34 Rhodora [Marcu 
respect for persons, etc., notwithstanding their undeniable importance 
are relatively accessory. 
Art. 5. No custom contrary to rule can be upheld if it leads to 
confusion or error. When a custom offers no serious inconvenience 
of this kind, it may be a ground for exceptions which we must however 
abstain from extending or copying. Finally in the absence of rule, 
or where the consequences of rules are doubtful, established custom 
becomes law. 
Art. 6. The principles and forms of nomenclature should be as 
similar as possible in botany and in zoology; but botanical nomen- 
clature is entirely independent of zoological nomenclature. 
Art. 7. Scientific names are in latin for all groups. When taken 
from another language, a latin termination is given them, except in 
cases sanctioned by custom. If translated into a modern language, 
it is desirable that they should preserve as great a resemblance as 
possible to the original latin names. 
Art. 8. Nomenclature comprises two categories of names: 1. 
Names, or rather terms, which express the nature of the groups 
comprehended one within the other. 2. Names peculiar to each 
of the groups of plants that observation has made known. 
Art. 9. The rules and recommendations of botanical nomen- 
clature apply to all classes of the plant kingdom, reserving special 
arrangements for fossil plants and non-vascular plants.’ 
Chapter II. On the manner of designating the nature and the 
subordination of the groups which constitute the 
plant kingdom. 
Art. 10. Every individual plant belongs to a species (species), 
every species to a genus (genus), every genus to a family (familia) 
every family to an order (ordo), every order to a class (classis), every 
class to a division (divisio). 
Art. 11. In many species we distinguish varieties (varietas) and 
forms (forma); and in some cultivated species, modifications still 
more numerous; in many genera sections (sectio), in many families 
tribes (tribus). 
Art. 12. Finally if circumstances require us to distinguish a 
greater number of intermediate groups, it is easy, by putting the 
1 These special arrangements have been reserved for the Congress of 1910. They 
comprise: 1, rules bearing on special points in relation to the nature of fossils or the 
lower plants; 2. lists of nomina conservanda for all divisions of plants other than Phan- 
erogams, 
