348 PLANT-LIFE 



the resemblance, and consequently leave the plant 

 alone. 



It is a matter of observation that Rhododendrons and 

 other low-growing shrubs are not " barked " by rabbits, 

 and that grazing animals do not eat their leaves. Neither 

 do they consume Horsetails (Equisetum), or tackle the 

 Crowberry (Empetrum) and Cowberry (Vaccinium 

 Vitis-Idcea). The reason is that these plants, as well as 

 others not mentioned, form a thick cuticle, and deposit 

 therein a quantity of silica. An animal that ventured to 

 eat these plants would have a bad attack of indigestion. 



In assimilating proteins, most plants form a poisonous 

 salt, oxalate of lime, as a by-product of their chemistry. 

 This salt is deposited in the tissues in the form of 

 single or aggregated hard crystals. They are plentifully 

 developed in the roots of the Rhubarb and in the outer 

 parts of a number of bulbs. It has been demonstrated 

 that in the case of bulbs, at any rate, the crystals are 

 a protection against the ravages of snails. 



Flowers, scented or otherwise, are usually avoided by 

 grazing animals. It is, of course, important that, in 

 view of their function, this should be so. But how is 

 the phenomenon to be accounted for ? They may not 

 be molested because they are posionous, or that their 

 flavour is disagreeable, or for the reason that they are 

 not particularly nutritious. In cases where flowers are 

 freely eaten, the plant, if it is to survive, must be able 

 to reproduce itself by vegetative means. The Daisy 

 must have vast vegetative resources, judging by the 

 manner in which it increases on our lawns, in spite of 

 the fact that the lawn-mower does not permit the 

 flowers to form seed. 



