Fabaceae
Overview
The Fabaceae or Leguminosae, commonly known as the legume, pea, or bean family, is a large and economically important family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 of flowering plant
Flowering plant
The flowering plants , also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants. Angiosperms are seed-producing plants like the gymnosperms and can be distinguished from the gymnosperms by a series of synapomorphies...

s. The group is the third largest land plant family, behind only the Orchidaceae
Orchidaceae
The Orchidaceae, commonly referred to as the orchid family, is a morphologically diverse and widespread family of monocots in the order Asparagales. Along with the Asteraceae, it is one of the two largest families of flowering plants, with between 21,950 and 26,049 currently accepted species,...

 and Asteraceae
Asteraceae
The Asteraceae or Compositae , is an exceedingly large and widespread family of vascular plants. The group has more than 22,750 currently accepted species, spread across 1620 genera and 12 subfamilies...

, with 730 genera and over 19,400 species. The largest genera are Astragalus
Astragalus
Astragalus is a large genus of about 3,000 species of herbs and small shrubs, belonging to the legume family Fabaceae, subfamily Faboideae. The genus is native to temperate regions of the Northern Hemisphere...

(over 2,400 species), Acacia
Acacia
Acacia is a genus of shrubs and trees belonging to the subfamily Mimosoideae of the family Fabaceae, first described in Africa by the Swedish botanist Carl Linnaeus in 1773. Many non-Australian species tend to be thorny, whereas the majority of Australian acacias are not...

(over 950 species), Indigofera
Indigofera
Indigofera is a large genus of about 700 species of flowering plants belonging to the family Fabaceae.The species are mostly shrubs, though some are herbaceous, and a few can become small trees up to tall. Most are dry-season or winter deciduous. The leaves are pinnate with 5–31 leaflets and the...

(around 700 species), Crotalaria
Crotalaria
Crotalaria is a genus of herbaceous plants and woody shrubs in the Family Fabaceae commonly known as rattlepods. Some 600 or more species of Crotalaria are described worldwide, mostly from the tropics; at least 500 species are known from Africa. Some species of Crotalaria are grown as ornamentals...

(around 700 species), and Mimosa
Mimosa
Mimosa is a genus of about 400 species of herbs and shrubs, in the subfamily Mimosoideae of the legume family Fabaceae. The generic name is derived from the Greek word μιμος , meaning "mimic."...

(around 500 species).

Plants of this family are found throughout the world, growing in many different environments and climates.
Encyclopedia
The Fabaceae or Leguminosae, commonly known as the legume, pea, or bean family, is a large and economically important family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 of flowering plant
Flowering plant
The flowering plants , also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants. Angiosperms are seed-producing plants like the gymnosperms and can be distinguished from the gymnosperms by a series of synapomorphies...

s. The group is the third largest land plant family, behind only the Orchidaceae
Orchidaceae
The Orchidaceae, commonly referred to as the orchid family, is a morphologically diverse and widespread family of monocots in the order Asparagales. Along with the Asteraceae, it is one of the two largest families of flowering plants, with between 21,950 and 26,049 currently accepted species,...

 and Asteraceae
Asteraceae
The Asteraceae or Compositae , is an exceedingly large and widespread family of vascular plants. The group has more than 22,750 currently accepted species, spread across 1620 genera and 12 subfamilies...

, with 730 genera and over 19,400 species. The largest genera are Astragalus
Astragalus
Astragalus is a large genus of about 3,000 species of herbs and small shrubs, belonging to the legume family Fabaceae, subfamily Faboideae. The genus is native to temperate regions of the Northern Hemisphere...

(over 2,400 species), Acacia
Acacia
Acacia is a genus of shrubs and trees belonging to the subfamily Mimosoideae of the family Fabaceae, first described in Africa by the Swedish botanist Carl Linnaeus in 1773. Many non-Australian species tend to be thorny, whereas the majority of Australian acacias are not...

(over 950 species), Indigofera
Indigofera
Indigofera is a large genus of about 700 species of flowering plants belonging to the family Fabaceae.The species are mostly shrubs, though some are herbaceous, and a few can become small trees up to tall. Most are dry-season or winter deciduous. The leaves are pinnate with 5–31 leaflets and the...

(around 700 species), Crotalaria
Crotalaria
Crotalaria is a genus of herbaceous plants and woody shrubs in the Family Fabaceae commonly known as rattlepods. Some 600 or more species of Crotalaria are described worldwide, mostly from the tropics; at least 500 species are known from Africa. Some species of Crotalaria are grown as ornamentals...

(around 700 species), and Mimosa
Mimosa
Mimosa is a genus of about 400 species of herbs and shrubs, in the subfamily Mimosoideae of the legume family Fabaceae. The generic name is derived from the Greek word μιμος , meaning "mimic."...

(around 500 species).

Plants of this family are found throughout the world, growing in many different environments and climates. A number are important agricultural plants, including: Glycine max (soybean), Phaseolus
Phaseolus
Phaseolus is a genus in the family Fabaceae of about fifty plant species, all native to the Americas.At least four of the species have been domesticated since pre-Columbian times for their beans. Most prominent among these is the common bean, P...

