Clover

Clover or trefoil are common names for plants of the genus Trifolium (Latin, tres "three" + folium "leaf"), consisting of about 300 species of flowering plants in the legume or pea family Fabaceae. The genus has a cosmopolitan distribution with highest diversity in the temperate Northern Hemisphere, but many species also occur in South America and Africa, including at high altitudes on mountains in the tropics. They are small annual, biennial, or short-lived perennial herbaceous plants. Clover can be evergreen. The leaves are trifoliate (rarely quatrefoiled; see four-leaf clover), cinquefoil, or septfoil, with stipules adnate to the leaf-stalk, and heads or dense spikes of small red, purple, white, or yellow flowers; the small, few-seeded pods are enclosed in the calyx.[3] Other closely related genera often called clovers include Melilotus (sweet clover) and Medicago (alfalfa or Calvary clover).

"Alsike" and "Trifolium" redirect here. For the Swedish locality, see Alsike, Sweden. For the Canadian locality, see Alsike, Alberta. For the trematode parasite, see Cladocystis trifolium. For other uses, see Clover (disambiguation).

Clover
Trifolium hybridum (alsike clover)
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Fabales
Family: Fabaceae
Tribe: Trifolieae
Genus: Trifolium
L.
Subgenera and sections[1]

subg. Chronosemium
subg. Trifolium

sect. Glycyrrhizum
sect. Involucrarium
sect. Lupinaster
sect. Paramesus
sect. Trichocephalum
sect. Trifoliastrum
sect. Trifolium
sect. Vesicastrum
Synonyms

Amoria C. Presl[2]
Bobrovia A. P. Khokhr.[2]
Chrysaspis Desv.[2]
Lupinaster Fabr.[2]
Ursia Vassilcz.[2]
Xerosphaera Soják[2]

Cultivation

Several species of clover are extensively cultivated as fodder plants. The most widely cultivated clovers are white clover, Trifolium repens, and red clover, Trifolium pratense. Clover, either sown alone or in mixture with ryegrass, has for a long time formed a staple crop for silaging, for several reasons: it grows freely, shooting up again after repeated mowings; it produces an abundant crop; it is palatable to and nutritious for livestock; it fixes nitrogen, reducing the need for synthetic fertilizers; it grows in a great range of soils and climates; and it is appropriate for either pasturage or green composting.[3]

In many areas, particularly on acidic soil, clover is short-lived because of a combination of insect pests, diseases and nutrient balance; this is known as "clover sickness". When crop rotations are managed so that clover does not recur at intervals shorter than eight years, it grows with much of its pristine vigor.[3]

Clovers are most efficiently pollinated by bumblebees, which have declined as a result of agricultural intensification.[4] Honeybees can also pollinate clover, and beekeepers are often in heavy demand from farmers with clover pastures. Farmers reap the benefits of increased reseeding that occurs with increased bee activity, which means that future clover yields remain abundant. Beekeepers benefit from the clover bloom, as clover is one of the main nectar sources for honeybees.

Colorful flowers of clovers, beside Zarivar Lake, in Iran
White clover

Trifolium repens, white or Dutch clover, is a perennial abundant in meadows and good pastures. The flowers are white or pinkish, becoming brown and deflexed as the corolla fades. Trifolium hybridum, alsike or Swedish clover, is a perennial which was introduced early in the 19th century and has now become naturalized in Britain. The flowers are white or rosy, and resemble those of Trifolium repens. Trifolium medium, meadow or zigzag clover, a perennial with straggling flexuous stems and rose-purple flowers,[3] has potential for interbreeding with T. pratense to produce perennial crop plants.[5]

Other species are: Trifolium arvense, hare's-foot trefoil; found in fields and dry pastures, a soft hairy plant with minute white or pale pink flowers and feathery sepals; Trifolium fragiferum, strawberry clover, with globose, rose-purple heads and swollen calyxes; Trifolium campestre, hop trefoil, on dry pastures and roadsides, the heads of pale yellow flowers suggesting miniature hops; and the somewhat similar Trifolium dubium, common in pastures and roadsides, with smaller heads and small yellow flowers turning dark brown.[3]

Symbolism

Shamrock, the traditional Irish symbol, which according to legend was coined by Saint Patrick for the Holy Trinity, is commonly associated with clover, although alternatively sometimes with the various species within the genus Oxalis, which are also trifoliate.[6]

Clovers occasionally have four leaflets, instead of the usual three. These four-leaf clovers, like other rarities, are considered lucky.[3] Clovers can also have five, six, or more leaflets, but these are rarer still. The record for most leaflets is 56, set on 10 May 2009.[7] This beat the "21-leaf clover",[8] a record set in June 2008 by the same discoverer, who had also held the prior Guinness World Record of 18.[9]

A common idiom is "to be (or to live) in clover", meaning to live a carefree life of ease, comfort, or prosperity.

