Stylosanthes
Stylosanthes hamata
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Fabales
Family: Fabaceae
Subfamily: Faboideae
Tribe: Dalbergieae
Genus: Stylosanthes
Sw.
Species

See text

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.[1][2] The common name pencilflower is sometimes used for plants in this genus.[3]

Description

The genus is characterised by trifoliate leaves and small yellow flowers [4] Species may be annual or perennial 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.[5]

Stylosanthes scabra foliage and flowers, Central Queensland

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.[6] The taxonomy is complicated by the existence of numerous natural tetraploid and hybrid populations.[7] Species within the genus fall within two subgenera: Styposanthes and Stylosanthes. Styposanthes possess a small rudimentary secondary floral axis, which is absent from Stylosanthes.[8] Stylosanthes is closely related to the peanut genus Arachis.[6]

All except two species of the genus are native to the Americas. S. fruticosa has a native range that extends from South Africa to Ethiopia, across Arabian Peninsula to Pakistan, India and Sri Lanka[9] and S. erecta is endemic to Tropical Africa, from Tanzania to Senegal.[10] The putative species S. sundaica, has a range that encompasses Malesia but is considered by most authors to be an adventive polypoliod variety of S. humilis.[9] Ecological range extends from savanna and thorn scrub to tropical forest and montane forests.[6]

Species

The following species are accepted:[11]

Usage

Species within the genus have many properties that make them valuable forage species. They are capable of nitrogen fixation and are capable of improving soil fertility in addition to providing high protein stock feed.[12] The genus is also noted for its ability to extract phosphorus from soils where it is not available to other species.[13] 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.[5] Many species are adapted to hot, dry climates and are drought resistant.[14]

These traits have made the genus the world’s most widely used tropical pasture legume.[14] 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 [15] This can lead to a ten-fold increase in productivity, though 2–3 fold increases are normal.[5] Stylosanthes are the most important forage legumes in South America[16] and the most important pasture legumes of tropical India.[17] Stylosanthes are also important forage species in tropical Africa.[5]

Stylosanthes are important green manure species in West and Central Africa, 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 India. 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, Africa and Australia. S. hamata used for intercropping with grain crops in India and Africa with yield increases up to 25%.[5]

Stylosanthes species have been used for land reclamation, soil stabilization and soil regeneration work because of their drought resistance, ability to restore soil fertility, improve soil physical properties and provide permanent vegetation cover.[17][18][19][20]

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 than grass.[5] Stylosanthes dominance can also lead to soil acidification, as soil nitrate levels build up and are then leached down the soil profile.[21] Stylosanthes species are considered invasive species and environmental weeds in Australia, Taiwan, the Pacific Islands and Hawaii.[6] Many Stylosanthes species are susceptible to anthracnose fungus (Colletotrichum gloeosporioides) which retards growth and seed development,[5] and this had led to numerous commercial cultivars being abandoned.

Notes

1 2 4 7 8 10 Some sources treat Stylosanthes acuminata, Stylosanthes aurea, Stylosanthes campestris, Stylosanthes gracilis, Stylosanthes grandifolia, and/or Stylosanthes hippocampoides as synonyms of Stylosanthes guianensis.
3 Some sources treat Stylosanthes bahiensis as a synonym of Stylosanthes pilosa.
5 Some sources treat Stylosanthes cayennensis as a synonym of Stylosanthes hispida.
6 15 Some sources treat Stylosanthes figueroae and/or Stylosanthes sundaica as synonyms of Stylosanthes humilis.
9 Some sources treat Stylosanthes guineensis as a synonym of Stylosanthes erecta.
11 Some sources treat Stylosanthes macrosoma as a synonym of Stylosanthes montevidensis.
12 14 16 Some sources treat Stylosanthes nervosa, Stylosanthes suffruticosa, and/or Stylosanthes tuberculata as synonyms of Stylosanthes scabra.
13 Some sources treat Stylosanthes subsericea as a synonym of Stylosanthes macrocarpa.

