''Stylosanthes'' is a genus of

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. They include all forbs (flowering plants without a woody stem), grasses and grass-like plants, a vast majority of ...

s in the

legume A legume () is a plant in the family Fabaceae (or Leguminosae), or the fruit or seed of such a plant. When used as a dry grain, the seed is also called a pulse. Legumes are grown agriculturally, primarily for human consumption, for livestock fo ...

family, Fabaceae and contains numerous highly important

pasture Pasture (from the Latin ''pastus'', past participle of ''pascere'', "to feed") 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 s ...

and

forage Forage is a plant material (mainly plant leaves and stems) eaten by grazing livestock. Historically, the term ''forage'' has meant only plants eaten by the animals directly as pasture, crop residue, or immature cereal crops, but it is also us ...

species. It was recently assigned to the informal

monophyletic In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic ...

''Pterocarpus'' clade of the

Dalbergieae The tribe Dalbergieae is an early-branching clade within the flowering plant subfamily Faboideae (or Papilionaceae). Within that subfamily, it belongs to an unranked clade called the dalbergioids. It was recently revised to include many gener ...

. The common name pencilflower is sometimes used for plants in this genus.

Description

The genus is characterised by trifoliate leaves and small yellow flowers Species may be

annual Annual may refer to: * Annual publication, periodical publications appearing regularly once per year **Yearbook **Literary annual * Annual plant *Annual report *Annual giving *Annual, Morocco, a settlement in northeastern Morocco *Annuals (band), ...

perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wide ...

and morphology varies between species as well as within species in response to grazing pressure. Some species such as '' S. scabra'' grow as a low woody shrub to 1.5 m, while others such as '' S. humilis'' will grow as a herbaceous shrub but can adopt a prostrate growth form and thrive under high grazing pressure.

Taxonomy and range

Taxonomy of the genus remains unsettled and controversial, with various authors favouring between 25 and 42 species, with at least 40 additional synonyms. The taxonomy is complicated by the existence of numerous natural

tetraploid Polyploidy is a condition in which the cells of an organism have more than one pair of (homologous) chromosomes. Most species whose cells have nuclei (eukaryotes) are diploid, meaning they have two sets of chromosomes, where each set contains ...

and

hybrid Hybrid may refer to: Science * Hybrid (biology), an offspring resulting from cross-breeding ** Hybrid grape, grape varieties produced by cross-breeding two ''Vitis'' species ** Hybridity, the property of a hybrid plant which is a union of two diff ...

populations. Species within the genus fall within two subgenera: ''Styposanthes'' and ''Stylosanthes''. ''Styposanthes'' possess a small rudimentary secondary

floral axis The floral axis (sometimes referred to as the receptacle) is the area of the flower upon which the reproductive organs and other ancillary organs are attached. It is also the point at the center of a floral diagram. Many flowers in division Angiosp ...

, which is absent from ''Stylosanthes''. ''Stylosanthes'' is closely related to the peanut genus ''

Arachis ''Arachis'' is a genus of about 70 species of annual and perennial flowering plants in the family ( Fabaceae), native to South America, and was recently assigned to the informal monophyletic ''Pterocarpus'' clade of the Dalbergieae. At least on ...

''. All except two species of the genus are native to the Americas. '' S. fruticosa'' has a native range that extends from

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring count ...

Ethiopia Ethiopia, , om, Itiyoophiyaa, so, Itoobiya, ti, ኢትዮጵያ, Ítiyop'iya, aa, Itiyoppiya officially the Federal Democratic Republic of Ethiopia, is a landlocked country in the Horn of Africa. It shares borders with Eritrea to the Er ...

, across Arabian Peninsula to

Pakistan Pakistan ( ur, ), officially the Islamic Republic of Pakistan ( ur, , label=none), is a country in South Asia. It is the world's List of countries and dependencies by population, fifth-most populous country, with a population of almost 24 ...

