ROBBER V AND MURDER. 237 



ambitious, and crafty plants, so that they can reach 

 as high as bulky-trunked forest-trees, may begin by 

 simply making use of the latter as convenient ladders, 

 and end by strangling them. 



Our European climbing plants seldom develop 

 such a murderous tendency. The Honeysuckle will 

 sometimes twist itself so tightly around the slender 

 stems of shrubs it climbs by as to leave deep spiral 

 indentations in their bark, as witness the walking-sticks 

 selected by the curious for the sake of this peculiar 

 appearance. Occasionally, therefore, even this harm- 

 less shrub may embrace its ally more tightly than is 

 good for it — may prevent the abundant rise of sap, 

 and the deposition of additional woody tissue. 

 The Lichens which sometimes grow so abundantly 

 on Apple-trees and shrubs, must, according to the 

 late Dr. Lauder Lindsay, abstract all their mineral 

 salts from the plants to which they are attached, for 

 they have no other source to derive them from. 

 Hence the necessity for keeping the Apple-trees 

 • " clean," in our cider-growing districts. We can 

 easily understand how this habit might be increased 

 under those intenser habits of growth and competition 

 which would ensue, for instance, if England were 

 once more to enjoy the greater warmth which pre- 

 vailed here so recently as during the Miocene Period. 



But, although our native flora is innocent of 

 producing vegetable Thugs, like those described 

 by tropical travellers, it has a criminal population 



