Citrus Pages / Native Australian varieties

Native Australian citrus varieties

Microcitrus australasica, Australian finger lime

Australian finger lime © UC-Riverside Citrus Collection

Australian desert lime © Petr Broža

Taxonomy of Microcitrus and Eremocitrus

Microcitrus

History
Distribution
Uses
Australian finger lime
Cultivated finger lime varieties
Wild Fingerlime's Citrus Caviar varieties
Faustrime
Australian Sunrise Lime
Red finger lime
Australian Blood Lime
Australian round lime
Sydney hybrid (Lemon-shaped Australian lime)
Mount White lime (Garraway's Australian lime)
Russel River lime (Large-leaf Australian lime)
Maiden's Australian wild lime
Brown River finger lime (Papuan wild lime)
New Guinea wild lime

Eremocitrus

Australian desert lime
Australian Outback lime
Eremolemon
Citrus gracilis

The taxonomy of Microcitrus and Eremocitrus

W.T. Swingle (1871 - 1952) assigned these citrus types in the genera Microcitrus and Eremocitrus based on several characteristics that botanically separate them from the genus Citrus. These are listed in "The Botany of Citrus", in Microcitrus and Eremocitrus. Swingle was familiar with the work of both F.M. Mueller (1825 - 1896), Government Botanist of Victoria and F.M. Bailey (1827-1915), Colonial Botanist of Queensland. Both botanists active in Australia included these types in the genus Citrus.

Well-known botanists of our time continue this tradition, D.J. Mabberley (b.1948), since 2005 president of IATP, perhaps the most notable among them. A 1998 paper of his discusses the issue of Australian native citrus classification. (See: Introduction, Mabberley). Australian citrus growers also prefer Citrus as the genus of their native varieties.

In this presentation, these classifications are listed as synonyms of Microcitrus and Eremocitrus, following the practice of most major plant databases today.

Microcitrus

History

The six known species of Microcitrus are the result of millions of years of slow evolution from a primitive ancestral type, which gave rise to the genera Eremocitrus and Microcitrus. This type may have resembled M. warburgiana, the New Guinea species, which has small leaves and small, nearly spherical fruits. From such an ancestral form, one line of evolution produced the so-called native orange, round lime, or Dooja (M. australis), that grows to a large tree and has subglobose fruits much larger than those of M. warburgiana, with long, slender, pointed, more or less twisted pulp-vesicles. Another line of evolution culminated in M. inodora and M. maideniana, highly specialized forms showing adaptations to tropical rain forests, with large leaves and paired spines; a third line of evolution led to the small-leaved species M. australasica and M. garrowayi, both with long-ovoid or very elongated cylindric fruits.

Distribution

These remarkable citrus fruits are extremely interesting, in that they show how evolution has proceeded in regions isolated as Australia and New Guinea have been during the last twenty or thirty million years since they were cut off from all other land masses. The evolution of other citrus fruits is not so easily followed, since Citrus, Fortunella, and Poncirus did not originate in regions that were geographically isolated in definitely dated geologic eras. The Microcitrus group contains seven species, five of which are native to Australia with the other two found in New Guinea. The Australian species occur in rainforests and their margins from Cape York Peninsula south to the northern rivers of New South Wales. They produce small, round or finger-shaped fruit, with a pleasant but very acid juice. Australia has six species of true native citrus classified in two genera: Eremocitrus (desert limes) and Microcitrus (finger limes).

Uses

They have a close relationship with conventional citrus, classified as the genus Citrus. Australian native citrus species are able to hybridise with a range of other citrus species. This ability, along with drought and salinity tolerance and disease resistance, has long attracted the interest of citrus researchers and breeders. Improved selections and hybrids of native citrus also have potential in their own right for commercial production for both the fresh and high-value processing markets. Fruit is used in a range of sweet and savoury processed products, such as marmalades and sauces, and is in demand by chefs producing ‘Australian Native Cuisine’ dishes. Traditionally most fruit has been harvested from the wild. Commercial orchard production began in the last decades of the twentieth century and because of quality and reliability of supply factors as well as environmental concerns, has slowly started to replace wild harvested fruit.


