Ginkgo

Ginkgos are woody, non-flowering plants from the sub-class of gymnosperms called Ginkgoidae. Only one solitary species, Ginkgo biloba, remains on Earth and is found naturally in a small area of China.

The ginkgo, also known as maidenhair tree, is an ancient plant with unique leaves that distinguishes it from all other plants. They can be extremely long-lived plants and are known to live for over 1500 years.

Growth form

The ginkgo is a tree that grow to around 30 m and has fan-shaped leaves with a unique vein pattern. The veins begin at the base of the leaf and run out to the edge of the leaf, each vein splitting into two new veins multiple times along the length of the leaf.

Ginkgos have initially fast growth rates with very little branching until they reach about 5 m. At this height they begin growing branches out laterally. They are deciduous trees and leaves turn yellow each autumn before falling off.

Distribution

Gingkos are naturally found in deciduous forests only in two small areas in the Zheijiang province of China. They were however once widespread through many parts of the world.

Although they only grow wildly in a very small area, Ginkgos have been planted and cultivated in many places around the world by humans.

Diversity and taxonomy

As already mentioned, there is only one species of Ginkgo remaining, Ginkgo biloba. There were, however, a number of species on Earth around 200 million years ago.

The Ginkgos belong to the class of plants known as Pinopsida which includes all other gymnosperms such as Conifers, Cycads and Gnetales. They are then separated into the own sub-class called Ginkgoidae and the order Gingkoales.

Evolution

The Ginkgos are an ancient group of plants and are thought to have possibly evolved from ‘seed ferns’. Fossils found from right back in the Permian period around 250 million years ago. Fossils in Antarctica have been found from the Jurassic period between 201-145 million years ago.

Apart from the one remaining species, all other species from the sub-class Gingkoidae are believed to have gone extinct 3 million years ago or earlier.

Reproduction

Being gymnosperms, ginkgos reproduce with seeds and without flowers. Gingko trees have unusually fleshy seeds that resemble fruit in appearance.

Ginkgo trees are either male or female. Male trees have small pollen cones which contain mobile sperm. Female trees do not have cones but have ovules containing eggs. Fertilisation of eggs occurs when pollen reaches the ovules and the mobile sperm enters the female’s eggs.

Last edited: 28 May 2015