This document discusses the anatomy of petioles and provides examples from various plant species. It was written by Keshav Narayan Pai, an MSc student of Botany at Manasagangotri in Mysore. The document lists plant species such as Apium, tomato, Glechoma hederaea, and Origanum vulgare that are used to demonstrate petiole anatomy. It also references two sources that provide further information on plant anatomy.