The cloverleaf interchange is named for the resemblance to the leaflets of a (four-leaf) clover when viewed from the air.[10]

Phylogeny

The first extensive classification of Trifolium was done by Zohary and Heller in 1984. They divided the genus into eight sections: Lotoidea, Paramesus, Mistyllus, Vesicamridula, Chronosemium, Trifolium, Trichoecephalum, and Involucrarium, with Lotoidea placed most basally.[11] Within this classification system, Trifolium repens falls within section Lotoidea, the largest and least heterogeneous section. Lotoidea contains species from America, Africa, and Eurasia, considered a clade because of their inflorescence shape, floral structure, and legume that protrudes from the calyx. However, these traits are not unique to the section, and are shared with many other species in other sections. Zohary and Heller argued that the presence of these traits in other sections proved the basal position of Lotoidea, because they were ancestral. Aside from considering this section basal, they did not propose relationships between other sections. Since then, molecular data has both questioned and confirmed the proposed phylogeny from Zohary and Heller. A genus-wide molecular study has since proposed a new classification system, made up of two subgenera, Chronosemium and Trifolium.[12] This recent reclassification further divides subgenus Trifolium into eight sections. The molecular data supports the monophyletic nature of three sections proposed by Zohary and Heller (Tripholium, Paramesus, and Trichoecepalum), but not of Lotoidea (members of this section have since been reclassified into five other sections). Other molecular studies, although smaller, support the need to reorganize Lotoidea.[13][14]

Selected species

The genus Trifolium currently has 245 recognized species:[1]

