GROWING PLANTS. 



assimilated and the plants would die, and we, too, 

 should perish for want of food. 



Then I expect you have noticed how long and thin 

 the white shoots of the potatoes are when they have 

 been stored in a dark place, that is because light 

 affects the rapidity of growth ; it checks it and 

 prevents the plant growing too fast. The white weak 

 potato shoots grow unhealthily and too fast for want 

 of light. This helps us to understand why plants 

 placed in a window bend towards the light, the side 

 of the stem away from the light grows faster than 

 the side which is towards it, and so the stem becomes 

 curved over upon its shortest side, that is towards the 

 light. You see that in a healthy plant just as in a 

 healthy boy or girl all the processes or movements of 

 life must go on in proper degree. 



So also plants are greatly affected by changes in 

 the temperature or heat of the atmosphere. The 

 heat which will suit some will destroy others, so 

 the " flora " or flowering plant life is different in 

 countries or districts according to their heat or cold. 

 Some plants which do very well in a greenhouse, 

 or sheltered south border of your garden, will not 

 thrive in more exposed and colder places, so that 

 with the plants in frames and green-houses gardeners 

 are always careful about the heat as well as about the 

 light they give to them. You will understand that 

 this is the more necessary when you remember about 

 transpiration, and because of assimilation and re- 



