Although not all fruits are berries, a berry is a type of fruit. A berry is defined as such because it is produced in a single ovary. Examples of this include grapes and persimmons. Although blackberries and blueberries are called berries, they are not true berries because they are not produced in a single ovary.
Nearly all fruits reproduce through pollination. In spring, the fruit plant produces flowers. Some plants self-pollinate, while others need the assistance of bees. The bees transfer pollen from one flower to the next, ensuring the fertilization of the ova. True berries are fruits in which the entire ova develops into a berry. The fruit contains seeds that are the key to the plant's propagation. These fruits are generally bright so that they catch the attention of potential hungry animals (or people) who will pick and eat them. This is how the plant scatters its seed and reproduces.
Fruits and berries can be produced on plants of any kind. Tomatoes and grapes grow on vines; apples, oranges and other fruit grow on trees. Strawberries grow on plant runners; blueberry and blackberry varieties both grow on canes. The diversity of fruit springs in part from the fact that its scientific classification is sometimes different than the way producers and consumers classify it.
The word berry has come to mean any small, sweet or tart fruit. Because of this, larger true berries such as plums are considered fruit, although they are not commonly considered berries. Even though the tomato is a true berry, some consumers think of it as a vegetable instead of a fruit. At the same time, fruits such as raspberries, which are aggregate fruits, are considered to be berries.
A berry is juicy and round or oval, with a fleshy skin and a pulp-filled inside. It does not have a stone the way that nectarines and cherries do, but may have multiple seeds. Not all berries are edible. A few berries are poisonous. Although citrus are berries, they are considered to be modified berries. Agregate berries such as the blackberry and raspberry are actually made up of a cluster of tiny fruits known as drupes.
The production of berries is driven by consumer demand. Large and small farms exist that specialize in a single type of fruit or berry crop. The largest fruit and berry crops grown in the United States are tomatoes, oranges, apples, grapes, strawberries and pineapple. Due to the large commercial demand for these crops, there is considerable push to develop heartier plants that produce more appealing fruit and disease-resistant plants. For example, tomato vine and apple tree grafting has developed to merge appealing varieties of fruit with disease-resistant root stock.