The flowers of the Michelia x albatree are pristinely white, giving it a very pure look. Recently, I could not find any caterpillars of the Tailed Jay on any of these trees in the park. Perhaps I wasn't looking hard enough or maybe this tree when planted in an open area in the full sun is not conducive enough for the female butterflies to lay its eggs.
Separately, the yellow flowers of the Michelia champaka are equally pretty and fragrant although it is not a butterfly host plant.
So what is the difference here? Definitely the texture of the leaves. Feel them and the answer is there.