Ficus (/ˈfaɪkəs/[2] or/ˈfiːkəs/[3][4]) is agenus of about 850species of woodytrees,shrubs,vines,epiphytes andhemiepiphytes in thefamilyMoraceae. Collectively known asfig trees orfigs, they are native throughout thetropics with a few species extending into the semi-warmtemperate zone. Thecommon fig (F. carica) is a temperate species native to southwest Asia and theMediterranean region (from Afghanistan to Portugal), which has been widely cultivated from ancient times for itsfruit, also referred to as figs. The fruit of most other species are also edible though they are usually of only local economic importance or eaten asbushfood. However, they are extremely important food resources for wildlife. Figs are also of considerable cultural importance throughout the tropics, both as objects of worship and for their many practical uses.
Ficus is apantropical genus of trees, shrubs, and vines occupying a wide variety ofecological niches; most areevergreen, but some deciduous species are found in areas outside of the tropics and to higher elevations.[5] Fig species are characterized by their uniqueinflorescence and distinctivepollination syndrome, which uses wasp species belonging to the familyAgaonidae for pollination. Adult plants vary in size fromFicus benghalensis (the Indian banyan), a tall and speading tree with many adventitious roots which may cover a hectare (2.5 acres) or more of ground toFicus nana ofNew Guinea which never exceeds one meter (forty inches) in height and width.[6]
Specific identification of many of the species can be difficult, but members of the genusFicus are relatively easy to recognize. Many haveaerial roots and a distinctive shape or habit, and their fruits distinguish them from other plants. The fruit ofFicus is aninflorescence enclosed in an urn-like structure called asyconium, which is lined on the inside with the fig's tiny flowers that develop into multiple ovaries on the inside surface.[7] In essence, the fig fruit is a fleshy stem with multiple tiny flowers that fruit and coalesce.
Notably, three vegetative traits together are unique to figs. All figs present a white to yellowishlatex, some in copious quantities; the twig shows pairedstipules —or circular scars if the stipules have fallen off; the lateral veins at the base of the leaf are steep, forming a tighter angle with the midrib than the other lateral veins, a feature referred to as "triveined".
Currentmolecular clock estimates indicate thatFicus is a relatively ancient genus, being at least 60 million years old,[8] and possibly as old as 80 million years. The main radiation ofextant species, however, may have taken place more recently, between 20 and 40 million years ago.
Some better-known species that represent the diversity of the genus include, alongside thecommon fig, whose fingeredfig leaf is well known in art andiconography: theweeping fig (F. benjamina), ahemiepiphyte with thin, tough leaves on pendulous stalks adapted to itsrain forest habitat; the rough-leavedsandpaper figs from Australia; and thecreeping fig (F. pumila), a vine whose small, hard leaves form a dense carpet of foliage over rocks or garden walls.
Moreover, figs with different plant habits have undergoneadaptive radiation in differentbiogeographic regions, leading to very high levels ofalpha diversity. In the tropics,Ficus commonly is the most species-rich plant genus in a particular forest. In Asia, as many as 70 or more species can co-exist.[9]Ficusspecies richness declines with an increase in latitude in both hemispheres.[10][11]
A description of fig tree cultivation is set out inIbn al-'Awwam's 12th-century agricultural work titled,Book on Agriculture.[12]
Many fig species are grown for their fruits, though onlyFicus carica is cultivated to any extent for this purpose.[citation needed][disputed –discuss] A fig "fruit" is a type ofmultiple fruit known as asyconium, derived from an arrangement of many small flowers on an inverted, nearly closed receptacle. The many small flowers are unseen unless the fig is cut open.[citation needed]
The fruit typically has a bulbous shape with a small opening (theostiole) at the outward end that allows access topollinators. The flowers are pollinated byvery small wasps such asPegoscapus that crawl through the opening in search of a suitable place to lay eggs. Without this pollinator service fig trees could not reproduce by seed. In turn, the flowers provide a safe haven and nourishment for the next generation of wasps. This accounts for the frequent presence of wasp larvae in the fruit, and has led to acoevolutionary relationship. Technically, a fig fruit proper would be only one of the many tiny matured, seed-bearinggynoecia found inside one fig – if you cut open a fresh fig, individual fruit will appear as fleshy "threads", each bearing a single seed inside. The genusDorstenia, also in the fig family (Moraceae), exhibits similar tiny flowers arranged on a receptacle but in this case the receptacle is a more or less flat, open surface.[citation needed]
Fig plants can bemonoecious (hermaphrodite)[clarification needed] orgynodioecious (hermaphrodite and female).[13] Nearly half of fig species are gynodioecious, and therefore have some plants with inflorescences (syconium) with long styled pistillate flowers, and other plants with staminate flowers mixed with short styled pistillate flowers.[14] The long-styled flowers tend to prevent wasps from laying their eggs within the ovules, while the short-styled flowers are accessible for egg laying.[15]
All the native fig trees of the American continent are hermaphrodites, as well as species likeIndian banyan (F. benghalensis),weeping fig (F. benjamina),Indian rubber plant (F. elastica),fiddle-leaved fig (F. lyrata),Moreton Bay fig (F. macrophylla),Chinese banyan (F. microcarpa),sacred fig (F. religiosa) andsycamore fig (F. sycomorus).[16] The common fig (Ficus carica) is a gynodioecious plant, as well aslofty fig or clown fig (F. aspera),Roxburgh fig (F. auriculata),mistletoe fig (F. deltoidea),F. pseudopalma,creeping fig (F. pumila) and related species. The hermaphrodite common figs are called "inedible figs" or "caprifigs"; in traditional culture in theMediterranean region they were considered food forgoats (Capra aegagrus). In the female fig trees, the male flower parts fail to develop; they produce the "'edible figs".Fig wasps grow in common fig caprifigs but not in the female syconiums because the female flower is too long for the wasp to successfully lay her eggs in them. Nonetheless, the wasp pollinates the flower with pollen from the caprifig it grew up in. In many situations, the wasp pollinator is unable to escape and dies within the fruit. When the wasp dies, it is broken down by enzymes (Ficain) inside the fig. Fig wasps are not known to transmit any diseases harmful to humans.
