80 EXPJSBIMENTS WITH PLANTS 



glass sides of a box, such as is shown in Fig. 66. As 

 the stems begin to grow up along the glass, fasten 

 small blocks of wood to the glass (by means of sealing- 

 wax) directly in their paths. Let some of the blocks 

 have several holes (about one-fourth of an inch in 

 diameter) bored in them, to see whether the plant will 

 find these and grow up through them. Do you see how 

 plants find the crevices in concrete and brick side- 

 walks and come up through them ? 



Does the position of the caulicle make any difference 

 in the time it takes the plant to get above ground? 



67. Sunflower seedlings penetrating the soil. 



Plant (about an inch deep) an equal number of seeds 

 of the same kind (at least ninety in all), some with 

 the caulicle up, some with the caulicle down, some with 

 the caulicle at one side. Keep them all under the 

 same conditions (as regards depth, moisture, warmth, 

 etc.), preferably all in the same box. Which appear 

 first above ground! 



Let us see what happens to the seed which lies 

 on the surface of the soil. Its first problem is to 

 get its root down into the ground. Have you ever 

 noticed what difficulty some seeds have in doing this ? 