LAT	Microcitrus australasica (F.Muell.) Swingle
Syn	Citrus australasica F.Muell.
	Australian finger lime, (Microcitrus australasica), occurs as an understorey shrub or tree in rainforests in southern Queensland and northern New South Wales. It produces finger-shaped fruit, up to 10cm long, with thin green or yellow skin and greenish-yellow compressed juice vesicles that tend to burst out when the skin is cut. A pink to red-fleshed form with red to purple or even black skin (known as Citrus australasica var. sanguinea) also occurs in the wild. Fruits are cylindric, 1.5-2.5 cm long, often slightly curved, narrowed at both tip and base. Peel rough with numerous oil glands, greenish-yellow at maturity; pulp-vesicles nearly free or loosely cohering, seeds numerous, small, 6-7 mm long, ovoid, usually flattened on one side. The first leaves are minute linear cataphylls; these gradually merge into juvenile foliage which, in turn, merges into the mature foliage, the leaves of which are smaller than those of any other True Citrus Fruit Tree with the exception of Eremocitrus glauca, when the latter occurs in very dry situations.
ENG	Finger lime, Australian finger lime
FRA	Lime digitée d'Australie
Photos		© UC-Riverside Citrus Collection
Link


LAT	Microcitrus australasica (F.Muell.) Swingle
Syn	Citrus australasica F.Muell.
	Other cultivated varieties: (Thumbnails from top to bottom) 'Blunobia Pink Crystal' 'Blunobia Red Blush' 'Byron Sunrise' 'Durhams Emerald' 'Jali Red' 'Mia Rose' 'Pink Ice' Several producers sell varieties with their own trade names. Wild Finger Lime with the tradename Citrus Caviar, see below. Finger Limeing Good Pty Limited with the tradename Limeburst®
ENG	Australian finger lime, cultivated varieties
FRA
Photos		Photos by Murray Fag © Australian National Botanic Gardens
Link	Australian National Botanic Gardens


LAT	Microcitrus australasica (F.Muell.) Swingle
Syn	Citrus australasica F.Muell.
	Wild Fingerlime markets finger limes in the subtropics of northern New South Wales, where the finger lime is endemic. Wild Fingerlime has conducted research within the Australian restaurant industry and selected a number of export markets to establish the most desirable cultivars. Wild Fingerlime's Citrus Caviar varieties from top to bottom: Rainforest Ruby 1 Rainforest Garnet 1 Rainforest Jade 1 Rainforest Pearl Rainforest Diamond Rainforest Jade 2 Rainforest Topaz
ENG	Wild Fingerlime's Citrus Caviar varieties
Photo		Photo provided by Wild Fingerlime
Link	Wild Fingerlime


LAT	Faustrime
Syn	Microcitrus australasica (F.Muell.) Swingle X Citrus x floridana (J. Ingram & H. Moore) Mabb. 'Limequat Eustis'
	Faustrime is a trigeneric hybrid of the Australian fingerlime (Microcitrus australasica) and Limequat Eustis, itself a hybrid of Mexican lime (Citrus aurantiifolia) and Round kumquat (Fortunella japonica). It has genes of three citrus fruit genera: Citrus, Microcitrus and Fortunella. The fruit of Faustrime are similar to Finger lime in shape but much larger in size. Faustrime seems to have inherited several characteristics from the Limequat parent. Unlike the Finger lime Faustrime turns yellow when ripe. The juice vesicles of Faustrime are oval whereas the juice vesicles of the Finger lime are round. Faustrime is juicier than Finger lime and the taste is a cross of Mexican lime and Finger lime. In the kitchen Faustrime can be used instead of lime. Faustrime is also grown as an ornamental plant. Disambiguation: Faustrimedin, see below.
ENG	Faustrime
Photos		© Laaz