(beans), Pisum sativum (pea), Cicer arietinum (chickpeas), Medicago sativa (alfalfa), Arachis hypogaea (peanut), Ceratonia siliqua (carob), and Glycyrrhiza glabra (licorice), which are among the best known members of Fabaceae.

A number of species are also weedy pests in different parts of the world, including: Cytisus scoparius
Cytisus scoparius
Cytisus scoparius, the Common Broom and Scotch Broom, syn. Sarothamnus scoparius, is a perennial leguminous shrub native to western and central Europe,....

(broom), Ulex europaeus (gorse), Pueraria lobata (kudzu), and a number of Lupinus species.

Etymology

The name 'Fabaceae' comes from the defunct genus Faba, now included in Vicia
Vicia
Vicia is a genus of about 140 species of flowering plants commonly known as vetches. It is in the legume family . Member species are native to Europe, North America, South America, Asia and Africa. Some other genera of their subfamily Faboideae also have names containing "vetch", for example the...

. The term "faba" comes from Latin, and appears to simply mean "bean". Leguminosae is an older name still considered valid, and refers to the typical fruit
Fruit
In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...

 of these plants, which are called legumes.

Distribution

The Fabaceae has an essentially worldwide distribution, being found everywhere except Antarctica and the high arctic.

Taxonomy

The Fabaceae are placed in the order Fabales
Fabales
Fabales is an order of flowering plants. It is included in the rosid group of the eudicots in the Angiosperm Phylogeny Group II classification system...

 according to most taxonomic systems, including the APG III system
APG III system
The APG III system of flowering plant classification is the third version of a modern, mostly molecular-based, system of plant taxonomy...

. The family includes three subfamilies:
  • Mimosoideae
    Mimosoideae
    Mimosoideae is a subfamily of the flowering plant family Fabaceae characterized by flowers with small petals and numerous prominent stamens...

    : 80 genera and 3,200 species. Mostly tropical and warm temperate Asia and America. Mimosa
    Mimosa
    Mimosa is a genus of about 400 species of herbs and shrubs, in the subfamily Mimosoideae of the legume family Fabaceae. The generic name is derived from the Greek word μιμος , meaning "mimic."...

    , Acacia
    Acacia
    Acacia is a genus of shrubs and trees belonging to the subfamily Mimosoideae of the family Fabaceae, first described in Africa by the Swedish botanist Carl Linnaeus in 1773. Many non-Australian species tend to be thorny, whereas the majority of Australian acacias are not...

    .
  • Caesalpinioideae
    Caesalpinioideae
    Caesalpinioideae is a botanical name at the rank of subfamily, placed in the large family Fabaceae or Leguminosae. Its name is formed from the generic name Caesalpinia....

    : 170 genera and 2,000 species, cosmopolitan
    Cosmopolitan distribution
    In biogeography, a taxon is said to have a cosmopolitan distribution if its range extends across all or most of the world in appropriate habitats. For instance, the killer whale has a cosmopolitan distribution, extending over most of the world's oceans. Other examples include humans, the lichen...

    . Caesalpinia
    Caesalpinia
    Caesalpinia is a genus of flowering plants in the legume family, Fabaceae. Membership within the genus is controversial, with different publications including anywhere from 70 to 165 species, depending largely on the inclusion or exclusion of species alternately listed under genera such as...

    , Senna
    Senna (genus)
    Senna , the sennas, is a large genus of flowering plants in the family Fabaceae, subfamily Caesalpinioideae. This diverse genus is native throughout the tropics, with a small number of species reaching into temperate regions. The number of species is usually estimated to be about 260, but some...

    , Bauhinia
    Bauhinia
    Bauhinia is a genus of more than 200 species of flowering plants in the subfamily Caesalpinioideae of the large flowering plant family Fabaceae, with a pantropical distribution. The genus was named after the Bauhin brothers, Swiss-French botanists....

    , Amherstia.
  • Faboideae
    Faboideae
    Faboideae is a subfamily of the flowering plant family Fabaceae or Leguminosae. One acceptable alternative name for the subfamily is Papilionoideae....

    : 470 genera and 14,000 species, cosmopolitan. Astragalus
    Astragalus
    Astragalus is a large genus of about 3,000 species of herbs and small shrubs, belonging to the legume family Fabaceae, subfamily Faboideae. The genus is native to temperate regions of the Northern Hemisphere...

    , Lupinus.


These three subfamilies have been alternatively treated at the family level, as in the Cronquist
Cronquist system
The Cronquist system is a taxonomic classification system of flowering plants. It was developed by Arthur Cronquist in his texts An Integrated System of Classification of Flowering Plants and The Evolution and Classification of Flowering Plants .Cronquist's system places flowering plants into two...

 and Dahlgren
Dahlgren system
One of the modern systems of plant taxonomy, the Dahlgren system was published by monocot specialist Rolf Dahlgren. His wife Gertrud Dahlgren carried on after his death.According to the extensive listing by Professor Reveal One of the modern systems of plant taxonomy, the Dahlgren system was...

 systems. However, this choice has not been supported by late 20th and early 21st century evidence, which has shown the Caesalpinioideae to be paraphyletic
Paraphyly
A group of taxa is said to be paraphyletic if the group consists of all the descendants of a hypothetical closest common ancestor minus one or more monophyletic groups of descendants...

 and the Fabaceae sensu lato to be monophyletic
Monophyly
In common cladistic usage, a monophyletic group is a taxon which forms a clade, meaning that it contains all the descendants of the possibly hypothetical closest common ancestor of the members of the group. The term is synonymous with the uncommon term holophyly...

