The scientists at the Smithsonian’s Department of Paleobiology need your help!

This August we are asking citizen scientists all over the United States to collect Ginkgo leaves and mail them to us in Washington DC. All leaves will be entered into the permanent Smithsonian collection and kept forever, capturing a geographically diverse moment in time for this interesting and ancient species. We will be comparing the leaf pores found in these modern leaves to fossil Ginkgo leaves and living leaves grown under multiple air conditions.

We want to create a record of how the atmosphere has changed through time by calculating the percentages of two different types of leaf cell (stomatal and epidermal) for many leaves from the present and the geological past. Looking at this percentage (the stomatal index) on fossil and modern leaves gives us a powerful proxy for tracking how the climate has changed over the past tens of millions of years.

We are using Ginkgo trees because they are so ancient. Ginkgo trees evolved before the dinosaurs, over 200 million years ago. The genus has survived three mass extinctions, but only one species is still living today. We can find fossils of Ginkgo leaves throughout this huge span of time and amazingly, they often capture enough detail that, with the right preparation and microscopes, anyone can count the pores all these millions of years later.
We will be using the samples to answer our research questions about climate conditions now and in the deep past, but we anticipate future research teams will also use the collection to answer research questions that we cannot yet imagine.