Citrus
Pomelo
Citrus medica - Citron
Citrus reticulata - Mandarin & Tangerine
Major hybrids
Citrus x aurantifolia - Lime
Citrus x aurantium - Bitter orange
Citrus x bergamia - Bergamot
Citrus x hystrix - Kaffir lime
Citrus x ichangensis - Ichang lemon
Citrus x limon - Lemon
Citrus x limonia - Rangpur
Citrus x paradisi - Grapefruit
Citrus x sinensis - Sweet orange
See also main text for other hybrids
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Citrus is a common term and
genus of
flowering plant in the Family
Rutaceae, originating in tropical and subtropical
Asia. The genus contains three
species, and numerous natural and cultivated origin
hybrids, comprising
trees such as
orange,
lemon,
grapefruit,
lime, and
tangerine. The
taxonomy of the genus is complex, but recent genetic evidence (see e.g. external link cited below) supports the presence of only three species,
C. maxima, C. medica and
C. reticulata, with all the other taxa previously accepted as species being of hybrid origin between these three. They are large
evergreen shrubs or small
trees, reaching 5-15 m tall.
Citrus fruits are notable for their fragrance, and most are juice-laden. They contain a high proportion of
citric acid giving them their characteristic astringent odour and flavour. They are also good sources of
vitamin C.
As citrus trees
hybridize very readily (e.g., seeds grown from limes can produce fruit similar to grapefruit), all commercial citrus cultivation uses trees produced by
grafting the desired fruiting
cultivars onto rootstocks selected for disease resistance and hardiness.
Culture
Citrus trees are not generally frost hardy. temperatures. A few hardy hybrids can withstand temperatures somewhat below freezing, but do not produce quality fruit. In the U.S., Florida, Texas, and California are major commercial citrus-producing regions, while smaller plantings are present in other Sun Belt states.
The trees do best in a consistently sunny, humid environment with fertile soil and adequate rainfall or irrigation. Though broadleaves, they are evergreen and do not drop leaves except when stressed. The trees blossom in the spring, and fruit is set shortly afterward. Fruit begins to ripen in fall or early winter months, depending on variety, and develops increasing sweetness afterward.
Some hobbyists grow dwarf citrus in containers or greenhouses in areas where it is too cold to grow it outdoors. Consistent climate, sufficient sunlight, and proper watering are crucial if the trees are to thrive and produce fruit.
List of citrus fruits
