PREFACE 



There is much confusion in the names applied to our North Ameri- 

 can grasses. This is partly due to the fact that much new material 

 has been collected since the revision of some of the important genera. 

 The practice, formerly more prevalent than at present, of erecting 

 new species on the basis of a single specimen or of a very few speci- 

 mens at most, has added to this confusion. The economic importance 

 which the grasses have assumed in the last two decades has made this 

 confusion all the more embarrassing. It therefore seems desirable 

 that the bibliography, synonymy, and systematic relationships of 

 American grasses be worked out as rapidly as possible. The present 

 paper by Professor Hitchcock is an attempt to do this for the genus 

 Leptocliloa. It is based chiefly upon the material in the herbarium of 

 the U. S. National Museum and that of the U. S. Department of Agri- 

 culture, but all the important public herbaria in this country were 

 consulted during its preparation. The descriptions of the species are 

 diagnostic rather than complete, but it is hoped that these will serve 

 the purpose of students of systematic botanj 7 . Much time has been 

 spent in working out the proper relationship of the species and it is 

 hoped that the short descriptions, the text figures illustrating the 

 spikelets of each species, the plates taken from herbarium specimens 

 of several species, and the key to our United States species will take 

 the place of more complete descriptions and render this paper valua- 

 ble to students of this genus. 



The species of Leptocliloa are inhabitants of the warmer regions, 

 only one or two of our species extending as far north as New York 

 and Illinois. One of the species, Leptocliloa dubia, called sprangle, is 

 an important range grass in the Southwest, and recent experiments 

 indicate that it will prove a desirable grass for cultivating in semiarid 

 regions. 



W. J. Spillman, 



Agrostologist. 



Office of the Agrostologist, 



Washington, D. C, October U, 1902. 



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