Ginkgo biloba (maidenhair tree)
Ginkgo biloba, or maidenhair tree, has been described as a ‘living fossil’ because it is the sole survivor of an ancient group of trees older than the dinosaurs.
Species Information
- Common name(s): maidenhair tree
- Conservation Status: Classified as Endangered (EN - B1+2c) on the IUCN Red List 2002.
- Habitat: The maidenhair tree is most suited to moist, deep, sandy soils in full sunlight but is extremely adaptable to a range of stressful conditions. It was the first tree in the vicinity of Hiroshima to bud after the atomic bomb of 1945. One tree, at Anraku-ji, still has scorch marks from the blast high up on its trunk.
- Key Uses: Ornamental. Medicinal.
- Known hazards: Ginkgotoxin (4'-O-methylpyridoxine), a constituent of the seeds, may cause poisoning unless the seeds are thoroughly cooked.
Taxonomy
- Class: Ginkgoopsida
- Subclass: Ginkgooidae
- Order: Ginkgoales
- Family: Ginkgoaceae
- Genus: Ginkgo
About this Species
This remarkable tree is known as a 'living fossil', as it is the sole survivor of an ancient group of trees that date back to beyond the time of the dinosaurs. Ginkgo fossils are common in the rocks of the Jurassic and Cretaceous, but today the Ginkgo tree is the only member of its genus, which is the only genus in its family, which is the only family in its order, which is the only order in its class. The maidenhair tree remains virtually unchanged today and represents the only living bridge between 'higher' and 'lower' plants (between ferns and conifers).
Geography & Distribution
Ginkgo biloba is native to China, where the survival of wild trees is not secure. Examples can be found in China on Mount Xitianmu in the Zhejiang Province, but it is unclear whether these are the last truly wild trees or descendents from temple gardens. The attractive maidenhair tree has been widely planted as an ornamental, and cultivated individuals exist around the world. Trees were traditionally planted in temple gardens in Japan and China, but today are popular in towns worldwide and are even farmed in plantations for their medicinal properties.
Description
More InformationTrees reach up to 40 metres in height and older individuals tend to have a more spreading appearance with irregular branches. The deeply fissured brown bark may appear cork-like in older individuals. Male and female trees are separate; male pollen is borne on catkin-like cones amongst the leaves whilst female ovules are more rounded. After fertilisation, yellowish seeds develop with a fleshy outer seed coat that resembles a plum in appearance.
The characteristic greenish-yellow leaves are fan-shaped and composed of two or more distinct lobes; the Latin species name biloba refers to this fact. The common name of maidenhair tree pertains to the similarity of the leaves to those of maidenhair ferns (Adiantum spp.). In autumn, the leaves of the Ginkgo tree turn a beautiful golden hue before falling to the ground .
It takes between 20-35 years for maidenhair trees to reach maturity and start bearing seeds. Pollen and ovules are produced in the spring on separate trees and, following fertilisation, rounded seeds develop with a fleshy outer coat. These fall to the ground in the autumn and as the seed coat decays it exudes a rancid butter-like smell. Maidenhair trees can be extremely long-lived, the oldest recorded individual being 3,500 years old.
Threats & Conservation
This fascinating species grew in the gardens of temples in the East and the first seeds were brought to Europe in the 1700s. The decline of the Ginkgo in the wild (it is native only to China) is likely to have been a result of deforestation.
It is uncertain whether the maidenhair tree still persists in the wild and at present there are no conservation projects in place. Cultivated trees, however, are found throughout the world, and a multi-million dollar industry has cashed in on the medicinal properties of the leaves. As a result, it is likely that this ancient tree will stand the test of time.
Conservation assessments carried out at Kew
Ginkgo biloba is being monitored as part of the IUCN Sampled Red List Index for Plants, which aims to produce conservation assessments for a representative sample of the world’s plant species. This information will then be used to monitor trends in extinction risk and help focus conservation efforts where they are needed most.
Learn more about some of the plants that were assessed as part of this project.
Uses
More InformationGinkgo biloba has a long history of cultural importance in Asia. Confucius was said to have given his teaching whilst sitting under a ginkgo tree, which is one of the reasons the species is revered in Chinese tradition.
