Cyperus rotundus (scientific name: Cyperus rotundus), also known as sedge, large nutgrass, earth nutgrass (in Taiwan and southern Fujian), water nutgrass, and ground cover grass, is a perennial herbaceous plant of the Cyperaceae family. It has an erect, triangular stem that grows up to 40 cm in height. The leaves emerge near the base, are slender and linear, slightly shorter than the stem, about 20 cm long. The leaf veins are parallel, with a prominent midrib, and it blooms and produces spikes in spring and summer. Nutgrass often grows on grassy slopes or wetlands near water and is widely distributed across many regions of China.