CODE OF BOTANICAL NOMENCLATURE 
Part I. PRINCIPLES. 
1. The primary object of formal nomenclature in systematic biol- 
ogy is to secure stability, uniformity and convenience in the 
designation of plants and animals. 
2. Botanical nomenclature is treated as beginning with the general 
application of binomial names of plants (Linnaeus’ Species 
Plantarum, 1753). 
3. Priority of publication is a fundamental principle of botanical 
nomenclature. Two groups of the same category cannot 
bear the same name. 
Nore.—Previous use of a name in zoology does not preclude its use in 
botany. 
4. The application of a name is determined by reference to its 
nomenclatorial type. 
Part II. Canons. 
Section I. Categories of Classification. 
Canon 1. Connected or coherent groups of individuals are termed 
species, 
Canon 2. Species are grouped into genera; genera into tribes ; 
tribes into families ; families into orders ; orders into classes ; 
classes into phyla. 
Nore.—Order is preferable to cohort and phylum to division, conforming 
to zoological usage. 
Canon 3. When additional categories are necessary for the con- 
venient présentation of relationships, they are to be obtained 
by the recognition of intermediate groups, the names of 
which are formed by prefixing sub- to the names of the 
above principal categories. 
EXAMPLES.—Subspecies, subgenus, subfamily, suborder. 
Canon 4. Other terms, such as group, section, series, division, 
and branch, may be used for more convenient temporary ar- 
rangement under the above categories, but their names are » 
to have no validity in formal taxonomy. 
NoTEe.—The term variety is relegated to horticultural usage. 
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