single common name often applies to multiple species of fishes. The lay public might simply not recognise or care about subtle differences in appearance between only very distantly related species. Many species that are rare, or lack economic importance, do not have a common name. Coining common names In scientific binomial nomenclature, names commonly are derived from classical or modern Latin or Greek or Latinised forms of vernacular words or coinages; such names generally are difficult for laymen to learn, remember, and pronounce and so, in such books as field guides, biologists commonly publish lists of coined common names. Many examples of such common names simply are attempts to translate the Latinised name into English or some other vernacular. Such translation may be confusing in itself, or confusingly inaccurate, for example, gratiosus does not mean "gracile" and gracilis does not mean "graceful". The practice of coining common names has long been discouraged; de Candolle's Laws of Botanical Nomenclature, 1868, the non-binding recommendations that form the basis of the modern (now binding) International Code of Nomenclature for algae, fungi, and plants contains the following: Various bodies and the authors of many technical and semi-technical books do not simply adapt existing common names for various organisms; they try to coin (and put into common use) comprehensive, useful, authoritative, and standardised lists of new names. The purpose typically is: to create names from scratch where no common names exist to impose a particular choice of name where there is more than one common name to improve existing common names to replace them with names that conform more to the relatedness of the organisms Other attempts to reconcile differences between widely separated regions, traditions, and languages, by arbitrarily imposing nomenclature, often reflect narrow perspectives and have unfortunate outcomes. For example, members of the genus Burhinus occur in Australia, Southern Africa, Eurasia, and South America. A recent trend in field manuals and bird lists is to use the name "thick-knee" for members of the genus. This, in spite of the fact that the majority of the species occur in non-English-speaking regions and have various common names, not always English. For example, "Dikkop" is the centuries-old South African vernacular name for their two local species: Burhinus capensis is the Cape dikkop (or "gewone dikkop", not to mention the presumably much older Zulu name "umBangaqhwa"); Burhinus vermiculatus is the "water dikkop". The thick joints in question are