Citrullus lanatus



Citrullus lanatus

(Thunb.) Matsum. & Nakai 1916

pronounced: SIT-ruh-luss lah-NAR-tuss

(Cucurbitaceae — the squash family)


common name: watermelon

Citrullus is the diminutive of citrus, referring to the colour of the flesh of some species; lanatus is Latin for ‘covered with wool, woolly’, referring to the leaves and stems.

This is an annual, broad-leaved, prostrate herb (or sometimes herbaceous climber up to 2 m high), spreading to about 4 m in diameter. The leaves are alternate, spiral, simple, petiolate (up to about 12 cm); the leaf blade is up to 20 cm long and 15 cm wide, deeply dissected, palmately lobed: there are 3–5 lobes, the centre lobe the longest. The leaf margins may be entire or crenate or dentate, and the whole leaf and the petioles are hairy.

The flowers are solitary, axillary, predominantly yellow. There are 5 sepals, all joined. The corolla is up to almost 2 cm long, with 5 petals, all joined. There are 3 stamens (staminodes in female flowers).

The fruit is a berry (known as a pepo), fleshy, green or yellow, or with mottled green stripes, becoming yellow, and can be anything up to about 50 cm long.

The caterpillars of the moth Anadevidia peponis can be a pest on watermelon plants.

Watermelon is thought to have originated in southern Africa, where it is found growing wild. It is not known when the plant was first cultivated, but it seems to have been cultivated in the Nile Valley as early as 2000 BC. Although it is not depicted in any Egyptian hieroglyphic text, and no writer mentions it, its seeds have been found in many sites from the Twelfth dynasty; and numerous seeds were recovered from Tutankhamun’s tomb. By the 10th century AD, watermelons were being cultivated in China, which is today the world’s largest producer of the fruit. By the 13th century, Moorish invaders had introduced the fruit into Europe. In Vietnam, legend has it that the watermelon was introduced there long before it came to China. Prince Mai An Tiêm was unjustly exiled to an island. He was told that, if he could survive for 6 months, he would be allowed to return home. While he was praying for guidance, a bird flew over him and dropped a seed. He cultivated the seed and called its fruit dua tây (western melon), as that was the direction from which the bird had flown. It is thought that the watermelon had been introduced into North America in the 1500s. Early French explorers found the native Americans cultivating it in the Mississippi valley.

Any reader who has struggled to fit a large watermelon into the fridge will appreciate the finding, in the Zentsuji region of Japan, of a way to grow cube-shaped watermelons. Farmers there grow the fruits in glass boxes, and let them naturally assume the shape of the container. The ripe melons are then easy to stack and store – the only problem is that they cost twice as much as ordinary watermelons.

Watermelon contains about 6% sugar and 92% water by weight. As with many other fruits, it is a source of vitamin C. Probably the most nutritious part of the melon is the inner rind (usually a light green or white in colour). It is edible, though not very palatable. In China, the rinds are often used as a vegetable – stir-fried, stewed, or, more often, pickled. When stir-fried, the de-skinned rind is cooked with olive oil, garlic, chilli peppers, scallions, sugar and rum. Watermelon juice can also be made into wine.


Photographs taken in Picnic Bay 2011
Page last updated 9th November 2018