. While the Mimosoideae and the Faboideae are largely monophyletic, the Caesalpinioideae appear to be paraphyletic and the tribe Cercideae
Cercideae
Cercideae is a tribe in the pea family, Fabaceae. Well-known members include Cercis , including species widely cultivated as ornamental trees in the United States and Europe, Bauhinia, widely cultivated as an ornamental tree in tropical Asia, and Tylosema esculentum , a traditional food crop in...

 is probably sister to the rest of the family. Moreover, there are a number of genera whose placement into the Caesalpinioideae is not always agreed on (e.g. Dimorphandra
Dimorphandra
Dimorphandra is a genus of legume in the Fabaceae family.-Species:* Dimorphandra caudata Ducke 1925 * Dimorphandra conjugata Sandwith 1932 * Dimorphandra macrostachya Benth. * Dimorphandra mollis Benth....

).

Description

Fabaceae range in habit from giant tree
Tree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...

s (like Koompassia excelsa
Koompassia excelsa
Tualang, or Koompassia excelsa, is an emergent tropical rainforest tree species in the Fabaceae family. It is found in Indonesia, Malaysia, the Philippines, and Thailand. It is one of the tallest tropical tree species: the tallest measured specimen is 85.8 m or 88 m tall.Tualangs grow mostly in...

) to small annual
Annual plant
An annual plant is a plant that usually germinates, flowers, and dies in a year or season. True annuals will only live longer than a year if they are prevented from setting seed...

 herb
Herbaceous plant
A herbaceous plant is a plant that has leaves and stems that die down at the end of the growing season to the soil level. They have no persistent woody stem above ground...

s, with the majority being herbaceous perennials. Plants have indeterminate inflorescences, which are sometimes reduced to a single flower. The flowers have a short hypanthium
Hypanthium
A hypanthium is a floral structure consisting of the bases of the sepals, petals, and stamens fused together. Its presence is diagnostic of many families, including the Rosaceae, Grossulariaceae, and Fabaceae...

 and a single carpel with a short gynophore
Gynophore
A gynophore is the stalk of certain flowers which supports the gynoecium , elevating it above the branching points of other floral parts....

, and after fertilization produce fruits that are legumes.

Roots

Many Fabaceae host bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

 in their roots within structures called root nodule
Root nodule
Root nodules occur on the roots of plants that associate with symbiotic nitrogen-fixing bacteria. Under nitrogen-limiting conditions, capable plants form a symbiotic relationship with a host-specific strain of bacteria known as rhizobia...

s. These bacteria, known as rhizobia
Rhizobia
Rhizobia are soil bacteria that fix nitrogen after becoming established inside root nodules of legumes . Rhizobia require a plant host; they cannot independently fix nitrogen...

, have the ability to take nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...

 gas (N2) out of the air and convert it to a form of nitrogen that is usable to the host plant ( NO3-
Nitrate
The nitrate ion is a polyatomic ion with the molecular formula NO and a molecular mass of 62.0049 g/mol. It is the conjugate base of nitric acid, consisting of one central nitrogen atom surrounded by three identically-bonded oxygen atoms in a trigonal planar arrangement. The nitrate ion carries a...

 or NH3
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...

 ). This process is called nitrogen fixation
Nitrogen fixation
Nitrogen fixation is the natural process, either biological or abiotic, by which nitrogen in the atmosphere is converted into ammonia . This process is essential for life because fixed nitrogen is required to biosynthesize the basic building blocks of life, e.g., nucleotides for DNA and RNA and...

. The legume, acting as a host, and rhizobia
Rhizobia
Rhizobia are soil bacteria that fix nitrogen after becoming established inside root nodules of legumes . Rhizobia require a plant host; they cannot independently fix nitrogen...

, acting as a provider of usable nitrate, form a symbiotic
Symbiosis
Symbiosis is close and often long-term interaction between different biological species. In 1877 Bennett used the word symbiosis to describe the mutualistic relationship in lichens...

 relationship.

Leaves

The leaves are usually alternate
Phyllotaxis
In botany, phyllotaxis or phyllotaxy is the arrangement of leaves on a plant stem .- Pattern structure :...

 and compound. Most often they are even- or odd-pinnate
Pinnate
Pinnate is a term used to describe feather-like or multi-divided features arising from both sides of a common axis in plant or animal structures, and comes from the Latin word pinna meaning "feather", "wing", or "fin". A similar term is pectinate, which refers to a comb-like arrangement of parts...

ly compound (e.g. Caragana
Caragana
Caragana is a genus of about 80 species of flowering plants in the family Fabaceae, native to Asia and eastern Europe.They are shrubs or small trees growing 1-6 m tall...

and Robinia
Robinia
Robinia is a genus of flowering plants in the family Fabaceae, subfamily Faboideae, native to North America and northern Mexico. Commonly known as "locusts", they are deciduous trees and shrubs growing 4-25 m tall. The leaves are pinnate with 7-21 oval leaflets. The flowers are white or pink, in...

respectively), often trifoliate (e.g. Trifolium, Medicago
Medicago
Medicago is a genus of flowering plants, commonly known as medick or burclover. The name is based on Latin medica 'alfalfa, lucerne,' from 'Median .'...

