The grapefruit is a medium to large subtropical citrus fruit known for its bitter flavor. It was first discovered in Barbados in 1750 and is thought to be a hybrid that resulted when pummelo seeds from the East Indies were brought to the West Indies and planted too close to sweet oranges. Count Odet Philippe introduced the grapefruit to Florida in the 1820s. Today, almost all grapefruit available in the U.S. is grown in Florida.
The grapefruit is a flowering, seed-producing tree, so it belongs to the plant kingdom division angiosperm. The seeds produce two seed leaves when germinated, the flower parts are multiples of four or five, the leaves have a network of veins radiating from a central main vein, and the stem has a ring of vascular cambium, which further classifies the grapefruit as a eudicotyledon.
The grapefruit is in the Rutaceae family, which is distinct for having perfect flowers--flowers that have both male and female reproductive organs on the same flower--and for being aromatic because of pellucid glands in the leaves.
Like other fruits that fall under the plant genus citrus, grapefruit is a pulpy fruit with a thick, leathery rind. The fruit is characterized by its notable fragrance and prevalence of citric acid which gives it a tangy flavor. The flowers have five petals and many stamens, and are strongly scented. Grapefruit is edible, and thus belongs to the sub-genus eucitrus.
Because of its tropical origin, the grapefruit's original binomial nomenclature was "Citrus paradisi." However, when it was discovered that the grapefruit is actually a hybrid of the sweet orange and the pummelo, its botanical name was changed to "Citrus x paradisi." The name grapefruit comes from the fact that the fruit grows in grape-like clusters. American horticulturists attempted to change the name to pomelo, but the new name caused too much confusion with pummelo.
Grapefruit come in several varieties. Varieties such as Marsh, Oroblanco, Paradise Navel, Sweetie and Triumph produce medium-to-large rounded fruit with pale yellow pulp and a thick, lightly pitted, yellow rind. The very juicy Duncan grapefruit is a pale yellow that is almost white, highly aromatic and unusually cold tolerant. Foster, Redblush, Star Ruby and Thompson all have a pink blush to the yellow rind and various shades of pink pulp. The most popular varieties of Florida grapefruit are the Marsh White and Ruby Red.