LAT	Microcitrus australasica 'Sunrise Lime'
Syn	Citrus australasica 'Sunrise Lime' Microcitrus australasica x (Fortunella margarita x Citrus reticulata var. austera) Faustrimedin 'Sunrise Lime'
	The Australian Sunrise Lime is an open pollinated seedling selected from a Faustrimedin, a hybrid of the Finger lime (Citrus australasica) and the Calamondin (Citrus madurensis), itself a hybrid between the Nagami kumquat (Fortunella margarita) and the sour mandarin (Citrus reticulata var. austera). The Faustrimedin is thus a trigeneric hybrid of the Fortunella, Citrus and Microcitrus genera and was originally bred in California in 1911. The parent tree of the Sunrise Lime was selected in 1990 at CSIRO Plant Industry. The variety has been grown commercially since 2001 and was so successful it was made available for home gardeners in 2005. The Sunrise Lime produces attractive golden-coloured fruit on an upright shrub to small tree, usually 2 to 3 m high and 1.5 to 2.5 m wide. Foliage is dark, glossy-green. The oval leaves are approximately 40 to 45 mm long by 20 to 30 mm wide. The cream-coloured flowers occur in spring to early summer. Fruits ripen in winter, are pearshaped and are usually 30 to 45 mm long by 20 to 40 mm wide. Seeds are small and plump. Juice squeezed from the fruit has a sharp, clean flavour and a light ‘floral’ aroma. The fruit may be eaten whole and like a kumquat, have a sharpish flesh and a sweet albedo and skin. They can be used in products such as in cordials, beverages, conserves, puree, pastes, sauces, marmalade, syrups and garnishes. Disambiguation: Faustrime, see above.
ENG	Australian Sunrise lime
FRA
Photos		© CSIRO Plant Industry


LAT	Microcitrus australasica (F.Muell.) Swingle var.sanguinea
Syn	Citrus australasica var. sanguinea F.M.Bailey
	Red finger lime, a pink to red-fleshed form of the Australian finger lime with red to purple or even black skin (known as Citrus australasica var. sanguinea) also occurs in the wild. This variety differs from the species in that the pulp-vesicles at maturity vary from pink to red in color. The red-pulp finger lime has been observed growing throughout the natural distribution of the finger lime. There are similar "pink" or red varieties of oranges (the so-called blood oranges) and grapefruit, some of which are known to have arisen as budsports. However, the red-pulped variety of the Australian finger-lime is found growing wild and can be propagated from seed; it seems to have originated without the aid of man.
ENG	Red finger lime, Red-pulped finger lime, Red-fleshed finger lime
FRA
Photos		© Petr Broža © Bernhard Voß


LAT	Microcitrus australasica 'Australian Blood Lime'
Syn	Microcitrus australasica var. sanguinea x Citrus limonia 'Rangpur'
	Australian Blood Lime is a hybrid between the Red finger lime (Citrus australasica var. sanguinea) and the Rangpur lime (Citrus x limonia 'Rangpur'). The parent tree of the Sunrise Lime was selected in1990 at CSIRO Plant Industry. Under the right conditions the tree produces striking, bloodred coloured fruit, which greatly enhances the appeal of the fresh and processed product. The variety also has potential as an ornamental tree. Fruit is produced on an attractive, dense, upright shrub to small tree, usually 2 to 3 m high and 2 m wide with dark, glossy-green foliage and red growth flushes. Fruits ripen in winter, are oval in shape and are usually 30 to 50 mm long, by 20 to 30 mm wide. The flesh and juice may show red tinges or may occasionally be more intensely red. Seeds are small and plump. The fruit is used in a variety of sweet and savoury dishes and it can be used in many value-added products such as marmalades, preserves, syrups, juices, beverages and sauces. The bottom picture shows Australian 'Blood', 'Outback' and 'Sunrise' limes.
ENG	Australian Blood lime, Australian Red Centre lime
FRA
Photos	The bottom picture shows Blood, Outback and Sunrise limes.	© CSIRO Plant Industry


