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Weed Seed: Conium maculatum (Poison hemlock)

Family

Apiaceae

Common Name

Poison hemlock

Regulation

Primary Noxious, Class 2 in the Canadian Weed Seeds Order, 2016 under the Seeds Act.

Distribution

Canadian: Occurs in AB, BC, NB, NS, ON, QC, SK (Brouillet et al. 2016Footnote 1).

Worldwide: Native to northern Africa, Europe and western and central Asia. Introduced to North and South America, southern Africa, Australia, New Zealand and Micronesia (USDA-ARS 2016Footnote 2).

Duration of life cycle

Biennial

Seed or fruit type

Schizocarp, divided into 2 mericarps

Identification features

Size

Shape

Surface Texture

Colour

Other Features

Habitat and Crop Association

Cultivated fields, pastures, roads and disturbed areas (Darbyshire 2003Footnote 3, CABI 2016Footnote 4). Invades a variety of crops, including cereal and vegetable crops, as well as orchards, often by encroachment from field edges (CABI 2016Footnote 4).

General Information

Poison hemlock was brought to the United States as a garden plant in the 19th century (DiTomaso and Healy 2007Footnote 5). Seed may have spread by mud, boots and other human clothing, as well as by machinery and transported soil (Ministry of Agriculture, Food, and Fisheries 2002Footnote 6).

Poison hemlock grows in lowlands on dry to moist soils and can tolerate poorly drained soils (Ministry of Agriculture, Food, and Fisheries 2002Footnote 6). It is poisonous to livestock (CABI 2016Footnote 4).

Similar species

Wild carrot (Daucus carota subsp. carota)

Photos

Poison hemlock (Conium maculatum) mericarps
Poison hemlock (Conium maculatum) mericarp, outer side
Poison hemlock (Conium maculatum) mericarp, inner side
Poison hemlock (Conium maculatum) mericarp, side view
Poison hemlock (Conium maculatum) mericarp, top-down view
Poison hemlock (Conium maculatum) mericarps

Similar species

Similar species: Wild carrot (Daucus carota) mericarps
Similar species: Wild carrot (Daucus carota) mericarp, outer side
Similar species: Wild carrot (Daucus carota) mericarp, inner side
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