Naiadaceae
An order of marine or fresh-water, annual or perennial herbs, widely distributed over the globe. Flowers hermaphrodite, monoecious or dioecious, small, often inconspicuous, spicate, racemose, or disposed on pedunculate, terminal, or axillary spadices, bracteate or ebracteate. Leaves submersed, emerging, or floating, in scape-bearing genera radical, linear, or rush-like; stem leaves opposite, alternate, or very rarely ternately whorled, sessile or petiolate, oblong, linear, or capillary, sheathed at base. The order comprises sixteen genera, and about 120 species. Examples: Aponogeton, Naias, and Triglochin.