1. Family: Fabaceae Lindl.
    1. Trifolium Tourn. ex L.

      1. This genus is accepted, and its native range is Temp. & Subtropical to Tropical Mountains.

    [LOWO]

    Legumes of the World. Edited by G. Lewis, B. Schrire, B. MacKinder & M. Lock. Royal Botanic Gardens, Kew. (2005)

    Note

    Trifolieae forms a morphologically distinctive tribe, although the position of both Ononis and Parochetus has been questioned (see below). In total there are 6 genera and c. 485 species, of which more than half belong to Trifolium (Fig. 56). The distribution of the tribe is centred in the N temperate regions of the Old World, particularly in areas of winter rainfall. Trifolium itself has spread into the tropics on mountains, where there has been considerable diversification, particularly in Ethiopia. It is also the only genus of the tribe to occur naturally in the New World. Parochetus occurs only on palaeotropical mountains. The importance of some genera as fodder legumes, particularly Trifolium and Medicago, has led to their introduction to many parts of the world.

    Ononis was placed in a tribe of its own, Ononideae, by Hutchinson (1964) and this has been followed by some (e.g., Yakovlev et al., 1996). The distinctness of Parochetus (and of Ononis) was emphasised by Small & Jomphe (1989), and Chaudhary & Sanjappa (1998a) have placed Parochetus in its own subtribe Parochetinae.

    Within the core of Trifolieae, there are some problems in generic delimitation, particularly between Trigonella, Medicago and Melilotus, with some (e.g., Yakovlev et al., 1996) recognising the intermediate genus Melilotoides. Distinctive species here placed in Medicago have been variously segregated as Radiata (Pseudomelissitus), Rhodusia, Crimea, Kamiella and Factorovskya. This treatment follows Small (1987) and Small et al. (1987) in recognising an expanded Medicago including all those species with explosively tripping flowers. In Trifolium, on the other hand, the generic boundaries are reasonably clear, but the unit can be treated either as a large genus with several well-defined sections (the course followed here), or as the separate genera Amoria, Chrysaspis, Lupinaster and Trifolium sens. strict. (see below).

    Trifolieae forms part of the ‘temperate epulvinate series’ of Polhill (1981a). In the same volume Heyn (1981) was unable to suggest a clear relationship to any other tribe. The morphological cladistic analysis of the whole family by Chappill (1995) placed Trifolieae next to Cicer. Kupicha (1977) had earlier suggested that Cicer is closest to Trifolieae, with the adnation of the stipules to the petiole in Trifolieae being the only differential character; the tribes Cicereae and Trifolieae also share the characters of long-stalked glandular hairs and serrate leaflets with craspedodromous venation. Doyle (1995) placed Trifolieae, along with Carmichaelieae, Cicereae, Galegeae, Hedysareae, Fabeae and some Millettieae in a group characterised by the loss of the inverted repeat (IR) (Liston, 1995). Endo & Ohashi (1997) placed Trifolieae as sister to the Cicereae and Fabeae (as Vicieae) in a cladistic analysis based on a range of non-molecular characters. Wojciechowski et al. (2000) distinguish a Vicioid clade that includes Trifolieae, Cicereae and Fabeae (as Vicieae), as well as Galega. Within this clade, Parochetus is basally branching to the rest of the taxa, and Galega plus Cicereae form a sister group to a paraphyletic Trifolieae, with Fabeae emerging as sister to Trifolium. In a clade sister to Trifolium and Fabeae, Wojciechowski et al. (2000) and Steele & Wojciechowski (2003) place Ononis basally branching to the sister monophyletic clades Medicago, and Melilotus-Trigonella (Fig. 56). The latter three genera comprise tribe Trigonelleae of Schulz (1901).

    Given that molecular phylogenies do not support a monophyletic Trifolieae in its current form, further study may reinforce the pattern of relationships suggested so far by these analyses. A tribe Trigonelleae could be recognised including the genus Ononis, and tribe Trifolieae would then only include the genus Trifolium, sister to tribe Fabeae. The Trifolieae in its broader paraphyletic sense is maintained here pending further study. The ‘supertree’ of Wojciechowski et al. (2001) is not supportive of the segregate genera of Trifolium; more thorough sampling of Trifolium and other large genera is desirable before any final conclusions can be drawn.

