Drupe

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The peach is a typical drupe (stone fruit)

A stone from a nectarine close up

In botany, a drupe is a type of fruit in which an outer fleshy part (exocarp or skin and mesocarp or flesh) surrounds a shell (the pit or stone) of hardened endocarp with a seed inside. These fruits develop from a single carpel, and mostly from flowers with superior ovaries. The definitive characteristic of a drupe is that the hard, lignified stone (or pit) is derived from the ovary wall of the flower.

Other fleshy fruits may have a stony enclosure that comes from the seed coat surrounding the seed. These fruits are not drupes.

Some flowering plants which produce drupes are coffee, jujube, mango, olive, most palms (including date, coconut and oil palms), pistachio and all members of the genus Prunus, including the almond (in which the mesocarp is somewhat leathery), apricot, cherry, nectarine, peach, plum and pecan.

The term stone fruit can be a synonym for "drupe" or, more typically, it can mean just the fruit of the Prunus species.

Black Butte Blackberry, a bramble fruit of aggregated drupelets

Drupes, with their sweet, fleshy outer layer, attract the attention of animals as a food, and the plant population benefits from the resulting dispersal of its seeds. The endocarp (pit or stone) is often swallowed, passing through the digestive tract, and returned to the soil in feces with the seed inside unharmed; sometimes it is dropped after the fleshy part is eaten.

Many stone fruits contain sorbitol, which can exacerbate conditions such as irritable bowel syndrome and fructose malabsorption.

The coconut is also a drupe, but the mesocarp is fibrous or dry (in this case, called a husk), so this type of fruit is classified as a simple dry fruit, fibrous drupe. Unlike other drupes, the coconut seed is unlikely to be dispersed by being swallowed by fauna, due to its large size. However it can float extremely large distances across oceans.

In an aggregate fruit composed of individual small drupes, each individual is termed a drupelet. Bramble fruits (such as the blackberry or the raspberry) are aggregates of drupelets. The fruit of blackberries and raspberries comes from a single flower whose pistil is made up of a number of free carpels. However, mulberries, which closely resemble blackberries, are actually derived from bunches of catkins, each drupelet thus belonging to a different flower.