, deep green to whitish-green, irregularly branched, with stems prostrate and branches prostrate to ascending. Primary stems to 15 cm long with leaves somewhat broader and more divergent than the closely imbricated branch leaves. Leaves to 3 mm, about 2: 1, symmetric and straight but with a twisted acumen, lightly or not at all concave, only obscurely plicate, ovate-lanceolate with acumen only gradually differentiated. Margins serrulate to entire at immediate base, but serrulate to serrate above the middle and on the acumen, somewhat recurved at base but plane above. Stem and branch leaves with a rather broad decurrency which extends to the base of the next lower leaf. Median cells smooth, spinulose and thin-walled, to 8 µm wide, mostly 12–15: 1, not pitted. Basal juxtacostal cells short-rectangular, to 4: 1, thin-walled without pitting. Alar region very poorly demarcated, with short rectangular, thin-walled, enlarged and pellucid cells to 20 µm wide, mostly 2–4: 1, gradually transitting to the more narrow and relatively longer cells of the mid-lamina. Marginal cells of alar region more narrow and more opaque than more interior alar cells. Costa ending below the leaf middle, rather broad and flattened at base but tapering to its apex, only rarely spinose at apex. Juvenile leaves strongly inflexed over bud, to 200 µm long, ovate to ovate-lanceolate, 1.5–2: 1, serrate across the acute apex. Axillary hairs persistent, to 120 µm, 3-celled with a single pale brown basal cell, thin-walled throughout but with the terminal cell tapering to a pointed apex. Rhizoids abundantly produced on prostrate stems, elongate and planar branched, brown to reddish-brown, smooth, to 15 µm in diameter, clustered on the abaxial leaf base. Stem cross-section with central strand, a stereome 1–3 cells thick, but without an hyaloderm.

   Autoicous. Perigonia bud-like, produced near the perichaetia on prostrate stems and large branches. Perichaetial leaves to 2.5 mm long, with costa absent or nearly so, sheathing at base but reflexed to squarrose in the abruptly contracted acumen, entire below but with a few coarse teeth on the acumen, without alar differentiation. Seta red-brown, coarsely papillose throughout, to 25 mm long, distally geniculate. Capsule dark brown to reddish brown, inclined to horizontal, lightly arcuate, not distorted or sulcate when dry. Urn to 3 mm, about 2: 1. Exothecial cells isodiametric to short rectangular, in regular rows, 20–25 µm wide, 1–2: 1, with thick lateral walls (lumen: wall ratio 3–4: 1) but with thin and oblique end walls. Stomata present on slightly raised pustules at base of capsule, short and vertical pored. Operculum conic, 1/3–1/4 as long as urn. Annulus present, of two rows of large and thin-walled cells. Exostome teeth inserted somewhat below mouth of capsule, united near base, to 450 µm long, narrowly lanceolate and obscurely shouldered, 6–8: 1, tapering to a very narrow tip, horizontally striate, yellow to yellow-brown. Endostome segments lightly papillose, about as long as exostome, with basal membrane about as long as the segments. Cilia 1–3, lightly papillose and nodose. Spores smooth or occasionally finely papillose, 12–15 µm.

Vouchers: Contra Costa Co.: Mitchell Canyon, Mt. Diablo State Park, Norris 100609; Fresno Co.: Redwood Creek above Highway 180, Monarch Wilderness, Sequoia National Forest, Shevock & York 12681 (determined by Ochyra); Inyo Co.: South Fork Bishop Creek, Inyo National Forest, Shevock 12549; Lake Co.: Library Park, Lakeport, Toren 7665 (CAS) [determined by McFarland]; Modoc Co.: Deep Creek, 2 miles west of Cedarville-Eagleville Road, Norris 18728; Santa Cruz Co.: Scotts Valley, Kellman 1122 (CAS); Sierra Co.: Highway 49 at Chapman Creek, Tahoe National Forest, Kellman 261 (CAS); Tulare Co.: Freeman Grove, Lloyd Meadows Basin, Sequoia National Forest, Shevock 3899 and General's Highway near Ash Mountain Headquarters, Sequoia National Park, Shevock 16747.

Literature: Ireland 1982; Kellman 2003; Kingman 1912; McGrew 1976; Shevock and Toren 2001.

Illustration References: Abramov and Volkova 1998; Ignatov 1998; Ireland 1982; Lawton 1971; Smith 1978.

Elevation by latitude plot for Brachythecium rutabulum
   in California