  • Trifolium acaule A. Rich.
  • Trifolium affine C. Presl
  • Trifolium africanum Ser.
  • Trifolium aintabense Boiss. & Hausskn.
  • Trifolium albopurpureum Torr. & A. Gray – rancheria clover
  • Trifolium alexandrinum L. – Egyptian clover, berseem clover
  • Trifolium alpestre L.
  • Trifolium alpinum L. – alpine clover
  • Trifolium amabile Kunth
  • Trifolium ambiguum M. Bieb.
  • Trifolium amoenum Greene – showy Indian clover
  • Trifolium andersonii A. Gray – Anderson's clover or fiveleaf clover
  • Trifolium andinum Nutt. – Intermountain clover
  • Trifolium andricum Lassen
  • Trifolium angulatum Waldst. & Kit.
  • Trifolium angustifolium L.
  • Trifolium apertum Bobrov
  • Trifolium argutum Banks & Sol.
  • Trifolium arvense L. – hare's-foot clover
  • Trifolium attenuatum Greene
  • Trifolium aureum Pollich – large hop trefoil
  • Trifolium baccarinii Chiov.
  • Trifolium badium Schreb.
  • Trifolium barbeyi Gibelli & Belli
  • Trifolium barbigerum Torr. – bearded clover
  • Trifolium barnebyi (Isely) Dorn & Lichvar
  • Trifolium batmanicum Katzn.
  • Trifolium beckwithii W. H. Brewer ex S. Watson – Beckwith's clover
  • Trifolium bejariense Moric.
  • Trifolium berytheum Boiss. & Blanche
  • Trifolium bifidum A. Gray – notchleaf clover
  • Trifolium bilineatum Fresen.
  • Trifolium billardierei Spreng.
  • Trifolium bivonae Guss.
  • Trifolium blancheanum Boiss.
  • Trifolium bocconei Savi
  • Trifolium boissieri Guss. ex Soy.-Will. & Godr.
  • Trifolium bolanderi A. Gray
  • Trifolium brandegeei S. Watson
  • Trifolium breweri S. Watson – forest clover
  • Trifolium brutium Ten.
  • Trifolium buckwestiorum Isely – Santa Cruz clover
  • Trifolium bullatum Boiss. & Hausskn.
  • Trifolium burchellianum Ser.
  • Trifolium calcaricum J. L. Collins & Wieboldt
  • Trifolium calocephalum Fresen.
  • Trifolium campestre Schreb. – hop trefoil
  • Trifolium canescens Willd.
  • Trifolium carolinianum Michx.
  • Trifolium caucasicum Tausch
  • Trifolium caudatum Boiss.
  • Trifolium cernuum Brot.
  • Trifolium cheranganiense J. B. Gillett
  • Trifolium cherleri L.
  • Trifolium chilaloense Thulin
  • Trifolium chilense Hook. & Arn.
  • Trifolium chlorotrichum Boiss. & Balansa
  • Trifolium ciliolatum Benth. – foothill clover
  • Trifolium cinctum DC.
  • Trifolium clusii Godr. & Gren.
  • Trifolium clypeatum L.
  • Trifolium congestum Guss.
  • Trifolium constantinopolitanum Ser.
  • Trifolium cryptopodium Steud. ex A. Rich.
  • Trifolium cyathiferum Lindl. – cup clover
  • Trifolium dalmaticum Vis.
  • Trifolium dasyphyllum Torr. & A. Gray
  • Trifolium dasyurum C. Presl
  • Trifolium davisii M. Hossain
  • Trifolium decorum Chiov.
  • Trifolium depauperatum Desv. – cowbag clover, balloon sack clover, or poverty clover
  • Trifolium dichotomum Hook. & Arn.
  • Trifolium dichroanthoides Rech. f.
  • Trifolium dichroanthum Boiss.
  • Trifolium diffusum Ehrh.
  • Trifolium dolopium Heldr. & Hausskn. ex Gibelli & Belli
  • Trifolium douglasii House
  • Trifolium dubium Sibth. – lesser hop trefoil
  • Trifolium echinatum M. Bieb.
  • Trifolium elgonense J. B. Gillett
  • Trifolium eriocephalum Nutt. – woollyhead clover
  • Trifolium eriosphaerum Boiss.
  • Trifolium erubescens Fenzl
  • Trifolium euxinum Zohary
  • Trifolium eximium Stephan ex Ser.
  • Trifolium fragiferum L. – strawberry clover
  • Trifolium friscanum (S.L. Welsh) S.L. Welsh
  • Trifolium fucatum Lindl. – bull clover or sour clover
  • Trifolium gemellum Pourr. ex Willd.
  • Trifolium gillettianum Jacq.-Fél.
  • Trifolium glanduliferum Boiss.
  • Trifolium globosum L.
  • Trifolium glomeratum L. – clustered clover or bush clover
  • Trifolium gordejevii (Kom.) Z. Wei
  • Trifolium gracilentum Torr. & A. Gray – pinpoint clover
  • Trifolium grandiflorum Schreb.
  • Trifolium gymnocarpon Nutt. – hollyleaf clover
  • Trifolium haussknechtii Boiss.
  • Trifolium haydenii Porter
  • Trifolium heldreichianum (Gibelli & Belli) Hausskn.
  • Trifolium hirtum All. – rose clover
  • Trifolium howellii S. Watson – canyon clover or Howell's clover
  • Trifolium hybridum L. – Alsike clover
  • Trifolium incarnatum L. – crimson clover
  • Trifolium israeliticum Zohary & Katzn.
  • Trifolium isthmocarpum Brot.
  • Trifolium jokerstii Vincent & Rand. Morgan
  • Trifolium juliani Batt.
  • Trifolium kingii S. Watson
  • Trifolium lanceolatum (J. B. Gillett) J. B. Gillett
  • Trifolium lappaceum L.
  • Trifolium latifolium (Hook.) Greene
  • Trifolium latinum Sebast.
  • Trifolium leibergii A. Nelson & J. F. Macbr. – Leiberg's clover
  • Trifolium lemmonii S. Watson – Lemmon's clover
  • Trifolium leucanthum M. Bieb.
  • Trifolium ligusticum Balb. ex Loisel.
  • Trifolium longidentatum Nábelek
  • Trifolium longipes Nutt. – longstalk clover
  • Trifolium lucanicum Gasp. ex Guss.
  • Trifolium lugardii Bullock
  • Trifolium lupinaster L.
