Sium

Scientific name

Sium L.

Common names

water parsnip

Family

Apiaceae

Similar genera

Acrostichum, Cicuta, Oenanthe

Native distribution

Africa, Asia, Europe, North America

Species cultivated

Sium sisarum L.

S. suave Walter

Adventive distribution

may have expanded within its native distribution

Weed status

not weedy

Habit

amphibious amphibious:
(adj) of a plant able to live on land or in water
terrestrial, floating, emergentemergent:
(adj) (syn. emersed) with parts raised out of the water; extending up out of the water
or submergedsubmerged:
(adj) (syn. submersed) under water; submerged below the water surface
herb

Brief description

Medium to large. Stem erect, occasionally creeping, branched above, round, striate or angled above, glabrousglabrous:
(adj) without hairs or scales
, rooting at lower nodes; roots fascicled, fibrous. Leaves emerge as a basalbasal:
(adj) at or pertaining to the base, or point of attachment
rosette, then become alternatealternate:
(adj) (of leaves) bearing one leaf per node; placed singly on the stem at different heights
; petiolatepetiolate:
(adj) relating to or in the form of a petiole; bearing petioles
; bladeblade:
(n) (syn. lamina) the flat, expanded part of a leaf, frond, or petal (excluding, e.g., the petiole)
1-pinnate, rarely 2-pinnate; leaflets lanceolatelanceolate:
(adj) lance-shaped; widest point below the middle, tapering to the apex
to ovateovate:
(adj) egg-shaped in outline; generally with the broad end at or near the base
, or oblongoblong:
(adj) two to four times longer than wide, with +/- parallel sides
, margins serrateserrate:
(adj) (of a leaf margin) bearing sharp teeth pointing forward or to the apex
; submergedsubmerged:
(adj) (syn. submersed) under water; submerged below the water surface
leaves 1- to 5-pinnate, leaflets linear, linear-filiform, or lanceolatelanceolate:
(adj) lance-shaped; widest point below the middle, tapering to the apex
. Inflorescenceinflorescence:
(n) the arrangement of flowers on the floral axis
a terminalterminal:
(adj) at the apex
and axillaryaxillary:
(adj) in, of, or produced from an axil
twice compoundcompound:
(adj) with two or more like parts, as in a compound leaf; divided into two or more subsidiary parts or orders, as in a compound inflorescence
umbel; pedunculatepedunculate:
(adj) borne on or possessing a peduncle
; bracts and bracteoles present, conspicuous, usually recurvedrecurved:
(adj) curved downward or backward
; pedicelspedicels:
(n) the stalk of a single flower in an inflorescence, or of a grass spikelet
spreading-ascending. Flowers small; sepals absent or minute; petals 5, white, wide, apexapex:
(n) the point farthest from the point of attachment; the tip (often pointed)
incurved; stamens exsertedexserted:
(adj) projecting beyond, sticking out or protruding
; styles divergent or reflexedreflexed:
(adj) abruptly curved or bent downward
.

Natural habitat

in and along soggy thickets, wet prairies, streams, swamps, bogs, floodplains, marshes, ponds, and ditches