CHAPTER V. 



RELATIONSHIP AMONGST PLANTS. 



Characters of importance in proving relationship. — Primary 

 Divisions of the Vegetable Kingdom. — Natural Orders of Plants. — 

 "What is a species ? 



IT is not intended in the present place to enter into a 

 lengthened dissertation on the Classification of plants, 

 but solely to indicate in broad lines the most generally 

 .acknowledged characters supposed to be of value in 

 indicating inter-relationship amongst plants. From 

 -what has been already written it will have been realized 

 that evolution in the broader sense is recognized as the 

 cause of the great variety of morphological or structural, 

 =and jphysiological or functional differences presented by 

 plants at the present day, as opposed to the older idea 

 of a special creation, in the sense of every plant having 

 ■existed from an ideal starting-point up to the present in 

 a comparatively unaltered condition. Having indicated 

 the principle of variation or evolution as afiFording the 

 basis on which plant affinity or relationship is founded, 

 it is necessary in the first instance to explain a few of 

 ihe most important terms employed by systematists 

 who deal with plant affinities. Although the modern or 

 ■so-called natural system of classification, as opposed to 

 ihe earlier artificial methods employed by Linnseus and 



