Watermelon Powder is a vine-like flowering plant originally from southern Africa. Its fruit, which is  also called watermelon, is a special kind referred to by botanists as a pepo, a berry which has a thick rind and fleshy center. Pepos are derived from an inferior ovary, and are characteristic of the Cucurbitaceae. The watermelon fruit, loosely considered a type of melon although not in the genus Cucumis has a smooth exterior rind and a juicy, sweet interior flesh.Watermelon rinds may have additional medical benefits. Research by the Agricultural Research Service discovered that watermelon rinds contain citrulline.