68 . THE SECOND BOOK OF BOTANY. 



in these respects. Their great value to the pupil, in 

 classification, at the beginning of study, lies in the 

 distinctness of the idea he gets from them as to how 

 his pattern-plant is constructed. 



The work of classification being now entered upon, 

 it will be resumed, from time to time, with further 

 explanations as we proceed, particularly when we 

 come to study such groups of plants as the grains and 

 grasses, the cone-bearing plants, the Composite, fa- 

 miliarly known as compound flowers, the Umbel- 

 liferae, etc. These striking natural orders will intro- 

 duce us to new principles in judging of affinities, and 

 pupils who are specially fond of this part of the study, 

 and are apt in tracing resemblances, will do well to 

 look over the chapters upon these plants without 

 waiting to reach them in the course of regular study. 



NOTE. There is often, among both teachers and pupils, an 

 aversion to skipping about. The idea of thoroughness with 

 them seems to imply moving steadily on from page to page of 

 a book, without ever deviating from its order. But in such a 

 science as botany it is not necessary to proceed in this way. 

 The subject cannot be marked off sharply into parts that 

 must be learned in a certain order. Of course, plant characters 

 must be known before they can be used in classification ; but, 

 when a few are known, they may be at once put to service. A 

 pupil cannot do better than to acquaint himself with the group 

 of cruciferous plants as soon as the special characters that be- 

 long to this group are familiar. Any group of plants may be 

 classified 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 



