As a simple fruit, a berry is derived from a single ovary of an individual flower. The middle and inner layers of the fruit wall often are not distinct from each other. Together with drupes and pomes, berries are one of the main types of fleshy fruits.

In order to be considered a berry, a fruit must develop from a flower that has one ovary. (Image credit: udaix/Shutterstock.com ) The same layered structure appears in other berries, including the banana and watermelon, although their exocarps are a bit tougher, taking the form of a peel and a rind, respectively.