When a caprifig ripens, another caprifig must be ready to be pollinated. In temperate climes, wasps hibernate in figs, and there are distinct crops. Caprifigs have three crops per year; common figs have two.[17] The first crop (breba) is larger and juicier, and usually eaten fresh.[17] In cold climates the breba crop is often destroyed by spring frosts.[18] Someparthenocarpiccultivars of common figs do not require pollination at all, and will produce a crop of figs (albeitsterile) in the absence of caprifigs and fig wasps.
Depending on the species, each fruit can contain hundreds or even thousand of seeds.[19] Figs can be propagated by seeds, cuttings, air-layering or grafting. However, as with any plant, figs grown from seed are not necessarily genetically identical to the parent and are only propagated this way for breeding purposes.
The unique figpollination system involves tiny, highly specific wasps, known asfig wasps, that enter viaostiole these subclosed inflorescences to both pollinate and lay their own eggs.[8] Each species of fig is pollinated by one or a few specialised wasp species, and therefore plantings of fig species outside of their native range results in effectively sterile individuals. For example, inHawaii, some 60 species of figs have been introduced, but only four of the wasps that fertilize them, so only those species of figs produce viable seeds there and can becomeinvasive species. This is an example ofmutualism, in which each organism (fig plant andfig wasp) benefit each other, in this case reproductively.[citation needed]
The intimate association between fig species and their wasp pollinators, along with the high incidence of a one-to-one plant-pollinator ratio have long led scientists to believe that figs and wasps are a clear example ofcoevolution. Morphological and reproductive behavior evidence, such as the correspondence between fig and wasp larvae maturation rates, have been cited as support for this hypothesis for many years.[20] Additionally, recent genetic and molecular dating analyses have shown a very close correspondence in the character evolution andspeciation phylogenies of these two clades.[8]
According to meta-analysis of molecular data for 119 fig species 35% (41) have multiple pollinator wasp species. The real proportion is higher because not all wasp species were detected.[21] On the other hand, species of wasps pollinate multiple host fig species.[22] Molecular techniques, likemicrosatellite markers and mitochondrial sequence analysis, allowed a discovery of multiple genetically distinct,cryptic wasp species. Not all these cryptic species are sister taxa and thus must have experienced a host fig shift at some point.[23] These cryptic species lacked evidence of geneticintrogression orbackcrosses indicating limited fitness forhybrids and effectivereproductive isolation andspeciation.[23]
The existence of cryptic species suggests that neither the number of symbionts northeir evolutionary relationships are necessarily fixed ecologically.[23] While the morphological characteristics that facilitate the fig-wasp mutualisms are likely to be shared more fully in closer relatives, the absence of unique pairings would make it impossible to do a one-to-one tree comparison and difficult to determine cospeciation.[citation needed]
With over 800 species,Ficus is by far the largest genus in the Moraceae, and is one of the largest genera of flowering plants currently described.[24] The species currently classified withinFicus were originally split into several genera in the mid-1800s, providing the basis for a subgeneric classification when reunited into one genus in 1867. This classification put functionallydioecious species into four subgenera based on floral characters.[25] In 1965,E. J. H. Corner reorganized the genus on the basis of breeding system, uniting these four dioecious subgenera into a single dioecious subgenusFicus.Monoecious figs were classified within the subgeneraUrostigma,Pharmacosycea andSycomorus.[26]
