Ricinus

L., 1753

Castor Beans, Castor Oil Plant, Castor Bean, Higuerilla, Mamona

Ricinus is a of flowering plants in the spurge Euphorbiaceae, containing the single Ricinus communis. This fast-growing shrub or small tree is to the southeastern Mediterranean Basin, East Africa, and India, but has become widespread throughout tropical and subtropical regions worldwide. The is economically significant as the source of castor , extracted from seeds that contain 40–60% oil rich in ricinoleic acid. All plant parts contain ricin, a highly potent water-soluble toxin that makes the seeds especially dangerous if ingested. The species exhibits remarkable morphological variability, with developed for both ornamental purposes and commercial oil production.

Ricinus by no rights reserved, uploaded by Adam Kranz. Used under a CC0 license.

Ricinus by no rights reserved, uploaded by 葉子. Used under a CC0 license.

Pronunciation

How to pronounce Ricinus: //ˈrɪsɪnʊs//

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

Distinguished from other Euphorbiaceae by the combination of large palmately lobed leaves, racemose with separate male and female flowers, and spiny three-lobed capsules containing three large mottled seeds with caruncles. The 'false castor ' Fatsia japonica (Araliaceae) is not closely related and differs in leaf structure and fruit . Within Euphorbiaceae, Ricinus is placed in its own subtribe Ricininae based on unique morphological and chemical characteristics including the production of ricin and castor oil with high ricinoleic acid content.

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Habitat

to warm temperate and tropical regions; thrives in disturbed , wastelands, and open areas. In tropical climates, establishes readily and can become . Grown extensively as an ornamental in parks and public areas, and as a in agricultural systems. Requires well-drained soils and full sun; not cold hardy, suffering frost damage below freezing temperatures.

Distribution

to the southeastern Mediterranean Basin, East Africa, and India. Naturalized and widespread throughout tropical regions worldwide. Cultivated globally in suitable climates including southern Europe, the Americas, Africa, and Asia. In the United States, grows wild in parts of the Southwest and California, notably in Griffith Park, Los Angeles.

Seasonality

In temperate regions, active growth occurs during warm months; flowers and fruits produced summer through fall. In tropical climates, with year-round growth potential. In frost-prone areas, grown as or overwintered in protected conditions.

Host Associations

Ariadne merione - Common castor
Samia cynthia ricini - Eri
Achaea janata - Castor semi-
Hypercompe hambletoni - Lepidopteran larval
Discestra trifolii - Nutmoth, larval
Evarcha culicivora - association consumes nectar and uses for courtship
Ants (various species) - Myrmecochory via caruncle (elaiosome) on seeds

Life Cycle

in tropical climates, behaving as in temperate regions with frost. Reproduces via mixed system favoring selfing by geitonogamy while capable of outcrossing via wind (anemophily) or (entomophily) pollination. Natural pollination rates range from 5–46%. Seeds dispersed by attracted to lipid-rich caruncle; after removing caruncle, ants discard seeds in favorable germination sites. Seeds germinate readily in warm conditions; growth rapid, with plants reaching 2–3 m in one year under optimal conditions.

Ecological Role

Provides food and for specialized including several . Seed with . Contains ricin, which provides natural protection against pests such as and has been investigated as a potential . Allelopathic properties inhibit germination of competing plants such as lettuce and tomato. potential in disturbed tropical habitats where it can outcompete vegetation.

Human Relevance

Economically important for castor production, with global production around two million tons annually; India produces over three-quarters of global yield. Oil used in lubricants, biodiesel, cosmetics, pharmaceuticals, and as chemical feedstock. Polyglycerol polyricinoleate derived from castor oil modifies cocoa butter flow in chocolate manufacture. Ornamental widely planted for foliage and architectural form. Historical medicinal use as laxative and topical treatment. Highly toxic: seeds contain ricin, one of the most potent toxins known; lethal dose in estimated at 4–8 seeds. Extremely allergenic (OPALS rating 10/10), with pollen, sap, and plant parts causing severe allergic reactions and asthma triggers. Misuse as instrument of coercion in historical political repression. Jewelry made from seeds poses poisoning risk if shells are damaged.

Similar Taxa

Fatsia japonica 'false castor ' refers to superficial resemblance in leaf shape, but belongs to Araliaceae, not Euphorbiaceae; differs in palmate leaves with fewer, broader lobes, and berry-like fruits rather than spiny capsules
Jatropha curcasAnother euphorb with toxic seeds and production potential; differs in smaller, less deeply lobed leaves, different structure, and non-spiny capsules

More Details

Cultivar Diversity

Numerous developed for distinct purposes: ornamental selected for foliage color ('Carmencita' series, 'Gibsonii', 'New Zealand Purple', 'Impala', 'Red Spire', 'Zanzibarensis') and production types selected for yield, reduced ricin content ('Brigham'), or mechanized harvest compatibility ('BRS Energia', 'Hale')

Toxicity and Safety

Commercial cold-pressed castor is non-toxic as ricin is water-soluble and does not partition into the oil. Intact seeds may through digestive tract without releasing toxin; poisoning requires seed breakage or chewing. Ricin investigated for potential therapeutic and insecticidal applications.

Etymology

named Ricinus from Latin word for , referring to seed appearance with bump at tip and markings resembling certain ticks. 'castor ' derives from use as replacement for castoreum (beaver gland product), not from the itself. Alternative name 'Palma Christi' (palm of Christ) refers to reputed healing properties.