240 The Ottawa Naturalist. [March 



latter, with some modifications, in Britton and Brown's Manual, 

 Mr. Macoun told of the work of the International Botanical 

 Congress at Paris in 1900 and at Vienna in 1905. The arrange- 

 ment of genera by Engler and Prantl will, with a few changes, 

 be the one used in future by practically all systematic botanists. 

 This will entail the rearrangement of nearly all Canadian 

 herbaria, as these now are, with very few exceptions, arranged 

 according to Macoun's Catalogue of Canadian Plants which 

 follows Bentham and Hooker. The rules of nomenclature 

 approved by the Vienna Congress and which haA'e already been 

 accepted by nearly all systematic botanists will entail no very 

 great changes in the names of plants as they are known to local 

 botanists who have used Gray's Manual. Between 3 and 5 per 

 cent, of the generic names, and something over 10 per cent, of 

 the specific names will need to be changed. If the Vienna rules 

 are strictly followed a much larger number of changes must be 

 made by those who have used Britton and Brown's Manual. 



As regards genera the chief point of difference between what 

 is known as the Rochester Code, that followed by Britton and 

 Brown, and the Vienna Rules, is the list of genera to which the 

 Vienna Congress decided its own rules should not apply. It has 

 been decided that botanical nomenclature of both genera and 

 species is to begin with the publication of Linnaeus' "Species 

 Plantarum" in 1753, but in order to avoid the very large number 

 of changes in genera which would be necessary if this rule were 

 strictly followed, the Vienna Rules provide a list of names 

 which must be followed in all cases. This hst includes about 

 400 generic names which of course carry with them many 

 thousand species. An important group of American botanists 

 has refused to accept these exceptions and will continue to use 

 the oldest generic names not, of course, going further back than 

 1753. Most amateur botanists, at least, will welcome the list 

 of exceptions and not hesitate to follow it. By doing so they 

 need not substitute Panicularia for Glyceria, Juncoides for 

 Luzida, Vagnera for Smilacina, Hicoria for Carya, Capnoides 

 for Corydalis, Falcata for Amphicarpcea, Ilicoides for Nemo- 

 panthus, Pneurmaria for Mertensia, Leptamnium for Epiphcgus, 

 Hedypnois for Taraxacum, and so on. A few of the more im- 

 portant rules adopted by the Vienna Congress were given by 

 Mr. Macoun. As these rules have been pubUshed in several 

 botanical periodicals they need not be reprinted here. They 

 will be found in the March, 1907^ issue of Rhodora, in the librarv 

 of the Club. --^CN'^it/i/ 



.V^_ < V J. M. M. 



