8 THE BANANA 



on the other hand, the upper surface of the leaves becomes 

 concave. 



In an allied plant, the " traveller's tree " (Ravenala), 

 it is well known that it is possible to get a drink of water 

 by piercing the hollow leaf stalk ; and in a similar way 

 the banana leaf collects the rain-drops of a shower and 

 conducts them along the fluted leaf stalk into the interior 

 of each concentric sheath. Each leaf provides for its own 

 sheath, but the central space, where the young growing 

 leaves or the flowers are pushing their way upwards, is 

 protected. Water supplied in this way, and quite in- 

 dependent of the amount at the roots, is important for 

 the proper " shooting " of the flower stalk ; it causes 

 expansion of the trunk and relieves the pressure on the 

 central space. An observant planter noticed that in dry 

 weather a shower of rain seemed to start his plants shoot- 

 ing, and when he found this process hanging fire used to 

 spray his bananas with a hose in imitation of the beneficent 

 shower. 



The function of the leaves is to provide food for the 

 requirements of growth in the plant. The energy or 

 motive power necessary for the work of manufacturing 

 the food is obtained from the sun's rays by means of the 

 green colouring matter. The water absorbed by the 

 roots, containing nitrogenous and mineral material, is 

 carried up to the leaves, and a union of these elements 

 with the carbonic acid of the air takes place. The manu- 

 factured food is transferred to any part of the plant where 

 growth is taking place, or, if not required for growth, it 

 is stored up in the bulb in the form of starch grains for 

 use later. The green colour of the trunk shows that it is 

 also taking part in the manufacture of food. 



THE FLOWERS 



If the flowering stalk (inflorescence) is examined in the 

 embryonic condition in the trunk, it will be found that 

 the flowers are arranged in clusters disposed spirally 



