John Sibthorp's Flora Oxoniensis (1794) is often regarded as the first British county Flora. The Flora, the only piece of work Sibthorp published during his short life, was the culmination of his investigations into the distribution of plants around Oxford. Studies of plant distribution, prominent during the nineteenth century, provided the evidence in the twentieth century that some once familiar plant species were declining, whilst once rare species were expanding their ranges. This talk will discuss how our knowledge of the taxonomy of Oxfordshire plants has changed since Sibthorp's work and how modern technologies enhance our abilities to conserve plant species. Dr Harris is the Druce Curator of Oxford University Herbaria. His background is in plant systematics and population genetics and he is interested in plant evolution, the history of botany and how we use and modify plants. He has worked in a range of temperate and tropical ecosystems.