DEFENCE. 109 



In the Common Holly, the leaf-teeth are spiny, and 

 similar spines are found on the Evergreen Oak. It has 

 been stated that, in both, the lower branches and those 

 plants that have been especially cropped and pruned 

 have much more spiny leaves than the higher branches, 

 or specimens which have been allowed to grow freely. 

 This would go to show that the injury done by grazing 

 animals directly promotes the growth of prickles. But the 

 fact is a little doubtful, though, as has been mentioned, 

 it is obvious to any one who has ever seen a desert flora 

 {e.g. that of the Sahara, of the Grecian Hills, or of Spain), 

 that a dry or desert climate certainly seems to produce 

 thorniness of one kind or another. Such climates always 

 produce an open scrub-like vegetation, and are especially 

 suitable for man, and for all grazing animals. 



From the botanical side, it is seen that branches may 

 become thorns ; leaves may turn into spines (Barberry), 

 or stipules (Acacia, Robinia), or the midrib of the leaf 

 (Astragalus tragacanthus) may do so. Prickles also occur 

 on the leaf, stem, and root. Two other cases may be 

 given to complete the series. The Alpine Festuca has 

 very sharp hard spiny-leaves, from which it often happens 

 that the cattle which graze in Alpine pastures, where 

 this plant grows, bleed severely from the nostrils. The 

 Rotang palms, such as Desmoncus have their leaflets 

 changed into long spines. These palms are climbers 

 often of great length and are exceedingly tough and 

 strong as well as abundantly thorny. The thickets 

 formed by them are almost impenetrable to mankind. 



The relation of thorns and spine to the strength and 

 teeth of the grazing animal cannot be further considered 

 here. It should of course cause no surprise, as the 

 intimate connection between an animal and its food 

 should lead to exactly what we find does exist. 



