PREFACE 



The accompanying paper, by Prof. A. S. Hitchcock, Systematic 

 Agrostologist of the United States Department of Agriculture, 

 entitled u Types of American grasses: a study of the American 

 species of grasses described by Linnaeus, Gronovius, Sloane, Swartz, 

 and Michaux," is an important contribution to our knowledge of 

 American grasses. 



It is regarded as of fundamental importance in the critical sys- 

 tematic investigation of any group of plants that the identity of the 

 species described by earlier authors be determined with certainty. 

 Often this identification can be made only by examining the type 

 specimen, the original description being inconclusive. Under the 

 American code of botanical nomenclature, which has been followed 

 by the author of this paper, "the nomenclatorial t} r pe of a species or 

 subspecies is the specimen to which the describer originally applied 

 the name in publication." 



The procedure indicated by the American code, namely, to appeal 

 to the type specimen when the original description is insufficient to 

 identify the species, has been much misunderstood by European 

 botanists. It has been taken to mean, in the case of the Linnsean 

 herbarium, for example, that a specimen in that herbarium bearing 

 the same name as a species described by Linnaeus in his Species 

 Plantarum must be taken as the type of that species regardless of all 

 other considerations. In point of fact, the specimen preserved in 

 the herbarium of Linnseus is often not the type specimen of the 

 species whose name it bears. Linnseus sometimes based a species 

 on the figure and description of an older author, but by mistake 

 placed in his herbarium a specimen belonging to a similar but distinct 

 species. He sometimes failed to preserve the specimen on which 

 one of his species was based, but later preserved some other specimen 

 incorrectly referred to the species. To consider such specimens 

 types would be quite contrary to the letter and the intent of the 

 American code. 



An examination of the methods pursued by Professor Hitchcock 

 in locating and identifying the type specimens of American grasses 



a Printed in Bull. Torr. Club 34: 167-178. 1907.' 



