PLANTS DEFEND THEMSELVES 37 



forces. Horses, cattle, and sheep fear and avoid it ; 

 small animals dodge around it; even man refrains 

 from too much intimacy. It has developed an ex- 

 tremely sharp thorn at the end of each branch; at 

 the base of the branch is a bunch of spine-like 

 needles or thorns; and, in addition, each branch 

 forms in itself a row of dagger-like points; the 

 whole presenting a formidable resistance to the on- 

 slaughts of destroying animals. And yet, even 

 as with the strongest of humans, the hawthorn has 

 its annoying, small enemies numbers of them 

 such as caterpillars and fungi, which it cannot fight, 

 but must tolerate. The hawthorn is, however, one 

 of the most independent of plants ; and being, like 

 man, of sociable nature, as soon as its success in 

 any locality is assured it begins to gather around it 

 many agreeable neighbours. 



There are three types of dangers against which 

 all plant life is forced to defend itself: insect pests; 

 voracious animal and plant life; and destructive 

 natural forces. 



For the land plants, the wingless insects, such 

 as ants, are the chief enemies in the pest class. In 

 plant life there is a rule that all insects which do 

 not give value received must be repelled. The fly- 

 ing insect, in acting as a carrier of pollen from 

 plant to plant, earns the right to sip honey from 



