Reading the evidence

You can probably identify the poison ivy in this photo. Poison ivy has three leaflets on each leaf stem. Some other plants have similar three leaflet leaf configurations. The clusters of little pea-sized green berries further and conclusively identify this plant as poison ivy.

You can see here that most of the leaves have been stripped from the vines. These vines were about 5 feet above ground. This evidence tells me that an adult deer has eaten the leaves.

The largest leaflets in this photo have small bumps on them. These bumps are called galls. Each gall is caused by a tiny gall wasp that deposited an egg inside the skin of the leaf.

Poison ivy sap contains a clear liquid compound called urushiol, which will cause incessant and sometimes severe itching in most people.