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Conium maculatum

Higher Taxonomy
Family: Apiaceae (Umbelliferae)View DescriptionDichotomous Key

Habit: Annual to perennial herb [shrub, tree], generally from taproot. Stem: generally +- scapose, generally ribbed, hollow. Leaf: basal and generally cauline, generally alternate; stipules generally 0; petiole base generally sheathing stem; blade generally much dissected, occasionally compound. Inflorescence: umbel or head, simple or compound, generally peduncled; bracts present in involucres or 0; bractlets generally present in "involucels". Flower: many, small, generally bisexual (or some staminate), generally radial (or outer bilateral); calyx 0 or lobes 5, small; petals 5, free, generally ovate or spoon-shaped, generally incurved at tips, generally +- ephemeral; stamens 5; pistil 1, ovary inferior, 2-chambered, generally with a +- conic, persistent projection or platform at tip subtending 2 free styles. Fruit: 2 dry, 1-seeded halves (= mericarps), separating from each other but generally +- persistent to central axis; ribs on halves 5, 2 marginal, 3 to back; oil tubes 1--several per interval between ribs.
Genera In Family: 300 genera, 3000 species: +- worldwide, especially temperate; many cultivated for food or spice (e.g., Carum, caraway; Daucus; Petroselinum); Bupleurum lancifolium Hornem. is historical garden weed; some toxic (e.g., Conium). Note: Mature fruit generally critical in identification, shape given in outline. Hydrocotyle moved to Araliaceae. Petroselinum crispum (Mill.) A.W. Hill is a waif.
eFlora Treatment Author: Lincoln Constance & Margriet Wetherwax, except as noted
Scientific Editor: Douglas H. Goldman, Bruce G. Baldwin.
Genus: ConiumView Description 

Habit: Biennial, taprooted; herbage glabrous, musty-scented. Stem: erect, branched. Leaf: blade ovate to triangular-ovate, pinnately dissected or compound, segments or leaflets lanceolate or oblong to ovate, serrate to 1--2-pinnately lobed. Inflorescence: umbels compound, terminal, lateral; bracts, bractlets small, few; rays, pedicels +- many, spreading-ascending. Flower: calyx lobes 0; petals wide, +- white, tips narrowed. Fruit: ovoid to spheric, +- compressed side-to-side; ribs +- equal, low; oil tubes 0; fruit axis divided to base. Seed: face grooved.
Species In Genus: +- 6 species: Europe, southern Africa. Etymology: (Greek name used by Dioscorides) Toxicity: TOXIC: highly toxic alkaloids used in ancient Greece for capital punishment (e.g., Socrates); many human deaths, rarely eaten by livestock.

Conium maculatum L.
Habit: Plant 5--30 dm. Stem: generally purple-spotted or -streaked. Leaf: petiole dilated; blade 1.5--3 dm, widely ovate, generally 2-pinnate. Inflorescence: many-branched; peduncles 2--8 cm; bracts 4--6, acuminate; bractlets 5--6, 1.5--2 mm, acuminate, generally +- fused at base, scarious; rays 10--20, 1.5--5 cm. Fruit: 2--3 mm wide, ovate; ribs generally wavy. Chromosomes: 2n=22.
Ecology: Common. Moist, especially disturbed places; Elevation: < 1500 m. Bioregional Distribution: CA-FP, GB (uncommon); Distribution Outside California: America; native to Europe. Flowering Time: Apr--Jul
eFlora Treatment Author: Lincoln Constance & Margriet Wetherwax
Jepson Online Interchange
Weed listed by Cal-IPC

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botanical illustration including Conium maculatum


Citation for this treatment: Lincoln Constance & Margriet Wetherwax 2016. Conium maculatum, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on May 05, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora,, accessed on May 05, 2016.

Conium maculatum
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© 2013 Keir Morse
Conium maculatum
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© 2009 Neal Kramer
Conium maculatum
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© 2009 Gary A. Monroe
Conium maculatum
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© 2009 Barry Rice
Conium maculatum
click for enlargement
© 2009 Gary A. Monroe
Conium maculatum
click for enlargement
© 2013 Keir Morse

More photos of Conium maculatum in CalPhotos

Geographic subdivisions for Conium maculatum:
CA-FP, GB (uncommon);
Markers link to CCH specimen records. If the markers are obscured, reload the page [or change window size and reload]. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues.
map of distribution 1
(Note: any qualifiers in the taxon distribution description, such as 'northern', 'southern', 'adjacent' etc., are not reflected in the map above, and in some cases indication of a taxon in a subdivision is based on a single collection or author-verified occurence).

View elevation by latitude chart
Data provided by the participants of the Consortium of California Herbaria.
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CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa.
Blue line denotes eFlora flowering time.