India India, officially the Republic of India ( Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the ...

and

Sri Lanka Sri Lanka (, ; si, ශ්‍රී ලංකා, Śrī Laṅkā, translit-std=ISO (); ta, இலங்கை, Ilaṅkai, translit-std=ISO ()), formerly known as Ceylon and officially the Democratic Socialist Republic of Sri Lanka, is an ...

and '' S. erecta'' is endemic to Tropical Africa, from

Tanzania Tanzania (; ), officially the United Republic of Tanzania ( sw, Jamhuri ya Muungano wa Tanzania), is a country in East Africa within the African Great Lakes region. It borders Uganda to the north; Kenya to the northeast; Comoro Islands ...

Senegal Senegal,; Wolof: ''Senegaal''; Pulaar: 𞤅𞤫𞤲𞤫𞤺𞤢𞥄𞤤𞤭 (Senegaali); Arabic: السنغال ''As-Sinighal'') officially the Republic of Senegal,; Wolof: ''Réewum Senegaal''; Pulaar : 𞤈𞤫𞤲𞤣𞤢𞥄𞤲𞤣� ...

. The putative species '' S. sundaica'', has a range that encompasses

Malesia Malesia is a biogeographical region straddling the Equator and the boundaries of the Indomalayan and Australasian realms, and also a phytogeographical floristic region in the Paleotropical Kingdom. It has been given different definitions. ...

but is considered by most authors to be an adventive polypoliod variety of ''S. humilis''. Ecological range extends from savanna and thorn scrub to tropical forest and montane forests.

Species

The following species are accepted: *''

Stylosanthes angustifolia ''Stylosanthes'' is a genus of flowering plants in the legume family, Fabaceae and contains numerous highly important pasture and forage species. It was recently assigned to the informal monophyly, monophyletic ''Pterocarpus'' clade of the Dalber ...

'' Vogel *'' Stylosanthes biflora'' (L.) Britton, Sterns & Poggenb. *''

Stylosanthes bracteata ''Stylosanthes'' is a genus of flowering plants in the legume family, Fabaceae and contains numerous highly important pasture and forage species. It was recently assigned to the informal monophyletic ''Pterocarpus'' clade of the Dalbergieae. ...

'' Vogel *''

Stylosanthes calcicola ''Stylosanthes'' is a genus of flowering plants in the legume family, Fabaceae and contains numerous highly important pasture and forage species. It was recently assigned to the informal monophyly, monophyletic ''Pterocarpus'' clade of the Dalber ...

'' Small *'' Stylosanthes campestris'' M.B.Ferreira & Sousa Costa *''

Stylosanthes capitata ''Stylosanthes'' is a genus of flowering plants in the legume family, Fabaceae and contains numerous highly important pasture and forage species. It was recently assigned to the informal monophyletic ''Pterocarpus'' clade of the Dalbergieae. ...

'' Vogel *''

Stylosanthes erecta ''Stylosanthes'' is a genus of flowering plants in the legume family, Fabaceae and contains numerous highly important pasture and forage species. It was recently assigned to the informal monophyletic ''Pterocarpus'' clade of the Dalbergieae. T ...

'' P.Beauv. *''

Stylosanthes falconensis ''Stylosanthes'' is a genus of flowering plants in the legume family, Fabaceae and contains numerous highly important pasture and forage species. It was recently assigned to the informal monophyletic ''Pterocarpus'' clade of the Dalbergieae. T ...

'' Calles & Schultze-Kr. *'' Stylosanthes fruticosa'' (Retz.) Alston *''

Stylosanthes guianensis ''Stylosanthes guianensis'', the stylo, is a species of flowering plant in the family Fabaceae. It is native to the New World Tropics and Subtropics, and has been introduced to Puerto Rico, the Windward Islands, Trinidad and Tobago, most of SubSa ...

'' (Aubl.) Sw. *''

Stylosanthes hamata ''Stylosanthes hamata'', the Caribbean stylo, is a species of flowering plant in the family Fabaceae. It is native to the islands of the Caribbean, and nearby areas on the mainland; Mexico, Guatemala, Costa Rica, Colombia, and Venezuela, and it ...

