ttOW PLANTS EAtf. 49 



wise, feather- wise, or with parallel veins and 

 how much, if at all, it is cut or divided. 



Endless varieties, however, occur, in accord- 

 ance with the peculiar place the plant and its 

 kind have been developed to inhabit. In 

 climbing plants, for example, the leaves are 

 usually opposite, so as to clutch more readily, 

 and they are almost always more or less heart- 

 shaped at the base, as in convolvulus and black 

 briony. The leaves of forest trees, on the other 

 hand, tend to be what is known as ovate in 

 shape, like the beech and the poplar ; while 

 those of the lime are a little one-sided, in order 

 that each leaf may not overshadow and rob its 

 neighbour. This one-sidedness is even more 

 markedly seen in the hot-house begonias. Some 

 leaves, again, are minutely subdivided into 

 leaflets twice or three times over ; such leaves 

 are said to be doubly or trebly compound. But 

 if you study plants as they grow (and this book 

 is written in the hope that it may induce you to 

 do so), you will generally be able to see that the 

 shapes and peculiarities of leaves have some 

 obvious reference to their place in the world, 

 and their habits and manners. 



I have spoken so far mainly of quite central 

 and typical leaves, which are arranged with a 

 single view to the need for feeding. But plants 

 are exposed to many dangers in life besides the 

 danger of starvation, and they guard in various 

 ways against all these dangers. One very 

 obvious one is the danger of being devoured 

 by grazing animals, and, to protect themselves 

 4 



