Plants hermaphroditic, caespitose or rhizomatous, perennial. Culms erect or ascending; internodes solid,
glabrous, terete; nodes glabrous or hairy. Leaves basal and cauline, not distinctly distichous; sheaths keeled
or terete, margins open; auricles absent; ligules a ciliate membrane or line of hairs; blades flat or folded
(narrow), linear, lax or stiff, apex acuminate. Spicate racemes terminal and axillary (cylindrical)
, sheaths subtending inflorescences not inflated or spathe-like; not aromatic; rachis glabrous; pedicels
without longitudinal groove, glabrous, terete. Spikelets paired or ternate at each inflorescence node;
dissimilar in size and shape, disarticulation below the glumes, dorsiventrally compressed; sessile (or
short pediceled) spikelets fertile, pedicellate (or long pediceled) spikelets sterile or staminate.
Pedicellate spikelets reduced (to vestigual), awnless. Sessile spikelets perfect; first glumes 2-keeled
, gland-like depressions or pits not present; abaxial surface convex smooth or rugose, coriaceous or
indurate, glabrous, awnless; second glumes length equal to first glumes; lower florets sterile or staminate or
neuter, hyaline or chartaceous, apex entire, awnless (2-veined); paleas absent or present (greatly reduced);
upper florets perfect; lemmas hyaline, entire (acuminate), awnless; paleas present, hyaline.
Stamens 3; anthers purple. Caryopses linear, dorsiventrally compressed. Base chromosome number x=9.
A genus of about 25 species. The species are frequently important parts of wet grasslands.