widespread in tropical and subtropical regions of the world
Species commonly cultivated
Acorus calamus L. (and varieties) (Asia and North America)
A. gramineus Sol. (and varieties) (Asia)
introduced into Europe and South America
not recorded as weedy
Perennial. Erect plant with creeping rhizome. Leaves in two sheathed rows, opposite distichous, equitant, linear, aromatic, with prominent midrib. Inflorescence a spadix, yellow-green, borne on stem that is fused with a leaf, arising approximately midway along leaf length. Spadix elongate, with numerous tiny bisexual flowers, spathe absent.
marshes, swamps, and open ponds