Pachypodium

Pachypodium is a genus of succulent, spiny trees and shrubs in the family Apocynaceae, native to Madagascar and southern Africa. The genus is renowned in caudex and caudiciform plant cultivation for its dramatically swollen, water-storing trunks and stems. Prominent species include P. lamerei (Madagascar palm) and P. rosulatum var. gracilius (gracilius), the latter prized for its globe-shaped caudex. Growth is extremely slow; plants in cultivation may take decades to reach 30–100 cm. During the warm growing season, full sun and moderate watering are required. As temperatures drop in autumn, plants shed leaves and enter dormancy, during which water should be withheld. A minimum winter temperature of around 10°C must be maintained, necessitating indoor overwintering in temperate climates. All species are listed under CITES appendices, restricting international trade.

Source: Wikipedia (CC BY-SA 4.0)