Drupe
 |
The peach is a typical drupe (stone fruit) |
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) derives 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,
peach,
nectarine, and
plum.
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.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.
