CLIMBING PLANTS. 



691 



of bark and the stumps of broken twigs, things which are impossible to twining 

 stems. Tendrils preferably twine round horizontal twigs and leaf -stalks, and 

 frequently round old tendril -bearing stems which have previously climbed up to 

 the crown of a tree. When they have reached up to the branches, they can pass 

 over from one bough to another, fasten themselves firmly above and below, and so 

 gradually invest the whole of the crown. From the summit fresh shoots arise 



Fig. 163.— Leaf -stalk tendrils of Atragene alpina. 



which curve downwards and are swayed by the lightest breath of wind; from 

 them new tendrils project, like the tentacles of some sea -monster, and if one of 

 them but touches a leaf -stalk or twig of a neighbouring tree, it curves round it 

 and grasps it firmly. Very soon a second, third, and fourth tendril will similarly 

 become attached, and, contracting spirally, will pull the pendent shoot up to the 

 neighbouring tree-crown. The bridge so formed is again used as a means of transit 

 by other climbing stems, and thus arise garlands and festoons, which hang from 

 tree to tree; whilst not infrequently an actual arcade is formed whose roof, 



