vi PREFACE 



the distinguishing points of difference have 

 been clearly noted, and if these are carefully 

 studied, any difficulty in determining them will 

 be obviated. 



In the Fern Family much confusion is apt to 

 arise from laying too much stress on the indu- 

 sium as a means of identification, since it must 

 be found in a certain stage of development to 

 be of value in determining the species. Just 

 when it is properly mature, the beginner is not 

 likely to know, and not a few students have be- 

 come discouraged at the outset by this method 

 of identification which is made prominent in 

 nearly all botanical works. 



Hence I have endeavored to set forth other 

 points of difference which are more stable, and 

 come more easily under the observation of the 

 amateur, while the indusium has been described 

 for those who depend upon it. 



The Fern Family has been treated first, it 

 being considered the most important of the four 

 families represented. The remaining three fami- 

 lies follow in order, according to the beauty of 

 their forms. 



Only a few of the more common species of the 

 Club-Moss and Horsetail Families have been 

 included. These are so often found during fern- 

 hunts that one naturally desires to know some- 

 thing about them. 



