Pachypodium is a genus of caudiciform succulents placed in the Apocynaceae family. Many of the species produce spectacular flowers. They exhibit a wide range of bizarre growth forms, from bottle-, cigar- or candelabrum-shaped trees to dwarf plants with very short stalks. Sizes range from a few centimetres above the soil to heights of more than 8 m. In southern Africa, the mystical elephant’s trunk or halfmens (Pachypodium namaquanum) is probably the best known and rarest member of the genus. Pachypodiums are characteristically plants of hotter, drier regions of southern Africa and Madagascar where they reach maximum diversity in terms of numbers of species. Most species grow well in pots and rockeries. Larger species like Pachypodium geayi and Pachypodium lamerei make excellent landscaping plants too.

Pachypodium densiflorum var. densiflorum is a succulent shrublet with a swollen stem that can attain a diameter of up to 2 m and a height of ± 0.7 m. It carries many short and upright, spiny branches. The flowers are yellow or sometimes tinted deep yellow and orange and appear in springtime. The leaves are elliptic, dark green above and paler below. The plants grow in southern, central and northern Madagascar on granite outcrops at altitudes of ± 1 500 m. This variety is distinguished from Pachypodium densiflorum var. brevicalyx by the shorter calyx of the latter. The corolla opens out almost flat, with a saucer-like depression in the centre in a deeper yellow than in Pachypodium rosulatum.