This member of the Apocynaceae family was given this name by Joseph Marie Henry Alfred Perrier de la Bâthie in 1934. It is found on Madagascar, growing in a well drained soil with some water and some sun. The stem can grow from ten to 50 centimetres in diameter, and the plant can reach a height from two to eight metres. The flowers are white to pale yellow.
The genera name from Greek; pachys; 'thick' and Greek podion; 'small foot' for the thick caudiciform trunk, formed by some species. The species is named after a Sofia, the river in the north-western Madagascar. Photo by Baja Costero, Garden.org.

