BOTANICAL CONSIDERATIONS. 21 



even when the beet has attained its maturity, the build- 

 ing-up of cell structure continues, the first or last cell 

 being essentially the same. The plantlet before appear- 

 ing above ground is like the engraving (Fig. 20), 

 as seen to the eye, but under a strong microscope the 

 structure of the root is made visible; the tip end shown 

 in Fig. 21 gives some important idea of just what the 

 cells in question look like. 



Upon general principles, we may admit that vege- 

 table growth consists of two things : Expansion of a cell 

 until it attains its full size, then multiplication of the 

 cells in number. As the outer layers are worn away 

 by the.root forcing itself through the soil, they are 

 renewed by inner layers, which in turn are replaced. 



Maturity. 



This in reality means the changes which occur 

 from the time the embryo is formed until b'ie grain may 

 be taken from the stalk. The fruit proper, until that 

 maturity is reached, is living just as live the leaves of 

 plants, viz.: During the day a different respiration from 

 that of the night. When the maturity is completed, the 

 tissue changes and the fibro-vascular detaches itself. 

 The cellulose of the fruit loses its carbon and hydro- 

 gen and becomes starch ; by the addition of water, this 

 is changed to sugar. When the maturity is complete, 

 the seed throws out the carbonic acid formed at the 

 expense of the sugar. Seeds on the lower part of the 

 stalks are said to be the first to mature; those on top 

 are last to ripen and frequently do not ripen. When 

 planted, these often germinate with difficulty. 



The engraving (Fig. 22) shows the appearance of 

 the entire root, with the stalks, when the beet matures 

 after the second year. The appearance of the seed 

 when matured upon its stalk is also of interest; as 

 shown (Fig. 23), the petals are still adhering and when 

 further dried will hide the seed proper almost 

 from sight. 



