Plant 76

Vicia faba L. (Fabaceae)


Broad bean

Before Columbus's discovery of the Americas, beans, to the peoples of Europe, the Near East and North Africa, meant broad beans. Broad beans are legumes, grown in gardens or fields, to which the economies of multiple western civilisations pulsed. Garden beans and field (or horse) beans were thought to be different species by early academic botanists, although most gardeners were not fooled; the differences were due to the richer soils and extra care beans got in the garden.

The proverb, 'where beans thrive, fools grow', plays to classical notions that the heady scent of broad bean flowers induce nightmares and madness. Despite the olfactory dangers, broad beans have been grown across the warm, dry Mediterranean, and cooler, temperate regions of Europe and Asia, for thousands of years. Theophrastus, the Greek father of botany, discussed the biology and cultivation of broad beans in detail. Yet Pythagoras banned his disciples from eating beans and, at the end of his life, apparently refused to cross a field of flowering beans. This has led to speculation he suffered from favism, a hereditary condition that is brought on by exposure to specific alkaloids contained in broad beans.

The origin of broad beans remains a botanical enigma, despite the technological and intellectual advances made in understanding crops and their wild relatives. The overall appearance of the broad bean suggests its closest wild relatives are a group of Mediterranean and Near Eastern broad bean-like vetches. If this were the case, crossing these wild vetches with broad bean should produce hybrids; decades of research have failed to make such hybrids. Cytological investigations show that broad beans and these vetches have different chromosome numbers; 12 in broad bean and 14 in the vetches. Not only are broad beans reproductively and cytologically unique, detailed DNA analysis reveals they are genetically distinct from all other vetches. These data imply the wild relative may be rare, with a restricted distribution, which has not yet been discovered or the wild relative of the broad bean is extinct. Furthermore, broad beans have never been found outside of cultivation, suggesting they may have originated in cultivation.

Beans played three roles in pre-twentieth century western civilisations: as protein-rich food for humans and their livestock, and as a nitrogen-rich green manure. However, as industrially synthesised nitrogen fertilisers and other food and fodder stuffs have become commonplace, annual broad bean production has declined to about four million tonnes.

Further reading

Duc G et al. 2010. Diversity maintenance and use of Vicia faba L. genetic resources. Field Crops Research 115: 270-278.

Meletis J 2012. Favism: a brief history from the "abstain from beans" of Pythagoras to the present. Archives of Hellenic Medicine 29: 258-263.

Zohary D et al. 2013. Domestication of plants in the Old World. Oxford University Press.

Stephen Harris

The 25th July 2021 marks 400 years of botanical research and teaching by the University of Oxford.

As a celebration and count-down to this anniversary, the University of Oxford Botanic Garden and Harcourt Arboretum, together with the Oxford University Herbaria and the Department of Plant Sciences, will highlight 400 plants of scientific and cultural significance. One plant will be profiled weekly, and illustrated with images from Oxford University's living and preserved collections.

  • Plant 75: Calycanthus floridus
  • Plant 74: Primula auricula
  • Plant 73: Strongylodon macrobotrys
  • Plant 72: Capsella bursa-pastoris
  • Plant 71: Barnadesia caryophylla
  • Plant 70: Erythronium dens-canis
  • Plant 69: Trifolium dubium
  • Plant 68: Forsythia spp.
  • Plant 67: Ananas comosus
  • Plant 66: Theobroma cacao
  • Plant 65: Nostoc sp.
  • Plant 64: Sciadopitys verticillata
  • Plant 63: Garrya elliptica
  • Plant 62: Psilotum nudum
  • Plant 61: Cyclamen species
  • Plant 60: Hevea brasiliensis
  • Plant 59: Semele androgyna
  • Plant 58: Monstera deliciosa
  • Plant 57: Musa textilis
  • Plant 56: Piper nigrum
  • Plant 55: Viscum album
  • Plant 54: Dieffenbachia seguine
  • Plant 53: Salvinia molesta
  • Plant 52: Saccharum officinarum
  • Plant 51: Metasequoia glyptostroboides
  • Plant 50: Equisetum sp.
  • Plant 49: Fraxinus excelsior
  • Plant 48: Rosmarinus officinalis
  • Plant 47: Ptelea trifoliata
  • Plant 46: Acer saccharum
  • Plant 45: Brassica oleracea
  • Plant 44: Helianthus annuus
  • Plant 43: Ricinus communis
  • Plant 42: Simmondsia chinensis
  • Plant 41: Chara sp.
  • Plant 40: Zingiber officinale
  • Plant 39: Aristolochia clematitis
  • Plant 38: Allium cepa
  • Plant 37: Galium tricornutum
  • Plant 36: Artemisia annua
  • Plant 35: Rosa canina
  • Plant 34: Nepenthes rajah
  • Plant 33: D. caryophyllus x barbatus
  • Plant 32: Taraxacum sp.
  • Plant 31: Victoria cruziana
  • Plant 30: Lathyrus odoratus
  • Plant 29: Heliconia rostrata
  • Plant 28: Senecio squalidus
  • Plant 27: Paulownia tomentosa
  • Plant 26: Urtica dioica
  • Plant 25: Euphorbia characias
  • Plant 24: Heliamphora nutans
  • Plant 23: Laurus nobilis
  • Plant 22: Tulipa sylvestris
  • Plant 21: Pleurococcus sp.
  • Plant 20: Gleditsia triacanthos
  • Plant 19: Tillandsia usneoides
  • Plant 18: Marchantia polymorpha
  • Plant 17: Daphne mezereum
  • Plant 16: Citrus medica
  • Plant 15: Coffea arabica
  • Plant 14: Gossypium species
  • Plant 13: Stachyurus praecox
  • Plant 12: Encephalartos ferox
  • Plant 11: Aloe vera
  • Plant 10: Araucaria angustifolia
  • Plant 9: Isoetes echinospora
  • Plant 8: Hamamelis virginiana
  • Plant 7: Lithops species
  • Plant 6: Sequoiadendron giganteum
  • Plant 5: Commiphora saxicola
  • Plant 4: Buxus sempervirens
  • Plant 3: Picea abies
  • Plant 2: Cinnamomum verum
  • Plant 1: Taxus baccata

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    The specimens at the Oxford herbaria and the living collections of the Oxford Botanic Garden and Oxford University Herbaria are being digitized using BRAHMS.


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