FOLIAGE. 



143 



The Coltsfoot leaves are upright when they begin to 

 unfold : then they turn over so as to be horizontal, and 

 rapidly overspread everything in the neighbourhood. 

 The Burdock and the Giant Coltsfoot, as well as the 

 Common Rhubarb, are all good examples of these over- 

 reaching leaves. 



Those plants, which have a main root developing 

 vertically downwards, very often arrange their leaves in 

 such a way that water falling on the leaf must trickle to 

 the centre of the stem, from which it will run down to 



Fig. 17. — Coltsfoot. The upright, white and woolly bud-lea\-es can be seen 

 nearly erect at first, but in the older specimens becoming dark green and bending 

 over. The hard points on the edge of the leaf can be distinguished on the older 

 specimens. 



the roots. The Common Lettuce shows this very clearly, 

 as every drop of rain falling on the broad leaves must 

 run down to the root. In those plants in which the 

 leaves stand out at an angle inclined upwards, the rain 

 generally runs down the leaf stalk and then trickles 

 down the stem, and sometimes the leaf produces, at its 

 point of attachment, two little lobes, or auricles, which 

 direct this rain current, and make it travel along the 

 stem. This arrangement can be easily seen in the 

 groundsel. 



It is not unusual to find that the leaves thus assist 



