Brazilian Water Grass

Perennials, Aquatic, growing in or on water, Terrestrial, not aquatic, Rhizomes present, Rhizome elongate, creeping, stems distant, Stolons or runners present, Stems nodes swollen or brittle, Stems geniculate, decumbent, or lax, sometimes rooting at nodes, Stems mat or turf forming, Stems caespitose, tufted, or clustered, Stems terete, round in cross section, or polygonal, Stems branching above base or distally at nodes, Stem internodes hollow, Stems with inflorescence less than 1 m tall, Stems, culms, or scapes exceeding basal leaves, Leaves mostly basal, below middle of stem, Leaves mostly cauline, Leaves conspicuously 2-ranked, distichous, Leaves sheathing at base, Leaf sheath mostly open, or loose, Leaf sheath smooth, glabrous, Leaf sheath hairy, hispid or prickly, Leaf sheath and blade differentiated, Leaf blades linear, Leaf blades lanceolate, Leaf blades 2-1 0 mm wide, Leaf blades mostly flat, Leaf blades mostly glabrous, Ligule present, Ligule an unfringed eciliate membrane, Inflorescence terminal, Inflorescence solitary, with 1 spike, fascicle, glomerule, head, or cluster per stem or culm, Flowers unisexual, Plants monoecious, Spikelets pedicellate, Spikelets laterally compressed, Spikelet less than 3 mm wide, Spikelets with 1 fertile floret, Spikelets solitary at rachis nodes, Spikelets unisexual, Spikelets disarticulating above the glumes, glumes persistent, Rachilla or pedicel glabrous, Monoecious - staminate and pistillate spikelets on separate inflorescences, Glumes completely absent or reduced to cuplike structure, Glumes present, empty bracts, Lemmas thin, chartaceous, hyaline, cartilaginous, or membranous, Lemma 3 nerved, Lemma glabrous, Lemma apex acute or acuminate, Lemma straight, Palea present, well developed, Palea membranous, hyaline, Palea about equal to lemma, Stamens 6, Styles 1, Stigmas 2, Fruit - caryopsis, Caryopsis ellipsoid, longitudinally grooved, hilum long-linear, Caryopsis finely striate or ribbed.