This species occurs in the Northern Madagascar.
Decaryi is a species similar to succulentum in its beginnings but resembles the lealii more as it matures. The leaves form a swirl around the top of the plant and the tip of the branches. The spines are located onnew growth and fall with the leaves leaving a smooth trunk and branch. The trunk is a light, silver green upright pachycaul with a bulbous base that branches. This species has white salverform flowers that are formed in groups similar to the saundersii. The flowers are white with a yellow center and emit a pleasant scent. Decaryi should be given full light and plenty of water during the warmer months.