Sium suave Walter
hemlock water-parsnip (hemlock waterparsnip)

Introduction to Vascular Plants


© Allan Carson     (Photo ID #68952)


E-Flora BC Static Map

Distribution of Sium suave
Click here to view the full interactive map and legend

Species Information

Terrestrial to semi-aquatic perennial herb from a very short, erect stem-base (not chambered) with fibrous roots that sometimes are tuberous-thickened; stems solitary, 0.5-1.2 m tall, stout, hollow, strongly ridged, generally branched above.
Stem leaves pinnately compound; leaf stalks with sheathing bases, blades 2-9 cm long, 1.5-10 (20) mm wide, divided into 7-15 leaflets that are lance-shaped to linear and toothed; submerged leaves much more finely divided; primary lateral veins of the leaflets not directed towards the base of the teeth.
Inflorescence of compound umbels; flowers white, small; calyx teeth minute or obsolete; involucel bractlets 6-10, narrow, reflexed.
Oval to elliptic, 2-3 mm long, prominently ribbed.

SourceThe Illustrated Flora of British Columbia


If more than one illustration is available for a species (e.g., separate illustrations were provided for two subspecies) then links to the separate images will be provided below. Note that individual subspecies or varietal illustrations are not always available.


Ecological Framework for Sium suave

The table below shows the species-specific information calculated from
original data (BEC database) provided by the BC Ministry of Forests and Range.
(Updated August, 2013)

Site Information
Value / Class




Elevation (metres)
753 0 1310
Slope Gradient (%)
0 0 18

Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]

226 58 290
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
7 5 8
Modal Nutrient Regime
# of field plots
 species was recorded in:
Modal BEC Zone Class

All BEC Zones (# of stations/zone) species was recorded in

BG(7), BWBS(7), CWH(9), ICH(15), IDF(59), MS(1), PP(1), SBPS(9), SBS(29)

Habitat and Range

Wet streamsides, swamps, marshes, lake and pond shores in the lowland and montane zones; common throughout BC except Queen Charlotte Islands and adjacent coast; N to AK, YT and NT, E to NF and S to FL, VA, KS and CA.

SourceThe Illustrated Flora of British Columbia


Synonyms and Alternate Names:
Sium cicutifolium Schrank
Sium floridanum Small
Sium suave var. floridanum (Small) C.F. Reed