Cheeseman. — Botanical Nomenclature. 459 



in favour of " rules " and " recommendations." The difference 

 between a rule and a recommendation is explained by Article 2, 

 which states that the rules are " destined to put in order the 

 nomenclature which the past has bequeathed to us, and to 

 form the basis for the future." Eecommendations " bear on 

 secondary points, their object being to insure for the future 

 a greater uniformity and clearness in nomenclature." Taken 

 collectively the rules are divided into three chapters, con- 

 taining 58 rules, or articles, as they are headed, and 37 recom- 

 mendations. " The rules are retroactive ; names or forms 

 of nomenclature which are contrary to a rule cannot be main- 

 tained." " Names or forms of nomenclature contrary to a 

 recommendation are not a model to copy, but cannot be 

 rejected." 



Article 9. — Under this rule it is provided that the nomen- 

 clature of cellular cryptogams and fossil plants shall be con- 

 sidered at the next International Congress, to be held at Brussels 

 in 1910. To this Congress is also to be presented a proposed 

 list of " Nomina Conservanda " for all divisions of plants other 

 than phanerogams. 



Articles 10-14. — These define the nature and subordination 

 of the groups constituting the vegetable kingdom. It will be 

 noticed that the word " order," which in the past has been 

 commonly applied to groups such as Ranunculacece, is now used 

 to designate those divisions of higher rank previously known 

 as " cohorts," the word " family " taking its place. In future 

 it will be necessary to speak of " the family Banunculacece," 

 " the family Cruciferce" &c. 



Article 15 provides that each group of plants, of what- 

 soever rank, can bear only one valid name, which must be the 

 oldest, provided that it is in conformity with other rules. 



Article 17. — " No one should change a name or a combina- 

 tion of names without serious motives, based on a more pro- 

 found knowledge of facts, or on the necessity of giving up a 

 nomenclature that is contrary to rules." It is to be hoped that 

 the spirit of this rule will be acted upon in the future. 



Article 19. — Under this rule it is definitely arranged that 

 botanical nomenclature shall commence with the publication 

 of the first edition of the " Species Plantarum " of Linnaeus 

 in 1753. The advantages of a fixed starting-point are undeni- 

 able, and the adoption of this rule alone marks a considerable 

 advance in the direction of stability of nomenclature. 



Article 20. — This important rule had better be quoted in 

 extenso : " However, to avoid disadvantageous changes in the 

 nomenclature of genera by the strict application of the rules of 

 nomenclature, and especially of the principle of priority in 



