80 BOTANY. 



can be used in classification ; but, when a few are known, 

 they may be at once put to service. A pupil can not do 

 better than to acquaint himself with the group of crucifer- 

 ous plants as soon as the special characters that belong to 

 this group are familiar. Any group of plants may be clas- 

 sified as soon as the characters upon which it is founded 

 are fairly known. To get a knowledge of classification 

 requires much time, and its study should, therefore, be 

 commenced at the earliest possible moment. 



There is another reason for skipping about, which will 

 be at once appreciated. It is this : Plants have their time 

 to flower, and their flowers must be studied at that time. 

 For example : the Coniferae blossom in spring, and spring 

 is the time to study them. Stamens may be found through- 

 out the entire season, and so may be studied at any time. 

 It would be folly, therefore, to let the period pass in which 

 the Coniferse might be studied, because you " hadn't come 

 to them " in the book, and pursue the study of stamens 

 because they are next in order. Again, the characters of 

 orchids are illustrated by a plant which has its season, and 

 the time to study orchids is when this plant makes its ap- 

 pearance. 



