Hoya, commonly known as waxplant, waxvine, or waxflower, is a genus of 200-300 species of tropical plants.
It is an evergreen vine or creeper or sometimes stumpy, and belongs to the dogbane family, Apocynaceae.
Hoya leaves vary in size, texture, color, and veins.
Some Hoya leaves appear to have no veins, while others have very prominent veins that are lighter or darker in color than the rest of the leaf.
Ref: