LAND PLANTS AND WATER-SUPPLY 259 



siderable surface, and in the aggregate form an excellent 

 canopy, wherefore we are not surprised at finding shelter 

 under them. But we can secure equally as satisfactory 

 shelter under a Pine or a Larch, and when we remember 

 the needle-like form of the leaves of these Conifers, we 

 are disposed to wonder that the ground is always so 

 remarkably dry beneath them. But their branching 

 and leaf arrangement is such that most of the rain which 

 falls upon the trees is always turned outwards, very 

 little making its way down the trunk. 



The Mulleins (Verhascum) have a tap-root, and the 

 outline of the aerial part of the plant is that of an 

 attenuated pyramid. The leaves at the base are larger 

 and broader than those above; indeed, it is to the 

 gradual decrease in the size of the leaves from base to 

 apex that the plant owes its tapering form. If we look 

 down upon a Mullein from above we can see that if the 

 stem could be " telescoped," the leaves would come 

 together in the form of a rosette, and, moreover, that 

 the actual leaf arrangement of the plant is that of a 

 rosette with an elongated axis (the stem) . This arrange- 

 ment is excellent both in relation to light and air, and 

 to falling rain. The short upper leaves turn water out- 

 wards, and it faUs from their apices on to the blades of 

 leaves under them. These under leaves are somewhat 

 longer, and turn the water, so that it falls on to those 

 below, which in turn are also longer. Eventually the 

 water reaches the lowest leaves, which are longer and 

 broader than all, and so tUted that the bulk of the 

 water that reaches them from the upper leaves is turned 

 inwards, so that ample water reaches the neighbourhood 

 of the tap-root. 



