46 PLANT LIFE ON THE FARM 



progress of growth be watched from day to day, then it will 

 be found that while the uppermost marks remain equi- 

 distant, those near the tip become more or less widely 

 separated. This experiment is easily carried out with a 

 hyacinth growing in a glass vase, or by allowing a bean to 

 germinate on the surface of wet moss. It will thus also be 

 seen that the actual area in which growth in length is going 

 on is very small, and that its greatest activity is not exactly 

 at the extreme point, but a little above it, between it and 

 the point where the root-hairs begin to emerge. There is, 

 then, in the growing root first, at the extreme tip a root 

 cap or shield, constantly renewed from within by the growth 

 of the cells above or within it ; then a region of very limited 

 extent, devoted to the growth in length of the root ; and 

 above that a portion, usually but not always, provided with 

 root-hairs, and which is especially told off to fulfil the duties 

 of absorption. 



As the upper, thicker part of the root is relatively fixed, 

 it will be seen how the fine root fibrils are, by the situation 

 of their growing point, enabled to push their way, by 

 constant renewal at their growing point, in amongst the 

 particles of the soil when the conditions are favourable. 



Growth of the Stem. In the case of the stem and 

 branches, the growing points, by whose agency increase in 

 length takes place, are placed at the summit of the stem or 

 of its subdivisions, the branches. The growing points then 

 form the substance of the "buds," which are either invested 

 by leaf-scales as protectors and stores of nourishment, as in 

 the case of bulb-scales, or by perfect leaves. The increase 

 in the thickness of stems takes place also by means of the 

 growing tissue or cambium, the situation of which is 



