Piptatheropsis exigua (Thurb.) Romasch., P. M. Peterson & Soreng

Oryzopsis exigua Thurber, in Torr. U. S. Expl. Exp. 17: 481. 1874.
Culms densely cespitose, the innovations numerous, stiffly erect, scabrous, 15-30 cm. tall; leaves mostly basal, the sheaths smooth or somewhat scabrous; ligule scaberulous, acute, 2-3 mm. long; blades involute-filiform, stiffly erect, scabrous, 5-10 cm. long, the culm-blades usually 2, shorter; panicle narrow, 3-6 cm. long, the short branches appressed, the lower 1-2 cm. long; spikelets short-pediceled, pale; glumes acute, about 4 mm. long, thin, faintly nerved; lemma elliptic-oblong, appressed-pilose, about as long as the glumes, the callus short and blunt; awn attached at one side between the 2 short lobes of the lemma, about 5 mm. long, obscurely scaberulous, a little bent about the middle, the lower part slightly twisted.
Type locality; Cascade Mountains. Oregon.
Distribution: Dry open ground or open woods. Montana to eastern Washington, and southward to Colorado, Oregon, and Nevada.

Perennials, Terrestrial, not aquatic, Stems nodes swollen or brittle, Stems erect or ascending, Stems caespitose, tufted, or clustered, Stems terete, round in cross section, or polygonal, Stem internodes hollow, Stems with inflorescence less than 1 m tall, Basal leaves equal to or exceeding stems, culms, or scapes, Stems, culms, or scapes exceeding basal leaves, Leaves mostly basal, below middle of stem, Leaves conspicuously 2-ranked, distichous, Leaves sheathing at base, Leaf sheath mostly open, or loose, Leaf sheath smooth, glabrous, Leaf sheath and blade differentiated, Leaf blades linear, Leaf blades very narrow or filiform, less than 2 mm wide, Leaf blade margins folded, involute, or conduplicate, Leaf blades mostly glabrous, Leaf blades scabrous, roughened, or wrinkled, Ligule present, Ligule an unfringed eciliate membrane, Inflorescence terminal, Inflorescence a contracted panicle, narrowly paniculate, branches appressed or ascending, Inflorescence solitary, with 1 spike, fascicle, glomerule, head, or cluster per stem or culm, Flowers bisexual, Spikelets pedicellate, Spikelets dorsally compressed or terete, 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 equal to or longer than adjacent lemma, Glumes 3 nerved, Glumes 4-7 nerved, Lemma coriaceous, firmer or thicker in texture than the glumes, Lemma 3 nerved, Lemma body or surface hairy, Lemma apex truncate, rounded, or obtuse, Lemma apex dentate, 2-fid, 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 awn twisted, spirally coiled at base, like a corkscrew, Lemma awn once geniculate, bent once, Lemma margins inrolled, tightly covering palea and caryopsis, Lemma straight, Callus or base of lemma evidently hairy, Callus hairs shorter than lemma, Palea present, well developed, 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.