This is probably the most peculiar species in the genus and surely a plant that exerts great attraction on collectors, although it can be somewhat difficult to grow if not grafted.
 

Photo and © copyright by Andrea B. (Bologna, Italy)
http://www.cactusfriends.com/Andrea/index.html 

Culture: They seem to be rot-prone under less than ideal conditions and care. Water sparingly and give extra well-drained soil to avoid waterlogged conditions . The watering program will change depending on temperatures and stage of growth, but it is best not to let this plant dry out completely for any length of time. It is sensitive to cold and should be kept warm at all times. It tends to lose its leave and go dormant in winter when watering should be reduced to a minimum.  It like full sun.

To make them less prone to rotting, they can be grafted onto P. gaeyi or P. lamairei. Plant grafted grow even faster and flower easily.

Family: Apocynaceae

Scientific name:  Pachypodium brevicaule Bak. in J. Linn. Soc. 22: 503, 1887

Conservation status:  Listed in CITES appendix II

Pachypodium brevicaule (during the winter rest)


Photo and © copyright by Andrea B. (Bologna, Italy)
http://www.cactusfriends.com/Andrea/index.html