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 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: Dianthus caryophyllus x Dianthus 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

  • Follow us on Twitter @Plants400

    The data and images available on this site may only be used for scientific purposes. They may not be sold or used for commercial purposes. All images are copyright of the University of Oxford, unless otherwise indicated.

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


    Dr Alison Foster (

    Dr Stephen Harris (

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    Plant 48

    Rosmarinus officinalis L. (Lamiaceae)




    Rosemary, an evergreen shrub, has been cultivated in Britain for its aromatic, faintly camphorous, needle-like leaves since the fourteenth century. Rosemary belongs to a small genus whose native distribution is the fire-prone Mediterranean region of Europe. Rosemary is widely used in Mediterranean cooking and is an important perfumery ingredient, for example, in eau de cologne and Hungary water. The plant's common and scientific names both derive from its classical Roman name ros marinus ('dew of the sea'), which apparently refers to its habitat close to the sea.

    Across its natural range, rosemary shows great morphological variation. Its habit varies from prostrate, ground-covering forms through squat shrubs to tall fastigiated forms. The insect-pollinated flowers also vary in colour, from white through pink to blue and deep purple. Similarly, leaves vary in shape, size, colour and even chemistry, often giving the crushed leaves subtly different flavours and scents.

    Rosemary leaves are long and thin, rigid and rolled over at the margins. They also have a thick cuticle on their dark upper surface and a dense carpet of simple and glandular hairs on their pale lower surface. Together such features are associated with a syndrome known as sclerophylly (literally 'hard leaf'), which is commonly found in Mediterranean plants. Various ideas have been proposed to explain sclerophylly in the Mediterranean flora, including adaptations to prolonged summer drought, herbivory and low soil nutrients.

    In addition to drought, Mediterranean plants must also cope with fire; they do this using two broad strategies. One strategy is to resprout from buds, protected from fire, under the soil surface. The other strategy, which is adopted by rosemary, is to produce abundant seed so that when the adult plant is killed the plant population rapidly regenerates from the soil seed bank.

    An adaptable, morphologically variable, easily managed, aromatic shrub makes an ideal garden plant. In the mid seventeenth century, rosemary was a functional plant, grown for its classical associations and its perceived medicinal and culinary value; occasionally it was used for hedging and topiary. In Oxford, the first Keepers (Jacob Bobart, father and son) of the Botanic Garden grew variegated and non-variegated types, whilst, in London, John Gerard and John Parkinson grew a handful of types in their gardens. In contrast, today, much of rosemary's natural variation is in cultivation, and a resurgence of interest has been shown because of rosemary's ability to grow in circumstances where water is limited.

    Mateu-Andrés I et al. 2013. Geographical patterns of genetic variation in rosemary (Rosmarinus officinalis) in the Mediterranean basin. Botanical Journal of the Linnean Society 171: 700-712.

    Stephen Harris