Mesa Dropseed

Sporobolus flexuosus (Thurb.) Rydb. Bull. Torrey Club 32:
601. 1905.
Vilfa cryptandra var. flexuosa Thurb.; Vasey, in Rothr. Bot. Wheeler's Surv. 282. 1878. Sporobolus cryptandrus var. flexuosus Thurb. in S. Wats. Bot. Calif. 2: 269. 1880. (Based on Vilfa cryptandra var. flexuosa Thurb.)
Perennial, resembling 5. cryptandrus; blades often involute; panicles larger, more open and spreading, often elongate, the spreading branches flexuous, drooping, or reflexed, the branchlets also spreading and loosely flowered.
Type locality: Nevada and Arizona (Wheeler Exped.).
Distribution: Mesas, western Texas to southern Utah, southeastern California, and northern Mexico.

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, Stems, culms, or scapes exceeding basal leaves, 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 hairy at summit, throat, or collar, Leaf sheath a nd blade differentiated, Leaf sheath enlarged, inflated or distended, Leaf blades linear, Leaf blades 2-10 mm wide, Leaf blades mostly flat, Leaf blade margins folded, involute, or conduplicate, Leaf blades mostly glabrous, Ligule present, Ligule a fringe of hairs, 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, Inflorescence or spikelets partially hidden in leaf sheaths, subtended by spatheole, 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, Rachilla or pedicel glabrous, Glumes present, empty bracts, Glumes 2 clearly present, Glumes distinctly unequal, Glumes shorter than adjacent lemma, Glumes 1 nerved, Lemmas thin, chartaceous, hyaline, cartilaginous, or membranous, Lemma similar in texture to glumes, Lemma 1 nerved, Lemma glabrous, Lemma apex acute or acuminate, Lemma awnless, Lemma straight, 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.

Sporobolus flexuosus is a species of grass known by the common name mesa dropseed. It is native to western North America, where it can be found in the deserts and woodlands of the Southwestern United States and Northern Mexico.

This bunchgrass forms a tuft of stems growing up to 1 metre (3.3 ft) long, erect to decumbent in form. It is a perennial grass but it is short-lived and is sometimes an annual. The leaves are up to 26 centimetres (10 in) long and rough-haired along the margins. The inflorescence is an open panicle of spreading branches bearing grayish spikelets.