Just a quick link through to a NERC blog on the use of Araucaria trees in investigating plant responses to higher carbon dioxide levels. The visiting researchers used NHM botany collections and those of a number of other institutions, in addition to growing and experimenting on living plants.
Araucaria includes the familar garden Monkey Puzzle tree and are part of a group of plants that reached its maximum diversity during the Jurassic and Cretaceous periods between 200 and 65 million years ago. It is known that in conditions of higher or lower carbon dioxide, plants will have different numbers of gas-exchange pores (stomata) on their leaves. The interest of Araucaria lies in whether the number of stomata in fossils can be used to understand more about past patterns of carbon dioxide variation and hence climate change linked to atmospheric changes.
Fossil Araucaria cones from the Jurassic