Grapefruit (Citrus paradisi)
Introduced to the New World by Christopher Columbus around 1500, grapefruits are believed to be a naturally occurring cross between a pomelo and an orange. Pomelo or pummelo (Citrus maxima) earns its name from its large size, and is similar to a puffy, eight-to-twelve-inch inflated ball. It has been grown in China for over 4000 years.

Lemon (Citrus limon)
This branch of the family traveled south from the Himalayas to the plains of India and Pakistan. One of the oldest known family members (2000 BC) is citron (Citrus medica), which has a very thick peel, lots of seeds, and not much else. Citron's pulp and meager supply of juice is not suitable for eating, but the peel is prized for its flavorful oils and fragrance.

Sourness is a desirable, identifiable flavor element in cooking, and prior to the use of lemons for this purpose, cooks used 'verjuice,' the sour juice of other fruits such as crabapples or sour grapes. The lemon's sourness comes from its high citric acid level, which, in addition to its wonderful flavor and aroma, can slow the oxidation in cut fruit, ward off scurvy, change milk into buttermilk, remove stains and odors from your hands, 'cook' fish without heat, and discolor aluminum pans!

Lemons, as we know them, arrived in the Mediterranean toward the end of the first century AD, and it was the Arabs who advanced lemon cultivation in Sicily, Spain, and Northern Africa. Once the lemon reached the New World, the large spreading evergreen tree with its fragrant flowers traveled rapidly. 'Eureka' is the main commercial variety grown in the United States.

Meyer lemons, much sweeter and completely edible from peel to juice, are gaining popularity. Frank Meyer, a renowned plant explorer for the USDA, brought the ornamental Meyer lemon tree to the U.S. from Beijing in 1908. It produced heavily, and really caught on until the 1940's when a virus named tristeza (Portuguese for 'sadness') was discovered on Meyer lemons. Growers feared that the virus would be transmittable to all species of lemons, and the Meyer lemon was banned in the U.S. until 1970, when a new virus-free Meyer lemon was developed. Only a few commercial growers raise Meyer lemons, as they require special care in handling, have a shorter growing season, are thin-skinned, and don't ship well. But the flavor of these firm, plump, fruits is exquisitely seductive, and is well worth a try.

Lime (Citrus auranifolia)
While the resemblance to their cousin the lemon is striking, limes are classified as a different species due to botanical differences in size, color, and clustering patterns of their blossoms. They are the most cold sensitive of the Citrus Family, and require warmth year-round. In the U.S., they grow only in southern-most California and Florida, and must be imported from Mexico to meet demand. Limes were brought westward to Iraq, Persia, and Palestine by the Arabs. In fact, the word 'lime' comes from the Arabic limah. Columbus included limes among the citrus he brought to Hispaniola (now Haiti), and the first Spanish settlers brought limes with them to Florida, where they flourished in the Keys, hence the name Key lime. This Key lime or Mexican lime, is a smallish fruit with a green rind and green flesh. It is the lime that British naval officers gave to their sailors to combat scurvy, which earned them the name 'limeys.' It was known that lemons were more effective in fighting scurvy as they are higher in vitamin C, but lemons required purchase from foreign (often hostile) countries. The lime juice was often served with the sailor's ration of rum, which proved to be an effective way of dealing with the sailor's nutritional needs!

Oranges (Citrus sinensis)
The name of this well-known citrus comes from the Sanskrit 'narunga,' which then translated to the Arabic 'narandj' as it traveled from its native China eastward across mountains and deserts. There are many types of oranges that differ widely in their shape, taste, and peel. Tangerines (named for the Moroccan port of Tangiers), Mandarins, and Tangelos-a cross between a grapefruit and a tangerine-are all easy to peel and segment. Similar varieties include Minneola with its distinctive knob on the end; Temple, a cross between a tangerine and sweet orange; Satsuma, a deliciously sweet Asian variety; and the very popular clementines. Navel oranges are one of the most widely known eating oranges; their thick, easy to peel skin and seedless segments make them perfect for snacking. The navel, or smaller cluster of segments tucked in the shallow cavity of the main part of the fruit opposite the stem end, is actually the start of another set of carpels. Valencia oranges are excellent juice oranges, usually having only a few seeds and a thinner skin. Moro, or blood, oranges have a distinctive deep maroon flesh, and the juice has just a hint of raspberry.

Invite the Citrus family into your home this winter. With so many varieties to choose from, you may never tire of their company.