Plants perennial; cespitose, not rhizomatous. Culms 15-60 cm tall, 1.5-2.5 mm thick, compressed, erect, not rooting at the lower nodes; internodes mostly hispidulous or glabrous, strigose to hispidulous below the nodes. Sheaths usually shorter than the internodes, smooth or scabridulous, compressed-keeled, not becoming spirally coiled when old; ligules 1-3(5) mm, membranous, truncate; blades 1.4-12 cm long, 1-3 mm wide, flat to folded, smooth or scabridulous abaxially, strigose adaxially. Panicles 5-16 cm long, 0.2-1.2 cm wide, spikelike, dense; primary branches 0.3-2 cm, appressed; pedicels 0.1-1.4 mm. Spikelets 2-3 mm, dark green or plumbeous. Glumes equal, 0.5-1.6 mm, usually 1/2-3/4 as long as the lemmas, 1-veined, scabridulous on the veins, acute or obtuse, abruptly narrowed to a short (0.5-1 mm) awn; lemmas 2-3 mm, lanceolate, appressed-pubescent on the basal 1/2-3/4 of the midveins and margins, hairs about 0.5 mm, apices scabridulous, acute to acuminate, mucronate, mucros 0.3-1 mm; paleas 1.9-3 mm, lanceolate, intercostal region pubescent, apices acute to acuminate; anthers 1.3-1.8 mm, greenish. Caryopses 1.2-2 mm, fusiform, brownish. 2n = unknown.

Muhlenbergia wrightii grows in gravelly prairies, on rocky slopes, and in meadows on granitic, sandstone, or limestone-derived soils, at elevations of 1100-3000 m. Its range extends from the southwestern United States to northern Mexico.

FNA 2003, Gould 1980

Common Name: spike muhly Duration: Perennial Nativity: Native Lifeform: Graminoid General: Tufted perennial developing into loose clumps with stems 15-60 cm tall, 1.5-2.5 mm thick, compressed, not rooting at lower nodes, internodes hispidulous to glabrous, strigose to hispidulous below nodes, sheaths compressed keeled. Vegetative: Blades 1.4-12 cm long, 1-3 mm wide, flat to folded, smooth or minutely roughened below, strigose above, ligules 1-3 mm, membranous, truncate. Inflorescence: Dense, spikelike panicles 5-16 cm long, 0.2-1.2 cm wide, primary branches 0.3-2 cm, appressed and spikelet bearing to the base, spikelets 2-3 mm, dark green or lead-colored; glumes equal, 0.5-1.6 mm, usually half to three quarters as long as lemmas, 1-veined, minutely roughened on veins, acute to obtuse, abruptly narrowed to a short awn, 0.5-1 mm; lemmas 2-3 mm, lanceolate, appressed-pubescent on the basal half to three-quarters of the midveins and margins, hairs about 0.5 mm, mucronate with mucros 0.3-1 mm. Ecology: Found in gravelly flats to rocky slopes, often in meadows on granitic, sandstone, or limestone parent material from 4,000-9,000 ft (1219-2743 m); flowers July-October. Notes: Distinctive because of the dense spikelike panicle that can be grayish and is interrupted at the base. Ethnobotany: Used to keep steam from escaping from between rocks while cooking. Etymology: Muhlenbergia is named for Gotthilf Heinrich Ernst Muhlenberg (1753-1815) a clergyman and botanist from Pennsylvania; wrightii is named for Charles Wright (1811-1885) an American botanical collector. Synonyms: None Editor: SBuckley, 2010