XX INTRODUCTORY. 
unnecessary, but presumptuous, in view of the long labor they and Professor 
Gray had bestowed upon the task. 
During the same interval, American botanists have received from the 
pen of Professor Gray the first part of vol. 2, Synoptical Flora of North 
America. Itis not possible to overestimate the importance of this to the 
science of our country. His work, when finished, must be forever the great 
landmark in American Botany. 
Of hardly less importance, or labor, is Mr. Watson’s Bibliographical 
Index to North American Botany, of which Part First, extending through 
the Polypetal, has been published during the year. The thorough man- 
ner in which it has treated, and will continue to treat, the synonymy of the 
subject, renders any extended citations out of place here. It is hoped that 
the most important changes in nomenclature indicated in these works will 
be found observed in this Report. 
Mr. H. W. Henshaw has aided at the Washington office in his careful 
attention while this Report was passing through the several stages of proof. 
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