'' (L.) Taub. *'' Stylosanthes hippocampoides'' Mohlenbr. *'' Stylosanthes hispida'' Rich. *''

Stylosanthes humilis ''Stylosanthes humilis'', the Townsville stylo, is a species of flowering plant in the family Fabaceae, native to the New World Tropics, and widely introduced as a forage to the tropics of Africa, India, Southeast Asia, Malesia, and Australia. A ...

'' Kunth *''

Stylosanthes ingrata ''Stylosanthes'' is a genus of flowering plants in the legume family, Fabaceae and contains numerous highly important pasture and forage species. It was recently assigned to the informal monophyletic ''Pterocarpus'' clade of the Dalbergieae. ...

'' S.F.Blake *'' Stylosanthes leiocarpa'' Vogel *''

Stylosanthes linearifolia ''Stylosanthes'' is a genus of flowering plants in the legume family, Fabaceae and contains numerous highly important pasture and forage species. It was recently assigned to the informal monophyletic In cladistics for a group of organism ...

'' M.B.Ferreira & Sousa Costa *'' Stylosanthes longicarpa'' Brandão & Sousa Costa *''

Stylosanthes longiseta ''Stylosanthes'' is a genus of flowering plants in the legume family, Fabaceae and contains numerous highly important pasture and forage species. It was recently assigned to the informal monophyletic ''Pterocarpus'' clade of the Dalbergieae. T ...

'' Micheli *''

Stylosanthes macrocarpa ''Stylosanthes'' is a genus of flowering plants in the legume family, Fabaceae and contains numerous highly important pasture and forage species. It was recently assigned to the informal monophyletic ''Pterocarpus'' clade of the Dalbergieae. ...

'' S.F.Blake *''

Stylosanthes macrocephala ''Stylosanthes'' is a genus of flowering plants in the legume family, Fabaceae and contains numerous highly important pasture and forage species. It was recently assigned to the informal monophyletic ''Pterocarpus'' clade of the Dalbergieae. ...

'' M.B.Ferreira & Sousa Costa *'' Stylosanthes macrosoma'' S.F.Blake *''

Stylosanthes maracajuensis ''Stylosanthes'' is a genus of flowering plants in the legume family, Fabaceae and contains numerous highly important pasture and forage species. It was recently assigned to the informal monophyletic ''Pterocarpus'' clade of the Dalbergieae. T ...

'' Sousa Costa & Van den Berg *''

Stylosanthes mexicana ''Stylosanthes'' is a genus of flowering plants in the legume family, Fabaceae and contains numerous highly important pasture and forage species. It was recently assigned to the informal monophyletic ''Pterocarpus'' clade of the Dalbergieae. ...

'' Taub. *'' Stylosanthes montevidensis'' Vogel *''

Stylosanthes nervosa ''Stylosanthes'' is a genus of flowering plants in the legume family, Fabaceae and contains numerous highly important pasture and forage species. It was recently assigned to the informal monophyletic ''Pterocarpus'' clade of the Dalbergieae. ...

'' J.F.Macbr. *''

Stylosanthes quintanarooensis ''Stylosanthes'' is a genus of flowering plants in the legume family, Fabaceae and contains numerous highly important pasture and forage species. It was recently assigned to the informal monophyletic ''Pterocarpus'' clade of the Dalbergieae. ...

'' Gama & Dávila *''

Stylosanthes recta ''Stylosanthes'' is a genus of flowering plants in the legume family, Fabaceae and contains numerous highly important pasture and forage species. It was recently assigned to the informal monophyletic ''Pterocarpus'' clade of the Dalbergieae. T ...

'' Vanni *''

Stylosanthes rostrata ''Stylosanthes'' is a genus of flowering plants in the legume family, Fabaceae and contains numerous highly important pasture and forage species. It was recently assigned to the informal monophyly, monophyletic ''Pterocarpus'' clade of the Dalber ...

'' (Burkart) Vanni *''

Stylosanthes ruellioides ''Stylosanthes'' is a genus of flowering plants in the legume family, Fabaceae and contains numerous highly important pasture and forage species. It was recently assigned to the informal monophyly, monophyletic ''Pterocarpus'' clade of the Dalber ...

