Ustilago esculenta

Ustilago esculenta is a species of fungus in the Ustilaginaceae, a family of smut fungi. It is in the same genus as the fungi that cause corn smut, loose smut of barley, false loose smut, covered smut of barley, loose smut of oats, and other grass diseases. This species is pathogenic as well, attacking Manchurian wild rice (Zizania latifolia), also known as Manchurian ricegrass, Asian wild rice, and wateroat. This grass is its only known host. Zizania latifolia is grown as an agricultural crop across Asia. The success of the crop depends on the smut fungus. The grass is not grown for its grain, as are other wild rice species, but for the stems, which swell into juicy galls when infected with the smut. The galled stems are harvested as a vegetable called gau-soon and kal-peh-soon (Pe̍h-ōe-jī: kha-pe̍h-sún; also, gau sun and kah peh sung) and jiaobai in China. Its Japanese name is makomotake. The galled section of the stem is 3 to 4 centimeters (1.2 to 1.6 in) wide and up to 20 centimete......read more on Wikipedia.