CHAPTER IV 



HOW SEEDLINGS GET ESTABLISHED 



20. Germination. Germinating seeds must have 

 water, air, and a certain amount of.warmth. The prompt- 

 ness of germination depends on how 

 well these conditions are provided. 

 In three or four days, seeds sown in 

 moist sand will be found to be very 

 much larger. They have absorbed 

 water from the sand, so much so 

 that the weight of the seed is now 

 much greater than when it was dry. 

 In some, the coverings of the seed 

 will be found broken, and tiny roots 

 pushing through. If they are watched 

 for some days, it will be found that 

 this tiny root grows in a downward 

 direction, regardless of the position 

 of the seed. The root makes a con- 

 siderable growth before the young 

 stem, with its tiny leaves, gets out 

 of the seed case. (Fig. 10.) When 

 the embryo plant inside the case 

 begins to grow, we say the seed is 

 germinating. 



Fig. 10. During the ea r . y 21. Root-hairs. The tiny rootlets 

 gro in f^te n r which we found pushing through 



tn6 SeeC * COat are J ust like tne thou- 

 gan( Js O f branches found On TOOtS of 



- 



dosperm. D, horny en- 

 dosperm. 



(12) 



