 One thing that pops into my mind is a plant called Franklinia which is a member of the tea family. It's a beautiful white flowering shrub and it grew wild in Florida along the Alatomah River and a couple of British botanists in the late 18th century 1780 something named Bartram collected apparently the entire population. It's never been found again wild and is presumed wild extinct in the wild. However it occurs in botanical gardens all over the world but we have many specimens of Franklinia from various places which is an extinct in the wild now. Perhaps others that we don't know about will turn out to be extinct.