Ricinus communis – Castor Bean

Ricinus communis - Castor Bean, Castorbean, Castor Oil Plant, Palma Christi

Ricinus communis - Castor Bean, Castorbean, Castor Oil Plant, Palma Christi (fruit and male flowers)

Ricinus communis - Castor Bean, Castorbean, Castor Oil Plant, Palma Christi (fruit and female flowers)

Ricinus communis - Castor Bean, Castorbean, Castor Oil Plant, Palma Christi

Ricinus communis - Castor Bean, Castorbean, Castor Oil Plant, Palma Christi (seeds)

Plant Name

Scientific Name: Ricinus communis

Common Name: Castor Bean, Castorbean, Castor Oil Plant, Palma Christi

Plant Characteristics

Duration: Annual, Perennial, Evergreen

Growth Habit: Tree, Shrub, Subshrub, Herb/Forb

Hawaii Native Status: Introduced. This naturalized weed and medicinal plant is native to Africa.

Flower Color: Inconspicuous, red female flowers, tan male flowers

Height: Up to 16 feet (5 m) tall, but usually less

Description: The plants are monoecious with separate male and female flowers on the same plant. The up to 1 foot (30 cm) long inflorescences contain both male and female flowers and are located at the stem tips. The small female flowers are located at the tips of the inflorescences and have red stigmas. The tan-colored male flower clusters are located at the base of the inflorescences. The female flowers are followed by clusters of spiny, rounded, trilobed, 3-seeded, green or red seed capsules that turn a dark red-brown color and explode open when dry. The shiny, grayish to beige seeds are mottled with dark brown and resemble spotted dog ticks in size, shape and markings. The leaves are large, prominently veined, green, purplish, or dark reddish in color, alternate, lopsidedly peltate with stout, reddish stalks, and palmately lobed with usually 7 to 11 point-tipped, sharply toothed lobes. The stems are erect, branched or single-stemmed, hairless, greenish red to brown in color, hollow to pithy, and woody at the base. The plants are weedy and fast-growing.

Here in Hawaii, Castor Bean grows in sunny, disturbed areas and along roadsides in dry to mesic (moderately wet) areas at low to middle elevations.

Special Characteristics

Edible – Castor oil, which is extracted from the oily seeds, is used as a laxative and as a labor-inducer. The non-yellowing oil is also used in cosmetics. Although the oil from the seeds is safe to consume, the seeds themselves are deadly poisonous and should never be eaten.

Poisonous – The seeds are extremely poisonous to both humans and animals and should be kept away from young children and livestock. The seeds contain the deadly toxin ricin. Castor Bean, along with Rosary Pea (Abrus precatorius), are two of the most poisonous plants in the World.

Classification

Kingdom: Plantae – Plants
Subkingdom: Tracheobionta – Vascular plants
Superdivision: Spermatophyta – Seed plants
Division: Magnoliophyta – Flowering plants
Class: Magnoliopsida – Dicotyledons
Subclass: Rosidae
Order: Euphorbiales
Family: Euphorbiaceae – Spurge family
Genus: Ricinus L. – ricinus
Species: Ricinus communis L. – castorbean

More About This Plant

Hawaii County Distribution Map