Botanists group plants into families according to their characteristics of flowers, leaves, stems, fruit and roots, nowadays supplemented by advanced techniques such as studies of gene sequences. This grouping process is known as classification and it allows botanists to organise their knowledge of the plant kingdom.
The classification system used at Kew is known as the Bentham-Hooker classification. This was devised by Sir Joseph Hooker, and another distinguished Kew botanist, George Bentham. At the time, it reflected views of evolutionary relationships of plants. Since then, botanists working at Kew and other botanical institutions around the world have improved the classification so that it reflects current thinking on plant evolution.
Kew's Herbarium contains a collection of over 7.5 million specimens of preserved plants, all classified and arranged according to this system.
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