Drupe

The definitive characteristic of a drupe is that the hard, woody (lignified) stone is derived from the ovary wall of the flower. In an aggregate fruit, which is composed of small, individual drupes (such as a raspberry), each individual is termed a drupelet, and may together form an aggregate fruit. Such fruits are often termed berries, although botanists use a different definition of berry. Other fleshy fruits may have a stony enclosure that comes from the seed coat surrounding the seed, but such fruits are not drupes.

Flowering plants that produce drupes include coffee, jujube, mango, olive, most palms (including açaí, date, sabal and oil palms), pistachio, white sapote, cashew, and all members of the genus Prunus, including the almond, apricot, cherry, damson, peach, nectarine, and plum.

The term drupaceous is applied to a fruit having the structure and texture of a drupe but not precisely fitting the definition of drupe.

Description

The boundary between a drupe and a berry is not always clear. Thus, some sources describe the fruit of species from the genus Persea, which includes the avocado, as a drupe; others describe the avocado as a berry. One definition of berry requires the endocarp to be less than 2 mm (3⁄32 in) thick, other fruits with a stony endocarp being drupes. In marginal cases, terms such as drupaceous or drupe-like are sometimes used.

A freestone is a drupe with a stone that can easily be removed from the flesh. A clingstone is a drupe with a stone which cannot easily be removed from the flesh. A tryma is a nut-like drupe. Hickory nuts (Carya) and walnuts (Juglans), in the Juglandaceae family, grow within an outer husk; these fruits are technically drupes or drupaceous nuts, not true botanical nuts.

Many drupes, with their sweet, fleshy outer layer, attract the attention of animals as food, and the plant benefits from the resulting dispersal of its seeds.