Sium

{{Short description|Genus of flowering plants}}

{{Automatic taxobox

|image = Sium suave var nipponicum1.jpg

|image_caption = Sium suave

|display_parents = 2

|taxon = Sium

|authority = L.

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Sium is a genus of flowering plants in the family Apiaceae. It is widely distributed across Europe, Asia, Africa, and North America.[http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=130526 Sium.] Flora of China. Plants of this genus are commonly called water parsnips.[https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=29557 Sium.] Integrated Taxonomic Information System (ITIS).

These are perennial herbs, including some fully aquatic plants and some species that grow near water. The branching stem roots at the nodes. The lower leaves are pinnate, divided into leaflets. They are borne on petioles that sheath the stem at their bases. The inflorescence is a compound umbel of flowers with white petals.

There are about 12 species in the genus.Spalik, K., et al. (2009). [http://www.life.illinois.edu/downie/Spalik_Sium_cpDNA.pdf Generic delimitations within the Sium alliance (Apiaceae tribe Oenantheae) inferred from cpDNA rps16-5'trnk (UUU) and nrDNA ITS sequences.] Taxon 58(3), 735-48.Spalik, K. and S. R. Downie. (2006). [https://web.archive.org/web/20171124111524/http://www.amjbot.org/content/93/5/747.full The evolutionary history of Sium sensu lato (Apiaceae): dispersal, vicariance, and domestication as inferred from ITS rDNA phylogeny.] American Journal of Botany 93(5), 747-61.

Species include:

• Sium bracteatum jellico, large jellico{{cite iucn |author=Lambdon, P.W. |author2=Ellick, S. |date=2016 |title=Berula bracteata |volume=2016 |page=e.T43985A67378473 |doi=10.2305/IUCN.UK.2016-1.RLTS.T43985A67378473.en |access-date=17 November 2021}}
• Sium burchellii – dwarf jellico{{cite iucn |author=Lambdon, P.W. |author2=Ellick, S. |date=2016 |title=Berula burchellii |volume=2016 |page=e.T43986A67378501 |doi=10.2305/IUCN.UK.2016-1.RLTS.T43986A67378501.en |access-date=17 November 2021}}
• Sium frigidum
• Sium latifolium – wideleaf water parsnip, great water parsnip
• Sium medium
• Sium ninsi
• Sium repandum
• Sium serra
• Sium sisaroideum
• Sium sisarum – skirret
• Sium suave – common water parsnip, hemlock water parsnip
• Sium tenue