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(moonseed), a genus of plants of the family Menispermaceae. They are perennial dioecious grasses, with twining stems that measure 2-5 m long. The leaves are alternate, long-petiolate, and shield-shaped; they have three to five lobes or, less frequently, are simple. The flowers are small, unisexual, and greenish; they grow in racemes or panicles. The fruit is a black drupe, with a single sickle-shaped seed. There are two species. Menispermum dahuricum grows in southeastern Siberia (west to Krasnoiarsk), the Far East, China, and the Korean Peninsula. It is found along forest edges and rivers. All parts of the plant, particularly the seeds, are poisonous. It is cultivated as an ornamental. Common moonseed (M. canadense) grows along the Atlantic coast of North America.