) and rarely palmately compound (e.g. Lupinus), in the Mimosoideae and the Caesalpinioideae commonly bipinnate (e.g. Acacia
Acacia
Acacia is a genus of shrubs and trees belonging to the subfamily Mimosoideae of the family Fabaceae, first described in Africa by the Swedish botanist Carl Linnaeus in 1773. Many non-Australian species tend to be thorny, whereas the majority of Australian acacias are not...

, Mimosa
Mimosa
Mimosa is a genus of about 400 species of herbs and shrubs, in the subfamily Mimosoideae of the legume family Fabaceae. The generic name is derived from the Greek word μιμος , meaning "mimic."...

). They always have stipule
Stipule
In botany, stipule is a term coined by Linnaeus which refers to outgrowths borne on either side of the base of a leafstalk...

s, which can be leaf-like (e.g. Pisum
Pisum
Pisum is a genus of the family Fabaceae, native to southwest Asia and northeast Africa. It contains one to five species, depending on taxonomic interpretation; the International Legume Database accepts three species, one with two subspecies :...

), thorn-like (e.g. Robinia
Robinia
Robinia is a genus of flowering plants in the family Fabaceae, subfamily Faboideae, native to North America and northern Mexico. Commonly known as "locusts", they are deciduous trees and shrubs growing 4-25 m tall. The leaves are pinnate with 7-21 oval leaflets. The flowers are white or pink, in...

) or be rather inconspicuous. Leaf margins are entire or, occasionally, serrate. Both the leaves and the leaflets often have wrinkled pulvini
Pulvinus
A pulvinus is a joint-like thickening at the base of a plant leaf or leaflet that facilitates growth-independent movement. It consists of a core of vascular tissue within a flexible, bulky cylinder of thin-walled parenchyma cells...

 to permit nastic movements
Nastic movements
Nastic movements are non-directional responses to stimuli . The movement can be due to changes in turgor or changes in oma. Nastic movements differ banaan tropic movements in that the direction of tropic responses depends on the direction of the stimulus, whereas the direction of nastic movements...

. In some species, leaflets have evolved into tendril
Tendril
In botany, a tendril is a specialized stem, leaf or petiole with a threadlike shape that is used by climbing plants for support, attachment and cellular invasion by parasitic plants, generally by twining around suitable hosts. They do not have a lamina or blade, but they can photosynthesize...

s (e.g. Vicia
Vicia
Vicia is a genus of about 140 species of flowering plants commonly known as vetches. It is in the legume family . Member species are native to Europe, North America, South America, Asia and Africa. Some other genera of their subfamily Faboideae also have names containing "vetch", for example the...

).

Many species have leaves with structures that attract ant
Ant
Ants are social insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from wasp-like ancestors in the mid-Cretaceous period between 110 and 130 million years ago and diversified after the rise of flowering plants. More than...

s that protect the plant from herbivore insects (a form of mutualism). Extrafloral nectaries are common among the Mimosoideae and the Caesalpinioideae, and are also found in some Faboideae (e.g. Vicia sativa). In some Acacia
Acacia
Acacia is a genus of shrubs and trees belonging to the subfamily Mimosoideae of the family Fabaceae, first described in Africa by the Swedish botanist Carl Linnaeus in 1773. Many non-Australian species tend to be thorny, whereas the majority of Australian acacias are not...

, the modified hollow stipules are inhabited by ants.

Flowers

The flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...

s always have five generally fused sepal
Sepal
A sepal is a part of the flower of angiosperms . Collectively the sepals form the calyx, which is the outermost whorl of parts that form a flower. Usually green, sepals have the typical function of protecting the petals when the flower is in bud...

s and five free petal
Petal
Petals are modified leaves that surround the reproductive parts of flowers. They often are brightly colored or unusually shaped to attract pollinators. Together, all of the petals of a flower are called a corolla. Petals are usually accompanied by another set of special leaves called sepals lying...

s. They are generally hermaphrodite
Plant sexuality
Plant sexuality covers the wide variety of sexual reproduction systems found across the plant kingdom. This article describes morphological aspects of sexual reproduction of plants....

, and have a short hypanthium
Hypanthium
A hypanthium is a floral structure consisting of the bases of the sepals, petals, and stamens fused together. Its presence is diagnostic of many families, including the Rosaceae, Grossulariaceae, and Fabaceae...

, usually cup shaped. There are normally ten stamen
Stamen
The stamen is the pollen producing reproductive organ of a flower...

s and one elongated superior ovary
Ovary (plants)
In the flowering plants, an ovary is a part of the female reproductive organ of the flower or gynoecium. Specifically, it is the part of the pistil which holds the ovule and is located above or below or at the point of connection with the base of the petals and sepals...

