Citron
The citron ("Citrus medica") is a large fragrant citrus fruit with a thick rind. It is one of the original citrus fruits from which all other citrus types developed through natural hybrid speciation or artificial hybridization. Though citron cultivars take on a wide variety of physical forms, they are all closely related genetically. It is used widely in Asian cuisine, and also in traditional medicines, perfume, and for religious rituals and offerings. Hybrids of citrons with other citrus are commercially prominent, notably lemons and many limes.
Watermelon
Citrullus lanatus is a plant species in the family Cucurbitaceae, a vine-like (scrambler and trailer) flowering plant originating in West 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. & Nakai for the watermelon, and a proposal to conserve the name with this meaning was accepted by the relevant nomenclatural committee and confirmed at the International Botanical Congress in Shenzhen.