    Roskov (1990a & b) recognises Trifolium in a restricted sense and treats Amoria, Chrysaspis and Lupinaster as good genera. The molecular studies of Watson et al. (2000), while they support Trifolium sens. lat. as monophyletic, support neither Amoria nor Trifolium sens. strict. as monophyletic; Chrysaspis is so supported but its recognition would make Trifolium paraphyletic; no members of Lupinaster were included in the analysis; the nine montane African taxa sampled form a monophyletic group within Trifolium
    Habit
    Herbs
    Ecology
    Mainly mediterranean, temperate and tropical montane grassland
    Distribution
    principally N temperate Eurasian (c. 150 spp., with c. 130 spp. in the Mediterranean region including Turkey), New World (mostly temperate N America, c. 60 spp.); also tropical and subtropical montane areas (c. 36 spp. in Africa, some in Andes of S America)
    [FTEA]

    Leguminosae, J. B. Gillett, R. M. Polhill & B. Verdcourt. Flora of Tropical East Africa. 1971

    Habit
    Annual or perennial herbs
    Leaves
    Leaves palmately (or, less often and not in the native species, pinnately) 3-foliolate (rarely, in NE. Asia, 5-foliolate); stipules well developed, green or straw-coloured, fused with the petiole in their lower part, their bases forming a ring round the stem; lateral nerves of leaflets well marked and ± parallel, the main ones (those which start at the midrib and run strongly through to the margin without interruption) and often some of their branches usually ending in small teeth (leaflets entire in No. 2)
    Inflorescences
    Inflorescences axillary or, less often, ± terminal, usually pedunculate, essentially racemose but condensed, with pedicels at most 6 mm. long, till they appear to be short spikes, compact umbels or heads, rarely flowers solitary; bracts present (often very small) or absent; bracteoles absent
    Calyx
    Calyx-tube ± campanulate, never, in Flora area, with less than 11 nerves, the upper (vexillary) commissural nerve being divided; teeth 5, in the Flora area subequal and always very acute
    Corolla
    Corolla glabrous, persistent, in the Flora area not above 14 mm. long, purple, pink or white, or, not in the native species, yellow; claws of the 4 lower petals ± as long as their blades, attached to the 9 lower united filaments and often also to the base of the standard
    Stamens
    Upper filament free; filaments slightly upturned towards their tips, some or all of which are dilated; anthers uniform, in the native species not above 0·7 mm. long
    Pistil
    Ovary sessile or shortly stipitate, with 1–12 (in the Flora area 2–9) ovules; style slightly upturned towards the tip; stigma small, punctate or capitate
    Fruits
    Pod surrounded, at least at the base, by the persistent calyx and corolla, in the native species having papery walls and greatly thickened sutures and dehiscing by splitting at the suture and often also by the irregular rupture of the walls
    Seeds
    Seeds in native species from 1·2 to 2·2 mm. long, with an almost circular hilum 0·1–0·2 mm. across; aril not conspicuous.
    [FZ]

    Leguminosae, various authors. Flora Zambesiaca 3:7. 2003

    Habit
    Annual or perennial herbs.
    Leaves
    Leaves digitately or pinnately (T. campestre) 3-foliolate (rarely 5-foliolate outside the Flora Zambesiaca area); leaflets mostly denticulate; stipules well developed, basally adnate to the petiole often also sheathing the stem, herbaceous or membranaceous.
    Inflorescences
    Racemes axillary, less often ± terminal, usually contracted and capitate, or spicate or umbellate, pedunculate or sessile; bracts present or absent; bracteoles absent.
    Flowers
    Flowers pedicellate or sessile.
    Calyx
    Calyx tubular or campanulate, (5)11- or more-nerved, sometimes bilabiate, accrescent, inflated, the mouth open or closed by a callosity or by a ring of hairs.
    Corolla
    Corolla purple, pink, white or yellow, glabrous, usually persistent; standard free or connate at the base with the wings and keel; wings often longer than keel; keel obtuse.
    Stamens
    Stamens with free portions of filaments usually dilated at the apex; vexillary filament free; anthers uniform.
    Pistil
    Ovary small, sessile or shortly stipitate, 1- or few-ovulate; style straight, slightly incurved towards the tip; stigma small, punctate or capitate.
    Fruits
    Pod small, ± included in the persistent calyx and corolla, usually membranous, indehiscent or rarely dehiscent.
    Seeds
    Seeds 1–2, globular to ovoid, reniform or lenticular.
    [LOWO]
    Use
    Introduced worldwide for fodder, soil and pasture improvement, as honey plants, hay and silage, and in horticulture; T. repens L. (white clover) is probably the most widely grown species with the greatest impact on agriculture of any cultivated forage plant; T. pratense L. (red clover) is also used for medicine; some species are eaten as human food; trefoil dermatitis associated with photosensitisation is a problem caused by animal ingestion of some Trifolium species

    Images

    Distribution

    Native to:

    Afghanistan, Alabama, Albania, Algeria, Altay, Amur, Angola, Argentina Northeast, Argentina Northwest, Argentina South, Arizona, Arkansas, Austria, Azores, Baleares, Baltic States, Belarus, Belgium, Bolivia, Botswana, Brazil South, Brazil Southeast, British Columbia, Bulgaria, Burundi, Buryatiya, California, Cameroon, Canary Is., Cape Provinces, Cape Verde, Central European Rus, Chile Central, Chile North, Chile South, China North-Central, Chita, Colombia, Colorado, Corse, Costa Rica, Cyprus, Czechoslovakia, Denmark, Djibouti, East Aegean Is., East European Russia, East Himalaya, Ecuador, Egypt, Equatorial Guinea, Eritrea, Ethiopia, Finland, Florida, France, Free State, Føroyar, Georgia, Germany, Great Britain, Greece, Guatemala, Gulf of Guinea Is., Gulf States, Hungary, Iceland, Idaho, Illinois, India, Indiana, Inner Mongolia, Iowa, Iran, Iraq, Ireland, Irkutsk, Italy, Japan, Kansas, Kazakhstan, Kentucky, Kenya, Khabarovsk, Kirgizstan, Korea, Krasnoyarsk, Kriti, Krym, Kuril Is., KwaZulu-Natal, Lebanon-Syria, Lesotho, Libya, Louisiana, Madagascar, Madeira, Malawi, Manchuria, Mauritania, Mexican Pacific Is., Mexico Central, Mexico Gulf, Mexico Northeast, Mexico Northwest, Mexico Southeast, Mexico Southwest, Mississippi, Missouri, Mongolia, Montana, Morocco, Mozambique, Namibia, Nepal, Netherlands, Nevada, New Mexico, Nicaragua, Nigeria, North Carolina, North Caucasus, North European Russi, Northern Provinces, Northwest European R, Norway, Ohio, Oklahoma, Oregon, Pakistan, Palestine, Paraguay, Pennsylvania, Peru, Poland, Portugal, Primorye, Romania, Rwanda, Sakhalin, Sardegna, Saudi Arabia, Sicilia, Sinai, South Carolina, South Dakota, South European Russi, Spain, Sudan, Swaziland, Sweden, Switzerland, Tadzhikistan, Tanzania, Tennessee, Texas, Transcaucasus, Tunisia, Turkey, Turkey-in-Europe, Turkmenistan, Tuva, Uganda, Ukraine, Uruguay, Utah, Uzbekistan, Virginia, Washington, West Himalaya, West Siberia, West Virginia, Wyoming, Xinjiang, Yakutskiya, Yemen, Yugoslavia, Zambia, Zaïre, Zimbabwe

    Introduced into:

    Aleutian Is., Amsterdam-St.Paul Is, Antipodean Is., Bahamas, Bangladesh, Bermuda, Chatham Is., China South-Central, China Southeast, Crozet Is., Cuba, Dominican Republic, Easter Is., Falkland Is., Fiji, Haiti, Hawaii, Honduras, Jamaica, Jawa, Juan Fernández Is., Kamchatka, Kerguelen, Kermadec Is., Magadan, Maryland, Nansei-shoto, New Guinea, New South Wales, New Zealand North, New Zealand South, Norfolk Is., Panamá, Puerto Rico, Queensland, Réunion, South Australia, South Georgia, Sri Lanka, St.Helena, Taiwan, Tasmania, Tristan da Cunha, Venezuela, Vermont, Victoria, Western Australia, Wisconsin

    Trifolium Tourn. ex L. appears in other Kew resources:

    First published in Sp. Pl.: 764 (1753)

    Accepted by

    • Tutin, T.G. & al. (eds.) (1968). Flora Europaea 2: 1-469. Cambridge University Press.

    Literature

    Flora of West Tropical Africa
    • —F.T.A. 2: 53.
    Flora Zambesiaca
    • M. Zohary & D. Heller, The Genus Trifolium (1984).
    • Gillett in Kew Bull. 7: 367–404 (1952).
    • Gen. Pl., ed. 5: 337 (1754).
    • Sp. Pl.: 764 (1753)
    Flora of Tropical East Africa
    • Gillett in K.B. 7: 367–404 (1952)
    • L., Gen. Pl., ed. 5: 337 (1754)
    • Sp. Pl.: 764 (1753)

    Sources

    Flora Zambesiaca
    Flora Zambesiaca
    http://creativecommons.org/licenses/by-nc-sa/3.0

    Flora of Tropical East Africa
    Flora of Tropical East Africa
    http://creativecommons.org/licenses/by-nc-sa/3.0

    Kew Backbone Distributions
    The International Plant Names Index and World Checklist of Selected Plant Families 2018. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
    © Copyright 2017 World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0

    Kew Names and Taxonomic Backbone
    The International Plant Names Index and World Checklist of Selected Plant Families 2018. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
    © Copyright 2017 International Plant Names Index and World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0

    Legumes of the World Online
    http://creativecommons.org/licenses/by-nc-sa/3.0