Zizaniopsis miliacea (Michx.) Döll & Asch.

Perennials, Aquatic, growing in or on water, Terrestrial, not aquatic, Rhizomes present, Rhizome elongate, creeping, stems distant, Stems nodes swollen or brittle, Stems erect or ascending, Stems geniculate, decumbent, or lax, sometimes rooting at nodes, Stems terete, round in cross section, or polygonal, Stem internodes hollow, Stems with inflorescence 1-2 m tall, Stems with inflorescence 2-6 m tall, Stems, culms, or scapes exceeding basal leaves, Leaves mostly cauline, Leaves conspicuously 2-ranked, distichous, Leaves sheathing at base, Leaf sheath mostly open, or loose, Leaf sheath smooth, glabrous, Leaf sheath and blade differentiated, Leaf blades linear, Leaf blades 1-2 cm wide, Leaf blades 2 or more cm wide, Leaf blades mostly flat, Leaf blades mostly glabrous, Ligule present, Ligule an unfringed eciliate membrane, Inflorescence terminal, Inflorescence an open panicle, openly paniculate, branches spreading, Inflorescence solitary, with 1 spike, fascicle, glomerule, head, or cluster per stem or culm, Inflorescence lax, widely spreading, branches drooping, pendulous, Inflorescence branches more than 10 to numerous, 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 same inflorescence, Glumes completely absent or reduced to cuplike structure, Lemmas thin, chartaceous, hyaline, cartilaginous, or membranous, Lemma 5-7 nerved, Lemma glabrous, Lemma apex acute or acuminate, Lemma mucronate, very shortly beaked or awned, less than 1-2 mm, Lemma distinctly awned, more than 2-3 mm, Lemma with 1 awn, Lemma awn less than 1 cm long, Lemma awned from tip, Lemma awns straight or curved to base, Lemma straight, Palea present, well developed, Palea longer than lemma, Stamens 6, Styles 1, Stigmas 2, Fruit - caryopsis, Caryopsis isodiametric, trigonous or globose, broadest at base or beaked, Caryopsis ellipsoid, longitudinally grooved, hilum long-linear.

Zizaniopsis miliacea is a species of flowering plant in the grass family, Poaceae. It is known by the common names giant cutgrass, water millet, and southern wildrice. The name giant cutgrass refers to the plant's large, rough-edged leaves, and the name southern wildrice refers to its resemblance to wildrice (Zizania spp.). It is native to the southeastern United States and it can also be found in central Mexico.

This perennial grass grows from rhizomes, producing stems up to 4 meters tall and 3.5 centimeters wide. The stems root at nodes that come in contact with the substrate. It also spreads via functional stolons (decumbent rooting stems) and vegetative buds that erupt from the stems. The blue-green leaves are up to a meter long and 3 centimeters wide. The panicles may exceed 80 centimeters long and are usually up to 20 centimeters wide.

This plant grows in aquatic habitat, such as marshes and riverbanks. It is also common in former rice paddies. This grass forms large colonies by spreading via its stolon-like stems and rhizomes. It grows in fresh and brackish water, tolerating some salt in the water. It is sometimes planted for erosion control in wetlands. Large stands of the plant are sometimes considered to be a nuisance, providing "poor wildlife habitat"; however, it does provide nesting sites, cover, and food for animals.

Zizaniopsis miliacea là một loài thực vật có hoa trong họ Hòa thảo. Loài này được (Michx.) Döll & Asch. miêu tả khoa học đầu tiên năm 1871.