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mat muhly, Matted muhly, muhlenbergie de Richardson, Richardson's muhly, soft-leaf muhly

mountain muhly

Habit Plants perennial; rhizomatous, not cespitose, often mat-forming. Plants perennial; cespitose, not rhizomatous.
Culms

5-30 cm tall, 0.4-1 mm thick, decumbent, geniculate, or erect;

internodes usually nodulose (occasionally smooth) for most of their length, puberulent or nodulose below the nodes.

10-80 cm, erect, rounded near the base;

internodes glabrous.

Sheaths

shorter or longer than the internodes, glabrous;

ligules 0.8-3 mm, membranous, acute to truncate, erose;

blades 0.4-6.5 cm long, 0.5-4.2 mm wide, flat or involute, straight or arcuate-spreading, glabrous abaxially, hirtellous adaxially.

smooth or scabridulous, becoming flattened, papery, and occasionally spirally coiled when old, lower sheaths longer than the internodes;

ligules 4-14(20) mm, membranous, acute to acuminate;

blades 6-25 cm long, 1-2.5 mm wide, flat, becoming involute, scabrous abaxially, hirsute adaxially.

Panicles

1-15 cm long, 0.1-1.7 cm wide, exserted, narrow or spikelike, rachises usually concealed by the branches;

primary branches 0.4-5 cm, usually closely appressed at maturity, rarely diverging up to 20° from the rachises;

pedicels 0.2-2 mm, setulose.

4-25 cm long, (1)2-6 cm wide, not dense;

primary branches 0.5-10 cm, appressed or diverging up to 40° from the rachises;

pedicels 0.5-6.5 mm, scabrous.

Spikelets

1.7-3.1 mm, occasionally with 2 florets.

3-7 mm.

Glumes

subequal, 0.6-2 mm, 1/3– 1/2 as long as the lemmas, green, 1(2)-veined, acute, sometimes mucronate, mucros less than 0.2 mm;

lemmas 1.7-2.6(3.1) mm, lanceolate, dark greenish, plumbeous, or mottled, glabrous, apices scabridulous, acute to acuminate, sometimes mucronate, mucros to 0.5 mm;

paleas 1.2-2.4(2.9) mm, lanceolate, acute;

anthers 0.9-1.6 mm, yellow to purplish.

subequal, (1)1.5-3.2(4) mm, smooth or scabridulous distally;

lower glumes 1-veined, sometimes with a less than 1 mm awn;

upper glumes 1/3–2/3 as long as the lemmas, 3-veined, truncate to acute, 3-toothed, teeth sometimes awned, awns to 1.6 mm;

lemmas 3-4.5(7) mm, lanceolate, loosely to densely appressed-pubescent on the lower portion of the mid-veins and margins, hairs to 0.8 mm, apices acute to acuminate, awned, awns (2)6-25 mm, flexuous;

paleas 3-4.5(7) mm, lanceolate, acute to acuminate;

anthers 1.5-2.3 mm, purplish.

Caryopses

0.9-1.6 mm, narrowly ellipsoid, brown.

1.8-2 mm, fusiform, light brown.

2n

= 40.

= 20, 40.

Muhlenbergia richardsonis

Muhlenbergia montana

Distribution
from FNA
AK; AZ; CA; CO; ID; ME; MI; MN; MT; ND; NE; NM; NV; OR; SD; UT; WA; WI; WY; AB; BC; MB; NB; NT; ON; QC; SK; YT
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CA; CO; MT; NM; TX; UT; WY
[WildflowerSearch map]
[BONAP county map]
Discussion

Muhlenbergia richardsonis grows in open sites in alkaline meadows, prairies, sandy arroyo bottoms, talus slopes, rocky flats and the shores of rivers, at elevations of 60-3300 m. It is the most widespread species of Muhlenbergia in the Flora region, extending from the Yukon Territory to Quebec in the north and to northern Baja California, Mexico, in the south. Morden and Hatch (1996) reported that it also grows in Alaska, but no voucher specimen has been located.

Muhlenbergia richardsonis is often confused with M. cuspidata, which differs in lacking rhizomes and having shorter ligules, and sometimes with M. filiformis, which differs in being a weak annual with glabrous internodes and obtuse, erose glumes.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Muhlenbergia montana grows on rocky slopes and ridge tops and in dry meadows and open grasslands, at elevations of 1400-3500 m. Its range extends from the western United States to Guatemala. Muhlenbergia montana is sometimes difficult to distinguish from M. filiculmis, but that species has shorter spikelets and lemma awns and tightly involute or filiform, sharp blades.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 25, p. 177. FNA vol. 25, p. 183.
Parent taxa Poaceae > subfam. Chloridoideae > tribe Cynodonteae > Muhlenbergia Poaceae > subfam. Chloridoideae > tribe Cynodonteae > Muhlenbergia
Sibling taxa
M. andina, M. appressa, M. arenacea, M. arenicola, M. arizonica, M. arsenei, M. asperifolia, M. brevis, M. bushii, M. californica, M. capillaris, M. crispiseta, M. curtifolia, M. cuspidata, M. depauperata, M. diversiglumis, M. dubia, M. dumosa, M. elongata, M. eludens, M. emersleyi, M. expansa, M. filiculmis, M. filiformis, M. fragilis, M. frondosa, M. glabrifloris, M. glauca, M. glomerata, M. jonesii, M. lindheimeri, M. longiligula, M. mexicana, M. microsperma, M. minutissima, M. montana, M. palmeri, M. pauciflora, M. pectinata, M. peruviana, M. polycaulis, M. porteri, M. pungens, M. racemosa, M. ramulosa, M. repens, M. reverchonii, M. rigens, M. rigida, M. schreberi, M. sericea, M. setifolia, M. sinuosa, M. sobolifera, M. spiciformis, M. straminea, M. sylvatica, M. tenuiflora, M. tenuifolia, M. texana, M. thurberi, M. torreyana, M. torreyi, M. uniflora, M. utilis, M. villiflora, M. wrightii, M. ×curtisetosa, M. ×involuta
M. andina, M. appressa, M. arenacea, M. arenicola, M. arizonica, M. arsenei, M. asperifolia, M. brevis, M. bushii, M. californica, M. capillaris, M. crispiseta, M. curtifolia, M. cuspidata, M. depauperata, M. diversiglumis, M. dubia, M. dumosa, M. elongata, M. eludens, M. emersleyi, M. expansa, M. filiculmis, M. filiformis, M. fragilis, M. frondosa, M. glabrifloris, M. glauca, M. glomerata, M. jonesii, M. lindheimeri, M. longiligula, M. mexicana, M. microsperma, M. minutissima, M. palmeri, M. pauciflora, M. pectinata, M. peruviana, M. polycaulis, M. porteri, M. pungens, M. racemosa, M. ramulosa, M. repens, M. reverchonii, M. richardsonis, M. rigens, M. rigida, M. schreberi, M. sericea, M. setifolia, M. sinuosa, M. sobolifera, M. spiciformis, M. straminea, M. sylvatica, M. tenuiflora, M. tenuifolia, M. texana, M. thurberi, M. torreyana, M. torreyi, M. uniflora, M. utilis, M. villiflora, M. wrightii, M. ×curtisetosa, M. ×involuta
Synonyms Sporobolus depauperatus, M. squarrosa
Name authority (Trin.) Rydb. (Nutt.) Hitchc.
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