  • Trifolium macilentum Greene
  • Trifolium macraei Hook. & Arn. – Chilean clover, double-head clover, or MacRae's clover
  • Trifolium macrocephalum (Pursh) Poir. – largehead clover
  • Trifolium masaiense J. B. Gillett
  • Trifolium mattirolianum Chiov.
  • Trifolium mazanderanicum Rech. f.
  • Trifolium medium L. – zigzag clover
  • Trifolium meduseum Blanche ex Boiss.
  • Trifolium meironense Zohary & Lerner
  • Trifolium michelianum Savi.
  • Trifolium micranthum Viv.
  • Trifolium microcephalum Pursh – smallhead clover
  • Trifolium microdon Hook. & Arn. – thimble clover
  • Trifolium miegeanum Maire
  • Trifolium monanthum A. Gray – mountain carpet clover
  • Trifolium montanum L.
  • Trifolium mucronatum Willd. ex Spreng.
  • Trifolium multinerve A. Rich.
  • Trifolium mutabile Port.
  • Trifolium nanum Torr.
  • Trifolium neurophyllum Greene
  • Trifolium nigrescens Viv.
  • Trifolium noricum Wulfen
  • Trifolium obscurum Savi
  • Trifolium obtusiflorum Hook. & Arn. – clammy clover
  • Trifolium ochroleucon Huds. - sulphur clover
  • Trifolium oliganthum Steud. – fewflower clover
  • Trifolium ornithopodioides L.
  • Trifolium owyheense Gilkey
  • Trifolium pachycalyx Zohary
  • Trifolium palaestinum Boiss.
  • Trifolium pallescens Schreb.
  • Trifolium pallidum Waldst. & Kit.
  • Trifolium pannonicum Jacq. – Hungarian clover
  • Trifolium parnassi Boiss. & Spruner
  • Trifolium parryi A. Gray
  • Trifolium patens Schreb.
  • Trifolium patulum Tausch
  • Trifolium pauciflorum d'Urv.
  • Trifolium petitianum A. Rich.
  • Trifolium philistaeum Zohary
  • Trifolium phitosianum N. Böhling et al.
  • Trifolium phleoides Pourr. ex Willd.
  • Trifolium physanthum Hook. & Arn.
  • Trifolium physodes Steven ex M. Bieb.
  • Trifolium pichisermollii J. B. Gillett
  • Trifolium pignantii Brongn. & Bory
  • Trifolium pilczii Adamović
  • Trifolium pilulare Boiss.
  • Trifolium pinetorum Greene
  • Trifolium plebeium Boiss.
  • Trifolium plumosum Douglas
  • Trifolium polymorphum Poir.
  • Trifolium polyodon Greene
  • Trifolium polyphyllum C. A. Mey.
  • Trifolium polystachyum Fresen.
  • Trifolium praetermissum Greuter et al.
  • Trifolium pratense L. – red clover[15]
  • Trifolium prophetarum M. Hossain
  • Trifolium pseudostriatum Baker f.
  • Trifolium purpureum Loisel.
  • Trifolium purseglovei J. B. Gillett
  • Trifolium quartinianum A. Rich.
  • Trifolium radicosum Boiss. & Hohen.
  • Trifolium reflexum L. – buffalo clover
  • Trifolium repens L. – shamrock (white clover)
  • Trifolium resupinatum L. – Persian clover, shaftal
  • Trifolium retusum L.
  • Trifolium riograndense Burkart
  • Trifolium roussaeanum Boiss.
  • Trifolium rubens L.
  • Trifolium rueppellianum Fresen.
  • Trifolium salmoneum Mouterde
  • Trifolium saxatile All.
  • Trifolium scabrum L.
  • Trifolium schimperi A. Rich.
  • Trifolium scutatum Boiss.
  • Trifolium sebastianii Savi
  • Trifolium semipilosum Fresen.
  • Trifolium setiferum Boiss.
  • Trifolium simense Fresen.
  • Trifolium sintenisii Freyn
  • Trifolium siskiyouense J. M. Gillett
  • Trifolium somalense Taub.
  • Trifolium spadiceum L.
  • Trifolium spananthum Thulin
  • Trifolium spumosum L.
  • Trifolium squamosum (or maritimum) L. – sea clover
  • Trifolium squarrosum L.
  • Trifolium stellatum L.
  • Trifolium steudneri Schweinf.
  • Trifolium stipulaceum Thunb.
  • Trifolium stoloniferum Muhl. ex A. Eaton – running buffalo clover
  • Trifolium stolzii Harms
  • Trifolium striatum L. – knotted clover
  • Trifolium strictum L.
  • Trifolium subterraneum L. – subterranean clover
  • Trifolium suffocatum L.
  • Trifolium sylvaticum Gérard ex Loisel.
  • Trifolium tembense Fresen.
  • Trifolium thalii Vill.
  • Trifolium thompsonii C. V. Morton – Thompson's clover
  • Trifolium tomentosum L.
  • Trifolium triaristatum Bertero ex Colla
  • Trifolium trichocalyx A. Heller – Monterey clover
  • Trifolium trichocephalum M. Bieb.
  • Trifolium trichopterum Pančić
  • Trifolium tumens Steven ex M. Bieb.
  • Trifolium ukingense Harms
  • Trifolium uniflorum L.
  • Trifolium usambarense Taub.
  • Trifolium variegatum Nutt. – whitetip clover
  • Trifolium vavilovii Eig
  • Trifolium velebiticum Degen
  • Trifolium velenovskyi Vandas
  • Trifolium vernum Phil.
  • Trifolium vesiculosum Savi
  • Trifolium vestitum D. Heller & Zohary
  • Trifolium virginicum Small
  • Trifolium wentzelianum Harms
  • Trifolium wettsteinii Dörfl. & Hayek
  • Trifolium wigginsii J. M. Gillett
  • Trifolium willdenovii Spreng. − tomcat clover
  • Trifolium wormskioldii Lehm. – cow clover
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gollark: You can just continue using memes or whatever regardless of them somehow being related to people you disagree with.
gollark: There may be context I didn't actually bother to check.
gollark: I mean, possibly.
gollark: How unreasonable of them.

