PREFACE. 



The revisions of genera, descriptions of new species, and other 

 systematic papers on grasses emanating from the OflSce of the Agros- 

 tologist of the Department of Agriculture have heretofore been 

 published as Bulletins of the Bureau of Plant Industry in that Depart- 

 ment. In view, however, of the transfer of the grass herbarium to the 

 Office of the Botanist, the Agrostologist has suggested that the accom- 

 panying manuscript entitled '' North American Species of Festuca," 

 by Professor Charles V. Piper, be published in the series of Contribu- 

 tions from the United States National Herbarium. This suggestion 

 has been adopted. The author of the manuscript regrets that it was 

 not possible to consult all the type specimens of the American spe- 

 cies, several of which are in European herbaria, but he considered it 

 preferable to offer his work for publication now rather than to delay 

 it indefinitely^ 



Frederick V. Coville, 

 Curator of the United States National Herharium. 



Ill 



