E-Flora BC: Electronic Atlas of the Flora of British Columbia

Conium maculatum L.
poison-hemlock (poison hemlock)

Introduction to Vascular Plants

© Bryan Kelly-McArthur  Email the photographer   (Photo ID #84241)

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Distribution of Conium maculatum
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Species Information

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Robust biennial herb from a stout whitish taproot, with a disagreeable odour, especially when crushed; stems erect, freely branched, purple-blotched, hollow, 0.5-3 m tall, glabrous, glaucous.
Stem leaves pinnately dissected, fernlike, with small ultimate segments giving the plant a lacy appearance; leaf stalks enlarged and sheathing at the base, the blades 15-30 cm long.
Inflorescence terminal and axillary in many compound umbels; flowers white; involucral bracts small, lance-shaped.
Egg-shaped, somewhat flattened, 2-2.5 mm long, glabrous, with prominent, raised, often wavy ribs.
Plants highly poisonous.

Source: The Illustrated Flora of British Columbia

Habitat / Range

Wet to mesic ditches and disturbed sites in the lowland zone; locally common in in SW BC (known in the Victoria area and Vancouver) rare in SC BC; introduced from Europe.

Source: The Illustrated Flora of British Columbia

Additional Notes

This is an extremely poisonous introduced European species in the carrot/parsley family (Apiaceae/Umbelliferae) that can be fatal if ingested. Because it is so toxic, it is important to carefully consider the key characteristics when making an identification. This is the plant that Socrates used to kill himself (Pojar and MacKinnon 1994).

Note Author: R. Klinkenberg


Pojar, Jim and Andy MacKinnon. 1994. Plants of Coastal British Columbia. Lone Pine Press, Edmonton.


Ecological Framework for Conium maculatum

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) 1359 1429 1500
Slope Gradient (%) 0 10 20
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
120 120 120
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
5 5 5
Modal Nutrient Regime
Number of field plots
 species was recorded in:
Modal BEC Zone Class
All BEC Zones (# of stations/zone) species was recorded in: ICH(1), MS(1)


The climate type for this species, as reported in the: "British Columbia plant species codes and selected attributes. Version 6 Database" (Meidinger et al. 2008), is not evaluated, unknown or variable.

Taxonomic and Nomenclatural Links

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General References