Pachypodium is a genus of the Apocynaceae family comprising succulent shrubs or small trees, up to 6 m in height.
The stems are usually large, swollen at the base, sometimes partly underground. The generic name, Pachypodium, is derived from the Greek prefix pachy- meaning thick and the also Greek word podos meaning foot, referring to the thick bases of these plants.
The sap of some species has been used in or as arrow poison. The sap of some others served as famine food; a clear indication of a learning curve required for those getting involved.
The simple leaves are alternate, spirally arranged or growing in terminal fascicles; short-petioled or sessile. There are no axillary glands, but the stipules are conspicuous: transformed into rigid, paired spines on a swollen stem cushion.
The flowers grow in cymes of variable size, with or without stalks. The small calyx has five ovate to oblong lobes. The short-tubed flower is bell-shaped, salver-shaped or funnel-shaped, the lobes shorter than or about equal to the tube, overlapping to the right.
There are five stamens and a cup-shaped disc that is slightly five-lobed. The ovary consists of two free carpels, the style cylindrical or compressed. The seeds are ovoid with a hair tuft at the top.
The genus comprises 18 species of which five occur in arid parts of southern Africa, the majority on Madagascar.
The plant in picture, seen west of Oudtshoorn may be Pachypodium bispinosum or P. succulentum, the two Little Karoo species identical but for their flowers (Leistner, (Ed.), 2000; Smith, et al, 2017; Vlok and Schutte-Vlok, 2015; iNaturalist).