X PREFACE 



the only tools which can be used effectively as the writer knows 

 by many years of hard practical experience, both in garden and 

 in field. Again, some simple expedient of little cost and easy 

 application, may do the work of many hands and increase by 

 many fold the soil's return for the labor. A wider acquaintance 

 with such methods of control seems desirable and therefore the 

 writer has endeavored to bring together, so far as could be learned, 

 the knowledge gained by much study and careful experiment in 

 many different parts of the country by earnest and thought- 

 ful workers. There is a great dearth of books on this most im- 

 portant subject, but such as could be obtained have been diligently 

 studied. The Bibliography on page 559 will indicate the writer's 

 debt in this regard. Many files of agricultural periodicals have 

 been consulted and most grateful acknowledgment is made for 

 assistance received from the publications of the Department of 

 Agriculture at Washington, and to the Agricultural Experiment 

 Station Bulletins of the various states and of the Canadian 

 Provinces. 



In nomenclature and order of classification the writer has fol- 

 lowed Gray's New Manual of Botany, seventh edition, 1908. For 

 plants outside of the geographic limits included in that book, 

 Coulter and Nelson's New Manual of Rocky Mountain Botany, and 

 W. L. Jepson's Flora of Western Middle California, have been con- 

 sulted. For range, season of bloom and fruit, and much other very 

 important and necessary information, most invaluable help has 

 been obtained from the New Illustrated Flora of the Northern 

 United States and Canada, by Britton and Brown, and the revised 

 Flora of the Southeastern United States, by Dr. J. K. Small. 

 Statements concerning plants that are poisonous or otherwise harm- 

 ful to health have been made on authority of publications issued by 

 the United States Department of Agriculture. Dr. L. H. Pammel's 

 Manual of Poisonous Plants has also been a helpful reference. 

 Mention is made of the fact that some weeds are medicinally valu- 

 able, and may occasionally be made to pay for the cost of their 

 extermination. The writer's authority for prices and modes of 

 preparation has been the interesting series of bulletins prepared by 

 Miss Alice Henkel, Assistant, Drug-Plant Investigations, at the 

 Bureau of Plant Industry at Washington. 



