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Vascular Plants of California
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Mercurialis annua

Higher Taxonomy
Family: EuphorbiaceaeView DescriptionDichotomous Key
Habit: Annual to shrub, tree [vine, cactus-like succulent]; monoecious or dioecious; sap clear or milky. Stem: generally branched [fleshy or spiny]. Leaf: generally simple, alternate to whorled, generally stipuled, sessile or petioled; blade entire, toothed, or lobed. Inflorescence: flowers solitary or in terminal or axillary cymes, racemes, spikes, or panicles, or (in Euphorbia) 1° inflorescence a compact, flower-like cyathium with much-reduced flowers enclosed within an involucre of fused bracts, cyathia terminal or axillary, 1 or in cyme-like arrays. Flower: unisexual, +- radial; sepals 0 or 2--6, free or fused; petals generally 0(5); stamens 1--many, free or filaments fused; ovary superior, chambers (1)3(4), styles free or fused, undivided, forked, or variously lobed. Fruit: generally capsule that splits into mericarps that then dehisce, releasing seeds. Seed: 1 per chamber; knob-like appendage sometimes present at attachment scar.
Genera In Family: 217 genera, 6000+ species: +- worldwide especially tropics; some cultivated (Aleurites, tung oil; Euphorbia species; Hevea, rubber; Ricinus). Toxicity: Many species +- highly TOXIC, due primarily to latex, especially if eaten or in contact with skin, eyes. Note: Eremocarpus moved to Croton, Tetracoccus moved to Picrodendraceae for TJM2; Chamaesyce moved to Euphorbia here (key to genera revised by Thomas J. Rosatti).
eFlora Treatment Author: Mark H. Mayfield & Grady L. Webster, except as noted
Scientific Editor: Bruce G. Baldwin.
Genus: MercurialisView Description 

Common Name: MERCURY
Habit: Annual [perennial herb], generally glabrous; sap clear; (monoecious) dioecious. Stem: central erect, branched; lateral < central, spreading to ascending. Leaf: cauline, opposite; stipules persistent; hairs simple. Staminate Inflorescence: spike-like, axillary; flowers clustered. Pistillate Inflorescence: flowers clustered, axillary. Staminate Flower: calyx 3-lobed; stamens 8--15(20), free; nectary 0. Pistillate Flower: sepals 3; staminodes 2, elongated; ovary 2-chambered, bristly, styles free, simple. Fruit: bristly. Seed: generally pitted; scar appendaged.
Species In Genus: 8 species: Eurasia, northern Africa. Etymology: (Geronimo Mercuriali, Italian physician, 1530--1606)
eFlora Treatment Author: Mark H. Mayfield & Grady L. Webster
Mercurialis annua L.
Habit: Annual, 1--3 dm. Leaf: stipules 1--1.5 mm, lance-deltate; petiole 0.5--2(2.5) cm; blade 2--5 cm, +- ovate, margin serrate, ciliate. Staminate Inflorescence: < 2 cm, short-peduncled. Pistillate Inflorescence: flowers 2--3; pedicel < 5 mm. Staminate Flower: calyx +- 1 mm; stamens exserted. Pistillate Flower: calyx +- 1 mm; ovary strigose, styles +- 1 mm. Fruit: 2--3 mm diam. Seed: 1.5--2 mm, shiny, pitted. Chromosomes: 2n=16,32.
Ecology: Open, disturbed areas; Elevation: < 200 m. Bioregional Distribution: SnFrB; Distribution Outside California: native to Europe. Flowering Time: Feb--Oct
Jepson eFlora Author: Mark H. Mayfield & Grady L. Webster
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Botanical illustration including Mercurialis annua

botanical illustration including Mercurialis annua


Citation for this treatment: Mark H. Mayfield & Grady L. Webster 2012, Mercurialis annua, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on March 21, 2019.

Citation for the whole project: Jepson Flora Project (eds.) 2019, Jepson eFlora,, accessed on March 21, 2019.

Mercurialis annua
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© 2007 Neal Kramer
Mercurialis annua
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© 2014 Neal Kramer
Mercurialis annua
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© 2014 Neal Kramer
Mercurialis annua
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© 2009 Neal Kramer
Mercurialis annua
click for enlargement
© 2007 Neal Kramer
Mercurialis annua
click for enlargement
© 2013 Neal Kramer

More photos of Mercurialis annua in CalPhotos

Geographic subdivisions for Mercurialis annua:
Markers link to CCH specimen records. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues. Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
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.
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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.