Euphorbia grantii


Euphorbia umbellata is a species of succulent plant in the family Euphorbiaceae, which is native to Africa.

Name

The specific epithet grantii is in honour of the Scottish explorer James Augustus Grant. It was originally described by Daniel Oliver in 1875. The plant has the common name of African milk bush.
The synonym Synadenium grantii is in circulation, too. The specific epithet, umbellata, is Latin for "umbrella" or "having umbels."

Description

It is a thornless, erect, multibranched shrub to small tree that reaches a size of 1.5 to 9 metres in height, with a smooth gray bark horizontally grooved, with semi-succulent green branches and large narrowly prominent leaf scars. The sessile, simple, fleshy, linear to linear-lanceolate leaves are 30 x 3 cm.
The alternate leaves are oblanceolate in shape, and are dark green at the top in colour with clear lateral veins and paler at the undersides. Colorful purplish bracts shelter the small flowers, which are borne in open heads.
Appearing in spring, the inflorescences are yellowish-green to green produced in cymes, with purplish green and reddish purple bracts, with red capsule fruits that feature short hair and three-lobes, and ovoid seeds that are 2mm long.

Distribution

The plant is native to the dry tropical areas of Burundi, Kenya, Rwanda, Sudan, Tanzania, Uganda, and Zaire. It grows at altitudes of 500–2100 meters in woodlands and savannahs. It has been introduced in many other tropical regions.

Cultivation

Its hardiness zone is 9a–11b. It is generally resistant to pest and diseases, though mealybugs and spider mites can affect the plant. Propagated by cuttings, they thrive in bright, indirect sunlight, and a well-drained soil with sand or loam, and prefer temperatures between to. Contact of the milky sap with the skin can cause a burning sensation, dermatitis and blisters.

Usage

It is often grown as a hedge plant and as a traditional grave marker among the peoples of central Kenya. In 1952 during the Mau Mau Uprising, the poisonous latex of the plant was used to kill cattle. In traditional medicine, the leaf sap has been used to treat abdominal parasites, coughs, earaches, sore throats, backaches, syphilis, cardiac issues, and abscesses. In Rwanda its latex is an ingredient of arrow poison.