菰 gu

Hydropyrum latifolium Grisebach in Ledebour, Fl. Ross. 4: 466. 1853; Zizania aquatica Linnaeus var. latifolia (Grisebach) Komarov; Z. caduciflora Handel-Mazzetti, nom. illeg. superfl.; Z. dahurica Turczaninow ex Steudel.

Perennial, rhizomatous. Culms erect, 1–2.5 m, ca. 1 cm thick, rooting at lower nodes, nodes glabrous. Leaf sheaths longer than internodes, thickened, lower sheaths tessellate; leaf blades broadly linear, 50–90 × 1.5–3.5 cm, abaxial surface scabrous, adaxial surface glabrous, tapering to base, apex abruptly narrowed to a long point; ligule triangular, 1–1.5 cm. Panicle 30–50 × 10–15 cm, lower branches with male spikelets, upper branches with female spikelets, middle branches mixed; branches semiverticillate, many at each node, sparsely spinulose; pedicel apex disk-shaped with spinulose margin. Male spikelet 0.8–1.5 cm; lemma elliptic-oblong, margin ciliate; awn 2–8 mm, scabrous; anthers 5–8 mm. Female spikelet 1.5–2.5 cm; lemma linear, scabrous on veins; awn 1.5–3 cm, scabrous. Caryopsis ca. 1 cm. Fl. and fr. Jun–Sep. 2n = 30, 34.

Shallow water of lake margins and swamps, forming large patches. Anhui, Fujian, Guangdong, Guangxi, Guizhou, Hainan, Hebei, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Jilin, Liaoning, Shaanxi, Shandong, Sichuan, Taiwan, Yunnan, Zhejiang [NE India, Japan, Korea, Myanmar, Russia; cultivated in SE Asia].

This species is cultivated as a vegetable in China. The young shoots and rhizomes are edible when infected, swollen, and softened by the fungus Ustilago esculenta. The presence of the fungus prevents flowering. The grains were used for food by the Emperor in ancient China, and are currently being used by fishermen.