References

  1. ^ Lavin M, Pennington RT, Klitgaard BB, Sprent JI, de Lima HC, Gasson PE (2001). "The dalbergioid legumes (Fabaceae): delimitation of a pantropical monophyletic clade". Am J Bot. 88 (3): 503–33. doi:10.2307/2657116. JSTOR 2657116. PMID 11250829.
  2. ^ Cardoso D, Pennington RT, de Queiroz LP, Boatwright JS, Van Wyk B-E, Wojciechowskie MF, Lavin M (2013). "Reconstructing the deep-branching relationships of the papilionoid legumes". S Afr J Bot. 89: 58–75. doi:10.1016/j.sajb.2013.05.001.
  3. ^ USDA, NRCS (n.d.). "Stylosanthes". The PLANTS Database (plants.usda.gov). Greensboro, North Carolina: National Plant Data Team. Retrieved 4 December 2015.
  4. ^ Sa R (萨仁); Salinas AD (2010). "笔花豆属" [61. Stylosanthes Swartz, Prodr. 7, 108. 1788.]. In Wu ZY (吴征镒); Raven PH; Hong DY (洪德元) (eds.). Flora Republicae Popularis Sinicae [Flora of China]. Vol. 10 (Fabaceae). Missouri Botanical Garden Press, St. Louis, and Science Press, Beijing. pp. 135–136. ISBN 9781930723917. Retrieved 12 February 2014.
  5. ^ a b c d e f g Cameron D, Chakraborty S (2004). "Forage potential of Stylosanthes in different production systems" (PDF). In Chakraborty S (ed.). High-Yielding Anthracnose-Resistant Stylosanthes for Agricultural Systems. Australian Centre for International Agricultural Research (ACIAR). pp. 27–38. ISBN 978-1-86320-442-2.
  6. ^ a b c d Maass B, Sawkins M (2004). "History, relationships and diversity among Stylosanthes species of commercial significance" (PDF). In Chakraborty S (ed.). High-Yielding Anthracnose-Resistant Stylosanthes for Agricultural Systems. Australian Centre for International Agricultural Research (ACIAR). pp. 9–26. ISBN 978-1-86320-442-2.
  7. ^ Gillies ACM, Abbott RJ (1996). "Phylogenetic relationships in the genus Stylosanthes (Leguminosae) based upon chloroplast DNA variation". Plant Syst Evol. 200 (3–4): 193–211. doi:10.1007/BF00984935. S2CID 28591537.
  8. ^ Chandra A. (2009). "Diversity among Stylosanthes species: Habitat, edaphic and agro-climatic affinities leading to cultivar development" (PDF). J Environ Biol. 30 (4): 471–478. PMID 20120482.
  9. ^ a b Cook B, Pengelly B, Brown S, Donnelly J, Eagles D, Franco A, Hanson J, Mullen B, Partridge I, Peters M, Schultze-Kraft R (2005). "Tropical Forages entry for Stylosanthes". Tropical Forages. CSIRO Sustainable Ecosystems (CSIRO), the Department of Primary Industries and Fisheries (DPI&F Queensland), el Centro Internacional de Agricultura Tropical (CIAT), and the International Livestock Research Institute (ILRI). Retrieved 12 February 2014.
  10. ^ "Stylosanthes erecta". Germplasm Resources Information Network. Agricultural Research Service, United States Department of Agriculture. Retrieved 12 February 2014.
  11. ^ "Stylosanthes Sw". Plants of the World Online. Board of Trustees of the Royal Botanic Gardens, Kew. 2017. Retrieved 11 June 2021.
  12. ^ Coates DB, Miller CP, Hendricksen RE, Jones RJ (1997). "Stability and productivity of Stylosanthes pastures in Australia. II. Animal production from Stylosanthes pastures". Trop Grassl. 31 (5): 494–502.
  13. ^ Kretschmer AE, Pitman WD (2001). "4. Germplasm Resources of Tropical Forage Legumes". In Sotomayor-Ríos A, Pitman WD (eds.). Tropical Forage PLants: Development and Use. CRC Press LLC, Boca Raton, Florida. pp. 41–58. doi:10.1201/9781420038781.ch4. ISBN 978-0849323188.
  14. ^ a b Jones PG, Sawkins MC, Maass BL, Kerridge PC (June 8–19, 1997). GIS and Genetic Diversity—Case Studies in Stylosanthes (PDF). XVIII International Grassland Congress. Winnipeg, Canada. pp. 73–74. Retrieved 12 February 2014.
  15. ^ Liu CJ (1997). "Geographical distribution of genetic variation in Stylosanthes scabra revealed by RAPD analysis". Euphytica. 9 (1–2): 21–27. doi:10.1023/A:1003026915825. S2CID 40393183.
  16. ^ Hall T, Glatzle A (2004). "Cattle production from Stylosanthes pastures" (PDF). In Chakraborty S (ed.). High-Yielding Anthracnose-Resistant Stylosanthes for Agricultural Systems. Australian Centre for International Agricultural Research (ACIAR). pp. 51–64. ISBN 978-1-86320-442-2.
  17. ^ a b Chandra A, Pathak PS, Bhatt RK (2006). "Stylosanthes research in India: Prospects and challenges ahead" (PDF). Curr Sci. 90 (7): 915–921.
  18. ^ Pathak P, Ramesh C, Bhatt R (2004). "Stylosanthes in the reclamation and development of degraded soils in India" (PDF). In Chakraborty S (ed.). High-Yielding Anthracnose-Resistant Stylosanthes for Agricultural Systems. Australian Centre for International Agricultural Research (ACIAR). pp. 85–96. ISBN 978-1-86320-442-2.
  19. ^ Obi ME (1999). "The physical and chemical responses of a degraded sandy clay loam soil to cover crops in southern Nigeria". Plant and Soil. 211 (2): 165–172. doi:10.1023/A:1004609104524. S2CID 19607724.
  20. ^ Ramesh CR; Bhag Mal; Hazra CR; Sukanya DH; Ramamurthy V; Chakraborty S (1997). "Status of Stylosanthes development in other countries. III. Stylosanthes development and utilisation in India". Trop Grassl. 31 (5): 467–476.
  21. ^ Noble AD, Cannon M, Muller D (1997). "Evidence of accelerated soil acidification under Stylosanthes-dominated pastures". Aust J Soil Res. 35 (6): 1309–1322. doi:10.1071/S97053.
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