I can find very little online on the origins of this plant; the best I can come up with is that it hails from Rangsang, Indonesia. There is a movement right now in the Hoya world to lump many previously separate species into single species with different clones dependent on locations and the like. I suspect that Hoya sp. Rangsan will be lumped in with Hoya latifolia. The flowers are identical to the flowers of macrophylla and polystachya, which are now all called Hoya latifolia.