Muhlenbergia arizonica Scribn.

Muhlenbergia arizonica Scribn. Bull. Torrey Club 15: 8. 1888
Perennial, in close tufts; culms slender, erect or decumbent at base, scaberulous, severalnoded, 1 5-40 cm. tall ; sheaths keeled, glabrous, or puberulent near the base ; ligule thin, 1-2 mm. long, decurrent; blades flat or folded, scaberulous or scabrous-pubescent, scabrous near the tip, mostly less than 5 cm. long, 1-2 mm. wide, the margins and midnerve white-cartilaginous; panicles open, finally long-e.serted, 5-12 cm. long, 4-8 cm. wide, the branches capillary, the slender pedicels being branches of the second or third order; glumes equal, ovate, subacute, glabrous, about 1 mm. long ; lemma narrowly lanceolate, minutely pubescent along the midnerve and margins below, about 3 mm. long, the awn about 1 mm. long from a minutely notched apex.
Type locality: Near Mexican Boundary, Arizona (Pringle in 1884). Distribution: Stony hills, southern Arizona, and southward to Durango.

Perennials, Terrestrial, not aquatic, Stems nodes swollen or brittle, Stems erect or ascending, Stems geniculate, decumbent, or lax, sometimes rooting at nodes, Stems caespitose, tufted, or clustered, Stems terete, round in cross section, or polygonal, Stem internodes hollow, Stems with inflorescence less than 1 m tall, Stems, culms, or scapes exceeding basal leaves, Leaves mostly basal, below middle of stem, Leaves mostly cauline, Leaves conspicuously 2-ranked, distichous, Leaves sheathing at base, Leaf sheath mostly open, or loose, Leaf sheath smooth, glabrous, Leaf sheath hairy, hispid or prickly, Leaf sheath and blade differentiated, Leaf blades linear, Leaf blades very narrow or filiform, less than 2 mm wide, Leaf blades mostly flat, Leaf blade margins folded, involute, or conduplicate, Leaf blade with prominently raised or widened midvein, Leaf blades mostly glabrous, Leaf blades scabrous, roughened, or wrinkle d, Ligule present, Ligule an unfringed eciliate membrane, Inflorescence terminal, Inflorescence an open panicle, openly paniculate, branches spreading, Inflorescence solitary, with 1 spike, fascicle, glomerule, head, or cluster per stem or culm, Inflorescence lax, widely spreading, branches drooping, pendulous, Inflorescence branches more than 10 to numerous, Flowers bisexual, Spikelets pedicellate, Spikelets laterally compressed, Spikelet less than 3 mm wide, Spikelets with 1 fertile floret, Spikelets solitary at rachis nodes, Spikelets all alike and fertille, Spikelets bisexual, Spikelets disarticulating above the glumes, glumes persistent, Spikelets disarticulating beneath or between the florets, Rachilla or pedicel glabrous, Glumes present, empty bracts, Glumes 2 clearly present, Glumes equal or subequal, Glumes shorter than adjacent lemma, Glumes 1 nerved, Lemmas thin, chartaceous, hyaline, cartilaginous, or membranous, Lemma similar in texture to glumes, Lemma 3 nerved , Lemma body or surface hairy, Lemma apex dentate, 2-fid, Lemma mucronate, very shortly beaked or awned, less than 1-2 mm, Lemma distinctly awned, more than 2-3 mm, Lemma with 1 awn, Lemma awn less than 1 cm long, Lemma awn from sinus of bifid apex, Lemma awns straight or curved to base, Lemma margins thin, lying flat, Lemma straight, Callus or base of lemma evidently hairy, Callus hairs shorter than lemma, Palea present, well developed, Palea membranous, hyaline, Palea about equal to lemma, Palea 2 nerved or 2 keeled, Stamens 3, Styles 2-fid, deeply 2-branched, Stigmas 2, Fruit - caryopsis, Caryopsis ellipsoid, longitudinally grooved, hilum long-linear.

Muhlenbergia arizonica là một loài thực vật có hoa trong họ Hòa thảo. Loài này được Scribn. mô tả khoa học đầu tiên năm 1888.