12 FIEST STUDIES IN PLANT LIFE 



swelling of the seed to the opening of the second pair 

 of leaves — the first pair of true leaves. 



12. The three needs in germination. We have 

 seen that seeds need heat and moisture before they 

 ■will grow. They also need air. Light is not needed, 

 and indeed, seeds germinate faster when light is shut 

 out. 



Exercises, experiments, etc.: — 



(1) Most seeds germinate like the French bean, but the seed- 

 leaves of some plants remain in the ground. Make experiments 

 with the garden pea, broad bean, sunflower, pumpkin, acorn, 

 castor-oil seed, cress. 



Notes. — (a) In each experiment a scholar should be made 

 responsible for watering, for marking dates, and so on. (6) Grow 

 some sunflower seedlings in a pot to be ready for the experiment 

 described in Chapter 9. 



(2) Suspend an acorn over water by a, piece of string in the neck 

 of a wide-mouthed glass jar. If the weather be warm, the 

 evaporating water will moisten the acorn and cause germination. 

 To show that light is not necessary, a second jar could be placed 

 in a dark place. 



(3) As a boy was stooping over a barn floor, a mase of hay fell 

 on his back. How could the boy exert most force to free himself? 

 Compare the method of the French bean seedling in bursting 

 through the ground. 



(4) Some split peas were accidentally sown, and some came up. 

 Explain how this could be. 



Composition exercise : — Tell the story of a French bean plant 

 from the seed to the first pair of true leaves. 



Drawing exercise : — Draw a French bean, (a) dry, (6) ger- 

 minating ; showing the progress of growth at intervals. Mark 

 the date on each sketch. 



