Watermelon is a scrambling and trailing vine in the flowering plant family Cucurbitaceae. The species was long thought to have originated in southern Africa, but this was based on the erroneous synonymization by L. H. Bailey (1930) of a South African species with the cultivated watermelon. The error became apparent with DNA comparison of material of the cultivated watermelon seen and named by Linnaeus and the holotype of the South African species. There is evidence from seeds in Pharaoh tombs of watermelon cultivation in Ancient Egypt.
Watermelon is grown in tropical and subtropical areas worldwide for its large edible fruit, also known as a watermelon, which is a special kind of berry with a hard rind and no internal division, botanically called a pepo. The sweet, juicy flesh is usually deep red to pink, with many black seeds, although seedless varieties have been cultivated. The fruit can be eaten raw or pickled and the rind is edible after cooking.
The watermelon is an annual that has a prostrate or climbing habit. Stems are up to 3 m long and new growth has yellow or brown hairs. Leaves are 60 to 200 mm long and 40 to 150 mm wide. These usually have three lobes which are themselves lobed or doubly lobed. Plants have both male and female flowers on 40-mm-long hairy stalks. These are yellow, and greenish on the back.
The watermelon is a large annual plant with long, weak, trailing or climbing stems which are five-angled (five-sided) 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 large, coarse, hairy pinnately-lobed and alternate; they get stiff and rough when old. The plant has branching tendrils. The white to yellow 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)