Some of the more interesting unusual citrus fruits include the following:
Australian finger lime (Microcitrus austalasica) can be classed as either a tall shrub or a small tree. Its spiny foliage makes it an attractive Australian ornamental. This tiny citrus variety has many lime characteristics, and its fruit is long and cylindrical in shape. Oil seeps from the rind into the pulp, giving the fruit a very acidic flavour and lingering turpentine-like aftertaste.
Box orange, severina (Citrus buxifolia and C. severina) is nearly black, and grows in clusters like berries. It is from a family of six species that include buxifolia, buxifolia brachhytic, disticha, linearis, paniculata, and retusa. The tree is distributed mainly in the Philippines, Malay Peninsula, India, and New Guinea, where it is used only as an ornament since its fruits are inedible. In China, box orange leaves are used to make yeast cakes called “tsau ping lak” (wine cake thorn) in Cantonese.
Calamondin, calamansi, kalamansi (Hawaii), calamondin/kalamondin (Philippines), Philippine lime (Citrus madurensis loureiro or Citrofortunella mitis) originated in China and was introduced into Florida around 1900 as an acid orange. It grows wild in Asia and the Philippines and closely resembles the mandarin with its small, oblate shape and flattened or depressed ends. The peel is thin, smooth, and a bright orange, separating easily from the juicy, acidy flesh which also matches the peel. There are five to nine segments containing seeds and cotyledons grouped around a small, semihollow axis.
Citrangequat (Fortunella sp. x [Citrus sinensis x Poncirus trifoliata]) is a trigenic hybrid cross between the trifoliate orange, sweet orange, and kumquat. In Florida, it is grown as the Thomasville variety. It is pear-shaped, with a blaze-orange rind that is quite pebbly. The flesh is golden and seedy. The flavour is acidic unless fully mature, when it becomes sweet enough for eating fresh. The citrangequat was developed at the turn of the 20th century with the hope of producing a fruit with the hardiness of a trifoliate and the sweetness of the orange.
Eustis, limequat (Fortunella x C. floridana) is an elliptical fruit with Mexican lime and Marumi kumquat or limequat parentage. The rind is smooth and lemon-yellow in colour. The sunbright yellow flesh has up to eight segments, with as many small seeds. The juice is sweet and plentiful, given the size of the fruit. The fruit looks much like a jumbo olive, and is mostly grown as an ornamental in Florida.
Flying dragon (Poncirus trifoliata [Trifoliate]) is the most important and interesting of all the dwarfed ornamental varieties. Also called the Japanese hiryo, this plant was introduced to the US in 1915. Although it bears lovely large and fragrant blossoms in the spring, it is mostly considered a curious monstrosity with its severe-looking limbs and jagged thorns. The botanical variety is monstrosa of Tokutaro Ito and bears golf-ball sized fruit having a rough orange rind. Its flesh is pale yellow with six to eight sections and many seeds.
I Chang (Citrus ichangensis) is formally known as the “Ichang papeda” and is truly a most extraordinary plant which grows wild in southwestern China,reportedly surviving subzero temperatures. The fruit is oblong in shape, much like a lemon, with rough, pale orange rind and meaty flesh packed with seeds.
Kaffir/kieffer/kuffre lime (Citrus hystrix) is a popular ingredient in Asian cooking, particularly in Laos, Cambodia, and Thailand. As Asian immigrants continually enter the West, the demand for this lime has prompted growers to begin cultivating it, particularly in California. The fruit is small and round, with a thick, bumpy, and tough rind. The pale green flesh is full of seeds and sour juice. The long slender notched leaves of the kaffir are used like bay leaves.
Lemonquat (Fortunella sp. x C. limon) is a hybrid of the lemon and the kumquat. It has a pearlike shape and a smooth rind. A cross-section reveals a daisylike pattern. The fruit has eight segments of orange-yellow flesh with many seeds and some juice.
Nasnaran (Citrus amblycarpa) looks like a sour orange with its light orange and pebbly rind that has a dimple at the stem. Its pale yellow flesh is divided into twelve segments with one seed per segment.
