Plant 84

Gunnera manicata Linden ex Delchev. (Gunneraceae)


Chilean rhubarb

Great Dixter's Christopher Lloyd wrote 'it is not grotesque, neither is it coarse, and those who think otherwise have clearly never lived in close proximity to one' in his description of Gunnera manicata; the largest perennial hardy enough to survive winter temperatures over a significant area of the British Isles. It has been a popular garden plant since its introduction to British horticulture in 1867, and is valued for the architectural qualities of its enormous leaves.

The genus Gunnera contains about 40 species, distributed across much of the southern hemisphere from South America and the Antarctic Islands, through South Africa and Madagascar to New Zealand. Gunnera manicata is the largest species, its leaves reaching a width of three metres. In contrast, Gunnera monoica, found in New Zealand, has leaves only three centimetres wide.

Gunnera manicata is native to southern Brazil. It is a pachycaul perennial, producing tiny flowers in dense, cone-like inflorescences in early summer (memorably described by Lloyd as looking like 'a cross between a vast fleshy fir cone and a fertility symbol'), on which the small seeds ripen inside startling orange fruits. In Britain, its dormant buds can be damaged by late-spring frosts therefore plants are protected from these frosts by a mulch of old leaves from the previous season. The plants grow to their largest in proximity to open water, although they can be grown successfully in drier soils as their roots penetrate to depths of over one metre.

Gunnera manicata's common name is an allusion to the shape of the large, palmate leaves of cultivated rhubarb. In Chile, consumption of the young, peeled petioles of Gunnera tinctoria is reminiscent of rhubarb consumption in Britain. Non-edible uses of Gunnera manicata include root tannins being used as a black dye, while the leaves have apparently been used as coverings for roofs and as makeshift umbrellas. Despite their superficial leaf and ethnobotanical similarities, Gunnera and rhubarb are not closely related to each other.

All Gunnera species form a symbiosis with Nostoc, a genus of nitrogen-fixing cyanobacteria which also form symbioses with some cycads and the water fern, Azolla. This relationship is the only one of its kind known among angiosperms. Nostoc enters the plant through glands below the cotyledons and inhabits the intracellular spaces in the petioles. High soil nitrogen is thought to be the explanation of why intercropping with Gunnera macrophylla can produce impressive yield increases in brassicas.

Further reading

Fern K 1997. Plants for a future: edible & useful plants for a healthier world. Permanent.

Lloyd C 1970. The well-tempered garden. Collins.

James Penny

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 83: Rosa chinensis
  • Plant 82: Aconitum napellus
  • Plant 81: Pteridium aquilinum
  • Plant 80: Wisteria sinensis
  • Plant 79: Passiflora alata
  • Plant 78: Matteuccia struthiopteris
  • Plant 77: Acer carpinifolium
  • Plant 76: Vicia faba
  • 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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