Cheeseman. — Botanical Nomenclature. 449 



reject names given by their own contemporaries. Then, as 

 time went on it became apparent that many of the genera 

 established by Linnaeus or others of the early systematists 

 required alterations in their characters. Some were much too 

 extensive in their scope, and had to be divided into two or 

 more ; others were seen to be too closely allied, and had to be 

 merged. All these changes involved alterations in nomencla- 

 ture. And as the opinions of different authors working upon 

 the same genera or groups of genera were naturally and probably 

 unavoidably diverse, and as these opinions were often based 

 upon totally different ideas as to the limitations of both genera 

 and species, it followed, as a matter of course, that the resultant 

 nomenclature was different. In the early days of botanical 

 research, too, botanists were often imperfectly acquainted 

 with each other's work. It often happened that two authors, 

 working unknown to one another upon similar material, 

 would independently propose new generic or specific names 

 for the same plants. And although there was a vague under- 

 standing that the name first published was the valid one, it 

 often occurred that the oldest name was not at first recognised, 

 either from being described in some obscure publication with a 

 small or purely local circulation, which consequently escaped 

 the attention of botanists, or on account of the superior influence 

 or position of one of the workers. It would be easy to enu- 

 merate other causes leading to disputed or uncertain nomen- 

 clature ; but enough has been said to show that, with the pro- 

 gress of systematic botany, the nomenclature of the science 

 yearly became more involved and difficult of application. 



About 1865 the eminent botanist Alphonse de Candolle was 

 induced to take up the question. After much careful study, 

 and after an extensive correspondence with the leading botanists 

 of the time, he prepared a code of rules or laws of nomenclature 

 for the guidance of authors in the future. This code was sub- 

 mitted to an International Congress of Botanists held at Paris 

 in 1867. It was then fully discussed, and, with a few unim- 

 portant alterations, accepted and issued to the world under the 

 title of " Lois de la Nomenclature Botanique adoptees par le 

 Congres International tenu a Paris en Aout 1867." These 

 laws embodied many essential principles, were well arranged 

 and carefully drafted, and must be considered as constituting 

 a decided step in advance. It was clearly laid down that in all 

 cases of synonymy the earliest-published name, if accompanied 

 by a sufficient description, should take precedence over names 

 of later date; and this law was made retrospective, no doubt 

 with the intention of providing that disputed questions of old 

 date should be settled by the application of a fixed rule rather 

 15— Trans 