, with a curved style. They are usually arranged in indeterminate inflorescence
Inflorescence
An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...

s. Fabaceae are typically entomophilous
Entomophily
Entomophily is a form of pollination whereby pollen is distributed by insects. Several insect are reported to be responsible for the pollination of many plant species, particularly bees, Lepidoptera , wasps, flies, ants and beetles. Some plant species co-evolved with a particular pollinator, such...

 plants (i.e. they are pollinated by insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...

s), and the flowers are usually showy to attract pollinator
Pollinator
A pollinator is the biotic agent that moves pollen from the male anthers of a flower to the female stigma of a flower to accomplish fertilization or syngamy of the female gamete in the ovule of the flower by the male gamete from the pollen grain...

s.

In the Caesalpinioideae
Caesalpinioideae
Caesalpinioideae is a botanical name at the rank of subfamily, placed in the large family Fabaceae or Leguminosae. Its name is formed from the generic name Caesalpinia....

, the flowers are often zygomorphic, as in Cercis
Cercis
Cercis , is a genus of about 10 species in the subfamily Caesalpinioideae of the pea family Fabaceae, native to warm-temperate regions. It contains small deciduous trees or large shrubs commonly known as Redbuds...

, or nearly symmetrical with five equal petals in Bauhinia
Bauhinia
Bauhinia is a genus of more than 200 species of flowering plants in the subfamily Caesalpinioideae of the large flowering plant family Fabaceae, with a pantropical distribution. The genus was named after the Bauhin brothers, Swiss-French botanists....

. The upper petal is the innermost one, unlike in the Faboideae
Faboideae
Faboideae is a subfamily of the flowering plant family Fabaceae or Leguminosae. One acceptable alternative name for the subfamily is Papilionoideae....

. Some species, like some in the genus Senna
Senna (genus)
Senna , the sennas, is a large genus of flowering plants in the family Fabaceae, subfamily Caesalpinioideae. This diverse genus is native throughout the tropics, with a small number of species reaching into temperate regions. The number of species is usually estimated to be about 260, but some...

, have asymmetric flowers, with one of the lower petals larger than the opposing one, and the style bent to one side. The calyx, corolla, or stamens can be showy in this group.

In the Mimosoideae
Mimosoideae
Mimosoideae is a subfamily of the flowering plant family Fabaceae characterized by flowers with small petals and numerous prominent stamens...

, the flowers are actinomorphic and arranged in globose inflorescences. The petals are small and the stamens, which can be more than just ten, have long coloured filaments, which are the most showy part of the flower. All of the flowers in an inflorescence open at once.

In the Faboideae
Faboideae
Faboideae is a subfamily of the flowering plant family Fabaceae or Leguminosae. One acceptable alternative name for the subfamily is Papilionoideae....

, the flowers are zygomorphic, and have a specialized structure. The upper petal, called the banner, is large and envelops the rest of the petals in bud, often reflexing when the flower blooms. The two adjacent petals, the wings, surround the two bottom petals. The two bottom petals are fused together at the apex (remaining free at the base), forming a boat-like structure called the keel. The stamens are always ten in number, and their filaments can be fused in various configurations, often in a group of nine stamens plus one separate stamen. Various genes in the CYCLOIDEA (CYC)/DICHOTOMA (DICH) family are expressed in the upper (also called dorsal or adaxial) petal; in some species, such as Cadia
Cadia (plant)
Cadia is a genus of flowering plants in the legume family, Fabaceae. It belongs to the subfamily Faboideae.Unlike most plants in the Faboideae, it has radially symmetrical flowers...

these genes are expressed throughout the flower, producing a radially symmetrical flower.

Fruit

The ovary most typically develops into a legume. A legume is a simple dry fruit that usually dehisces
Dehiscence (botany)
Dehiscence is the opening, at maturity, in a pre-defined way, of a plant structure, such as a fruit, anther, or sporangium, to release its contents. Sometimes this involves the complete detachment of a part. Structures that open in this way are said to be dehiscent...

 (opens along a seam) on two sides. A common name for this type of fruit is a "pod", although that can also be applied to a few other fruit types. A few species have evolved samarae
Samara (fruit)
A samara is a type of fruit in which a flattened wing of fibrous, papery tissue develops from the ovary wall. A samara is a simple dry fruit and indehiscent . It is a winged achene...

, loment
Loment
A loment is a type of modified legume that breaks apart at constrictions occurring between the segments of the seeds. Being a legume, it is dry at maturity and is dehiscent, meaning that it will split open at maturity....

s, follicles
Follicle (fruit)
In botany, a follicle is a dry unilocular many-seeded fruit formed from one carpel and dehiscing by the ventral suture in order to release seeds, such as in larkspur, magnolia, banksia, peony and milkweed....

, indehiscent legumes, achene
Achene
An achene is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate and indehiscent...

s, drupe
Drupe
In botany, a drupe is a fruit in which an outer fleshy part surrounds a shell of hardened endocarp with a seed inside. These fruits develop from a single carpel, and mostly from flowers with superior ovaries...

s, and berries from the basic legume fruit.

Evolution

It has been suggested, based on fossil and phylogenetic evidence, that legumes originally evolved in arid and/or semi-arid regions along the Tethys seaway
Tethys Ocean
The Tethys Ocean was an ocean that existed between the continents of Gondwana and Laurasia during the Mesozoic era before the opening of the Indian Ocean.-Modern theory:...

 during the early Tertiary
Tertiary
The Tertiary is a deprecated term for a geologic period 65 million to 2.6 million years ago. The Tertiary covered the time span between the superseded Secondary period and the Quaternary...

