Euphorbia tenax

Euphorbia tenax, until recently known as E. arceuthobioides and scientifically apparently also as E. rhombifolia at some stage, deserves its Afrikaans common name of ystervarkmelkbos (porcupine milkbush) on looks alone. The stems resemble porcupine quills. A milk-resembling sap or latex appears wherever a stem is damaged. The name of the succulent shrub was probably earned, however, by the tuberous rootstock that is listed on the porcupine menu of delicatessen. And porcupine quills don’t branch!

The plant is also known in Afrikaans as the steenbokmelkbos (steenbok milkbush), a common name shared with E. burmannii. It is not known whether the steenbok feeds on the plant. The Afrikaans names boknoors (buck euphorbia or noors) and steenbokbos (steenbok bush) also exist. The specific name tenax is a Latin word meaning, gripping, tenacious, sticky or firm. This probably refers to getting entangled in the branches of this so-called stick euphorbia. 

The species distribution is in the Western Cape as far northwards as Kotzesrus in the Northern Cape and eastwards across the Karoo and Little Karoo into some arid parts of the Eastern Cape. Some records state that this species occurs more widely, from Namibia to KwaZulu-Natal. There is speculation as to whether E. tenax and E. arceuthobioides are the same. This plant was photographed on the Rooiberg south of Calitzdorp in October when there clearly had been good rains. Van Jaarsveld, et al, state that this species grows in the Cape Peninsula (2006). They even report it as growing on Table Mountain.

The habitat is succulent Karoo and fynbos to karoid shrubland on shale slopes. The species is not considered threatened in habitat early in the twenty first century (Smith, et al, 2017; Vlok and Schutte-Vlok, 2015; Bond and Goldblatt, 1984; iNaturalist; iSpot; JSTOR; http://redlist.sanbi.org).