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Vascular Plants of California
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Ricinus communis

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: RicinusView Description 

Common Name: CASTOR BEAN

Etymology: (Latin: tick, from seed shape)
eFlora Treatment Author: Mark H. Mayfield & Grady L. Webster
Ricinus communis L.
Habit: Shrub, occasionally tree-like, 1--3 m, +- glabrous; sap clear; monoecious. Stem: trunk ascending to erect, branched above. Leaf: cauline, alternate, peltate; stipules fused, 1--1.5 cm, sheath-like, deciduous; petiole 1--3 dm, glandular distally; blade 1--5 dm, +- round, palmately 7--11-lobed, sharply toothed. Inflorescence: panicle, terminal, 1--3 dm; staminate flowers proximal to pistillate flowers. Staminate Flower: sepals 3--5; stamens many, clustered; nectary 0. Pistillate Flower: sepals 3--5; ovary 3-chambered, bristly, styles 2-lobed, plumose, +- red. Fruit: 1.2--2 cm diam, +- spiny. Seed: 9--22 mm, smooth, shiny, mottled; scar appendaged. Chromosomes: 2n=20.
Ecology: Disturbed areas; Elevation: < 300 m. Bioregional Distribution: GV, CCo, SCo, expected elsewhere; Distribution Outside California: eastern United States; native to Europe. Toxicity: Highly TOXIC: seeds attractive to children, fatal when ingested. Flowering Time: All year
Jepson eFlora Author: Mark H. Mayfield & Grady L. Webster
Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)
View the CDFA Pest Rating page for Ricinus communis
Weed listed by Cal-IPC

Previous taxon: Ricinus
Next taxon: Stillingia

Botanical illustration including Ricinus communisbotanical illustration including Ricinus communis

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Citation for this treatment: Mark H. Mayfield & Grady L. Webster 2012, Ricinus communis, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on July 13, 2024.

Citation for the whole project: Jepson Flora Project (eds.) 2024, Jepson eFlora,, accessed on July 13, 2024.

Ricinus communis
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©2013 Keir Morse
Ricinus communis
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©2010 Neal Kramer
Ricinus communis
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©2010 Neal Kramer
Ricinus communis
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©2009 Thomas Stoughton
Ricinus communis
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©2011 Neal Kramer

More photos of Ricinus communis
in CalPhotos

Geographic subdivisions for Ricinus communis:
GV, CCo, SCo, expected elsewhere
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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 occurrence).


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 Flowering-Fruiting Monthly Counts

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 (fruiting time in some monocot genera).