Pachypodium ambongense, one of the least known pachypodiums and the last species to be introduced to cultivation.
Shrub 1-2 m high (but usually do not exceed 1 metre) sparingly and erratically branched from just below each terminal inflorescence.
It is regarded as related to Pachypodium geayi.
1-1.5 m, flask-shaped, laterally compressed, 10-40 cm in diameter, bark grey-green, smooth or with leaf scars, Branches short, 7-18 cm in diameter. Branchlets 18-40 x 5-6 mm, covered with paired straight spines, 2-10 mm long, 0.5-2 mm wide at the base somewhat puberulent when young.