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

nimblewell, nimblewill, nimblewill muhly

Habit Plants perennial; rhizomatous, not cespitose, often mat-forming. Plants perennial (appearing annual); usually cespitose, not rhizomatous, sometimes stoloniferous.
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.

10-45(70) cm, geniculate, often rooting at the lower nodes, glabrous or puberulent below the nodes;

internodes often smooth, shiny, 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.

shorter than the internodes, glabrous for most of their length, margins shortly (0.3-1.2 mm) pubescent distally, not becoming spirally coiled when old;

ligules 0.2-0.5 mm, truncate, erose, ciliate;

blades (1)3-10 cm long, 1-4.5 mm wide, flat, smooth or scabridulous.

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.

3-15 cm long, 1-1.6 cm wide, contracted, often interrupted below;

branches 0.4-5.5 cm, appressed or diverging up to 30° from the rachises, spikelet-bearing to the base;

pedicels 0.1-4 mm, scabrous to hirsute;

disarticulation above the glumes.

Spikelets

1.7-3.1 mm, occasionally with 2 florets.

1.8-2.8 mm, borne singly.

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.

unequal, shorter than the florets, thin and membranous throughout, unawned;

lower glumes lacking or rudimentary, veinless, rounded and often erose;

upper glumes 0.1-0.3 mm, veinless;

lemmas 1.8-2.8 mm, oblong-elliptic, mostly scabrous, calluses hairy, hairs to 0.8 mm, veins greenish, lower 1/4 of the midveins with a few appressed hairs, apices acute to acuminate, awned, awns 1.5-5 mm, straight;

paleas 1.8-2.8 mm, oblong-elliptic, acute to acuminate;

anthers 0.2-0.5 mm, yellow.

Caryopses

0.9-1.6 mm, narrowly ellipsoid, brown.

1-1.4 mm, fusiform, brownish.

2n

= 40.

= 40, 42.

Muhlenbergia richardsonis

Muhlenbergia schreberi

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
AL; AR; AZ; CA; CO; CT; DC; DE; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; NC; NE; NH; NJ; NY; OH; OK; PA; RI; SC; SD; TN; TX; UT; VA; VT; WI; WV; ON
[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 schreberi grows in moist to dry woods and prairies on rocky slopes, in ravines, and along sandy riverbanks, at elevations of 60-1600 m. It is also common in disturbed sites near cultivated fields, pastures, and roads at these elevations. Its geographic range includes central, but not northern, Mexico. Records from the western United States probably reflect receent introductions. The species is considered a noxious, invasive weed in California.

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

Source FNA vol. 25, p. 177. FNA vol. 25, p. 162.
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. montana, 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. 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 M. palustris, M. diffusa
Name authority (Trin.) Rydb. J.E Gmel.
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