This produces a waxy covering that protects the plant from insects, bacteria, and fungi.

The answer is the inner periderm. The inner periderm is made up by the cork and cork cambium. This two help protect the plants from pest infestation and plant illnesses. It protects the plant by creating a wax to stop the fungi and bacteria to get into the plant spores. 

If there were no memes, there would be no life.