Abstract
— Hennig conceived a method to build a “phylogenetic system”, with the stipulation that a “properly drawn phylogenetic tree must be directly translatable into the language of phylogenetic systematics”. Consequently, this system could be the general reference system of biology. A review of the classificatory technical improvements, conventions and rules which have been proposed for the past twenty years together with their application to the classification of the Proboscidea, leads to the conclusion that more than one formal system can be built upon one given cladogram. As words are used more frequently for communication than diagrams, schemes or graphs, the “general reference system of biology1‘ remains somewhere in Utopia. The “phylogenetic system” is rather more synonymous with a cladogram than with a written classification.