. However, others contend that Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...

 (or even the Americas
Americas
The Americas, or America , are lands in the Western hemisphere, also known as the New World. In English, the plural form the Americas is often used to refer to the landmasses of North America and South America with their associated islands and regions, while the singular form America is primarily...

) cannot yet be ruled out as the origin of the family.

One of the key features of Fabaceae is that some members are able to nodulate. The current hypothesis about the evolution of the genes needed for nodulation is that they were recruited from other pathways after a polyploidy event. Several different pathways have been implicated as donating duplicated genes to the pathways need for nodulation. The main donors to the pathway were the genes associated with the arbuscular mycorrhiza symbiosis genes, the pollen tube formation genes and the haemoglobin genes. One of the main genes shown to be shared between the arbuscular mycorrhiza pathway and the nodulation pathway is SYMRK and it is involved in the plant-bacterial recognition. The pollen tube growth is similar to the infection thread development in that infection threads grow in a polar manner that is similar to a pollen tubes polar growth towards the ovules. Both pathways include the same type of enzymes, pectin-degrading cell wall enzymes. The enzymes needed to reduce nitrogen, nitrogenases, are require a substantial input of ATP but at the same time are sensitive to free oxygen. To meet the requirements of this paradoxical situation, the plants express a type of haemoglobin called leghaemoglobin that is believed to be recruited after a duplication event. These three genetic pathways are believed to be part of a gene duplication event then recruited to work in nodulation.

The family has also evolved a unique chemistry. Pterocarpan
Pterocarpan
Pterocarpans are derivatives of isoflavonoids found in the Fabaceae family. It is a group of compounds which can be described as benzo-pyrano-furano-benzenes Pterocarpans are derivatives of isoflavonoids found in the Fabaceae family. It is a group of compounds which can be described as...

s are a class of molecules (derivatives of isoflavonoid
Isoflavonoid
Isoflavonoids are a class of flavonoid polyphenolic compounds. They are biologically active compounds, such as phytoestrogens, produced by pea family plants.Isoflavonoids are derived from the flavonoid biosynthesis pathway via liquiritigenin or naringenin....

s) found only in the Fabaceae.

Uses

The history of legumes is tied in closely with that of human civilization, appearing early in Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

, the Americas
Americas
The Americas, or America , are lands in the Western hemisphere, also known as the New World. In English, the plural form the Americas is often used to refer to the landmasses of North America and South America with their associated islands and regions, while the singular form America is primarily...

 (the common bean
Common bean
Phaseolus vulgaris, the common bean, is an herbaceous annual plant domesticated independently in ancient Mesoamerica and the Andes, and now grown worldwide for its edible bean, popular both dry and as a green bean. The leaf is occasionally used as a leaf vegetable, and the straw is used for fodder...

, several varieties) and Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

 (broad beans) by 6,000 BC
Anno Domini
and Before Christ are designations used to label or number years used with the Julian and Gregorian calendars....

, where they became a staple, essential for supplementing protein where there was not enough meat.

Their ability to fix atmospheric nitrogen
Nitrogen fixation
Nitrogen fixation is the natural process, either biological or abiotic, by which nitrogen in the atmosphere is converted into ammonia . This process is essential for life because fixed nitrogen is required to biosynthesize the basic building blocks of life, e.g., nucleotides for DNA and RNA and...

 reduces fertilizer
Fertilizer
Fertilizer is any organic or inorganic material of natural or synthetic origin that is added to a soil to supply one or more plant nutrients essential to the growth of plants. A recent assessment found that about 40 to 60% of crop yields are attributable to commercial fertilizer use...

 costs for farmers and gardeners who grow legumes, and means that legumes can be used in a crop rotation
Crop rotation
Crop rotation is the practice of growing a series of dissimilar types of crops in the same area in sequential seasons.Crop rotation confers various benefits to the soil. A traditional element of crop rotation is the replenishment of nitrogen through the use of green manure in sequence with cereals...

 to replenish soil that has been depleted of nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...

. Legume seeds and foliage have a comparatively higher protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

 content than non-legume materials, due to the additional nitrogen that legumes receive through the process. Some legume species perform hydraulic lift
Hydraulic redistribution
Hydraulic redistribution refers to the mechanism by which some vascular plants redistribute soil water. It occurs in vascular plants that commonly have roots in both wet soil and extremely dry soil, especially plants with both taproots that grow vertically down to the water table, and lateral roots...

, which makes them ideal for intercropping
Intercropping
Intercropping is the practice of growing two or more crops in proximity. The most common goal of intercropping is to produce a greater yield on a given piece of land by making use of resources that would otherwise not be utilized by a single crop. Careful planning is required, taking into account...

.

Farmed legumes can belong to numerous classes, including forage
Fodder
Fodder or animal feed is any agricultural foodstuff used specifically to feed domesticated livestock such as cattle, goats, sheep, horses, chickens and pigs. Most animal feed is from plants but some is of animal origin...

, grain
Cereal
Cereals are grasses cultivated for the edible components of their grain , composed of the endosperm, germ, and bran...

