Jepson eFlora: Taxon page
Key to families | Table of families and genera
Previous taxon Index to accepted names and synonyms:
| A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z |
Next taxon
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)

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
eFlora Treatment Author: Mark H. Mayfield & Grady L. Webster
Jepson Online Interchange

Previous taxon: Mercurialis
Next taxon: Ricinus

Name Search
botanical illustration including Mercurialis annua


Citation for this treatment: Mark H. Mayfield & Grady L. Webster 2016. Mercurialis annua, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on April 29, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora,, accessed on April 29, 2016.

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

More photos of Mercurialis annua in CalPhotos

Geographic subdivisions for Mercurialis annua:
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.
View all CCH records

CCH collections by month

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