VI PREFACE 



secure specimens to illustrate the entire course with- 

 out difficulty. If the plants of the woods and fields 

 are to be used, as many observations as possible 

 should be carried out in the summer, spring, and 

 autumn, and a supply of roots, corms, tubers, bulbs, 

 seeds, and fruits, should be collected for use during 

 the winter season. Many of these may be preserved 

 in the same manner as potatoes, and forced to grow 

 when brought into a warm living-room in January 

 or later. This may be done with the material used 

 in the following paragraphs : 8, 10, 13, 19, 26, 38, 

 39, 43, 44, 45, 46, 47, 48, 50, 51, 53, 54, 77, 97, 106, 

 108, 109, 120, 129, 148, 165, 167, 168, 169, 180, 181, 

 182, 183, 184, 185, 195, 211, 212, 213, 214, 216, 

 217, 225, and 229. 



Desirable material may be obtained from dealers 

 in native plants if the student is unable to collect it 

 himself. It is quite important that the plants used 

 should be properly identified, and this may be done 

 by the use of a manual of the flora of the region in 

 which the work is done, which may be selected from 

 the following list : 



BRITTON and BROWN, Flora of the Northern States and 

 Canada, Charles Scribner's Sons, New York. 



