The one constant in life is change
|I have one called Plumeria Pudica that has plain white flowers with a very small yellow throat. The leaves are distinctive - not a pointed oval like most plumeria, but they have a wide lobe at one end. It's a nice shrub but the flowers were disappointing to me because they have no scent. I went out to try for a picture but it is very tall and all the flowers are up at the top. Found a fallen flower though, is this the one you're asking about?
There certainly could be other plumeria that are plain white, though. I'm not sure as there are many, many varieties.