'' Mart. ex Benth. *''

Stylosanthes salina ''Stylosanthes'' is a genus of flowering plants in the legume family, Fabaceae and contains numerous highly important pasture and forage species. It was recently assigned to the informal monophyletic ''Pterocarpus'' clade of the Dalbergieae. T ...

'' Sousa Costa & Van den Berg *'' Stylosanthes scabra'' Vogel *'' Stylosanthes seabrana'' B.L.Maass & 't Mannetje *''

Stylosanthes sericeiceps ''Stylosanthes'' is a genus of flowering plants in the legume family, Fabaceae and contains numerous highly important pasture and forage species. It was recently assigned to the informal monophyletic ''Pterocarpus'' clade of the Dalbergieae. ...

'' S.F.Blake *'' Stylosanthes suffruticosa'' Mohlenbr. *''

Stylosanthes sympodialis ''Stylosanthes'' is a genus of flowering plants in the legume family, Fabaceae and contains numerous highly important pasture and forage species. It was recently assigned to the informal monophyletic ''Pterocarpus'' clade of the Dalbergieae. T ...

'' Taub. *''

Stylosanthes tuberculata ''Stylosanthes'' is a genus of flowering plants in the legume family, Fabaceae and contains numerous highly important pasture and forage species. It was recently assigned to the informal monophyletic ''Pterocarpus'' clade of the Dalbergieae. ...

'' S.F.Blake *''

Stylosanthes vallsii ''Stylosanthes'' is a genus of flowering plants in the legume family, Fabaceae and contains numerous highly important pasture and forage species. It was recently assigned to the informal monophyletic ''Pterocarpus'' clade of the Dalbergieae. ...

'' Sousa Costa & Van den Berg *'' Stylosanthes venezuelensis'' Calles & Schultze-Kr. *''

Stylosanthes viscosa ''Stylosanthes'' is a genus of flowering plants in the legume family, Fabaceae and contains numerous highly important pasture and forage species. It was recently assigned to the informal monophyletic ''Pterocarpus'' clade of the Dalbergieae. ...

'' (L.) Sw.

Usage

Species within the genus have many properties that make them valuable forage species. They are capable of

nitrogen fixation Nitrogen fixation is a chemical process by which molecular nitrogen (), with a strong triple covalent bond, in the air is converted into ammonia () or related nitrogenous compounds, typically in soil or aquatic systems but also in industry. At ...

and are capable of improving soil fertility in addition to providing high protein stock feed. The genus is also noted for its ability to extract phosphorus from soils where it is not available to other species. Seeds are hard and long lived leading to high soil seed banks and rapid recovery following fire or heavy grazing. Seed survives passage through the gut of grazing animals and is dispersed widely in this manner allowing for rapid dispersal. Many species are adapted to hot, dry climates and are drought resistant. These traits have made the genus the world’s most widely used tropical pasture legume. ''Stylosanthes'' has been introduced across the tropical world as a pasture species. Its most important use has been in Australia where over a million hectares of primarily native pasture have been oversown with ''Stylosanthes'' species; primarily '' S. hamata'', ''S. scabra'' and ''S. humilis'' This can lead to a ten-fold increase in productivity, though 2–3 fold increases are normal. ''Stylosanthes'' are the most important forage legumes in

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the souther ...

and the most important pasture legumes of tropical

. ''Stylosanthes'' are also important forage species in tropical Africa. ''Stylosanthes'' are important green manure species in

West West or Occident is one of the four cardinal directions or points of the compass. It is the opposite direction from east and is the direction in which the Sun sets on the Earth. Etymology The word "west" is a Germanic word passed into some ...

and

Central Africa Central Africa is a subregion of the African continent comprising various countries according to different definitions. Angola, Burundi, the Central African Republic, Chad, the Democratic Republic of the Congo, the Republic of the Congo, E ...

