CHAPTER II 



THE GEOGRAPHICAL DISTRIBUTION OF PLANTS 



* No siaeculation is idle or fruitless that is not opposed to truth 

 or to probability, and which, whilst it co-ordinates a body of well 

 established facts, does so without violence to nature, and with a due 

 regard to the possible results of future discoveries.' 



Sir Joseph Hooker. 



In the vegetation of the British Isles the leading 

 role is played by that large group to which the term 

 Flowering Plants is frequently applied. This group, 

 including the two sub-divisions Dicotyledons and 

 Monocotyledons, is known by the name xAngiosperms, 

 a designation denoting the important fact that the 

 seeds are developed in an ovary or protective seed- 

 case (dyyelov, a vessel or box). The fact that these 

 highly elaborated products of development made 

 their appearance, so far as we know, at a compara- 

 tively late stage in the history of the plant-world, 

 att'ests their efficiency as a class and demonstrates 

 the rapidity with which they have overspread the 

 surface of the earth as successful competitors in 