This traditional classification has been called into question by recentphylogenetic studies employing genetic methods to investigate the relationships between representative members of the various sections of each subgenus.[8][25][27][28][29] Of Corner's original subgeneric divisions of the genus, onlySycomorus is supported as monophyletic in the majority of phylogenetic studies.[8][25][28] Notably, there is no clear split between dioecious and monoecious lineages.[8][25][27][28][29] One of the two sections ofPharmacosycea, a monoecious group, form a monophyletic clade basal to the rest of the genus, which includes the other section ofPharmacosycea, the rest of the monoecious species, and all of the dioecious species.[29] These remaining species are divided into two main monophyletic lineages (though the statistical support for these lineages is not as strong as for the monophyly of the more derived clades within them). One consists of all sections ofUrostigma except for sectionUrostigma s. s.. The other includes sectionUrostigma s. s., subgenusSycomorus, and the species of subgenusFicus, though the relationships of the sections of these groups to one another are not well resolved.[8][29]
Figs have figured prominently in some human cultures. There is evidence that figs, specifically thecommon fig (F. carica) and sycamore fig (Ficus sycomorus), were among the first plant species that were deliberately bred for agriculture in the Middle East, starting more than 11,000 years ago. NinesubfossilF. carica figs dated to about9400–9200 BCE were found in the earlyNeolithic villageGilgal I (in theJordan Valley, 13 km, or 8.1 mi, north ofJericho). These were aparthenogenetic type and thus apparently an early cultivar. This find predates the first known cultivation ofgrain in the Middle East by many hundreds of years.[40]
Numerous species of fig are found in cultivation in domestic and office environments, including:[41]
F. carica, common fig – hardy to −10 °C (14 °F). Shrub or small tree which can be grown outdoors in mild temperate regions, producing substantial harvests of fruit. Many cultivars are available.
F. benjamina, weeping fig, ficus – hardy to 5 °C (41 °F). Widely used as an indoor plant for the home or the office. It benefits from the dry, warm atmosphere of centrally-heated interiors, and can grow to substantial heights in a favoured position. Several variegated cultivars are available.
F. elastica, rubber plant – hardy to 10 °C (50 °F): widely cultivated as a houseplant; several cultivars with variegated leaves
F. lyrata, fiddle-leaf fig – hardy to 10 °C (50 °F)
Fig trees have profoundly influenced culture through several religious traditions. Among the more famous species are thesacred fig tree (Pipal, bodhi, bo, or po,Ficus religiosa) and otherbanyan figs such asFicus benghalensis. The oldest living plant of known planting date is aFicus religiosa tree known as theSri Maha Bodhi planted in the temple atAnuradhapura, Sri Lanka by King Tissa in 288 BCE. In Asia, figs are important inBuddhism andHinduism. TheBuddha is traditionally held to have foundbodhi (enlightenment) while meditating for 49 days under asacred fig.[42] The same species wasAshvattha, the "world tree" of Hinduism. ThePlaksa Pra-sravana was said to be a fig tree between the roots of which theSarasvati River sprang forth; it is usually held to be a sacred fig but more probably isFicus virens. InJainism, the consumption of any fruit belonging to this genus is prohibited.[43] The common fig is one of two significant trees inIslam, and there is asura in Quran named "The Fig" orAt-Tin (سوره تین). The common fig tree is cited in theBible:Adam and Eve cover their nakedness with fig leaves. The fig fruit is one of thetraditional crops of Israel, and is included in the list of food found in the Promised Land. The fig tree was sacred in ancientGreece andCyprus, where it was a symbol offertility.[citation needed]
^Valdeyron, Georges; Lloyd, David G. (June 1979). "Sex Differences and Flowering Phenology in the Common Fig, Ficus carica L.".Evolution.33 (2):673–685.doi:10.2307/2407790.JSTOR2407790.PMID28563939.
^abHerre, E.; Machado, C.A.; Bermingham, E.; Nason, J.D.; Windsor, D.M.; McCafferty, S.; Van Houten, W.; Bachmann, K. (1996). "Molecular phylogenies of figs and their pollinator wasps".Journal of Biogeography.23 (4):521–530.Bibcode:1996JBiog..23..521H.doi:10.1111/j.1365-2699.1996.tb00014.x.
^abcJousselin, E.; Rasplus, J.-Y.; Kjellberg, F. (2003). "Convergence and coevolution in a mutualism: evidence from a molecular phylogeny of Ficus".Evolution; International Journal of Organic Evolution.57 (6):1255–1269.doi:10.1554/02-445.PMID12894934.S2CID1962136.
^Brickell, Christopher, ed. (2008).The Royal Horticultural Society A-Z Encyclopedia of Garden Plants. United Kingdom: Dorling Kindersley. p. 448.ISBN9781405332965.
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