The above-ground and underground stem of P. geayi is spongy, forms water storage tissue and is tolerant for dry circumstances.
It can grow 8 to 10m in height and the leaves grow in clusters at the tip of the branch.
The surface of the trunk is metallic green-grey and is water tight.
Bunches of 3 spines are dotted on the surface and beneath the spines there is a mark where the leaf was right under it.
When matured, the thorn becomes pointed and long.
Initially, the flower is light green, the petals soon bend backwards and become white.
The anther is v-shaped and fuses together at the center of the flower.
| Classification ||Apocynaceae Pachypodium|
| Scientific name ||Pachypodium geayi Cost. et Bois.|
| Japanese name ||Aasokai|
| English name ||---|
| Native locality ||Southwestern Madagascar|
Ecological description ||---|
| RDB ||---|
| Planting place ||Succulent Greenhouse|