OF THE GENUS ULEX. 37 



the other accessory branches were very short, or remained unde- 

 veloped. Each of these branches repeated the same modifications 

 as regards reduction of the spiny nature and sturdiness that we 

 have already considered. 



I think we may safely consider therefore that the environment 

 has a considerable effect upon the spine-producing nature of the 

 Furze plant and that it is largely reduced by a plentiful supply of 

 moisture. The production of spines however has been explained 

 as a protection against animals, and whether drought has caused 

 this directly or not, there is no doubt that, in the majority of cases, 

 the spinescent character is of great value to the plant against the 

 attacks of animals. That there is a necessity for the Furze to be 

 protected in this way is seen in the fact that, even in its present 

 condition, if properly prepared so as to destroy the spines, it 

 serves animals as food, In the article "Agriculture_" in the Ency- 

 clopcBdia Britannica. for example, we find that the young shoots of 

 Furze are palatable and nutritious as food for cattle and horses. 

 It must be chopped and bruised to destroy the spines. This is 

 done now by a variety of machines ; formerly by beating it upon 

 a block of wood with a mallet. It yields valuable food in poor 

 dry soils (it also increases the amount of Nitrogenous matter in 

 the soil, as do other leguminous plants, by means of the tubercles 

 on its roots). Cows fed upon it give much rich milk free from 

 any unpleasant flavour. It may be sown and treated as an ordin- 

 ary green crop, and a succession of cuttings may be obtained 

 from the same field for several years. Professor Muir also, in his 

 work on "Agriculture," states that stock like it very much when 

 crushed and chopped, and it is particularly useful because it is 

 ready for consumption in the winter when green food is usually 

 scarce. 



Mr. Henslow, in his book. The Origin of Plant Structures, 

 seems to take it that the development of the spiny character is 

 due entirely to drought, and does not admit that selection due to 

 animals has had any part in it. The two great factors, according 

 to him, are the tendency to variability and the environment. But, 

 even could one admit that the reduction in the leaves is due 

 directly to drought without the mtervention of natural selection, 

 spines could not be explained in that way. Spines, as such, do 