LAT	Microcitrus australis (F. Mueller) Swingle
Syn	Citrus australis (A. Cunn. ex Mudie) Planchon
	Australian round lime, Microcitrus australis (Citrus australis), is a shrub or tall narrow tree occurring on the open and drier rainforest margins of southeast Queensland, from Brisbane northwards. It produces round fruit with a thick, green to lemon-coloured skin and pale green pulp, very similar to a small commercial lime in appearance. This species, called "Dooja" by the aborigines and round lime or native orange by other Australians, is readily distinguished from all the other species of Microcitrus (and from Eremocitrus as well) by its globose or slightly pear-shaped, rough-skinned fruits, 2.5 to 5 cm in diameter (about the size of a large walnut), and by its short-stalked pulp-vesicles that taper gradually into blunt tips often more or less deformed and twisted by mutual pressure. These pulp-vesicles are very different in shape from those of the finger-lime, M. australasica, or those of the other species of Microcitrus. They are similar to those of the commonly cultivated citrus fruits except that they contain, along their central axis, large masses of yellowish oil. The Australian round lime grows to be a tree 10 - 20 metres (30 to 60 feet) high and is the largest of any of the native citrus fruit trees. The fruit is used for preserves in Queensland.
ENG	Australian round lime, Round lime, Gympie lime
FRA	Lime ronde d'Australie
Photos		© UC-Riverside Citrus Collection (2) © Home Citrus Growers © Saga Univ. Dept of Agriculture


LAT	Microcitrus virgata Swingle & Reece
Syn	Citrus x virgata Mabb. Rofaustrime (Tanaka) Microcitrus australasica (F. Muell.) Swingle x Microcitrus australis (Planchon) Swingle
	Sydney hybrid, a cross between Australian finger lime (Microcitrus australasica) and Australian round lime (Microcitrus australis), was provisionally given the scientific name of Microcitrus virgata before its hybrid nature was established. Recently D.J. Mabberley has classified it as Citrus x virgata. It is notable for its extreme vigour, exceeding that of all other known citrus in the length of twigs produced. The leaves are intermediate in shape between the two parent species, but, owing to the enormous number of twigs and consequent great profusion of leaves, they are not intermediate in size between those of the parent species, but nearer that of the small-leaved parent, the finger lime. The fruits are elongate-obovoid or ellipsoid, 35-50 X 20-28 mm, with the tip abruptly rounded.
ENG	Sydney hybrid wild lime, Lemon-shaped Australian wild lime
FRA	Lime sauvage hybride de Sydney
Photos		© Saga Univ. Dept of Agriculture


LAT	Microcitrus garrowayi (F.M. Bailey) Swingle
Syn	Citrus garrawayi F.M.Bailey
	Mount White lime, Microcitrus garrowayi (Citrus garrawayi), occurs in rainforests on Cape York Peninsula. It produces a finger-shaped fruit, similar to Finger lime, Microcitrus australasica, though shorter and thicker, with a pale lemon skin and light green pulp. Due to its limited distribution this species is considered rare in the wild and fruit is not traded commercially. Mount White lime is endemic to the foothills and upland rainforest of the Cook District on Cape York Peninsula. It grows in deciduous vine thickets as an understorey shrub and has been recorded at a height of 15 m. Mount White Lime is similar to Finger lime, but has broader leaves. Fruit forms from April to November. The fruits are also “finger-shaped”, with a green skin and greenish-white pulp on maturity. The fruit can be used for value-added products. On Home Citrus Growers Mike Saalfeld has more about the Mount White Lime. The two pictures are of the first fruit he managed to grow.
ENG	Mount White lime, Garraway's Australian wild lime
FRA
Photos		© Home Citrus Growers


