Portulacaria pygmaea was collected by Neville Pillans (1884-1964) on an expedition to the Richtersveld in October 1926. He collected his plant among stony hills at Grootderm along the Orange River (Gariep) in the Richtersveld (Pillans 49). He grew the plant on and it came into flower in his garden at Rosebank, Cape Town, during February and he was then able to draw up a description. Pillans was a horticulturist and self-taught botanist with a keen interest in succulent plants, especially stapeliads. He joined the staff of the Bolus Herbarium in 1918. He had a large collection of succulent plants at his home in Rosebank, Cape Town.  He is commemorated in various succulents such as the giant quiver tree Aloidendron pillansii, Stapelia pillansii and Duvalia pillansii. (Gunn & Codd)

The original name of the Orange River is the Gariep, which, according to Nienaber & Raper (1983), is of Khoekhoe in origin, and means ‘the great or large river’and it is the largest river in South Africa. This name was translated by local Khoehoe people to the Afrikaans name Grootrivier. Rivers play an immense role in plant distribution and diversity and small wonder the lower Orange River Valley is a centre of succulent and other plant diversity (Van Wyk & Smith 2001). Of the 5 species of Portulacaria in South Africa, 4 are confined to the lower Orange River: P. armiana, P. fruticulosa, P. namaquensis and P. pygmaeum. Aptly named as P. pygmaea, as it represents the smallest of the genus Portulacaria. Interestingly, within a few kilometers of P. pygmaea, the large-leaved Portulacaria armiana occurs, a perennial to 7 m tall, and the tallest of all the species in the genusPortulacaria and also the one with the largest leaves. Of the 7 species of Portulacaria, P. afra is the most widely spread, occurring from the Klein Karoo to the Limpopo Province.

Fig. 5. A very old, mature plant of Portulacaria pygmaea. Note the layers of bark and the succulent caudex. ǀAi-ǀAis/Richtersveld Transfrontier Park.