Ginkgo (Ginkgo biloba)

Ginkgo biloba is probably most commonly seen, or rather noticed, as an extract and health supplement sitting on pharmacy shelves. But the ginkgo has a rather poignant history. It’s been found in fossils dating back 270 million years, which means that it’s been around for a very, very long time. Its distinct fan-shaped leaves are hard to miss, being a light green in the spring and summer, turning to a golden yellow in the autumn before falling off in the winter. Unfortunately for it, it’s now the only member of its division (or phylum) surviving today. This means that it’s only very distantly related to any other plant on Earth, and in that sense, a very lonely species. Luckily for it though, it’s found its own way to have some company. The ginkgo is dioecious, meaning that there are separate male and female trees. Male trees bear cones, whilst female trees bear ovules. It’s actually somewhat romantic, if you think about it.

male ginkgo tree

Male ginkgo tree

Ginkgo biloba probably owes its continued existence to Chinese monks. Based on fossil evidence, its range had shrunk from being widespread throughout the world to a small area of China, where monks propagated them and kept them alive. They’re very long lived trees, and some are reportedly thousands of years old. A part of the reason is that these trees are particularly resistant to common killers, such as diseases and insects, and uncommon killers, such as the atomic bomb in Hiroshima, Japan. Based on the work of scientists in China, who sequenced the draft genome of Ginkgo biloba, it contains around 41,840 genes, many of which could contribute to its defence mechanisms. It helps that the tree is rather good at propagating itself. Seeds easily grow into new trees, and old trees are also capable of engaging in clonal reproduction, where aerial roots grow from the branches down towards to the soil and establish a new plant. Today, ginkgo trees can be found in China, Japan, Korea, North America, and even Europe.

And in the typical nature of human pride, we’ve managed to find a way to eat what insects won’t even touch. An extract of the leaves, which is what we see in stores, is thought to be useful in enhancing brain function, perhaps even in the treatment of Alzheimer’s disease or dementia. For those amongst you who are Asian, we’ve also seen its seeds in dessert or herbal soups. They’re a nightmare to shell, requiring hammers and fingernails, more patience than you have, and if improperly hammered would squish out a whitish sticky juice that I didn’t quite appreciate. They’re a little bitter, and are somewhat elastic, a little starchy, with a consistency like roasted chestnuts. Whether raw or cooked, there’s a distinct smell to them that some might enjoy, but could also be described as being a little pungent. If it isn’t yet clear, I wasn’t a fan, but ate the ginkgo seeds anyway, more because we’d spent hours getting those things peeled than because I actually wanted to. Nevertheless, in traditional Chinese medicine they’re thought to be effective in treating ailments of the lung, asthma, and coughs. It has to be noted, firmly, that over-consumption of the seed is not advisable. At high concentrations, the chemical compounds can lead to convulsions, excessive bleeding, heart palpitations, and gastrointestinal discomfort, to name a few. As with all medicinal plants and supplements, no matter how beneficial they are, they have to be consumed in moderation.

So the next time you see a ginkgo, remember that it’s not just another tree. It’s a very special type of tree, one whose ancestors have seen the birth of human history.

References

  1. http://www.baike.com/wiki/%E7%99%BE%E6%9E%9C
  2. http://www.bbc.com/news/science-environment-38057741
  3. https://academic.oup.com/gigascience/article-lookup/doi/10.1186/s13742-016-0154-1
  4. https://en.wikipedia.org/wiki/Ginkgo_biloba
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