7.2: Ginkgos

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As of 2019, the most recent genetic studies have placed Ginkgos as the oldest of the extant gymnosperms. This does not mean that it was the first gymnosperm. From the fossil record, it seems that most early gymnosperms went extinct. The sole remaining species in this group, Ginkgo biloba, is a living fossil virtually unchanged from its fossilized ancestors. It is possible that this species was only kept alive due to cultivation efforts by Buddhist monks for its medicinal properties. This species is also long-lived, a single tree can live for thousands of years, and resistant to most pests. Ginkgo biloba can be recognized by the following features:

Leaves deciduous, but tough, fan-shaped
Dioecious (di- meaning two, oecious meaning house), with male and female strobili on separate plants. Females plants have paired ovules at the tips of branches, males have catkin-like structures that produce pollen.
Wind pollinated

Two fan-shaped green leaves that are broken into two main lobes. The vascular tissue is parallel. — Figure \(\PageIndex{1}\): Ginkgo leaves have a distinctive shape that has remained relatively unchanged from their fossil record: a fan-shaped leaf that is often deeply dissected in the center. The fossil leaf on the right is around 60 million years old. First: *Ginkgo biloba* leaves, photo by Onidiras, CC-BY-NC. Second: Fossil Ginkgo leaf by Anders Sandberg from Oxford, UK, CC BY 2.0, via Wikimedia Commons.

A fossil of a fan-shaped leaf with parallel vascular tissue — Figure \(\PageIndex{1}\): Ginkgo leaves have a distinctive shape that has remained relatively unchanged from their fossil record: a fan-shaped leaf that is often deeply dissected in the center. The fossil leaf on the right is around 60 million years old. First: *Ginkgo biloba* leaves, photo by Onidiras, CC-BY-NC. Second: Fossil Ginkgo leaf by Anders Sandberg from Oxford, UK, CC BY 2.0, via Wikimedia Commons.

Looking up the trunk of a large Gingko tree. All of the leaves are golden. — Figure \(\PageIndex{2}\): Leaves of *Ginkgo biloba* are xerophytic and somewhat tough. However, they are deciduous. In fall, they turn a beautiful golden yellow before dropping from the tree. Ginkgo biloba, photo by Chocochan, CC-BY-NC.

A male gingko tree with several microstrobili that look like catkins — Figure \(\PageIndex{3}\): Male *Ginkgo biloba* trees produce microstrobili that look a bit like inflorescences. Inside these structures, pollen is produced. Photo by Belvedere04, CC-BY-NC.

Female ginkgo tree producing many fleshy, paired ovules — Figure \(\PageIndex{4}\): Female *Ginkgo biloba* trees produce fruit-like megastrobili as fleshy, paired ovules. Each globose structure contains a developing seed. Apparently, they can smell quite putrid. Photo by Kim, Hyun-tae, CC-BY.

The other side of the tree trunk, showing descending root-like structures — Figure \(\PageIndex{5}\): Ginkgos can be quite long-lived. This ginkgo tree is approximately 750 years old. It bears burn scars from WWII and has a complex trunk structure. It is sometimes referred to as the inverted or upside down tree due to the numerous aerial roots growing steadily downward. *Ginkgo* *biloba* at Zenpuku-ji in Azabu. Photo by Belvedere04, CC-BY-NC.