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
Figure 7.2.1: 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 bilobaleaves, photo by Onidiras, CC-BY-NC. Second: Fossil Ginkgo leaf by Anders Sandberg from Oxford, UK, CC BY 2.0, via Wikimedia Commons.Figure 7.2.2: 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.Figure 7.2.3: Male Ginkgo bilobatrees produce microstrobili that look a bit like inflorescences. Inside these structures, pollen is produced. Photo by Belvedere04, CC-BY-NC.Figure 7.2.4: Female Ginkgo bilobatrees 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.Figure 7.2.5: 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 bilobaat Zenpuku-ji in Azabu. Photo by Belvedere04, CC-BY-NC.