Sium suave

Fibrous-rooted from a very short erect crown; stem solitary, angular, stout, to 2 m; principal lvs with 7-17 linear to lance-ovate lfls 5-10 cm, sharply serrate, the primary lateral veins bearing no obvious relationship to the teeth or sinuses; submersed lvs, if present, bipinnately dissected; umbels 3-12 cm wide; bracts and bractlets usually 5 or 8; fr oval, 2-3 mm, nearly as wide; carpophore wanting; 2n=12. Sunny wet meadows and swamps; Nf. to Alas. and Siberia, s. to Fla. and Calif. July-Sept. (S. floridanum, a lax shade-form; S. carsonii, a lax aquatic form with few lfls or even simple lvs)

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

©The New York Botanical Garden. All rights reserved. Used by permission.

From Flora of Indiana (1940) by Charles C. Deam

In the shallow water of the borders of ponds and sloughs and in springy places along streams, swampy woodland, and ditches.

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Indiana Coefficient of Conservatism: C = 5

Wetland Indicator Status: OBL

Diagnostic Traits: glabrous perennial; leaves heterophyllous, emersed leaves pinnately compound with 7-17 lanceolate leaflets, their margins finely, sharply serrate; flowers white; fruits ovate to round, ca. 2-3 mm long, the ribs corky thickened.