and convenes periodic international meetings to further that purpose. Common names and the binomial system The form of scientific names for organisms, called binomial nomenclature, is superficially similar to the noun-adjective form of vernacular names or common names which were used by prehistoric cultures. A collective name such as owl was made more precise by the addition of an adjective such as screech. Linnaeus himself published a flora of his homeland Sweden, Flora Svecica (1745), and in this, he recorded the Swedish common names, region by region, as well as the scientific names. The Swedish common names were all binomials (e.g. plant no. 84 Råg-losta and plant no. 85 Ren-losta); the vernacular binomial system thus preceded his scientific binomial system. Linnaean authority William T. Stearn said: Geographic range of use The geographic range over which a particularly common name is used varies; some common names have a very local application, while others are virtually universal within a particular language. Some such names even apply across ranges of languages; the word for cat, for instance, is easily recognizable in most Germanic and many Romance languages. Many vernacular names, however, are restricted to a single country and colloquial names to local districts. Constraints and problems Common names are used in the writings of both professionals and laymen. Lay people sometimes object to the use of scientific names over common names, but the use of scientific names can be defended, as it is in these remarks from a book on marine fish: Because common names often have a very local distribution, we find that the same fish in a single area may have several common names. Because of ignorance of relevant biological facts among the lay public, a single species of fish may be called by several common names, because individuals in the species differ in appearance depending on their maturity, gender, or can vary in appearance as a morphological response to their natural surroundings, i.e. ecophenotypic variation. In contrast to common names, formal taxonomic names imply biological relationships between similarly named creatures. Because of incidental events, contact with other languages, or simple confusion, common names in a given region will sometimes change with time. In a book that lists over 1200 species of fishes more than half have no widely recognised common name; they either are too nondescript or too rarely seen to have earned any widely accepted common name. Conversely, a