Plants perennial; cespitose, rhizomatous. Culms 60-350 cm, annual, internodes solid. Leaves mostly basal; cleistogenes not developed; prophylls shorter than the sheaths; sheaths open; ligules membranous, ciliate; blades initially flat, becoming involute, bases becoming indurate and curved. Inflorescences panicles, loosely contracted, somewhat 1-sided. Spikelets pedicellate, laterally compressed, with 2-6 florets; rachillas hairy, hairs 2-3 mm, prolonged beyond the distal florets; disarticulation above the glumes and beneath the florets. Glumes subequal, more than 1/2 as long as the adjacent lemmas, scarious or chartaceous, 3-5-veined, awn-tipped; florets 10-12 mm; calluses 0.2-0.5 mm, rounded, strigose; lemmas coriaceous, smooth, 5-7-veined, mostly glabrous, hairy over and adjacent to the basal 1/2 of the midvein, hairs 1-2 mm, apices bidentate or bilobed, mucronate or awned from the sinuses, lemma-awn junction not conspicuous; paleas subequal to the lemmas, 2-keeled, keels extending as teeth, flat between the keels; lodicules 3, lanceolate, membranous, ciliate; anthers 3, 6-8 mm; ovaries pubescent distally; styles 2, white. Caryopses fusiform, subterete, grooved adaxially, not ribbed; hila linear; starch grains simple. x = 12. Name from the Greek ampelos, 'vine', and desmos, 'a bond', referring to the use of the leaves to tie grape vines together.