46 PLANTS OF NEW ZEALAND 



not obtain a sufficient amount of light to enable it to 

 flourish. Hence, it is to be expected that plants whose seeds 

 are provided with good means for distribution, should be 

 found widely spread over the country, and this is often, 

 though by no means always, the case. The dandelion grows 

 everywhere, but Senecio perdicioides, with similar means of 

 distriljution is confined to one locality. It is often difficult 

 to say why one plant survives, and another becomes extinct, 

 in the struggle for existence. However, new light is being 

 thrown on plant mechanisms daily, and we are beginning 

 to understand more fully the many adjustments of the plant to 

 its environment. It is certain, too, that our outlook upon the 

 vegetable world is gradually altering, and that the centre of 

 gravity of our ideas concerning the principles that guide plant 

 evolution is also shifting to some extent. 



Classification. 



The vegetable world may readily be separated into two 

 great divisions, plants without flowers, and plants with flowers. 

 The former division includes the bacteria, sea-weeds, pond- 

 slimes, moulds, fungi, toadstools, lichens, liverworts, mosses, 

 ferns, and club-mosses. They do not come within the scope 

 of this work. The flowering plants may again be readily 

 divided into two classes : (1) those in which the ovules are 

 not enclosed in an ovary, Gymnosperms (pines, firs, etc.) ; 

 ("2) those with the ovules enclosed in an ovary {Angiosperms) . 

 There are probably about 100,000 distinct kinds or species of 

 angiosperms at present living on the face of the earth. They 

 include the vast majority of all flowering plants. In order 

 that they may be properly studied they have to be classified in 

 a complete and complicated fashion. One of the chief objects 