, primarily '' S. guianensis'' and ''S. hamata'', and species are planted and harvested for commercial leaf meal production for poultry and pig feed in China and

. The genus has also been used as a nitrogen input into low input or organic cropping systems. Species are used as fallow species in

Peru , image_flag = Flag of Peru.svg , image_coat = Escudo nacional del Perú.svg , other_symbol = Great Seal of the State , other_symbol_type = Seal (emblem), National seal , national_motto = "Fi ...

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

and Australia. S. hamata used for intercropping with grain crops in India and Africa with yield increases up to 25%. ''Stylosanthes'' species have been used for land reclamation, soil stabilization and

soil regeneration Soil regeneration, as a particular form of ecological regeneration within the field of restoration ecology, is creating new soil and rejuvenating soil health by: minimizing the loss of topsoil, retaining more carbon than is depleted, boosting biodi ...

work because of their drought resistance, ability to restore soil fertility, improve soil physical properties and provide permanent vegetation cover. Despite their ability to dramatically improve productivity in grazing lands, ''Stylosanthes'' can also cause problems. ''Stylosanthes'' can dominate pasture at the expense of grass which can lead to problems because the plants provides less protection from

erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is di ...

than grass. ''Stylosanthes'' dominance can also lead to

soil acidification Soil acidification is the buildup of hydrogen cations, which reduces the soil pH. Chemically, this happens when a proton donor gets added to the soil. The donor can be an acid, such as nitric acid, sulfuric acid, or carbonic acid. It can also b ...

, as soil nitrate levels build up and are then leached down the soil profile. ''Stylosanthes'' species are considered invasive species and environmental weeds in Australia,

Taiwan Taiwan, officially the Republic of China (ROC), is a country in East Asia, at the junction of the East and South China Seas in the northwestern Pacific Ocean, with the People's Republic of China (PRC) to the northwest, Japan to the northe ...

, the

Pacific Islands Collectively called the Pacific Islands, the islands in the Pacific Ocean are further categorized into three major island groups: Melanesia, Micronesia, and Polynesia. Depending on the context, the term ''Pacific Islands'' may refer to one of ...

and

Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only ...

. Many ''Stylosanthes'' species are susceptible to

anthracnose A plant canker is a small area of dead tissue, which grows slowly, often over years. Some cankers are of only minor consequence, but others are ultimately lethal and therefore can have major economic implications for agriculture and horticultur ...

fungus (''

Colletotrichum gloeosporioides ''Glomerella cingulata'' is a fungal plant pathogen, being the name of the sexual stage ( teleomorph) while the more commonly referred to asexual stage (anamorph) is called ''Colletotrichum gloeosporioides''. For most of this article the pathoge ...

'') which retards growth and seed development, and this had led to numerous commercial cultivars being abandoned.

Notes

:Some sources treat ''Stylosanthes acuminata'', ''Stylosanthes aurea'', ''Stylosanthes campestris'', ''Stylosanthes gracilis'', ''Stylosanthes grandifolia'', and/or ''Stylosanthes hippocampoides'' as synonyms of ''Stylosanthes guianensis''. :Some sources treat ''Stylosanthes bahiensis'' as a synonym of ''Stylosanthes pilosa''. :Some sources treat ''Stylosanthes cayennensis'' as a synonym of ''Stylosanthes hispida''. :Some sources treat ''Stylosanthes figueroae'' and/or ''Stylosanthes sundaica'' as synonyms of ''Stylosanthes humilis''. :Some sources treat ''Stylosanthes guineensis'' as a synonym of ''Stylosanthes erecta''. :Some sources treat ''Stylosanthes macrosoma'' as a synonym of ''Stylosanthes montevidensis''. :Some sources treat ''Stylosanthes nervosa'', ''Stylosanthes suffruticosa'', and/or ''Stylosanthes tuberculata'' as synonyms of ''Stylosanthes scabra''. :Some sources treat ''Stylosanthes subsericea'' as a synonym of ''Stylosanthes macrocarpa''.

References

{{Taxonbar, from=Q2701631 Fabaceae genera Forages Taxa named by Olof Swartz