Muhlenbergia rigens (Benth.) Hitchc., Poaceae

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Present on Pacific Islands?  no

Primarily a threat at high elevations?  no

Risk assessment results:  High risk, score: 7 (Go to the risk assessment)

Common name(s): [more details]

English: deer grass, deer muhly

Habit:  grass

Description:  "Habit: Perennial; caespitose. Culms erect; 60-100 cm long. Ligule an eciliate membrane, or a ciliolate membrane; 1-3 mm long. Leaf-blades involute; 15-50 cm long; 1-4 mm wide; stiff. Leaf-blade surface ribbed; scabrous; rough adaxially. Leaf-blade apex filiform.   Inflorescence a panicle. Panicle spiciform; linear; continuous, or interrupted; 30-60 cm long. Primary panicle branches 1-4 cm long. Spikelets solitary. Fertile spikelets pedicelled.  Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate; laterally compressed; compressed slightly; 2.5-3.5 mm long; breaking up at maturity; disarticulating below each fertile floret. Glumes persistent; similar; shorter than spikelet; similar to fertile lemma in texture. Lower glume lanceolate; 2-3 mm long; 1 length of upper glume; membranous; without keels; 1-veined. Lower glume lateral veins absent. Lower glume surface scabrous. Lower glume apex obtuse, or acute. Upper glume lanceolate; 2-3 mm long; 0.8 length of adjacent fertile lemma; membranous; without keels; 1-veined. Upper glume lateral veins absent. Upper glume surface scabrous. Upper glume apex obtuse, or acute. Florets: Fertile lemma elliptic; 2.5-3.5 mm long; membranous; without keel; 3-veined. Lemma midvein pubescent; hairy above. Lemma surface scaberulous; rough above. Lemma margins pubescent; hairy below. Lemma apex obtuse, or acute; muticous, or mucronate. Palea 1 length of lemma; 2 -veined. Palea surface scabrous. Flower: Lodicules 2; cuneate; fleshy. Anthers 3; 1.5-1.7 mm long. Caryopsis with adherent pericarp; fusiform; 2 mm long"  (GrassBase, the Online World Grass Flora).

Habitat/ecology:  (no habitat/ecology info known by PIER)

Propagation:  Seed

Native range:  Mexico and southwestern United States (GRIN).

Presence:

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Mexico Mexico	Mexico (United Mexican States)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
United States (west coast) United States (west coast states)	USA (California)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)

Also reported from
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
United States (continental except west coast) United States (other states)	United States (other states)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011) Arizona, Nevada, New Mexico, Texas

Additional information:
Fact sheet from USDA NRCS (PDF).
Plant guide from USDA NRCS (PDF).

Additional online information about Muhlenbergia rigens is available from the Hawaiian Ecosystems at Risk project (HEAR).

Information about Muhlenbergia rigens as a weed (worldwide references) may be available from the Global Compendium of Weeds (GCW).

Taxonomic information about Muhlenbergia rigens may be available from the Germplasm Resources Information Network (GRIN).

References:

Clayton, W.D./Harman, K.T./Williamson, H. 2011. World Grass Species: Descriptions, Identification, and Information Retrieval [GrassBase - The Online World Grass Flora]. The Board of Trustees, Royal Botanic Gardens, Kew.

U. S. Government. 2011. Integrated Taxonomic Information System (ITIS) (on-line resource).

U.S. Dept. Agr., Agr. Res. Serv. 2011. National Genetic Resources Program. Germplasm Resources Information Network (GRIN). Online searchable database.