162 CLIMBING PLANTS 



borders. 1 Other perennials, like the stonecrop, inhabit 

 ground so poor and parched, or, like the sundew, so 

 wet and sour, that they run no risk of being smothered 

 by rampant rivals. Others again, like the foxgloves 

 and mullein, are endowed with the power to send up a 

 stout flowering stem to a height of several feet, whereby 

 they escape suffocation. Such plants, however, that are 

 exempt, while young, from the obligation to perpetuate 

 their species, employ their time in building up a woody 

 stem that, in some species, continues to increase in 

 bulk for hundreds of years. The beech, for instance, 

 never flowers and fruits till it is forty years old. 



There is, however, another class of plants which, 

 being unable to form stems strong enough to bear aloft 

 their foliage and flowers, have recourse to robust neigh- 

 bours for support. There are four expedients available 

 for plants in that predicament, namely, leaf-climbing, 

 tendril-climbing, root-climbing, and simple twining. 



There is no better example of a leaf-climber than the 

 clematis or virgin's-bower. The stalks of the young 

 leaves are exceedingly sensitive, and the leaves them- 

 selves continually move about, independently of the 

 wind, groping for support. As soon as a leaf comes in 



1 Sir Joseph Hooker devoted much attention to this weed. He 

 entertained a well-rooted objection to the unnecessary multiplication 

 of species. The older botanists had assigned specific distinction to 

 the various forms of Cardamine in Europe, Asia, Africa, and America. 

 Hooker resolved them all into one. 'I wish,' he wrote to W. H. 

 Harvey, who differed with his diagnosis, ' that you had spent as many 

 hours over this wretched weed as I have.' Again, to Charles Darwin : 

 ' The little Cardamine or Cress I prove, by comparison of about fifty 

 states of it running through the whole continent of S. America, to be 

 the same as the most common European weed, C. hirsuta.' 