, blooms, pharmaceutical/industrial, fallow/green manure and timber species, with most commercially farmed species filling two or more roles simultaneously.

There are of two broad types of forage legumes. Some, like alfalfa
Alfalfa
Alfalfa is a flowering plant in the pea family Fabaceae cultivated as an important forage crop in the US, Canada, Argentina, France, Australia, the Middle East, South Africa, and many other countries. It is known as lucerne in the UK, France, Australia, South Africa and New Zealand, and known as...

, clover
Clover
Clover , or trefoil, is a genus of about 300 species of plants in the leguminous pea family Fabaceae. The genus has a cosmopolitan distribution; the highest diversity is found in the temperate Northern Hemisphere, but many species also occur in South America and Africa, including at high altitudes...

, vetch, and Arachis
Arachis
Arachis is a genus of about 70 species of annual and perennial flowering plants in the pea family , native to South America. At least one species, the peanut , is a major food crop species of global importance; some of the other species are cultivated for food to a small extent in South America....

, are sown in pasture
Pasture
Pasture is land used for grazing. Pasture lands in the narrow sense are enclosed tracts of farmland, grazed by domesticated livestock, such as horses, cattle, sheep or swine. The vegetation of tended pasture, forage, consists mainly of grasses, with an interspersion of legumes and other forbs...

 and grazed by livestock. Other forage legumes such as Leucaena
Leucaena
Leucaena is a genus of flowering plants in the subfamily Mimosoideae of the legume family Fabaceae. It contains about 24 species of trees and shrubs, which are commonly known as Leadtrees. They are native to the Americas, ranging from Texas in the United States south to Peru...

or Albizia
Albizia
Albizia is a genus of about 150 species of mostly fast-growing subtropical and tropical trees and shrubs in the subfamily Mimosoideae of the legume family, Fabaceae. The genus is pantropical, occurring in Asia, Africa, Madagascar, Central, South, and southern North America and Australia, but mostly...

are woody shrub or tree species that are either broken down by livestock or regularly cut by humans to provide stock feed.

Grain legumes are cultivated for their seed
Seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...

s, and are also called pulse
Pulse (legume)
A pulse is an annual leguminous crop yielding from one to twelve seeds of variable size, shape, and color within a pod. Pulses are used for food and animal feed. The term "pulse", as used by the Food and Agricultural Organization , is reserved for crops harvested solely for the dry seed...

s. The seeds are used for human and animal consumption or for the production of oil
Vegetable fats and oils
Vegetable fats and oils are lipid materials derived from plants. Physically, oils are liquid at room temperature, and fats are solid. Chemically, both fats and oils are composed of triglycerides, as contrasted with waxes which lack glycerin in their structure...

s for industrial uses. Grain legumes include both herbaceous plants like bean
Bean
Bean is a common name for large plant seeds of several genera of the family Fabaceae used for human food or animal feed....

s, lentil
Lentil
The lentil is an edible pulse. It is a bushy annual plant of the legume family, grown for its lens-shaped seeds...

s, lupin
Lupin
Lupinus, commonly known as Lupins or lupines , is a genus in the legume family . The genus comprises about 280 species , with major centers of diversity in South and western North America , and the Andes and secondary centers in the Mediterranean region and Africa Lupinus, commonly known as Lupins...

s, pea
Pea
A pea is most commonly the small spherical seed or the seed-pod of the pod fruit Pisum sativum. Each pod contains several peas. Peapods are botanically a fruit, since they contain seeds developed from the ovary of a flower. However, peas are considered to be a vegetable in cooking...

s and peanut
Peanut
The peanut, or groundnut , is a species in the legume or "bean" family , so it is not a nut. The peanut was probably first cultivated in the valleys of Peru. It is an annual herbaceous plant growing tall...

s. and trees such as carob, mesquite
Mesquite
Mesquite is a leguminous plant of the Prosopis genus found in northern Mexico through the Sonoran Desert and Chihuahuan Deserts, and up into the Southwestern United States as far north as southern Kansas, west to the Colorado Desert in California,and east to the eastern fifth of Texas, where...

 and tamarind
Tamarind
Tamarind is a tree in the family Fabaceae. The genus Tamarindus is monotypic .-Origin:...

.

Bloom legume species include species such as lupin
Lupin
Lupinus, commonly known as Lupins or lupines , is a genus in the legume family . The genus comprises about 280 species , with major centers of diversity in South and western North America , and the Andes and secondary centers in the Mediterranean region and Africa Lupinus, commonly known as Lupins...

, which are farmed commercially for their blooms as well as being popular in gardens worldwide. Laburnum
Laburnum
Laburnum is a genus of two species of small trees in the subfamily Faboideae of the pea family Fabaceae, Laburnum anagyroides and L. alpinum . They are native to the mountains of southern Europe from France to the Balkan Peninsula...

, Robinia
Robinia
Robinia is a genus of flowering plants in the family Fabaceae, subfamily Faboideae, native to North America and northern Mexico. Commonly known as "locusts", they are deciduous trees and shrubs growing 4-25 m tall. The leaves are pinnate with 7-21 oval leaflets. The flowers are white or pink, in...

