Plants annual. Culms 5-40 cm, slender, erect; internodes mostly glabrous, scabridulous or smooth, scabridulous or strigulose below the nodes. Sheaths shorter or longer than the internodes, smooth or scabridulous; ligules 1-2.6 mm, hyaline, truncate to obtuse, sometimes with lateral lobes; blades 0.5-4(10) cm long, 0.8-2 mm wide, flat or involute, scabrous abaxially, shortly pubescent adaxially. Panicles 5-16.2(21) cm long, 1.5-6.5 cm wide, open; primary branches 8-42 mm, often capillary, diverging 25-80° from the rachises; pedicels 2-7 mm, straight or curved, but rarely curved as much as 90°. Spikelets 0.8-1.5 mm. Glumes sparsely strigulose, at least near the apices, 1-veined; lower glumes 0.5-0.8 mm, obtuse to acute; upper glumes 0.6-0.9 mm, broader than the lower glumes, obtuse; lemmas 0.8-1.5 mm, lanceolate, brownish to purplish, glabrous or the midveins and margins appressed-pubescent, apices obtuse to subacute, unawned; paleas 0.8-1.4 mm, shortly pubescent or glabrous; anthers 0.2-0.7 mm, purplish. Caryopses 0.6-0.9 mm, fusiform to elliptic, brownish. 2n = 60, 80.
Muhlenbergia minutissima grows in sandy and gravelly drainages, rocky slopes, flats, road cuts, and open sites. It is usually found in yellow pine and oak-pine forests, pinyon-juniper woodlands, thorn-scrub forests, and oak-grama savannahs, at elevations of 1200-3000 m. Its range extends from the western United States to southern Mexico.
FNA 2003, Gould 1980
Common Name: annual muhly Duration: Annual Nativity: Native Lifeform: Graminoid General: Slender erect annual with stems 5-40 cm, simple or branched below, strigose below the nodes, sheaths shorter or longer than the internodes, smooth or minutely roughened. Vegetative: Blades 0.5-4 cm long, 0.5-2 mm wide, flat or loosely involute when dry, scabrous below, short pubescent above, ligules 1-2.5 mm, hyaline, truncate to obtuse, sometimes with lateral lobes. Inflorescence: Open panicle 5-16 cm long, 1.5-6.5 cm wide, open, primary branches 8-42 mm, often capillary, diverging 25-80 degrees from the rachises, pedicels 2-7 mm, straight or curved; spikelets 0.5-1.5 mm, tawny or greenish, glumes subequal, sparsely strigulose to pilose near apex, 1-veined; lemmas 0.5-1.5 mm, lanceolate, brownish to purplish, glabrous or the midveins and margins appressed-pubescent, unawned or with a minute mucro. Ecology: Found on sandy to gravelly flats, often on disturbed sites from 4,000-9,000 ft (1219-2743 m); flowers August-October. Notes: Awnless annual, with strigulose glumes, sheaths and stem internodes. Ethnobotany: Unknown Etymology: Muhlenbergia is named for Gotthilf Heinrich Ernst Muhlenberg (1753-1815) a clergyman and botanist from Pennsylvania; minutissima means very small or minute. Synonyms: Sporobolus confusus Editor: SBuckley, 2010