SIMPLE AND AGGREGATE FRUITS
After pollination and subsequent fertilization, ovules develop into seeds, and ovaries develop into fruits. Fruits have developed as a means of dispersal for the seeds. Fruits are classified on their underlying structure.

Simple fruits are composed of material from a single pistil of a single flower. The pistil may be composed of several fused carpels.

Simple fruits exhibit a variety of forms. Fleshy simple fruits with a few seeds are referred to as berries (e.g., tomato), while those with a hard central pit are drupes (e.g., peach). Most of the simple fruits are dry and in the form of pods that break open to release seeds. Examples are legumes (e.g., bean pods), follicles (e.g., milkweed pods), and capsules. Nuts (e.g., acorns), grains, and achenes are also dry simple fruits, but they contain a single seed and do not break open at maturity.

Aggregate fruits develop from a single flower that has many separate carpels. Each carpel will develop into a fleshy globule that contains one of several seeds. Blackberries are an example of an aggregate fruit.