This species occurs in Northwestern Madagascar in the Ambongo River region.
Ambongense is a species similar to lamerii only its trunk is tapered shape and it branches form at shorter heights. The leaves form a swirl around the top of the plant and the tip of the branches. The spines are also similar to that of lamerii. The trunk is light green, upright pachycaul with a swollen base that tapers upward. This species white salverform flowers are formed individually. They are white with a yellow center which contrasts beautifully. Ambongense should be given full light and plenty of water during the warmer months.