Editing Citrus aurantiifolia

{| class="wikitable" style="float: right; width: 320px; margin-left: 1.25em; margin-bottom: 1em;"
|-
! colspan="2" style="background: #e8e8e8;" | Key lime (''Citrus aurantiifolia'')
|-
| colspan="2" style="text-align: center;" | [[File:Citrus aurantifolia.jpg|thumb|center|250px|Key lime tree in Adjara, Georgia. Photo by AlexandreAssatiani, CC BY 4.0.]]
|-
! Scientific name
| ''Citrus aurantiifolia''
|-
! Common names
| Key lime; Mexican lime; West Indian lime
|-
! Genus
| [[Citrus]]
|-
! Family
| [[Rutaceae]]
|-
! Order
| [[Sapindales]]
|-
! Fruit type
| Citrus hesperidium
|-
! Growth form
| Small evergreen tree or large shrub
|-
! Native range
| Southeast Asia; now widely cultivated in warm tropical and subtropical regions
|-
! Mature size
| About 1.8 to 4 m (6 to 13 ft), depending on selection and conditions
|-
! Climate and site
| Warm tropical or subtropical; full sun and protection from cold winds
|-
! Propagation
| Polyembryonic seed, cuttings, air-layers, budding, or grafting
|-
! Fruit
| Small, thin-skinned, aromatic, highly acidic, usually 10 to 15 seeds
|-
! Years to fruit
| Cuttings or air-layers may fruit within 1 year; grafted trees about 3 years; seedlings about 4 to 5 years
|-
! Harvest
| Some fruit year-round; principal season varies by region, often summer
|}

'''Key lime''' ('''''Citrus aurantiifolia'''''; also Mexican lime and West Indian lime) is a small, thorny evergreen citrus grown for its aromatic, highly acidic fruit. It is a warm-climate plant and is distinct from Persian lime (''Citrus × latifolia''), which generally has larger, less seedy fruit. Current taxonomic databases may display the Key lime as ''Citrus × aurantiifolia'', reflecting its complex hybrid origin.<sup id="cite_ref-1">[[#cite_note-1|[1]]]</sup><sup id="cite_ref-2">[[#cite_note-2|[2]]]</sup><sup id="cite_ref-3">[[#cite_note-3|[3]]]</sup>

== Description ==
[[File:Ripekeylime.jpg|thumb|left|240px|Tree-ripened Key lime, yellow at full maturity. Photo by Marc Averette, CC BY 3.0.]]

Key lime forms a dense, bushy shrub or small tree with slender branches and short to medium thorns. The evergreen leaves are small, glossy, and elliptic to oblong, with narrowly winged petioles; crushed foliage is aromatic. Fragrant white flowers are borne in axillary clusters, with flowering possible throughout the year and a main flush commonly in spring.<sup id="cite_ref-4">[[#cite_note-4|[4]]]</sup><sup id="cite_ref-5">[[#cite_note-5|[5]]]</sup>

The fruit is round to oval, usually 38 to 51 mm across, with a thin smooth peel, 10 to 12 segments, greenish-yellow pulp, and a strong acidic aroma. Fruit is commonly picked green for culinary use and turns greenish-yellow to yellow as it ripens. Key lime is generally smaller, more aromatic, more acidic, and more seedy than Persian lime.<sup id="cite_ref-4">[[#cite_note-4|[4]]]</sup><sup id="cite_ref-5">[[#cite_note-5|[5]]]</sup>

The hybrid origin of Key lime has been described in different ways as citrus relationships have been revised. Genetic studies support a complex hybrid history involving citron, pummelo-related ancestry, and a small-fruited ''Citrus'' relative; this history does not make Key lime interchangeable with Persian lime or with every plant sold simply as lime.<sup id="cite_ref-6">[[#cite_note-6|[6]]]</sup><sup id="cite_ref-7">[[#cite_note-7|[7]]]</sup>

