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Key to families | Table of families and genera

Previous taxon Indexes to all accepted names and synonyms:
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Mark H. Mayfield & Grady L. Webster, except as noted

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.
217 genera, 6000+ species: ± worldwide especially tropics; some cultivated (Aleurites, tung oil; Euphorbia species; Hevea, rubber; Ricinus). Many species ± highly TOXIC, due primarily to latex, especially if eaten or in contact with skin, eyes. [Yang et al. 2012 Taxon 61:764–789] Eremocarpus moved to Croton, Tetracoccus moved to Picrodendraceae for TJM2; Chamaesyce moved to Euphorbia here (key to genera revised by Thomas J. Rosatti). —Scientific Editor: Bruce G. Baldwin.

Key to Euphorbiaceae

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.
8 species: Eurasia, northern Africa. (Geronimo Mercuriali, Italian physician, 1530–1606)

M. annua L.
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.
2n=16,32. Open, disturbed areas; < 200 m. San Francisco Bay Area; native to Europe. Feb–Oct [Online Interchange]

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Citation for the whole project: Jepson Flora Project (eds.) 2013. Jepson eFlora,, accessed on Nov 25 2015
Citation for this treatment: [Author of taxon treatment] 2013. Mercurialis, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on Nov 25 2015

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Geographic subdivisions indicated for the distribution of 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).

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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.
Blue line denotes eFlora flowering time.