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

alkali muhly, or alkali muhly, scratch grass

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

10-60(100) cm, decumbent-ascending, bases somewhat compressed-keeled;

internodes glabrous, shiny below the nodes.

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.

glabrous, margins hyaline;

ligules 0.2-1 mm, firm, truncate, ciliate, without lateral lobes;

blades 2-7(11) cm long, 1-2.8(4) mm wide, flat, occasionally conduplicate, smooth or scabridulous abaxially, scabridulous adaxially, margins and midveins not conspicuously thickened, greenish, apices acute, not sharp.

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.

6-21 cm long, 4-16 cm wide, broadly ovoid, open;

primary branches 3-12 cm, capillary, lower branches spreading 30-90° from the rachises, never appearing fascicled;

pedicels 3-14 mm, longer than the spikelets.

Spikelets

1.7-3.1 mm, occasionally with 2 florets.

1.2-2.1 mm, occasionally with 2 or 3 florets.

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.

equal, 0.6-1.7 mm, purplish, scabridulous, particularly on the veins, 1-veined, apices acute;

lemmas 1.2-2.1 mm, lanceolate to oblong-elliptic, somewhat plumbeous, glabrous, usually smooth, occasionally scabridulous near the apices, apices acute, unawned or mucronate, mucros to 0.3 mm;

paleas 1.2-2.1 mm, lanceolate, glabrous, acute;

anthers 1-1.3 mm, greenish-yellow to purplish at maturity.

Caryopses

0.9-1.6 mm, narrowly ellipsoid, brown.

0.8-1 mm, fusiform, brownish.

2n

= 40.

= 20, 22, 28.

Muhlenbergia richardsonis

Muhlenbergia asperifolia

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; IA; ID; IL; IN; KS; KY; MD; MI; MN; MO; MT; ND; NE; NM; NV; NY; OH; OK; OR; PA; SD; TX; UT; WA; WI; WY; AB; BC; MB; ON; SK
[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 asperifolia grows in moist, often alkaline meadows, playa margins, and sandy washes, on grassy slopes, and around seeps and hot springs, at elevations of 55-3000 m. Its geographic range includes northern Mexico. Muhlenbergia asperifolia is morphologically similar to the southeastern M. torreyana, but differs in having glabrous, weakly compressed culms and more widely divergent panicle branches.

The caryopses of Muhlenbergia asperifolia are frequently infected by a smut, Tilletia asperifolia Ellis & Everhart, which produces a globose body filled with blackish-brown spores.

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

Source FNA vol. 25, p. 177. FNA vol. 25, p. 179.
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. 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. 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. (Nees & Meyen ex Trin.) Parodi
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