Citrullus lanatus is a plant species in the family Cucurbitaceae, a vine - like (scrambler and trailer) flowering plant originally from sub-Saharan Africa. It is cultivated for its fruit. The subdivision of this species into two varieties, watermelons ( Citrullus lanatus (Thunb.) var. lanatus) and citron melons ( Citrullus lanatus var. citroides (L. H. Bailey) Mansf.), originated with the erroneous synonymization of Citrullus lanatus (Thunb.) Matsum. & Nakai and Citrullus vulgaris Schrad. by L.H. Bailey in 1930. Molecular data including sequences from the original collection of Thunberg and other relevant type material, show that the sweet watermelon ( Citrullus vulgaris Schrad.) and the bitter wooly melon Citrullus lanatus (Thunb.) Matsum. & Nakai are not closely related to each other. Since 1930, thousands of papers have misapplied the name Citrullus lanatus (Thunb.) Matsum.
