Yes, but how do we know this? The evidence comes from fossil relatives of a plant that is familiar to many - the maidenhair tree, Ginkgo biloba. It is often called a ‘living fossil’, because its earliest remains extend to 200 million years ago (mya), and close relatives to 300 mya. What’s particularly interesting is that it’s the outer ‘skin’ (epidermis), of its fossilized leaves provide evidence about ancient climates, and in particular, atmospheric CO2.
