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Montana Field Guide

Montana Field Guides

Poison Hemlock - Conium maculatum
Other Names:  Poison-hemlock, Devil's Bread, Carrot Fern, Devil's Porridge, Poison Parsley, Spotted Corobane, Spotted Hemlock

Non-native Species

Global Rank: G5
State Rank: SNA
C-value: 0

Agency Status


External Links

General Description
Glabrous, highly poisonous biennials. Stems stout, hollow, erect, branched, 0.5–3 m, purple-spotted. Leaves basal and cauline, petiolate; blades ovate in outline, 15–30 cm long, tripinnate; leaflets lobed; ultimate segments <1 mm long. Umbels terminal and axillary, compound; involucral and involucel bracts, lanceolate to ovate. Flowers white; stylopodium low-conic; styles reflexed. Mericarps ovoid, slightly compressed parallel to the commissure, glabrous, 2–3 mm long; ribs barely winged; oil tubes many in the intervals (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Species Range
Montana Range Range Descriptions


Range Comments
Introduced throughout most of temperate North America; native to Eurasia (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Observations in Montana Natural Heritage Program Database
Number of Observations: 880

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density



(Observations spanning multiple months or years are excluded from time charts)

Moist, disturbed soil along streams, ditches, cool open slopes; plains, valleys (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).
Predicted Suitable Habitat Model

This species has a Predicted Suitable Habitat Model available.

To learn how these Models were created see


  • Literature Cited AboveLegend:   View Online Publication
    • Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
  • Additional ReferencesLegend:   View Online Publication
    Do you know of a citation we're missing?
    • Eggers, M.J.S. 2005. Riparian vegetation of the Montana Yellowstone and cattle grazing impacts thereon. M.Sc. Thesis. Montana State University, Bozeman, MT. 125 p.
    • Hendrick, U. P., ed. 1972. Sturtevant's edible plants of the world. Dover Pub., New York. 188 pp.
    • Hodgson, J.R. 1970. Ecological distribution of Microtus montanus and Microtus pennsylvanicus in an area of geographic sympatry in southwestern Montana. Ph.D. Dissertation. Bozeman, Montana: Montana State University. 65 p.
    • James, W. R. 1973. Know your poisonous plants. Naturegraph Publishers, Healdsburg, Ca. 99pp.
    • Lesica, P., M.T. Lavin, and P.F. Stickney. 2022. Manual of Montana Vascular Plants, Second Edition. Fort Worth, TX: BRIT Press. viii + 779 p.
    • Munz, P.A., and D.D. Keck. 1973. A California flora and supplement. Univ. California Press, Berkeley, CA.
    • Robbins, W. W., M. K. Bellue, and W. S. Ball. 1970. Weeds of California. State of California, Department of Agriculture.
  • Web Search Engines for Articles on "Poison Hemlock"
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Citation for data on this website:
Poison Hemlock — Conium maculatum.  Montana Field Guide.  .  Retrieved on , from