It is planted as an ornamental or bonsai tree, or as a shade tree. Male trees are preferable due to the unpleasant smell of the fleshy cones dropped by female trees. Despite the smell, these are a delicacy, hence the name ‘silver apricot’ in Chinese.
The seeds, known as ginkgo nuts, are eaten roasted or in birds' nest soup. The taste is said to be similar to that of a pine nut or sweet chestnut when baked. Ginkgotoxin (4'-O-methylpyridoxine), a constituent of the seeds, may cause poisoning unless the seeds are thoroughly cooked.
Gingko has been used in Chinese traditional medicine for centuries. Today, it is also cultivated for use in Western medicine. The leaves are used in herbal remedies for cognitive complaints, such as Alzheimer’s disease, dementia and vertigo. The phytochemistry and bioactivity of Ginkgo biloba have been the subject of extensive research.
Cultivation
More InformationFruits of Ginkgo biloba (Image: Wolfgang Stuppy)
Male trees are usually selected for cultivation, as female ones bear strong-smelling fruits that some find repulsive. These fruits are fleshy and yellow, containing a large seed. At Kew the seeds are collected during the autumn for production of seedlings and for rootstocks for grafting. The seeds are prepared by removal of the flesh, and then by placing them in a cold store for stratification.
The seeds are sown into open gritty compost in the spring. Tony Hall, who manages this collection at Kew, reports that germination usually takes eight to ten weeks and is predictable, with a similar performance from all the seeds. Germination takes place in a cool greenhouse, kept frost free (at a minimum of 5 °C), in natural light. The seedlings are generally free from pests and diseases. They are planted out in the Arboretum Nursery field when large enough. This is usually the following spring. After two years the plants can be as tall as 1.5 m at which point they are planted out into their final positions in the garden.
The maidenhair tree at Kew
There is a good collection of cultivars of Ginkgo biloba in the areas around the Waterlily Pond and the Bamboo Garden. In 2009 Her Majesty the Queen planted one of the seedlings raised in the Arboretum Nursery near to the Orangery for Kew’s 250th anniversary celebrations.
Perhaps the most well known tree of this species is the ‘Old Lion’ west of the Princess of Wales Conservatory (see image, right). This was one of the first of this species to be planted in Britain, Dating back to at least 1762 - less than 40 years after the first specimens had been introduced to Europe from China. It is one of the few trees at Kew remaining from the first botanic garden started by Princess Augusta, George III's mother, in 1759. Its hardiness was unknown, so it was planted against the wall of the Great Stove glasshouse for protection. This was subsequently demolished in 1861, which left the ginkgo standing alone. It is a multistemmed tree, probably due to the transplanting and moving early in its life which may have accounted for it losing its growing point. Past curators of the gardens recall the tree being grown against the wall of the great stove where it 'was trained like a fruit tree'. Other instances of Ginkgo trees being trained in this way have been reported. Several Ginkgo were planted at Kew in 1773 under the direction of Sir Joseph Banks.
In 2002 it became one of the 50 'Great British Trees' in a scheme run by the Tree Council to celebrate the Queen’s Golden Jubilee.
References & Credits
Acupuncture Today: http://www.acupuncturetoday.com/herbcentral/ginkgo_biloba.html
Bruneton, J. (1999). Pharmacognosy, phytochemistry, medicinal plants. 2nd Ed. Lavoisier, Paris.
Ginkgo biloba: http://perso.wanadoo.fr/ginkgo.dm/GINKGO/
Mabberley, D.J. (2008). Mabberley’s Plant Book: A Portable Dictionary of the Vascular Plants. 3rd Ed. Cambridge University Press.
Sun, W. (1998). Ginkgo biloba. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.3. <www.iucnredlist.org>. Downloaded on 22 September 2010.
Williamson, E.M. (2003). Potter’s herbal cyclopaedia. C.W. Daniel, Saffron Walden.
Kew Science Editor: Monique Simmonds
Authored in partnership with ARKive. For thousands of videos, images and fact-files illustrating the world's species visit www.arkive.org
While every effort has been taken to ensure that the information contained in these pages is reliable and complete, the notes on hazards, edibility and suchlike included here are recorded information and do not constitute recommendations. No responsibility will be taken for readers’ own actions. Full website terms and conditions.
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