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Related to Sium: Sium sisarum
a genus of plants of the family Umbelliferae. The plants are perennial herbs with pinnate leaves. The umbels have involucres, and the petals are white and fold inward. The fruits are ribbed and slightly laterally compressed. There are ten to 15 species, distributed in Eurasia, North Africa, and North America. The USSR has six species. S. latifolium grows in shallows and along shores in the European USSR, the Caucasus, Siberia, and Kazakhstan. The entire plant, especially the roots, is poisonous to cattle; the fruits and flowers contain essential oil, including as much as 80 percent limonene. The species S. sisarum is sometimes grown for its edible tuberous roots. It was cultivated throughout Europe in the 15th and 16th centuries.