== Cultivation ==

Key lime is adapted to warm tropical and subtropical climates and is among the most cold-sensitive cultivated citrus. Choose the warmest available position, with good airflow and protection from cold northerly winds. Containers are useful in climates where winter freezes make outdoor culture unreliable.<sup id="cite_ref-4">[[#cite_note-4|[4]]]</sup><sup id="cite_ref-5">[[#cite_note-5|[5]]]</sup>

=== Soil and water ===

Native and cultivated examples occur in varied settings, including rocky calcareous soils and sandy or gravelly ground. In gardens, light to medium-textured soil with good aeration and drainage is the safest general target. Key lime tolerates a broad pH range, but heavy clay, prolonged saturation, and standing water promote decline. In a site with a high water table or occasional flooding, a raised mound improves drainage. Deep sandy soil can produce vigorous growth but may give fewer, larger, less juicy fruit.<sup id="cite_ref-4">[[#cite_note-4|[4]]]</sup><sup id="cite_ref-5">[[#cite_note-5|[5]]]</sup>

Water newly planted trees regularly while roots establish, then reduce irrigation during prolonged wet weather. Mature trees usually need supplemental water mainly during extended dry periods; overwatering can reduce vigor and contribute to root or foot-rot problems. High-pH calcareous soil may induce iron or other micronutrient deficiencies, so foliage and new growth should be monitored rather than fertilized heavily by default.<sup id="cite_ref-4">[[#cite_note-4|[4]]]</sup>

=== Sun and humidity ===

Full sun gives the best growth, fruit set, and fruit quality. The species tolerates heat, sun, humidity, and drought after establishment, but it does not tolerate shade well. Good air movement helps reduce disease pressure, while cold wind can injure foliage and wood. In marginal climates, grow the tree in a container that can be moved under cover before freezing weather.<sup id="cite_ref-5">[[#cite_note-5|[5]]]</sup><sup id="cite_ref-4">[[#cite_note-4|[4]]]</sup>

=== Seasonal changes ===

Flowering can occur in every season, with a major spring flush. Some fruit may mature on the tree year-round, while regional main crops commonly occur in early summer in southern Florida and later summer farther north. Irrigation should increase during prolonged dry spells, but wet-season drainage and canopy airflow become more important when rainfall is frequent. Cold protection is required before temperatures near freezing; leaf injury may begin around 30 to 32 °F (-1 to 0 °C), and wood damage or death is reported below about 29 °F (-2 °C).<sup id="cite_ref-4">[[#cite_note-4|[4]]]</sup>

== Propagation ==

* '''Seed:''' Key lime seeds are highly polyembryonic, so several embryos in one seed may be maternal and produce seedlings close to the parent type. Seed propagation is therefore more reliable here than in many citrus, although seedling trees still vary and are slower to bear than grafted trees.
* '''Cuttings and air-layers:''' Hardwood cuttings and air-layers can produce fruit quickly; UF/IFAS reports that some trees propagated by these methods fruit within a year of planting. Establishment success depends on material, season, humidity, and aftercare.
* '''Budding and grafting:''' Budded or grafted trees commonly fruit sooner than seedlings and can be matched to rootstocks suited to local soil or disease conditions. Rootstock choice is especially relevant on calcareous soils and where foot rot or tristeza is a concern.<sup id="cite_ref-4">[[#cite_note-4|[4]]]</sup><sup id="cite_ref-5">[[#cite_note-5|[5]]]</sup>

== Flowering, fruiting, and harvest ==

The flowers contain both male and female parts, and Key lime does not require cross-pollination to set fruit. Trees propagated from cuttings or air-layers may bear within about a year; budded or grafted trees usually bear within about three years; seedlings may need another year or two. These are production-guide ranges, not a guarantee for every climate, rootstock, or plant size.<sup id="cite_ref-4">[[#cite_note-4|[4]]]</sup><sup id="cite_ref-5">[[#cite_note-5|[5]]]</sup>

