Pachypodium

Pachypodium is a genus of succulent spine-bearing trees and shrubs, native to Madagascar and Africa. It belongs to the dogbane family, Apocynaceae. Pachypodium comes from a Latin form from Greek pachus (thick) and podion (foot) (or Gk podos, root form of pous, foot), hence meaning thick-footed.

Genus characteristics

All Pachypodium are succulent plants that exhibit, to varying degrees, the morphological characteristics of pachycaul trunks and spinescence. These are the most general features of the genus and can be considered distinguishing characteristics.

The pachycaul trunk is a morphologically enlarged trunk that stores water so as to survive seasonal drought or intermittent periods of root desiccation in exposed, dry, and rocky conditions. Whereas there is great variation in the habit of the plant body, all Pachypodium exhibit pachycaul growth. Variation in habit can range from dwarf flattened plants to bottle shaped shrubs to dendroid-shaped trees.

The second general characteristic of Pachypodium is spinescence, or having spines. The spines come clustered in either pairs or triplets with these clusters often arranged in rings or whorls around the trunk. Spines emerge with leaves, and like leaves grow for a short period before stopping growth and hardening. Spines do not regenerate so weathering and abrasion can wear away all but the youngest spines from older specimens - leaving smooth trunks and branches.