Muhlenbergia richardsonis

(Trin.) Rydb.
Common names: Mat muhly Muhlenbergie de richardson
Synonyms: Sporobolus depauperatus Muhlenbergia squarrosa
Treatment appears in FNA Volume 25. Treatment on page 177.

Plants perennial; rhizomatous, not cespitose, often mat-forming. 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. 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. 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. Spikelets 1.7-3.1 mm, occasionally with 2 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. Caryopses 0.9-1.6 mm, narrowly ellipsoid, brown. 2n = 40.

Distribution

Maine, Oreg., Colo., N.Mex., Wash., Wyo., Utah, Alaska, Minn., Mich., Wis., Idaho, Mont., Nev., Ariz., Calif., N.Dak., Nebr., S.Dak., Alta., B.C., Man., N.B., N.W.T., Ont., Que., Sask., Yukon

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.

Selected References

None.

Lower Taxa

None.

"decumbent" is not a number.

... more about "Muhlenbergia richardsonis"
yellow +  and purplish +
0.09 cm0.9 mm <br />9.0e-4 m <br /> (0.16 cm1.6 mm <br />0.0016 m <br />) +
awned +  and entire +
scabridulous +
mucronate +, acute +  and acuminate +
Paul M. Peterson +
(Trin.) Rydb. +
1 (?) +  and 3 (?) +
sinuous +, flexuous +  and straight +
multiple +, , +  and single +
curled +
keeled +  and rounded +
pseudopetiolate +  and branching +
not fused +
intravaginal +, extravaginal +, branching +  and basal +
swelling +
membranous +
not pseudopetiolate +
straight +
0.4 cm4 mm <br />0.004 m <br /> (6.5 cm65 mm <br />0.065 m <br />) +
hirtellous +  and glabrous +
involute +  and flat +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.42 cm4.2 mm <br />0.0042 m <br />) +
spikelike +
with hairs +  and glabrous +
0.09 cm0.9 mm <br />9.0e-4 m <br /> (0.16 cm1.6 mm <br />0.0016 m <br />) +
triangular +  and dome--shaped +
sometimes longer +
membranous +
Mat muhly +  and Muhlenbergie de richardson +
5 cm50 mm <br />0.05 m <br /> (30 cm300 mm <br />0.3 m <br />) +
geniculate +
2 cm20 mm <br />0.02 m <br /> (300 cm3,000 mm <br />3 m <br />) +
0.04 cm0.4 mm <br />4.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
Maine +, Oreg. +, Colo. +, N.Mex. +, Wash. +, Wyo. +, Utah +, Alaska +, Minn. +, Mich. +, Wis. +, Idaho +, Mont. +, Nev. +, Ariz. +, Calif. +, N.Dak. +, Nebr. +, S.Dak. +, Alta. +, B.C. +, Man. +, N.B. +, N.W.T. +, Ont. +, Que. +, Sask. +  and Yukon +
not waisted +
capillary +
pistillate +  and staminate +
bisexual +  and fertile +
round +  and compressed +
reduced +
shorter or longer +
subtending +
1/3 +  and 1/2 +
mucronate +  and acute +
subequal +
0.06 cm0.6 mm <br />6.0e-4 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
uncinate +
paniculate +  and racemose +
hollow +  and solid +
not absent +
mottled +, plumbeous +  and dark greenish +
lanceolate +
0.17 cm1.7 mm <br />0.0017 m <br /> (0.26 cm2.6 mm <br />0.0026 m <br />) +
acute to truncate +
0.08 cm0.8 mm <br />8.0e-4 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
membranous +
inconspicuous +
0 cm0 mm <br />0 m <br /> (0.05 cm0.5 mm <br />5.0e-4 m <br />) +
concealed +  and prominent +
2 +  and 1 +
acute +  and lanceolate +
0.12 cm1.2 mm <br />0.0012 m <br /> (0.24 cm2.4 mm <br />0.0024 m <br />) +
1cm +  and 15cm +
cleistogamous +
spikelike +
0.1 cm1 mm <br />0.001 m <br /> (1.7 cm17 mm <br />0.017 m <br />) +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
dry +  and fleshy +
0.4 cm4 mm <br />0.004 m <br /> (5 cm50 mm <br />0.05 m <br />) +
spikelike +
shorter or longer +
1 +  and 60 +
compressed +
0.17 cm1.7 mm <br />0.0017 m <br /> (0.31 cm3.1 mm <br />0.0031 m <br />) +
1 +  and 3 +
compound +  and simple +
2 (?) +  and 3 (?) +
Sporobolus depauperatus +  and Muhlenbergia squarrosa +
Muhlenbergia richardsonis +
Muhlenbergia +
species +
membranous +
shorter than to longer than the florets +
7 (?) +  and 13 (?) +
plant +, mat-forming +  and not cespitose +
aquatic +  and terrestrial +
dioecious +, monoecious +  and synoecious +