the citron ("citrus medica") is a species of citrus fruit. it usually has a thick rind and small sections. originally, the tree came from southeast asia. today it is mainly grown in sicily, morocco, crete, and corsica, as well as puerto rico. the tree can grow to a size of about 3 metres. the fruit can grow to a size of about 25 cm in length, and about 4 kg in weight. the pulp of the fruit is hardly ever used. the rind is used. it is made into an additive for cooking. jam can also be made from the rind. the rind is also used to make vegetable oil, which is used for perfumes.