Phragmites

Perennial, robust, tall reed, long-rhizomatous. Leaves cauline; leaf blade long, linear-lanceolate to lanceolate, expanded or inrolled from margins, deciduous at base of blade or at base of leaf sheath; ligule a fringed membrane or a fringe of hairs. Inflorescence a large, drooping, densely plumose panicle, open or contracted; spikelets solitary, pedicelled. Spikelet laterally compressed, disarticulating above glumes; glumes very unequal, shorter than spikelet, membranous, 3-5-nerved, acuminate, subacute. Florets 3-11; lowermost floret male or sterile, usually 3-nerved, acuminate, awnless; succeeding florets bisexual or rarely uppermost reduced; lemma decreasing in size upwards, similar in texture to glumes, membranous, linear-lanceolate, 1-3-nerved, glabrous but enveloped by long, silky hairs from callus, finely acuminate or tapering into an awn; awn straight, shorter than body of lemma; callus long, slender, blunt, hairy with long, silky hairs; palea shorter than lemma, oblong, linear-oblong or ovate-lanceolate; obtuse, 2-keeled, membranous or subhyaline. Lodicules 2. Stamens 3, sometimes 2 in lowest male floret, if present. Ovary glabrous; style distinct, stigma plumose. x= 12 (aneuploids, high polyploidy).