Anthos is the name of a database and search system for quality-controlled chorological and taxonomic information on the vascular plants of Spain. It provides a trustworthy solution for the handling of accepted names and their synonyms, based on an analysis of nomenclatural relations. It is based on the MS SQL-Server relational database system. Information can be found on any plant, using its accepted name or synonyms or vernacular names. The geographical search options include lists of all plants of a given territory, a province, a region or an area delimited by its UTM coordinates. Additional information is available in the form of photographs or drawings, chromosome numbers, vernacular names and synonyms.