Seasonal Wild Flowers

Latin name

Ricinus communis

Other names

Castor Bean Plant

Family

Euphorbiaceae

Flowering season

July to September

English distribution

It is cultivated in gardens and amenity areas throughout

the country but escapes are only thinly scattered.

For a map see the Botanical Society of Britain and Ireland –

Caster-oil-plant

Habitat

It is a neophyte introduced into the UK from tropical Africa

in the first half of the 16th century.

It was first recognised in the wild in the mid 1860s.

Nowadays it is found as a casual on waste ground and

by tips as a result of garden throw outs or oil-seed waste.

Description

Caster-oil-plant is a striking erect herb growing up to 3m.

It is an annual in the UK but perennial in warmer climes.

It is monoecious with female flowers above the males on

the same plant.

They are on stalks up to 40cm.

Male flowers have 3-5 membranous tepals and numerous

cream stamens on branched filaments.

Female flowers have smaller tepals and 5 pink

starfish-like styles. Ovaries are 3 celled and each

produce 3 seeds..

Fruits are capsules up to 25mm and covered in soft

red spines. They spines stiffen as they mature. 

The seeds are the source of ricin, a powerful poison.

 Leaves are opposite on long petioles (up to 40cm) and

palmately lobed (up to 60cm).

Stems are smooth and often red or purple.

Castor-oil- plants are one of the most poisonous plants

for humans.

Ricin is lethal, but castor oil is a useful commodity.

See the article on Ricinus in this Wikepedia link on

the toxicity of ricin and the uses of castor oil.