Spring Oddities

spring differences in poison ivy leaves

Here we have a good example of how different poison ivy leaves can appear, from the first leaves of spring.

Notice how the top "leaves of three" is a typical set of three, all pointed, about the same size.

But right under that leaf group there is a weird one, with a huge, round center leaf, whose edges are almost scalloped. It is not at all clear why a single poison ivy plant expresses itself in such different ways, but yet there it is. 

Any input from plant botany experts is welcome!