See also

References
  1. "Species Nomenclature in GRIN". Archived from the original on 2008-10-14. Retrieved 2010-08-04.
  2. "Genus Nomenclature in GRIN". Retrieved 2010-07-09.
  3.  One or more of the preceding sentences incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). "Clover". Encyclopædia Britannica. 6 (11th ed.). Cambridge University Press. p. 561.
  4. Bumbles make beeline for gardens, study suggests Retrieved 27 November 2010.
  5. Isobe, S.; Sawai, A.; Yamaguchi, H.; Gau, M.; Uchiyama, K. (2002). "Breeding potential of the backcross progenies of a hybrid between Trifolium medium × T. pratense to T. pratense". Canadian Journal of Plant Science. 82 (2): 395–399. doi:10.4141/P01-034.
  6. "Shamrock (Oxalis)". Fine Gardening. Retrieved February 28, 2017.
  7. "Most Leaves on a Clover". Guinness World Records. 2011. Retrieved 2011-04-23.
  8. Clover Sets Record. Neatorama. Retrieved on 2008-12-07 from http://www.neatorama.com/2008/06/11/21-leaf-clover-sets-record 21-leaf. Archived July 22, 2009, at the Wayback Machine
  9. "Most leaves on a clover". Guinness World Records. Archived from the original on March 25, 2008. Retrieved 22 December 2016.
  10. Pollard, Michael (1986). Travel by Road and Rail. Independence, Ohio: Schoolhouse Press. p. 31. ISBN 9780808610403.
  11. 1898-1983., Zohary, Michael (1984). The genus Trifolium. Heller, D. Jerusalem: Israel Academy of Sciences and Humanities. ISBN 978-9652080561. OCLC 11057949.CS1 maint: numeric names: authors list (link)
  12. Ellison, Nick W.; Liston, Aaron; Steiner, Jeffrey J.; Williams, Warren M.; Taylor, Norman L. (2006). "Molecular phylogenetics of the clover genus (Trifolium—Leguminosae)". Molecular Phylogenetics and Evolution. 39 (3): 688–705. doi:10.1016/j.ympev.2006.01.004. PMID 16483799.
  13. Vižintin, Liliana; Javornik, Branka; Bohanec, Borut (2006). "Genetic characterization of selected Trifolium species as revealed by nuclear DNA content and ITS rDNA region analysis". Plant Science. 170 (4): 859–866. doi:10.1016/j.plantsci.2005.12.007.
  14. Watson, L. E.; Sayed-Ahmed, H.; Badr, A. (2000-09-01). "Molecular phylogeny of Old WorldTrifolium (Fabaceae), based on plastid and nuclear markers". Plant Systematics and Evolution. 224 (3–4): 153–171. doi:10.1007/BF00986340. ISSN 0378-2697.
  15. "Detox and Cleansing". 2014-12-24. Archived from the original on March 6, 2016. Retrieved March 12, 2016.
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