Drupe

In botany, a drupe, also called a stone fruit, is a special kind of fruit. It has a soft outside part made of the exocarp (skin) and mesocarp (flesh). Inside this soft part is a hard shell. This hard shell protects a tiny seed, also called a kernel. Drupes do not open up to let the seed out; they are indehiscent.

These fruits usually grow from one carpel. The hard shell is made from lignified material and comes from the ovary wall of the flower. In some fruits made of many small parts, like a raspberry, each small part is called a drupelet.

Many flowering plants make drupes. Some examples include coffee, mango, olive, date, pistachio, and all fruits from the genus Prunus, such as the almond, cherry, peach, and plum.

Description

Sometimes it can be tricky to know if a fruit is a drupe or a berry. For example, some people think the avocado is a drupe, while others call it a berry.

A freestone is a drupe where the hard part comes away from the soft part easily. A clingstone is a drupe where the hard part sticks to the soft part and is tough to remove. A tryma is a nut-like drupe. Fruits such as hickory nuts (Carya) and walnuts grow inside a covering and are actually drupes, not true nuts.

Many drupes have a sweet outer layer that animals enjoy eating. When animals eat these fruits, they help spread the plant's seeds.

Examples

Some common fruits that are drupes include apricots, olives, loquat, peaches, plums, cherries, mangoes, pecans, and amlas. The coconut is also a drupe.

Fruits like blackberries and raspberries are made up of many small drupes grouped together. Mulberries look similar to blackberries but grow together as one fruit. Some drupes grow in clusters on plants, such as dates and certain palms found in places like central Chile and the Sonoran Desert.

Even some plants not usually thought of as flowering plants, like cycads, ginkgos, and some cypresses, produce fruits that look like drupes.