Vlll PREFACE. 



species. It is sufficient to say that the two methods hold the 

 relation to each other of former and latter in the preparation 

 of this book. 



In groups of species certain contrasting characters have been 

 italicized, according to the method of Gray's Manual. This 

 is done to facilitate the work of the student, but with the 

 mental reservation that its abuse may more than offset its 

 advantage. Ten years' experience as a teacher has shown 

 that the ordinary student will fix his attention upon the itali- 

 cized characters to the neglect of the description as a whole. 

 The student is here warned that the specific descriptions in 

 this book have been so much reduced that no unimportant 

 characters are intended to be given. 



JOHN M. COULTER. 



Wabash College, Crawfordsville, Indiana, 

 January t. 1885. 



