Muhlenbergia tenuifolia
Muhlenbergia rigida
mesa muhly, slender muhly
purple muhly
20-70 cm, erect or decumbent;
internodes mostly scabridulous or smooth, always scabridulous below the nodes.
40-100 cm, erect, not conspicuously branched;
internodes mostly smooth, sometimes scabridulous below the nodes.
usually shorter than the internodes, glabrous, smooth or scabridulous, usually without necrotic spots, not becoming spirally coiled when old;
ligules 1.2-3(5) mm, membranous throughout, acute, often lacerate;
blades 2-13 cm long, 1.2-2.5 mm wide, flat or loosely involute, scabridulous or glabrous abaxially, scabrous adaxially, usually without necrotic spots.
longer than the internodes, smooth or scabridulous, basal sheaths rounded, not becoming spirally coiled when old;
ligules (1)3-12(15) mm, firmer basally than distally, obtuse to acute, often lacerate;
blades 12-35 cm long, 1-3 mm wide, flat or involute, smooth or scabridulous abaxially, scabridulous or hirtellous adaxially.
numerous, terminal and axillary, 7-20 cm long, 0.3-1.4(3) cm wide, contracted, often lax, nodding, interrupted below;
primary branches 3.5-7.5 cm, ascending or diverging up to 70° from the rachises, spikelet-bearing to the base;
pedicels 1-3 mm, antrorsely scabrous;
disarticulation above the glumes.
10-35 cm long, 2-5(12) cm wide, loosely contracted to open, purplish;
primary branches 0.4-10 cm, lax, capillary, usually appressed to ascending, occasionally diverging up to 80° from the rachises, naked basally;
pedicels 1-10 mm.
2-4 mm, often purplish, borne singly.
3.5-5 mm, purplish.
1.2-2.8 mm, shorter than the florets, 1-veined, veins scabrous, apices often erose, unawned or awned, awns to 0.5 mm;
lower glumes 1.2-2 mm, acute to acuminate;
upper glumes 1.5-2.8 mm, acute;
lemmas 2-3.5(4) mm, lanceolate, mostly smooth, scabridulous distally, pubescent on the calluses, lower 1/2 of the midveins, and margins, hairs 0.5-1.5 mm, apices acuminate to acute, awned, awns 10-30 mm, scabrous, sinuous to flexuous;
paleas 1.8-3.4(3.8) mm, lanceolate, sparsely villous basally, apices acuminate to acute;
anthers 0.9-1.5 mm, yellowish.
equal, 1-1.7(2) mm, exceeded by the florets, usually glabrous, sometimes mostly hirtellous but glabrous distally, 1-veined, obtuse to subacute, unawned;
lemmas 3.5-5 mm, narrowly lanceolate, purplish, calluses hairy, hairs to 0.5 mm, lemma bodies scabridulous to scabrous, apices acuminate, awned, awns 10-22 mm, clearly demarcated from the lemma bodies, flexuous;
paleas 3.5-5 mm, narrowly lanceolate, scabridulous, acuminate;
anthers 1.7-2.3 mm, purplish.
1-2.2 mm, narrowly fusiform, brownish.
2-3.5 mm, fusiform, brownish.
panicles not present.
= 20, 40.
= 40, 44.
Muhlenbergia tenuifolia
Muhlenbergia rigida
Muhlenbergia tenuifolia grows in gramma grasslands and pine-oak woodlands on rocky slopes, limestone rock outcrops, gravelly roadsides, and in sandy drainages, at elevations of 1200-2200 m. Its range extends through Mexico to northern South America.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Muhlenbergia rigida grows on rocky slopes, ravines, and sandy, gravelly slopes derived from granitic and calcareous substrates, at elevations of 1200-2200 m. It is often a common upland bunchgrass, and is also grown as an ornamental plant.
Muhlenbergia rigida grows in two disjunct areas: the southwestern United States south to Chiapas, Mexico, and in Ecuador, Peru, Bolivia, and Argentina. It differs from M. setifolia and M. reverchonii in its purplish, scabridulous to scabrous lemmas.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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