The Aerial Roots of Poison-Oak

 At the bottom of this picture is a root. Real roots grow along a path of least resistance; as a result they are crooked.

Above the real root are two examples of aerial roots. Aerial roots develop close to some branching points. When the stems lie on the soil surface or in leaf litter, the aerial roots become real roots. When the stems touch a support, such as a tree, the aerial roots grab that support.

____________________________________

The AERIAL ROOTS of Poison-Ivy

When looking at poison-oak that is growing on support, the plant appears to just be woven on. Only when the attempt is made to remove the poison-oak are the points of attachment discovered.

Quite the opposite is true of poison-ivy. Long portions of poison-ivy stems are hairy with aerial roots. The attachment to its support is obvious and intimate. Poison-ivy grows 15 meters high on supports, but only one meter standing free; it is considerably more dependent on support than poison-oak.