Conium maculatumL.

poison hemlock

WFO wfo-0000617964 Accepted WFO 2026-06 8 photographs CC0 / CC BY In the accuracy benchmark

Plate 1 figs. a–h

Conium maculatum, photographed by Violet T.
fig. a Violet T., CC BY 4.0 / 2022-06-10 / obs. 204987861
Conium maculatum, photographed by Violet T.
fig. b Violet T., CC BY 4.0 / obs. 205848212
Conium maculatum, photographed by giantcicada
fig. c giantcicada, CC BY 4.0 / obs. 205495950
Conium maculatum, photographed by Daniel Cahen
fig. d Daniel Cahen, CC BY 4.0 / obs. 205523458
Conium maculatum, photographed by Rebecca Gimenez Husted
fig. e Rebecca Gimenez Husted, CC BY 4.0 / obs. 205828258
Conium maculatum, photographed by inbetweenbays
fig. f inbetweenbays, CC BY 4.0 / obs. 203739104
Conium maculatum, photographed by Dominic Gentilcore
fig. g Dominic Gentilcore, CC BY 4.0 / obs. 205044816
Conium maculatum, photographed by Charles Joynson
fig. h Charles Joynson, CC0 1.0 / obs. 203499125

Every figure is a research-grade observation under CC0, CC BY or CC BY-SA, rehosted with the photographer’s name, the licence and the observation it came from. Photographs under a NonCommercial licence are excluded from this site and are never stored, which costs us a great many pictures and is not negotiable.

Confused withby our own model

These are not lookalikes we guessed at. Each one is a species our identification model genuinely mistook for this plant, and how many times. The error rate is published.

Flowering n = 7,680 observations

Peak flowering in Jun, from 7,680 community-annotated observations worldwide. This is a global aggregate, not a forecast for your garden: the same species flowers on different dates in different hemispheres, and citizen-science records cluster near cities, at weekends, and in spring. Where a species has fewer than 30 annotated records we do not draw this chart at all.

Also published as 24 synonyms

A synonym is not an error. It is a record of botanists disagreeing, in print, about where this plant belongs. Each of these was somebody’s considered answer.

  • Cicuta major Lam.
  • Cicuta major Garsault
  • Cicuta officinalis Crantz
  • Conium ceretanum Sennen
  • Conium cicuta (Crantz) Neck.
  • Conium croaticum Waldst. & Kit. ex Willd.
  • Conium leiocarpum (Boiss.) Stapf
  • Conium maculatum subsp. croaticum (Waldst. & Kit. ex Willd.) Drude
  • Conium maculatum subsp. leiocarpum (Boiss.) Drude
  • Conium maculatum subsp. viride (DC.) Espeut
  • Conium maculatum var. barceloi O.Bolòs & Vigo
  • Conium maculatum var. immaculatum Schur
  • Conium maculatum var. leiocarpum Boiss.
  • Conium maculatum var. viride DC.
  • Conium maculosum Pall.
  • Conium nodosum Fisch. ex Steud.
  • Conium pyrenaicum Sennen & Elias
  • Conium sibiricum hort. ex Steud.
  • Conium strictum Tratt.
  • Conium tenuifolium Mill.
  • Coriandrum cicuta Crantz
  • Coriandrum maculatum Roth
  • Selinum conium E.H.L.Krause
  • Sium conium Vest

Sourcesevery claim on this page

  1. World Flora Online Plant List. accepted name, authority, classification. CC0. Retrieved 2026-07-12.
  2. iNaturalist. photographs and flowering annotations, CC0 / CC BY / CC BY-SA only. per photograph. Retrieved 2026-06-27.

We publish what we can source and we say so when we cannot. This page has no care advice, no toxicity claim and no native range, because we do not yet have those from a source we can cite.