In botanical terms, a coconut fruit is best described as a dry drupe. A dry drupe has an outer fleshy skin surrounding a dry husk; the dry husk encases a hard shell; it is the hardened shell which contains the seed.
Contrast the dry drupe of the coconut with the wet drupe of a peach.
The seed (or nut) of an immature fruit contains a lot of water (also called liquid endosperm). The water provides nourishment to help the growth of the ‘meat’, or solid endosperm, inside the hard shell of the fruit.
So the greatest amount of coconut water is found in the young, immature fruits.
As the fruits mature as they grow on the palm tree, the amount of water in the seeds decreases at the same time as the amount of meat increases.
Growing naturally in the wild, the common coconut has the ability to disperse its seeds very effectively across oceans.
After falling off a palm tree…
the plant’s thick, dry husk prevents damage to the coconut as it falls to the ground from even the tallest of palm trees.
The dry husk keeps the coconut buoyant as it drifts thousands of miles through ocean currents.
The husk also prevents sea water seeping into the shell destroying the nut. A coconut can survive in seawater for anything up seven months….
until it makes landfall on a beach.
If it is washed ashore in high winds above the high tide mark, it stands a good chance of germinating.
After being swept onshore above the high tide mark it will start germinating once it comes into contact with fresh water. The embryo (labelled A) now starts to grow and develop.
It pushes upwards into the seed cavity…..
where it becomes significantly enlarged.
The embryo is now called a cotyledon; the cotyledon develops into a spongy mass which absorbs the nutrient rich flesh and water of the coconut. It is the cotyledon, seen below the shell removed, which supplies the growing shoots and roots with sugar and minerals.
In this image the husk has been removed; in the wild the roots and shoots grow through one of three eyes (or germination pores) in the hard shell…
and through the husk…
to produce saplings.
It was the three germination pores that has given the coconut its name; in 1498 by sailors of the Portuguese explorer Vasco da Gama discovered the fruit growing in East Africa. The three germination pores reminded the sailors of a monkey’s face, or macaco, in Portuguese.
Drifting across oceans is not the only way in which the coconut disperses its seeds. Like its endangered cousin, the Coco de Mer palm tree, the Common Coconut also disperses its seeds by gravity. In this image you can see how a seed has dropped and taken root very close to the parent tree.
As with other forms of seed dispersal, it is often a matter of chance whether a seed is able to germinate, put down roots and establish itself.
Throughout the centuries humans have dispersed coconut palms far from their ancestral homelands in South East Asia
Today coconut palms can be found in most coastal tropical countries of the world.
As human have dispersed coconut palms in tropical regions around the globe they have engineered changes to coconuts. Wild varieties have elongated, thick husks and small nuts.
By way of contrast, domesticated varieties have larger, more spherical nuts; the larger nuts contain more meat ( or endosperm)
There are many different varieties of domesticated coconut; these are but a few of them:
There are also many different sizes of palm tree from tall to dwarf.
The common coconut, one of 1500 species in the palm (Palmaceae) family, is a plant which humans use in many different ways. To quote a proverb from the Philippines;
“He who plants a coconut tree, plants pots and clothes, food and drink, a house for himself, and an inheritance for his children.”
All parts of the coconut and palm tree can be used in one form or another. These are just a few of the many uses of the Cocos nucifera:
Leaves are woven to make roofs for houses….
and the mid ribs of leaves used to make brooms.
The fibres (coir) from the husks are woven to make coir rope…
and coir carpets.
The meat is used to make coconut milk…..
….and beauty products.
The spathe (see below ) is used to make fruit bowls.
Immature flowers are housed in a protective sheathe called a spathe.
As the flowers mature the protective sheathe opens out to reveal the flowers.
The male and female flowers are both found on the same inflorescence. The more numerous smaller male flowers are are found at the top of each stem; the larger, round female flowers are located at the bottom.
In this image you can see both male and female flowers emerging on different stems out of their protective sheathes.
Pollen is dispersed from male to female flower by the wind or by insects. It is the female flowers which grow into coconuts. With natural pollination, 50 to 70% of the fruits either fall off or never mature into adult fruits. Once pollinated it takes 12 months for the female flowers to develop into fully mature fruits.
Some varieties of coconut palm, such as this Malayan Red Dwarf variety below, self pollinate. Pollen grains from the stamens of male flowers are transferred to the ovules of female flowers on the same tree. This method of pollination provides an evolutionary advantage to coconut palms which grow in areas with few insects.
Other varieties of coconut palm cross pollinate; the pollen from the male flowers of one tree is transferred to the female flowers of a different tree.
Yet other types of coconut pollinate using insects to transfer the pollen from the male flower of one tree to the female flower of a different tree.