New Guinea lime (Microcitrus waburgiana) comes from an exotic-looking leafy plant. The lime itself is an elongated crescent-shaped fruit. The deep green rind covers a pale green flesh that houses several seeds. It has no segments, but is instead a flesh of one large collection of carpels. This is the only species of the genus Microcitrus outside of Australia.
Nigerian powder flasks (Afraegle paniculata) is part of a West African group of hard-shelled, citrus-like ball fruit. The trees can grow as high as sixteen feet and can be found in villages throughout Benin and Nigeria. The seeds are edible and contain an essential oil. The fruit is small, containing only eight segments which are full of seeds.
Nippon orangequat (Citrus reticulata satsuma x Fortunella margarita medua) is a medium-sized, mildly-flavoured fruit. It has a thick, red-orange rind that is sweet and edible. Its sweet meaty pulp has a slight acidic aftertaste, and its six sections are well defined and contain some seeds. It is a fruit used in marmalades or candied. The name given to this hybrid is misleading since its parentage is of mandarin rather than orange.
Orange jasmine (Murraya paniculata) is an exotic shrub found throughout India, Sri Lanka, Myanmar, China, and Australia. The species grows as an evergreen and is used most often as a greenhouse ornament. Although there are many varieties and strains of Murraya, the orange jasmine is the most common. The cranberry-like fruit has an ovoid shape, one or two seeds, and is only one-half inch in diameter. It buds a striking white flower that is fragrant and rich in essential oil. The fruit trees of the genus Murraya are remote citroid fruit trees in the orange subfamily.
Ortanique (Citrus x nobilis) was discovered in Jamaica, as were its cousin the tangors (temple orange and ugli). The name is an amalgam of OR(ange)TAN(gerine)(un)IQUE. Climate affects the look, feel, and taste of this fruit dramatically. In tropical Jamaica, the fruit is seedless and a pale orange in colour, with juicy, sweet orange overtones and a thin rind. In Mediterranean Israel, the fruit has some seeds, a fairly thick rind, and a mid-orange colour. In semitropical Cyprus, is has a deep orange colour, many seeds, and a thicker rind.
Procimequat (Citrus aurantifolia x Fortunella japonica x Fortunella hindsii) is a cross between the Eustic limequat and the Hong Kong kumquat. This small, round fruit grows in clusters on thorny branches with long deep green leaves. The smooth orange rind is soft and easy to tear. The flesh is dense and contains a few seeds and cotyledons. This is one of the fruits leading the study of true bigeneric backcrosses and a trigeneric hybrid, resulting in PRO(to)C(itrus)(L)imequat.
Rangpur, mandarin lime (Citrus limonia osbeck) was imported from India, where it originated, to Florida in 1887. Its greatest selling points are its rootstock and its use as an ornamental. Rangpur lime is a highly acidic fruit that resembles a mandarin in appearance. The fruit is tender and juicy, oblate in shape, with rather a complex tangerine-lime flavour. The rind is reddish-orange, and the flesh is a deep orange with seeds. In India, mandarin juice is improved by adding 20-40% Rangpur juice.
Sinton (Citrangequat) is an oval kumquat and rusk citrange hybrid that was first bred in Sinton, Texas. It is an attractive ornamental plant, with brightly coloured but highly acidic fruit. It has a tapered neck and a striking orange rind. The flesh is lemon yellow with a few seeds. The Sinton is harvested from December through March.
Sydney hybrid (Microcitrus austalasica x australasica) is a hybrid cross between the Australian lime and one finger lime. The green, elongated fruit is acidic and seedless. New growth is purple with red buds and a spicy odour. It makes a striking ornamental with its colours and thorny twigs. The pulp of the Sydney is reminiscent of glistening green caviar eggs.
Yuzu (C. aurantium formerly C. junos) is a distinctive hybrid citrus fruit, likely a variety of bitter orange. One of the most cold-resistant of the citrus fruits, it grows wild in Tibet and the interior of China. It is cultivated on a small scale in parts of China, but more so in Japan. The yuzu tree bears fruit from late autumn, and the sight of ripe golden yuzu suggests to the Japanese that winter is approaching. The fruit is the size of a mandarin orange and has a thick uneven skin and paler flesh containing many seeds. It smells something like a lime, but its fragrance is unique. The Japanese often wrap several of the fruits in cheesecloth and float them in a hot bath so they will give off a relaxing scent.