The Vascular Plant Herbarium aims to give a complete illustration of the flora of Wales by means of collections which are international in scope, importance and quality. To enable the Welsh flora to be put into context, there is also material from the remainder of the British Isles, Europe and the rest of the world. The collections are of international importance.
The herbarium contains approximately 40% Welsh material, 25% remainder of British Isles, 22% foreign and 3% cultivated. Virtually all native British plants are represented, as well as many introduced species. There are outstanding collections of critical groups including Hieracium, Rubus, Sorbus and Taraxacum collection. Associated collections include the library, timber collections, photographic slides, spirit, carpological, seed, wax models, stamps and cigarette cards, and economic plants. The herbarium also contains a small, but very precious Ghost Orchid collection
The herbarium originated in 1870 when Cardiff Museum purchased a small collection of dried plants collected in the 1830s by Charles Conway. In 1888 this collection was added to when John Storrie gave his collections to the Museum and around 1900 two important collections were received from A. Bennett and H.J. Riddelsdell. In 1912 the collection was taken over by the newly constituted National Museum of Wales, when it constituted some 3,500 mounted specimens. By 2009 the collections had expanded to some 255,000 specimens through gifts, exchange, purchase of herbaria and fieldwork.