Conservation of Britain’s biodiversity: Hieracium riddelsdellii (Asteraceae), Riddelsdell’s Hawkweed

Hieracium riddelsdellii Pugsley, Riddelsdell’s Hawkweed, is a rare Welsh endemic plant. It was first found in 1899, was described as a variety in 1907, and raised to a species in 1941. It has been reported from four sites, but is currently only known in two localities in the Brecon Beacons (v.c. 42) and one in Carmarthenshire (v.c. 44), with an estimated total population of about 870 plants. Records for Berwickshire (v.c. 81) refer to another taxon. It qualifies as ‘Vulnerable ’ under the IUCN Threat Criteria. The main threat is the spread of Cotoneaster integrifolius over its Carboniferous Limestone rocky habitats, but all populations would also benefit from relaxation of grazing pressure. It is being cultivated at the National Botanic Garden of Wales and seed has been deposited in the Millennium Seed Bank