Oleanane
From Wikipedia, the free encyclopedia
Oleanane is the name given to a chemical produced by many flowering plants, which has a suppressing effect on some insect threats.
It is considered a key marker differentiating flowering plants from other life, and in fact has been used in the effort to determine the evolution of flowers, called the Abominable Mystery by Charles Darwin because it had been so poorly explained by the fossil record, which has only recently begun to change.
This chemical appears, in fact, to have been shared by a group of plants called gigantopterids, which lived twice as long ago as the oldest known flower fossils, yet are now thought to probably have been close relatives, moving the appearance of flowers from 130 million years to a possible 250 million years ago.