Plants perennial but often seeming annual; 5–45 cm tall, tufted or loosely matted.
Culms compressed-keeled, branching at lower nodes; internodes mostly glabrous or sometimes minutely puberulent below the nodes.
Leaves blades 1–15 cm × 0.8–2 mm, flat to conduplicate; lower surface smooth or minutely scabrous; upper surface minutely hairy.
Inflorescences 2–20 × (0.2)2.5–6 cm, diffuse; primary branches approximately 0.1 mm thick, ascending, diverging 10–60° from the inflorescence axes, naked basally; pedicels 0.2–7 mm, glabrous.
Spikelets 1.3–2.1 mm, dark purplish to gray.
Glumes equal, 0.4–1.3 mm, glabrous on the veins, 1-veined; tips scabrous, acute to obtuse, sometimes erose, awnless.
Lemmas 1.2–2 mm, oblong-elliptic, dark purplish to gray, glabrous, faintly 3-veined; tips acute to obtuse, awnless.
Anthers 0.6–0.9 mm, purple.
Bogs and lakeshores. 0–100 m. Est. British Columbia, northeastern North America. Exotic.
Muhlenbergia uniflora is a diffuse-panicled bog grass that resembles M. minutissima, which has smaller spikelets with minutely hairy glumes and lives in alkaline habitats. Muhlenbergia uniflora was first collected in a Curry County cranberry bog in 1997 and was likely introduced with planting stock from eastern North America.
as described under Muhlenbergia uniflora
Plants perennial; loosely matted. Culms 5-45 cm, arising from the bases of old depressed culms, compressed-keeled, developing branches below the lower leaf nodes; internodes mostly glabrous, sometimes minutely puberulent below the nodes. Sheaths longer than the internodes, keeled, keels scabridulous, not becoming papery or spirally coiled when old; ligules 0.5-1.5 mm, membranous, truncate to obtuse, erose, without lateral lobes; blades 1-15 cm long, 0.8-2 mm wide, flat to conduplicate, smooth or scabridulous abaxially, hirtellous adaxially, midveins thickened and whitish proximally. Panicles 2-20 cm long, (0.2)2.5-6 cm wide, diffuse; primary branches 0.4-6 cm long, about 0.1 mm thick, ascending, diverging 10-60° from the rachises, naked basally; pedicels 0.2-7 mm, glabrous. Spikelets 1.3-2.1 mm, dark purplish to plumbeous, occasionally with 2 florets. Glumes equal, 0.4-1.3 mm, glabrous, 1-veined, apices scabrous, acute to obtuse, sometimes erose or notched, unawned; lemmas 1.2-2 mm, oblong-elliptic, dark purplish to plumbeous, glabrous, faintly 3-veined, apices acute to obtuse, unawned; paleas 1.3-2.1 mm, oblong-elliptic, glabrous, acute to obtuse; anthers 0.6-0.9 mm, dark purple. Caryopses 0.6-0.8 mm, ovoid, brownish. 2n = 42.
Muhlenbergia uniflora grows in bogs, wet meadows, and lake shores in sandy or peaty, often acidic, soils, at elevations of 0-650 m. It is native to eastern North America, but was collected once in British Columbia, probably having been introduced from ship ballast, and was recently collected from a commercial cranberry bog in Oregon. The collection from Texas may also be an introduction.