This member of the Euphorbiaceae family was given this name by Joseph Dalton Hooker in 1865. It is found in Angola, Botswana, Namibia, South Africa and Zimbabwe, growing in a well drained soil with some water and lots of sun. The thickened stem can grow to seven centimetres or more in diameter and 75 centimetres or more high. The flowers are green and brown.
The genera name; Euphorbia dates back to the first century BC, where King Juba II of Mauritania used it in a reference to his doctor, Euphorbos, and that name was kept as a generic name by Carl von Linnaeus. The species name is named after Mount Ng'iro in northern Kenya, which Hooker deliberately Latinized to 'Monteirus'.

