14 BOTANY 



be covered with simple oval dark-green leaves just 

 like any other ordinary shrub. But if you examine 

 these " leaves " closely you will see that they have just 

 beneath each of them a small scale-like structure. 

 This is the true leaf, and the big apparent leaf is a 

 flattened branch coming in the axil of the reduced leaf. 

 The stem nature of these apparent leaves becomes 

 obvious at the time of flowering. Then a little flower 

 or tuft of flowers arises in the middle of its surface. 

 Text-figure 1 shows a sketch of a Ruscus branch with 

 its false leaves that are really stems. 



The Leaves are of all the organs the most subject to 

 variation, and their modifications are endless. The 

 normal foliage leaf is flat and expanded, its outline may 

 be quite simple or deeply cut and elaborately shaped. 

 Commonly there is a leaf stalk which attaches it to the 

 stem. Foliage leaves are green because they contain 

 the green substance which is such an essential factor 

 for the nutrition of plants (see Chapter V.). Leaves 

 are modified, however, to serve innumerable purposes, 

 and, according to the functions they perform, so do they 

 become changed sometimes almost out of recognition. 

 They may be rendered f unctionless and useless by the 

 position in which they find themselves, as, for instance, 

 when the stem bearing them runs underground. They 

 are then reduced to the merest remnant of scales, 

 brown or colourless, and thin of texture. Sometimes 

 in the underground position they take on a new function 

 that of storage. Where they cannot produce food 

 they adapt themselves to store what the other air leaves 

 have produced, and this we see in the bulbs of Tulips 

 and Lilies and Onions. The fleshy part of the " bulb " 

 is composed of the modified leaves filled with the stored 

 food. In many trees we find modified leaves on the 



