Susyn Andrews heads the Horticultural Taxonomy Unit at the Royal Botanic Gardens, Kew and was a co-founder and Chairman of the horticultural Taxonomy Group (HORTAX), 1988-1998. She specialises in Ilex and Lavandula, has a keen interest in temperate and subtropical woody plants and is a member of ISHS Commission for Nomenclature and Registration. Alan Leslie, as Senior Registrar for The Royal Horticultural Society, is responsible for all the international cultivar registration undertaken by the RHS. He is currently a member of the International Commissions dealing with the Cultivated Plant Code and the appointment of International Registration Authorities. Crinan Alexander is Chairman of the Horticultural Taxonomy Group and was involved in the European Garden Flora project from its inception in 1979. He is based at the Royal Botanic Garden, Edinburgh and is now working on Rosaceae (Spiraeoideae) for the Flora of China.