, Gleditsia
Gleditsia
Gleditsia is a genus of locust trees in the family Fabaceae, subfamily Caesalpinioideae, native to North America and Asia. The Latin name commemorates Johann Gottlieb Gleditsch, director of the Berlin Botanical Gardens, who died in 1786....

, Acacia
Acacia
Acacia is a genus of shrubs and trees belonging to the subfamily Mimosoideae of the family Fabaceae, first described in Africa by the Swedish botanist Carl Linnaeus in 1773. Many non-Australian species tend to be thorny, whereas the majority of Australian acacias are not...

, Mimosa
Mimosa
Mimosa is a genus of about 400 species of herbs and shrubs, in the subfamily Mimosoideae of the legume family Fabaceae. The generic name is derived from the Greek word μιμος , meaning "mimic."...

, and Delonix
Delonix
Delonix is a genus of flowering plants in the pea family, Fabaceae, subfamily Caesalpinioideae. It contains trees that are native to Madagascar and east Africa. By far the best known species is the Royal Poinciana ....

are ornamental
Ornamental plant
Ornamental plants are plants that are grown for decorative purposes in gardens and landscape design projects, as house plants, for cut flowers and specimen display...

 tree
Tree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...

s and shrub
Shrub
A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...

s.

Industrial farmed legumes include Indigofera
Indigofera
Indigofera is a large genus of about 700 species of flowering plants belonging to the family Fabaceae.The species are mostly shrubs, though some are herbaceous, and a few can become small trees up to tall. Most are dry-season or winter deciduous. The leaves are pinnate with 5–31 leaflets and the...

, cultivated for the production of indigo
Indigo
Indigo is a color named after the purple dye derived from the plant Indigofera tinctoria and related species. The color is placed on the electromagnetic spectrum between about 420 and 450 nm in wavelength, placing it between blue and violet...

, Acacia
Acacia
Acacia is a genus of shrubs and trees belonging to the subfamily Mimosoideae of the family Fabaceae, first described in Africa by the Swedish botanist Carl Linnaeus in 1773. Many non-Australian species tend to be thorny, whereas the majority of Australian acacias are not...

, for gum arabic
Gum arabic
220px|thumb|right|Acacia gumGum arabic, also known as acacia gum, chaar gund, char goond, or meska, is a natural gum made of hardened sap taken from two species of the acacia tree; Acacia senegal and Acacia seyal...

, and Derris
Derris
Derris is a climbing leguminous plant of Southeast Asia and the southwest Pacific islands, including New Guinea. Its roots contain rotenone, a strong insecticide and fish poison....

, for the insecticide action of rotenone
Rotenone
Rotenone is an odorless chemical that is used as a broad-spectrum insecticide, piscicide, and pesticide. It occurs naturally in the roots and stems of several plants such as the jicama vine plant...

, a compound it produces.

Fallow or green manure
Green manure
In agriculture, a green manure is a type of cover crop grown primarily to add nutrients and organic matter to the soil. Typically, a green manure crop is grown for a specific period of time , and then plowed under and incorporated into the soil while green or shortly after flowering...

legume species are cultivated to be tilled back into the soil to exploit the high nitrogen levels found in most legumes. Numerous legumes are farmed for this purpose, including Leucaena
Leucaena
Leucaena is a genus of flowering plants in the subfamily Mimosoideae of the legume family Fabaceae. It contains about 24 species of trees and shrubs, which are commonly known as Leadtrees. They are native to the Americas, ranging from Texas in the United States south to Peru...

, Cyamopsis
Cyamopsis
Cyamopsis is a genus of the family Fabaceae. Its species are distributed across Africa, Asia and the Pacific....

and Sesbania
Sesbania
Sesbania is a genus of flowering plants in the pea family, Fabaceae and the only genus found in Tribe Sesbanieae. Notable species include the Rattlebox , Spiny Sesbania , and Sesbania sesban, which is used in cooking...

.

Various legume species are farmed for timber production worldwide, including numerous Acacia
Acacia
Acacia is a genus of shrubs and trees belonging to the subfamily Mimosoideae of the family Fabaceae, first described in Africa by the Swedish botanist Carl Linnaeus in 1773. Many non-Australian species tend to be thorny, whereas the majority of Australian acacias are not...

species, Dalbergia
Dalbergia
Dalbergia is a large genus of small to medium-size trees, shrubs and lianas in the pea family, Fabaceae, subfamily Faboideae. The genus has a wide distribution, native to the tropical regions of Central and South America, Africa, Madagascar and southern Asia...

species, and Castanospermum australe.

Genera

The genera included in this family can be viewed on the following three pages:
  • List of Mimosoideae genera
    Mimosoideae
    Mimosoideae is a subfamily of the flowering plant family Fabaceae characterized by flowers with small petals and numerous prominent stamens...

  • List of Caesalpinioideae genera
    Caesalpinioideae
    Caesalpinioideae is a botanical name at the rank of subfamily, placed in the large family Fabaceae or Leguminosae. Its name is formed from the generic name Caesalpinia....

  • List of Faboideae genera
    Faboideae
    Faboideae is a subfamily of the flowering plant family Fabaceae or Leguminosae. One acceptable alternative name for the subfamily is Papilionoideae....


External Links

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