Fruits are the mature ovary or ovaries of one or more flowers. They are found in three main anatomical categories: aggregate fruits, multiple fruits, and simple fruits.
In some fruits, the edible portion is not derived from the ovary, but rather from the aril, such as the mangosteen or pomegranate, and the pineapple from which tissues of the flower and stem provide food.
The grains of grasses are single-seed simple fruits wherein the pericarp and seed coat are fused into one layer. This type of fruit is called a caryopsis. Examples include cereal grains, such as wheat, barley, oats and rice.