What is "quisumbingia"

Quisumbingia is a genus of plants in the Apocynaceae first described as a genus in 1915. It was initially given the name Petalonema, but this turned out to be an illegitimate homonym. In other words, someone else had already used the name for a very different species, in this case a cyanobacterium (formerly known as blue-green alga). So another name had to be chosen. It contains only one known species, ' Quisumbingia merrillii ', endemic to the Philippines.