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Vascular Plants of California
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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, Orogenia moved to Lomatium, Sphenosciadium moved to Angelica. 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.
eFlora Treatment Author: Lincoln Constance & Margriet Wetherwax
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
Jepson eFlora Author: Lincoln Constance & Margriet Wetherwax
Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)
Weed listed by Cal-IPC

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Botanical illustration including Conium maculatum

botanical illustration including Conium maculatum


Citation for this treatment: Lincoln Constance & Margriet Wetherwax 2012, Conium maculatum, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on December 15, 2019.

Citation for the whole project: Jepson Flora Project (eds.) 2019, Jepson eFlora,, accessed on December 15, 2019.

Conium maculatum
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© 2013 Keir Morse
Conium maculatum
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© 2011 Barry Breckling
Conium maculatum
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© 1999 California Academy of Sciences
Conium maculatum
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© 2015 Barry Breckling
Conium maculatum
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© 2008 Keir Morse
Conium maculatum
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© 2010 Neal Kramer

More photos of Conium maculatum in CalPhotos

Geographic subdivisions for Conium maculatum:
CA-FP, GB (uncommon)
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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).


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Data provided by the participants of the  Consortium of California Herbaria.
View all CCH records
All markers link to CCH specimen records. The original determination is shown in the popup window.
Blue markers indicate specimens that map to one of the expected Jepson geographic subdivisions (see left map). Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues.

CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa, if there are more than 1 infraspecific taxon in CA.
Blue line denotes eFlora flowering time.