COMPARING AND CLASSIFYING PLANTS. 67 



belong to roots, leaves, stems, etc., there are none 

 that are so uniform throughout large numbers of dif- 

 ferent plants as these features of cohesion and adhe- 

 sion in flowers. Since you began to observe plants, 

 you have not been taught to notice any points of 

 structure that would serve so well for uniting plants 

 into groups, the members of which are truly and 

 somewhat nearly related to each other. 



But the grounds on which you are to begin to 

 classify plants, although important, and, in many 

 cases, quite sufficient, are not the only ones on which 

 classification is based. Though they may sometimes 

 be found too narrow, yet you must begin somewhere, 

 and, to make your beginning as free as possible from 

 complexities, you start with the features named in the 

 flower-schedule. In working with this, much of your 

 experience will be clear and satisfactory, but you may 

 meet with difficulties. By-and-by, however, the sub- 

 ject will be resumed, and, if you have sometimes been 

 confused and puzzled in classifying by the flower- 

 schedule alone, new ideas will be all the more wel- 

 come. 



Students who have the botanical charts will find 

 them very helpful in the work of classification. Upon 

 these charts there are pictured in the colors of Nature 

 some forty pattern-plants, magnified, and shown in 

 section, so that their structure is easily seen. These 

 plants have been selected because the differences they 

 present are just those broad contrasts that separate 

 groups of plants in Nature. At this stage of your 

 study, while your thoughts are confined to the feat- 

 ures of the flower-schedule^ the first, second, third, 

 and fifth charts present pattern-plants of all varieties 



