function as if they had been in the Code in 1753, and indeed as if the Code had existed in 1753. In reality, the Code did not exist until Alphonse de Candolle published his Lois de la Nomenclature Botanique in 1867 (Candolle, 1867), and much of the content of the Code today was added since 1867.
Novice and veteran users of the Code alike would agree that it is a very complex document. This complexity has evolved over 17 editions beginning with Candolle’s Lois. Throughout this more than 150-year history, diverse issues have arisen prompting scientists to refine the rules every few years at an International Botanical Congress, and since 2018 also at an International Mycological Congress, each time making the Code a little more precise but at the same time a little more complex. Some rules are of fundamental importance, whereas others exist only to govern rare cases. The fundamental rules are sometimes quite simple, whereas the rare-case ones are sometimes formidably complex, and vice versa. It is not necessary to learn and understand every rule in the Code in order achieve competence in nomenclature. This guide aims to highlight the most important rules.
The rules of the Code are not law but are voluntarily followed with an international consensus, i.e. the majority of botanists, mycologists, and phycologists worldwide have agreed to follow the rules. Scientific names published in compliance with these rules can achieve international acceptance. Names published under alternative sets of rules might gain acceptance among the particular groups of scientists who follow those particular rules, but they will not be generally accepted by the international scientific community.
THE DRAFT BIOCODE
Over the last few decades, efforts have been made to harmonize the terminology and rules of the current separate biological codes into a single set of rules for biological nomenclature, which came to be called the Draft Bio Code (Greuter & al., 1998, 2011). The current codes, while they have a great deal in common, have quite different rules for some situations. For example, the Code for algae, fungi, and plants rules that a tautonym, in which the specific epithet exactly repeats the generic name, cannot be validly published, whereas tautonyms such as Glis glis and Rattus rattus are permitted by the ICZN. There is also a problem with homonyms, i.e. two or more names spelled exactly alike but applying (usually) to different organisms. While a later (or junior) homonym cannot be legitimate under the Code for algae, fungi, and plants, or potentially valid under the ICZN, these rules apply mostly within their respective codes, rarely across them, so that, e.g., Pieris applying to a woody plant and Pieris applying to a butterfly are both legitimate/potentially valid names. There is also a problem with terminology between the codes, in which different terms are used for the same concept and the same term is used for different concepts. This is illustrated by the examples in Table 1 (p. 14).
The Draft Bio Code, developed by the International Committee on Bionomenclature (http://www.bionomenclature.net/), was intended to solve these problems through
INTRODUCTION13