LAT	Microcitrus inodora (F.M. Bailey) Swingle
Syn	Citrus inodora F.M.Bailey
	Russel River lime or Large-leaf Australian wild lime, Microcitrus inodora (Citrus inodora), is now rare in the wild. It is native to the high-rainfall lowland rainforest at the foot of the Bellenden-Ker Range between Cairns and Innisfail in northern Queensland, much of which has now been cleared to grow sugar cane or bananas. It is a shrub or small tree 2 to 4 meters high with the trunk 4 to 5 cm in diameter and produces a lemon-shaped fruit. Fruit is not traded commercially. The twigs are angular like those of Citrus sinensis (the sweet orange) and have one or two slender, very sharp spines, 6 to 12 mm long. Leaves are the biggest in the Microcitrus group. As the botanical name suggests there is very little oil in the leaves and consequently no odour. The bottom picture is of a fruit 6 mm x 12 mm in size, which Mike Saalfeld managed to grow in the UK. See Home Citrus Growers
ENG	Russel River lime, Large-leaf Australian wild lime
FRA
Photos		© Saga Univ. Dept of Agriculture © UC-Riverside Citrus Collection © Home Citrus Growers


LAT	Microcitrus maideniana (Domin.) Swingle	If you have a picture to share, please send one to Citrus Pages
Syn	Citrus inodora (F.M. Bailey) var. maideniana
	Commonly known as Maiden’s Australian lime, Microitrus maideniana is often described as a variety or subspecies of the Russel River lime. The two species have a similar distribution, limited to a small area in far North Queensland. The deeply depressed apex of the fruit is the only clearly distinctive character known. Fruit is not commercially traded. Some botanists today consider Russel River lime (Microcitrus inodora) and Maiden's Australian wild lime (Microcitrus maideniana) to be one and the same species and the name Microcitrus inodora valid for both.
ENG	Maiden's Australian wild lime


LAT	Microcitrus papuana Winters
Syn	Citrus wintersii Mabb.
	The new name given by D.J. Mabberley, Citrus wintersii, commemorates Harold F. Winters of the USDA, Beltsville, who first described the plant. Finding information on the two Microcitrus species not of Australian origin, the Brown River finger lime, Microcitus papuana (Citrus wintersii) and New Guinea wild lime Microcitrus warburgiana (Citrus warburgiana) is very difficult. Information on the Brown River finger lime from Papua New Guinea (Microcitrus papuana) is very scarce indeed. The only useful information on the web is on Mike Saalfeld's Home Citrus Growers site where he shares the available info with his readers and describes his own experiments with growing Microcitrus papuana himself.
ENG	Brown River finger lime, Papuan wild lime
FRA	Lime digité de Brown River
Photos		© Saga Univ. Dept of Agriculture


LAT	Microcitrus warburgiana (F.M. Bailey) Tanaka
Syn	Citrus warburgiana F.M. Bailey
	New Guinea wild lime is the other Microcitrus species not native to Australia. The tree has an upright growth habit and grows very slowly. The leaves are long and dark green. The small flowers are white. The fruits are small, about 3 cm in diametre, globose, with three to six segments and 5-7 seeds. The skin colour is dark green. The petioles differ from those of the other species of Microcitrus in having a very narrowly crenulate margin or wing. The veins are numerous, making only a small angle (35° to 50°) with the midrib, and soon branch, forming a reticulation of veinlets not unlike those of M. garrowayi, although the latter species has smaller leaves with fewer veins. The ultimate twigs, especially the short lateral branchlets, are remarkably slender, the smallest lateral twigs being 1 to 1.5 mm or even only 0.5 to 0.8 mm in diameter.
ENG	New Guinea wild lime
FRA	Lime sauvage de Nouvelle-Guinée
Photos		(1) © UC-Riverside Citrus Collection (2,3) © Saga Univ. Dept of Agriculture

Eremocitrus

The Eremocitrus group contains one species, Eremocitrus glauca, known commonly as the Australian desert lime. The typical form of this species as it occurs in southeastern Queensland is a small tree or a large shrub, sometimes only a few feet in height. This genus is in many ways the best characterized and most distinct of any of the near relatives of the genus Citrus. It is the only plant in the whole orange subfamily that is able to survive extreme drought. Eremocitrus hybrids include eremolemons, eremoranges, eremoradias (a hybrid with the sour orange) and citrangeremos (a hybrid with citrange).


