(Citrullus lanatus var. lanatus, family Cucurbitaceae) is a vine-like (scrambler and trailer) flowering originally from southern Africa . It is a large, sprawling annual plant with coarse, hairy pinnately-lobed leaves and white to yellow flowers. It is grown for its edible fruit, also known as a watermelon, which is a special kind of berry referred to by botanists as a pepo. The fruit has a smooth hard rind, usually green with dark green stripes or yellow spots, and a juicy, sweet interior flesh, usually deep red to pink, but sometimes orange, yellow, or white, with many seeds.
The plant has been cultivated in Egypt since at least the 2nd millennium BC and by the 10th century AD had reached India and China. It later spread into southern Europe and on into the New World. Much research effort has been put into breeding disease-resistant varieties and into developing a seedless strain. Nowadays a large number of cultivars are available, many of them producing mature fruit within 100 days of planting the crop. The fruit is rich in vitamins A and C and can be eaten raw or cooked in a variety of ways.
The watermelon is thought to have originated in southern Africa, where it is found growing wild. It reaches maximum genetic diversity there, with sweet, bland and bitter forms. In the 19th century, Alphonse de Candolleconsidered the watermelon to be indigenous to tropical Africa.Citrullus colocynthis is often considered to be a wild ancestor of the watermelon and is now found native in north and west Africa. However, it has been suggested on the basis of chloroplast DNA investigations, that the cultivated and wild watermelon diverged independently from a common ancestor, possibly C. ecirrhosus from Namibia.
Evidence of its cultivation in the Nile Valley has been found from the second millennium BC onward. Watermelon seeds have been found at Twelfth Dynasty sites and in the tomb of Pharaoh Tutankhamun.Watermelon is also mentioned in the Bible as a food eaten by the ancient Israelites while they were in bondage in Egypt.
In the 7th century, watermelons were being cultivated in India and by the 10th century had reached China, which is today the world's single largest watermelon producer. Moorish invaders introduced the fruit into Europe and there is evidence of it being cultivated in Córdoba in 961 and also in Seville in 1158. It spread northwards through southern Europe, perhaps limited in its advance by summer temperatures being insufficient for good yields. The fruit had begun appearing in European herbals by 1600, and was widely planted in Europe in the 17th century as a minor garden crop.
European colonists and slaves from Africa introduced the watermelon into the New World. Spanish settlers were growing it in Florida in 1576, and it was being grown in Massachusetts by 1629, and by 1650 was being cultivated in Peru, Brazil and Panama as well as in many British and Dutch colonies. Around the same time, Native Americans were cultivating the crop in the Mississippi valley and Florida. Watermelons were rapidly accepted in Hawaii and other Pacific islands when they were introduced there by explorers such as Captain James Cook
The watermelon is an annual plant with long, weak, trailing or climbing stems which are five-angled and up to 3 m (10 ft) long. Young growth is densely woolly with yellowish-brown hairs which disappear as the plant ages. The leaves are stemmed and are alternate, large and pinnately-lobed, stiff and rough when old. The plant has branching tendrils. The flowers grow singly in the leaf axils and the corolla is white or yellow inside and greenish-yellow on the outside. The flowers are unisexual, with male and female flowers occurring on the same plant (monoecious). The male flowers predominate at the beginning of the season and the female flowers, which develop later, have inferior ovaries. The styles are united into a single column and the large fruit is a kind of modified berry called a pepo. This has a thick rind (exocarp) and fleshy center (mesocarp and endocarp).Wild plants have fruits up to 20 cm (8 in) in diameter while cultivated varieties may exceed 60 cm (24 in). The rind of this fruit is mid- to dark green and usually mottled or striped, and the flesh contains numerous pips and is red, orange, pink, yellow, green or white.