Acacia Saplings don't grow on moss

It appears that Oak, Birch, Spruce, and Cherry Blossom saplings can all grow on moss. Unfortunately, Acacia Saplings can not. I would assume that all the saplings should be able to grow, and one should not be singled out. I put the saplings in the same conditions, and they would only start to grow if I replaced the moss with dirt/grass.