I] THE SEEDLING 5 



the shoot-system. The green colour of the foliage of our 

 common trees and shrubs is strongly in contrast with the 

 non-green of the roots, and this green colour is especially 

 correlated with the aerial position of the shoot, an organ 

 normally adapted to life in the air and the light. 



Most elongated shoots exhibit definite segmentation 

 into joints or nodes, where the leaves are inserted, and 

 internodes, the stretches of stem between, and this joint- 

 ing is frequently accentuated by swellings at the leaf- 

 insertions, e.g. the Vine. 



The typical shoot-system, as exemplified by an Oak 

 or Beech, a Blackthorn, Holly or Barberry bush, exhibits 

 degrees of subdivision into outgrowths of various kinds 

 which necessitate such terms as stem, branches, twigs, 

 leaves, spines or prickles, flowers, and others, but the 

 student should note that the idea of the shoot-system, as 

 opposed to the root-system, by no means depends essen- 

 tially on the presence or absence of distinct internodes, or 

 segments, or any particular form of outgrowth. 



It is a fundamental peculiarity extending to all the 

 plants with which we are here concerned, that each 

 commences its external life as a seedling, developed from 

 a seed : the fact that numerous plants exist which never 

 form seeds does not here concern us at all, and we may 

 dismiss them altogether from consideration. Even the 

 tallest tree and we may note that there are trees in 

 existence over four hundred feet in height and over a 

 thousand years of age was once a seedling, consisting 

 essentially of four discernible parts, as shown in Fig. 1. 

 There is first the minute thread-like primary root, or 

 Radicle, the first outgrowth of the root-system, which, in 

 the case selected, descends into the earth to afford the 

 first support to the plant, and to absorb the first supplies 

 of water, with dissolved salts, from the soil. Then, secondly, 