Fruit generally takes about 5 to 6 months from flowering to harvest, although some references allow as much as 9 months. Pick fruit green for the familiar sharp culinary profile, or allow it to mature yellow for a softer peel color and different flavor balance. Fruit that remains on the tree can be harvested in stages, and a vigorous mature tree may produce roughly 13 to 23 kg (30 to 50 lb) per year under suitable conditions.<sup id="cite_ref-4">[[#cite_note-4|[4]]]</sup><sup id="cite_ref-5">[[#cite_note-5|[5]]]</sup>

== Fruit and uses ==

Key lime juice and zest are used in drinks, marinades, sauces, preserves, desserts, and baked foods. The fruit is also squeezed over fish, meat, and fresh-cut produce. The aromatic peel and leaves are used as flavorings in some regional cuisines. Key lime pie is associated with the fruit's name, although commercial recipes may use Persian lime or blended lime juice instead.<sup id="cite_ref-4">[[#cite_note-4|[4]]]</sup><sup id="cite_ref-5">[[#cite_note-5|[5]]]</sup>

The fruit is seedy and highly acidic; the small size, thin peel, and strong aroma are useful identification clues. Food and traditional-use claims should be limited to the documented plant part and preparation. Key lime is also susceptible to citrus canker, anthracnose, tristeza, foot rot, and citrus greening, so disease-free propagation material and local extension guidance matter in affected regions.<sup id="cite_ref-4">[[#cite_note-4|[4]]]</sup>

== Photos ==
[[File:Key lime (Citrus × aurantiifolia) - DSC09279.jpg|260px|Key limes shown in a market setting. Photo by Daderot, CC0.]]

== References ==

* <span id="cite_note-1"></span>[[#cite_ref-1|↑]] '''[1]''' [https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:59599-2/general-information Plants of the World Online: ''Citrus × aurantiifolia''].

* <span id="cite_note-2"></span>[[#cite_ref-2|↑]] '''[2]''' [https://api.gbif.org/v1/species/match?name=Citrus%20aurantiifolia GBIF species match: ''Citrus aurantiifolia''].

* <span id="cite_note-3"></span>[[#cite_ref-3|↑]] '''[3]''' [https://www.gbif.org/species/3190164 GBIF species page: ''Citrus × aurantiifolia''].

* <span id="cite_note-4"></span>[[#cite_ref-4|↑]] '''[4]''' [https://ask.ifas.ufl.edu/publication/CH092 UF/IFAS: ''Key Lime Growing in the Florida Home Landscape''].

* <span id="cite_note-5"></span>[[#cite_ref-5|↑]] '''[5]''' [https://plants.ces.ncsu.edu/plants/citrus-x-aurantiifolia/ North Carolina Extension Gardener Plant Toolbox: ''Citrus x aurantiifolia''].

* <span id="cite_note-6"></span>[[#cite_ref-6|↑]] '''[6]''' [https://doi.org/10.1093/aob/mcw005 Curk et al., “Phylogenetic origin of limes and lemons revealed by cytoplasmic and nuclear markers,” ''Annals of Botany''].

* <span id="cite_note-7"></span>[[#cite_ref-7|↑]] '''[7]''' [https://doi.org/10.1093/aob/mcx179 Rouiss et al., “Origin of ''C. latifolia'' and ''C. aurantiifolia'' triploid limes,” ''Annals of Botany''].

== Image credits ==

* Summary image: [https://commons.wikimedia.org/wiki/File:Citrus_aurantifolia.jpg AlexandreAssatiani], CC BY 4.0.
* Description image: [https://commons.wikimedia.org/wiki/File:Ripekeylime.jpg Marc Averette], CC BY 3.0.
* Photos image: [https://commons.wikimedia.org/wiki/File:Key_lime_%28Citrus_%C3%97_aurantiifolia%29_-_DSC09279.jpg Daderot], CC0.

[[Category:Fruits]]
[[Category:Citrus]]
[[Category:Tropical fruit plants]]
[[Category:Container fruit]]