PREFACE. 



The following account of the flora of the State of Washington, by 

 Prof. C. V. Piper, is based on his study of the plants of that State 

 during a period of tAventy years. This work was carried on in chance 

 hours of leisure and in occasional summer vacations. During most 

 of the college year 1899-1900, however, Professor Piper was at the 

 Gray Herbarium looking up critical material and examining the 

 specimens of older collectors, especially those upon which publications 

 had been based. Considerable time was devoted also to other large 

 Jierbaria, particularly those of the United States National Museum, 

 of the Academy of Natural Sciences of Philadelphia, and of the 

 New York Botanical Garden. The private herbaria of Prof. L. F. 

 Henderson, of Mr. Thomas Howell, and of Mr. W. N. Suksdorf were 

 likewise freely consulted. 



Most of the types of the new species published by Professor Piper 

 in the j^resent work and in earlier papers are in the United States 

 National Herbarium, and a large part of the whole material on which 

 this flora is based is also represented there. 



In the course of his work Professor Piper examined specimens of 

 nearly all the collections made within the confines of the State of 

 Washington, so far as these are to be found in American herbaria. 

 Thus it w^as possible to ascertain the identity of nearly all the species 

 which had been accredited to the State through erroneous determi- 

 nation. Unfortunately several of the specimens upon which the 

 names in published lists were based are not now to be found in 

 the herbaria in which they might be expected. This is true particu- 

 larly of Cooper's plants and in less degree of those of the Wilkes 

 Expedition, so that the identity of such plants can only be surmised. 

 In publications on the collections of Menzies, Douglas, Scouler, and 

 Tolmie there are many plant names that can be definitely rectified 

 only by examining the original specimens. It is quite certain also 

 that the current interpretation of a number of species based on these 

 early collections is erroneous. Their correction will require an exam- 

 ination of the types, which are in European herbaria. 



With few exceptions no species has been admitted into this flora 

 unless its author has actually studied Washington specimens. 



In the course of the preparation of this work Professor Piper be- 

 came indebted to many botanists for assistance. He states that he 



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