The University of Oxford Botanic Garden is the oldest botanic garden in Great Britain and one of the oldest scientific gardens in the world. The garden was founded in 1621 as a physic garden growing plants for medicinal research. Today it contains over 5,000 different plant species on 1.8 ha (4+1⁄2 acres). It is one of the most diverse yet compact collections of plants in the world and includes representatives from over 90% of the higher plant families.