iv FOREWORD 



The flowering plants or Spermatophyta are described more fully than the 

 previous groups, and under the various orders and subdivisions we have also 

 added notes on economic and medicinal plants. Those who desire fuller in- 

 formation in regard to other American species of the different orders described 

 should consult the latest editions of Gray's or Britton's Manuals, in which the 

 descriptions are full and complete. Of course, one cannot expect to add 

 much to the excellent descriptions given in these treatises. 



I have freely made use of published literature in the systematic portions as 

 well as in the more technical matter pertaining to poisons, and I wish to acknowl- 

 edge my assistance from these sources. 



In order that the species named may be more readily recognized, a large 

 number have been figured. 



In addition to the descriptive part of the work there has been added a 

 chapter on the active principles of plants, by my colleague, Prof. A. A- 

 Bennett. I am also greatly indebted to Miss Harriette S. Kellogg who has 

 carefully read the manuscript and assisted me in other ways besides preparing 

 the bibliography. To Dr. Trelease of the Missouri Botanical Garden, I am 

 indebted for the use of a number of books on the subject. Miss Charlotte M. 

 King, Miss Ada Hayden, Mr. W. S. Dudgeon, and my daughter, Lois, have 

 made drawings especially for this work. Other illustrations are taken from 

 special works, due credit being given in each case. 



I am indebted for the use of cuts to the following persons : Dr. C. F. Curtiss 

 of the Iowa Agricultural Experiment Station, Dr. B. D. Halsted of the New 

 Jersey Agricultural Experiment Station, Profs. S- B. Green and Washburn of 

 the Minnesota Station and Prof. A. D. Selby of the Ohio Station, and to the 

 United States Department of Agriculture. Some have been reproduced from 

 Baillon's Diet, and from Bentham's Handbook of British Plants. I have 

 endeavored in each case to give credit for the drawing or cut. 



I am indebted to Drs. R. R. Dykstra and C. H. Stange, Profs. L. G. Michael, 

 C. V. Gregory and A. A. Bennett for proof reading and to Dr. W. H. Stuhr for 

 some matter in Part I. 



The work does not pretend to be complete; we hope, however, that it may 

 prove useful to the Veterinarian, Physician and Layman. 



Ames, Iowa, June 1, 1909. 



