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

Mexican muhly, muhlenbergie du mexique, muhlenbergie mexicaine, wire-stem muhly, wood satin grass

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

30-90 cm tall, 0.5-2 mm thick, erect, much branched above the base;

internodes dull, puberulent or glabrous for most of their length, sometimes strigose immediately 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.

smooth or scabridulous, somewhat keeled;

ligules 0.4-1 mm, membranous, truncate, lacerate-ciliolate;

blades 2-20 cm long, 2-6 mm wide, flat, scabrous or smooth, those of the secondary branches similar in length and width to those of the main branches.

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.

terminal and axillary, 2-21 cm long, 0.3-3 cm wide, dense;

primary branches 0.3-5.5 cm, appressed or diverging up to 30° from rachises;

pedicels to 2 mm, strigose;

axillary panicles exserted on long peduncles.

Spikelets

1.7-3.1 mm, occasionally with 2 florets.

1.5-3.8 mm, often purple-tinged.

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, 1.5-3.7 mm, equaling or slightly shorter than the lemmas, 1-veined, tapering from the bases to the acuminate apices, unawned or awned, awns to 2 mm;

lemmas 1.5-3.8 mm, lanceolate, pubescent on the calluses, lower portion of the mid-veins, and margins, hairs shorter than 0.7 mm, apices scabridulous, acuminate, unawned or awned, awns to 10 mm;

paleas 1.5-3.8 mm, narrowly lanceolate, apices acuminate;

anthers 0.3-0.5 mm, yellow to purplish.

Caryopses

0.9-1.6 mm, narrowly ellipsoid, brown.

1.1-1.6 mm, fusiform, brown.

2n

= 40.

= 40.

Muhlenbergia richardsonis

Muhlenbergia mexicana

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; DE; IA; ID; IL; IN; KS; KY; MA; MD; ME; MI; MN; MO; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; HI; BC; MB; NB; NS; ON; QC; SK; YT
[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 mexicana usually grows in mesic to wet areas such as moist prairies and woodlands, stream banks, roadsides, ditch banks, lake margins, swamps, bogs, and hot springs, at elevations 50-3300 m, and is found in many different plant communities. Despite its name, M. mexicana grows only in Canada and the United States.

Plants with awns 3-10 mm long belong to Muhlenbergia mexicana var. filiformis (Torr.) Scribn., and those without an awn or with awns less than 3 mm long to Muhlenbergia mexicana (L.) Trin. var. mexicana. Early in the flowering season, M. mexicana may be confused with plants of M. bushii in which the axillary panicles are poorly developed, but they differ in their dull internodes and the fact that the blades on the secondary branches are usually similar in length and width to those of the main branches.

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

Source FNA vol. 25, p. 177. FNA vol. 25, p. 154.
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. 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. (L.) Trin.
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