There are two forms of this species found in very different areas. The smaller form is found at the northern part of the island of Madagascar growing near sea level. Picture below, which I found during a competition in Chiangmai on April 25th, 2010. The second and larger form is found in the Comoro Islands growing at about 910 m above sea level.
It is a medium sized epiphyte that grows to 15-20 cm wide, and about 15 cm tall. The flower is about 8 cm tall and 6 cm wide.