Ginkgo tree: Ginkgo biloba

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Interactive Botanical tour

Point No. 6

Species: Ginkgo biloba L.

Family: Ginkgoaceae

 

This is a Ginkgo biloba tree, commonly known as maidenhair tree, named after the similarity of its leaves to that of the maidenhair fern. It is one of the the most ancient of all gymnosperms (seed-producing, non-flowering plants), and is the sole survivor of its order, Ginkgoales, the family dating back to a quarter of a billion years ago. As one of the oldest living tree species it is a true living fossil.

 

By User:SNP ; User:tangopaso - English Wikipedia, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=6532895

 

Description

The species name is a corruption of a latinised Japanese loan word for the tree, meaning "silver apricot", refering to its small "fruit", which are actually fleshy cones. Biloba is latin meaning two lobes, as the leaves look like two lobes fused together to make a semi-circle. These leaves are how we know how old this species is, with prehistoric leaf fossils looking identical to the leaves above you, with most of the plant’s traits being virtually unchanged since it arose all that time ago. These fossils are older than dinosaurs, meaning that this species is older than them, and survived the extinction that wiped them out!¹

It is a large deciduous tree, meaning that it loses its leaves in winter, and is known for its leathery leaves turning a bright yellow before they fall.¹ These trees are dioecious, meaning that there are separate plants for male and female trees. This one is a male, you can tell by the tiny spiky cones on its branches, looking like small bumpy fingers. These cones will release pollen, which reaches female ginkgo’s ovule via wind pollination, fusing to make a zygote, which will grow into a seed. After fertilisation, this hard seed will be surrounded by a peach-coloured fleshy "fruit", around the size of cherries. These stink of rancid butter or vomit, or to our cheese educated friends- apparently it smells like Limburger cheese!

Photo 54805267, (c) michelleleung, some rights reserved (CC BY-NC)
 

Photo 132687538, (c) Лариса Перекати-Кошка Осколкова, some rights reserved (CC BY-NC), uploaded by Лариса Перекати-Кошка Осколкова

 

Ginkgo is native to China, where it is known as Bai guo. It is most well suited for temperate climates and deep moist soils, and although it is not able to withstand much climatic variation, it is able to withstand severe trauma, as an example, after the atomic bomb landed on Hiroshima in 1945, at least 6 Ginkgo trees were known to have survived the fireball, while most human structures were destroyed. It is also very capable of surviving pollution, which is why it’s been able to live in urban areas.

 

Seemingly extinct in the wild, the tree has been conserved and spread by humans for ornamental and medicinal purposes for millenia, first being described in Japanese records in the medieval period, indicating that it was likely transported from China to Japan around this time. In the 1700’s it was transported to Europe, where it was officially named and recorded as a species by Linnaeus. It was then introduced into the USA around 1780, where it is now one of their most common ‘street plants’, with over 60 000 Ginkgo trees currently growing in New York. It is still very common and beloved throughout Asia, particularly found in temple gardens in China and Japan.

A very long lived plant, some individual trees being over 3000 years old, the species itself has survived multiple mass extinctions, and outlived its pests and predators, seed vectors and the entire ecosystem it evolved in! As well as "living fossil", perhaps we should also call them "ecological fossils", because the world that existed when these plants reached their final form is tens of millions of years gone!

Perhaps it is due to their incredibly deep root system, allowing them to reach water deep in the Earth even during droughts. Maybe it’s because these trees contain a wide variety of secondary metabolites, chemicals that they produce internally. These chemicals aid the plant by preventing abiotic and biotic stress by fending off diseases, repelling insects and resisting fungi. They also produce a fire-retardant sap protecting them from fire damage. This overall leads to a tree that is very hard to kill. With its long life and toughness, it is sometimes referred to as a ‘bearer of hope’ in its native regions.

History at University of Pretoria

The biggest individual on campus is located near the old Botany building. It was planted around the same time the building was constructed. Currently, there are 3 male individuals and one lone female individual on campus. These trees fruit after 25-30 years.

Uses

This prehistoric plant has boasted a number of medical benefits since it was first used in ancient China where it was believed to alleviate the symptoms of asthma and provide cognitive benefits such as memory improvement. Its use has continued today taken as a supplement for its circulatory benefits, protection against free radicals and improvement in memory and cognition. While safe when a leaf extract is prepared, the hard centre of the Ginkgo "fruit" are poisonous unless correctly prepared and thoroughly cooked.³ 

Overall, the plant in front of you is a great display of how to stand the test of time as through the ages the Ginkgo has stood tall and will hopefully do so for years to come.

 

 

 

Text prepared by Jemima Van Hagen & Joshua Pretorius, 2022 BOT 366 class.

 

Cited sources:

¹ Crane, P. R. (2019). An evolutionary and cultural biography of ginkgo. PLANTS, PEOPLE, PLANET, 1(1), 32–37. https://doi.org/10.1002/ppp3.7

² Zhao, Y., Paule, J., Fu, C., & Koch, M. A. (2010). Out of China: Distribution history of Ginkgo biloba L. TAXON, 59(2), 495–504. ^{https://doi.org/10.1002/tax.592014}  

³ Ginkgo: Overview, uses, side effects, precautions, interactions, dosing and reviews. (n.d.). Retrieved November 3, 2022, from https://www.webmd.com/vitamins/ai/ingredientmono-333/ginkgo