184 



HXPEBIMENTS WITH PLANTS 



main as long as possible on the plant. You can also 

 see why they should have as large a surface as they 

 can, since the more light they catch the more starch 

 they can make. You can see, too, why the seed-leaves 



103. Two lots of Squash seedlings of the same age. Those on the left were grown in 

 the light, those on the right in the dark. 



need to be thick and bulky, so as to store up a great 

 deal of starch. The reasons for the other differences in 

 structure will become apparent as we go on. Perhaps 

 you do not see why the foliage -loaves are green and 

 the seed-leaves pale yellow. You will understand this 

 if you put a few seeds into a pot containing soil or saw- 

 dust and keep it entirely in the dark until the plants 