LAT	Eremocitrus glauca (Lindlay) Swingle
Syn	Citrus glauca (Lindlay) Burkill
	Australian desert lime is originally from southeastern Queensland. It is able to withstand long periods of severe drought and strong, hot winds. The tree will defoliate, leaving its thin, weeping green branches resembling a smoke tree. It can endure high concentrations of salts in the soil and can grow up to over 7 metres (25 ft) with access to water. Eremocitrus leaves are linear in shape and fruits are green, about the size of a marble, and taste much like a regular lime. It has the shortest flowering to fruit maturity period (about 8 weeks) of any member of the citrus family. Australian desert lime grows wild in Queensland and New South Wales with some isolated occurrences in central South Australia. It is the only known member of the citrus family which is a xerophyte: it is able to withstand severe drought and hot dry winds. Under such conditions the leaves fall off and the leafless gray-green twigs carry on photosynthesis on a reduced scale. The plant tolerates high temperatures (up to 45°C) and when dormant in late winter is able to withstand temperatures below freezing point without injury. Seedlings develop an enormous root system before making vigorous aerial growth and developing full-sized leaves. A new species, Citrus gracilis, has recently been described and grows wild as a straggling tree in Eucalypt woodland in the Northern Territory. It has a similar growth habit to Eremocitrus glauca and produces round fruit up to 8cm in diameter.
ENG	Australian desert lime
FRA	Lime du désert australien
Photos		© UC-Riverside Citrus Collection (3,4) © Petr Broža


LAT	Eremocitrus glauca 'Outback Lime'
Syn	Citrus glauca 'Outback Lime'
	The Australian Outback Lime (also known as ‘Australian Desert’) is a variety of desert lime (Citrus glauca). It is a cultivar selected and developed from a collection of different native desert lime trees, producing small, green, juicy fruits which ripen at Christmas time. The variety was selected in 1990 at CSIRO Plant Industry. It has been grown commercially since 2001 and was so successful it was made available for home gardeners in 2005. Under commercial cultivation it is an open, upright shrub to small tree, usually 2 to 4 m high and 1.5 to 2 m wide. Small, white flowers occur in spring. The crop is carried on the previous season’s growth, towards the outside of the canopy. The flowering to harvest time is extremely short, in the order of 2 to 3 months. The spherical fruits (to 20 mm) have a thin skin and turn from green to yellow as they ripen in early summer. The fruits can be used for preparing sauces.
ENG	Australian Outback lime
FRA
Photos		© CSIRO Plant Industry


LAT	Eremolemon
Syn	Eremocitrus glauca x Citrus meyerii
	Eremolemon is believed to be Australian desert lime crossed with a Meyer lemon. The leaves are dark green and lanceolate. The fruit is yellow and about 20 mm in diameter. The trees seem to grow larger than a regular Eremocitrus glauca but seem to have the same tolerance for saline soils. Seedlings grow rapidly with deep taproots.
ENG	Eremolemon
FRA
Photos		© UC-Riverside Citrus Collection © Home Citrus Growers


LAT	Citrus gracilis Mabb.	If you have a picture to share, please send one to Citrus Pages
Syn
	Citrus gracilis has recently been described and named by D.J. Mabberley and grows wild as a straggling tree in eucalypt woodland in the Northern Territory. It has a similar growth habit to Citrus glauca and produces round fruit up to 8cm in diameter.Fruit is not traded commercially. Northern Territory Herbarium lists this as near threatened and endemic to NT. The specific epithet (gracilis) refers to the graceful aspect of the flowering twigs. Superficially resembling Citrus wintersii Mabb. in its narrow leaves, it differs from that New Guinea endemic in not having cylindrical fruits. From the other New Guinea endemic, Microcitrus warburgiana, with which some forms share the broader leaves characteristic of many specimens of that species, it differs in its much larger fruit as it also does from Eremocitrus glauca, which also has narrow leaves and suckering spiny shoots. For more information and pictures see Mike Saalfed's Home Citrus Growers.
ENG	Humpty Doo lime, Kakadu lime
FRA
Photos