2 THE FLOWERING PLANT. 



resemblances which connect plants into groups are not the result 

 of mere chance, but express actual relationship, what, in animals, 

 would be called " blood "-relationship. The different groups of 

 plants do not form a " linear series," i.e., they cannot, as regards 

 affinity, be placed in a line, the most complex members of one 

 group coming just below the least complex of the next group, and 

 so on ; but they naturally fall into a tree-like arrangement. This 

 is now believed to represent, in a general sort of way, a genea- 

 logical tree. The second great use of Systematic Botany is, there- 

 fore, to help in the construction of plant-genealogies. Apart from 

 the great theoretical interest attaching to this kind of work, there 

 is a very practical application affecting medicine and many manu- 

 factures. Broadly speaking, closely related plants have similar 

 properties, and a classification which represents affinities with fair 

 accuracy will be of the greatest service in the search for new 

 drugs, dyes, fibres, &c. , &c. The uses, if any, of a newly-discovered 

 plant can also be judged of with some accuracy even without 

 experiment. The branch Economic Botany, which deals with the 

 question, "Of what use to man?" is therefore an appendix to 

 Systematic Botany. The present volume, however, has little or 

 nothing to do with this branch, nor is it concerned with Geo- 

 graphical and Fossil Botany, which endeavour to answer the 

 questions, "Where found?" and "When found?" that is to 

 say, try to elucidate problems regarding distribution in space 

 and time. 



Differences between Plants and Animals. — It might at first 

 be thought that plants, with which Botany deals, could easily be 

 distinguished from animals, which form the subject-matter of the 

 sister science, Zoology. No one is in danger of confounding a 

 cow with a cabbage, and, as a matter of fact, ordinary plants are 

 marked off with sufficient distinctness. But when we come to 

 lower forms, often of minute size, it is frequently difficult to say 

 for certain whether a given form be plant or animal. The recog- 

 nition of this fact has emphasized the close connection between 

 the two divisions of the organic world, and called into existence 

 the science of Biology, which deals with life generally, and in- 

 cludes both Botany and Zoology. 



The largest subdivisions of the vegetable kingdom are those of 

 Flowerless Plants (Cryptogams) and Flowering Plants (Phanero- 

 gams), without and with conspicuous flowers respectively. What 

 flowers exactly are will be seen in the sequel. We shall here 

 deal, from an elementary point of view, with Flowering Plants 

 only. These differ from animals in several important par- 

 ticulars : — 



(t.) A typical member of the group is dependent upon gaseous 



