- Sium, genus Sium - perennial of wet and marshy places in the northern hemisphere: water parsnips
--1 is a kind of rosid dicot genus
--1 is a member of
--1 has members:Umbelliferae, family Umbelliferae, Apiaceae, family Apiaceae, carrot family water parsnip, Sium suave; greater water parsnip, Sium latifolium; skirret, Sium sisarum