30 CLASSIFICATION AND TAXONOMY OF FUNGI 



indicate their evolutionary position and genealogical relationship. 

 Such a system could appropriately be designated the natural sys- 

 tevi. In lieu of a natural system, purely artificial or predomi- 

 nantly artificial systems are in general use. 



In any scheme of classification the worker must deal with 

 units, each of which must have a designation, such as phylum, 

 class, order, family, genus, and species. Definition of these terms 

 is a vexatious academic problem upon which systematists are not 

 in accord but have a variety of opinions. 



Nomenclature. As a natural consequence of attempts by dif- 

 ferent persons to apply names to plants and of difficulties at- 

 tendant on printing and exchanging information on this subject, 

 the same organism often came to bear more than one name. This 

 situation of course could lead only to confusion. Moreover a 

 name at first was either a single word or a brief descriptive 

 phrase. Since the publication of Linnaeus' Species Plaiitarum in 

 1753, however, each species bears two names, the first being that 

 of the genus to which it belongs, and the second being that of 

 the species. Subsequently, as new^ organisms were described, the 

 principle of priority came to be accepted in determining the 

 proper binomial. According to this principle, the oldest bino- 

 mial used is the accepted one. If this principle is regarded as 

 sacrosanct and its strict application is insisted upon in spite of 

 general usage and common sense, there is little chance of estab- 

 lishing stability in nomenclature, especially for certain old and 

 well-known genera. Other problems in nomenclature meanwhile 

 arose, and the machinery for their settlement was created at the 

 International Congress of Paris in 1900. The codes and rules 

 agreed upon by committees then and at subsequent International 

 Congresses constitute a working basis for the solution of all 

 such problems. A composite statement of these international 

 rules was published as a supplement to The Journal of Botany 

 (British and Foreign) for June, 1934, and should be carefully 

 perused by all biologists. 



Among the facts important to mycologists in these rules are: 

 {a) the nomenclature of the Myxomycetes begins with Linnaeus' 

 Species Plantarzim, 1753; (b) the nomenclature of the Uredinales, 

 Ustilaginales, and Gastromycetes begins with Persoon's Synopsis 

 Methodica Fungoruvi^ 1801; and {c) the nomenclature of all 

 other fungi is based on Fries's Sy sterna Mycologiciim, 1821-1832. 



