Stipules can be used by the plants in various ways, and some uses of stipules are not well understood or may be vestigial.
It is known that foliaceous stipules are used like leaves to make energy for the plants. Sometimes stipules protect the next leaf or bud as it grows in then falls off after the leaf unfolds, as with Tulip Poplars.Stipules can be used as climbing tendrils by climbing plants. Spiny stipules can be used to help protect the plant from animals.