20 



THE GROWTH OF THE TREES. 



something like the smallest bladder imaginable. The sac is the 

 embryo-sac and the small body or cell is the embryo in its 

 primary state. 



Now although nature has provided that this little cell should 

 be present its future growth is dependent on whether or no the 

 stigma has received from a stamen the golden dust, or pollen. 

 In fact, it can never become other than what it originally is un- 

 less the process of fertilization has taken place. When this is 

 so, however, the tiny grain of powder that alights on the moist 

 surface of the stigma, sends forth from its under side a minute 

 tube. It pierces down through the stigma and style until it 

 reaches the orifice of the ovule, then it enters the embryo-sac 

 and finally touches and quickens the little cell into life. Within 

 this vitalized germ there are usually some tiny grains, a muci- 

 laginous liquid and a pulpy mass, or its nucleus. As we have 

 already seen they are all enclosed in a fine, membranous coat. 

 We have here then a typical cell, as it is generally called, and 

 one that is the ancestor of all the countless millions of similar 

 ones that combine to form the structure of a small plant or the 

 greatest tree. It is simply by the expansion and multiplication 

 of such cells that growth takes place. 



After this first cell has enlarged to its limit, it forms a cross 

 partition which divides i*- into two cohering cells. Soon 

 another one forms a partition and divides into two more cells ; 

 and so they continue to increase and to form the hypocotyl of 

 the embryo. It is thus that, encased in its brown seed coat, the 

 miniature tree or embryo is formed and begins to grow. As it 

 does so it draws freely on the nourishing matter that in various 

 forms it finds close at hand. 



Dame Nature never forgets, and so well equipped is the em- 

 bryo that when it touches the soil and begins to germinate, it 

 has but to continue the multiplication of its cells, or as more 

 generally expressed, to increase in cellular tissue ; to assume 

 the upright position of a tree and to bear its two first leaves 

 upward to the light and air. At the same time from the bottom 



