PREFACE 



proceed, but it presents numerous difficulties and creates doubts 

 and uncertainty. It gives too much weight to unscientific work. 

 One is never sure of finality. It necessitates researches not only 

 in the literature devoted to the genus under consideration and 

 to allied genera, but even in that devoted to distinct families. 

 When priority sanctions the reinstatement of the name of a genus 

 which has been lost sight of for years because it was originally 

 referred to the wrong family, it not only calls for a close scrutiny 

 of all systematic literature, but demands an examination of the 

 type material of every obscure or insufficiently characterized 

 genus and species. Prolonged effort may ultimately do away with 

 the confusion which the laws based on priority are sure to cause 

 in the beginning, but it is doubtful if the end warrants the means. 

 If priority is absolute it places a burden on the systematist 

 which must in the end render him indiffisrent to nomenclature. 

 In the first place actual dates of publication must be known, 

 otherwise priority becomes a misnomer. There are rules which 

 we may follow when in doubt regarding the date of publication 

 of a work, but these rules are arbitrary and useless if accident or 

 other means discover that the date on a title-page is misleading 

 or incorrect. This difficulty is not confined to the older litera- 

 ture of botany. Kranzlin's Orchidacearum Genera et Species, for 

 example, bears 1901 on the title-page of the first volume as date 

 of publication. Yet the parts of this volume were issued in 1897, 

 1898, 1899, 1900, and 1901. If the original covers of the parts 

 are not available Kranzlin's work would be useless in fixing pri- 

 ority of publication. In my copy of Dr. Kranzlin's work the six- 

 teenth fascicle, which contains the title-page and preface, is dated 

 1897 on the original cover. This fascicle appeared in 1901. Then 

 again botanical periodicals, the parts of which appear monthly, 

 are often inconclusive in settling dates of pubUcation, as a part 



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