Watering 



test of the efficiency of a gardener than that imposed 

 by the operation of watering. A gardener who\\\, 

 studies the structure of his plants with a view to 

 realising their water requirements, and has the 

 opportunity and gumption to regulate his treatment 

 accordingly, win be Uttle troubled with plant diseases. , , 



This is not the place to describe the various 

 modifications of leaf-form devised to regulate water 

 supply, but it should be clearly realised that large- 

 leaf surface, dry air and draughts, bright light and 

 high temperature, increase the amount of water lost 

 by the foliage, and the loss can be made good only 

 by absorption of water by the roots. A small 

 amount of foliage, moist air, shade, and low tempera- 

 ture diminish the loss. Finally, it may be said that 

 the plant can, by opening or closing the pores in its 

 leaves, regulate the loss to a considerable extent, 

 and that it can within certain limits alter the 

 structure of its foliage to suit changed conditions, 

 as long as the conditions are brought about gradually, 

 as in the process of " hardening off." Different 

 plants are able to make these modifications to 

 different extents, and some only to a very slight 

 extent. 



The remaining organs of the plant, the flower, 

 fruit and seed, are connected with reproduction, 

 and broadly speaking, if the other organs are in good 

 working order these wiU do their work efficiently. ' 

 Flowering is usually connected with a quiescent 



16 



