The use of different and often outmoded systems for the arrangement of collections in botanic gardens and herbaria hampers international research because it makes finding the location of a specific genus and family unpredictable. Following a series of international workshops, intended to develop a set of widely accepted circumscriptions of vascular plant families, a European and Australian consortium, the Vascular Plant Classification Committee (VPCC), was formed in 2008 to address the challenge of harmonizing collections (of living and preserved material and associated literary archives) across Europe and Australia; this was envisaged as an ambitious first step towards a globally accepted alignment of family circumscriptions and the use of an accepted unified linear sequence. In 2009, agreement on this was reached among six of the largest European botanical organizations, a pioneering scientific and political accomplishment. Global acceptance of this arrangement is now beginning to gather pace. A network of organizations adopting this new classification and sequence (or intending to, when resources allow) is developing and now reaches across five continents. In this article, we outline the aims of and progress made by the VPCC, and acknowledge the resources required for the reorganization of large collections, with a particular focus on those at the Royal Botanic Gardens, Kew. The importance of a dynamic sequence, reflective of taxonomic changes, and the ways in which such changes can be incorporated into collections are discussed.© 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 172, 127-141. © 2013 The Linnean Society of London 172 2 June 2013 10.1111/boj.12031 Original Articles Original Article © 2013 The Linnean Society of London.