36 



THE ROOT 



VI. THE ROOT 



45. Origin. — Roots ordiuaiily come from stems, not, as 

 is generally thought, stems from roots. It is true that in 



springtime flowering herbs 

 like the Trillium, and the 

 Bloodrocit (Fig. 2.5 ), are 

 seen to break from the 

 ground as if }>r()dueed from 

 a root ; but the suljter- 

 ranean stock in all such 

 cases is a true stem. 



46. Exceptions to the 

 general rule are not uncom- 

 mon, for many roots, espe- 

 cially if severed from the 

 stem, have a jjower (if 

 forming afresh w ithin tlicir 

 tissues, buds developing 

 into leafy shoot s.^ 



47. The initial stem of 

 the embr3'o produces from 

 its end a root which be- 

 comes the first or primarij 

 root of the plant. Some 

 plants keep this as a main 



or taproot throughout the whole of their life, and send out 

 cnly small side roots (Fig. 42); but commonly the main 

 root divides off very soon, and is lost in its branches. A 

 root system is thus formed with no marked central axis. 

 In plants of large size, as trees, the roots often extend on 

 all sides, not far below the surface, sometimes to a con- 

 siderable distance beyond the limits of the aerial parts. ^ 



1 The reprnduction of lacking parts fas buds by roots, roots by stems, 

 and both roots and stems by cut leaves) is lenned regeneration. The 

 faculty is common to many plants, and to not a few animals, especially 

 those of the lower types. 



2 "Those of an elm have been known to fill up drains fifty yards dis- 

 Unt from the tree." — Goudale, " rhyBiological Botany," p. i'oo, 



TlieBlor.droot producing in spring' 

 leaves and tlnwers from an un- 

 derground stem which is i3opu- 

 larly mistaken for a root. 



