FORMS OF ROOTS. 



105 



ground, in proportion to the growth of the branches and 

 twigs of the stem above. The axis itself may not descend 

 to any great depth, and after a few years may be found far 

 exceeded in growth by its own branches which extend hori- 

 zontally in a better soil. The greater the growth of tlie root) 

 the more firm will be its hold upon the ground, and the great- 

 er its capacity for drinking in liquid nourishment for the tree. 



220. The roots of herbaceous 

 plants take a great variety of 

 forms. Some are tuberous, some 

 fibrous. The tuberous are such as 

 consist of a large axis or body, with 

 small branches ; as in the Beet, 

 Ground-nut, Spring Beauty, and 

 many other biennial plants. 



221. The Jlh'ous are such as con- 

 sist mostly of fibres, with scarcely 

 any axis ; as in Buttercups, Grass- 

 es. In such cases the axis ceased 

 to grow immediately after ger- 

 mination, and lonoj thread-like r- oo.^ rr ^ j ^ y 



' ^ ^ ^ Ftff. 336. Tuberous and fusifonn 



branches supplied its place. root of Beet. 



222. The filrO-tulerOUS roots ^'^' ^^^- Tuberous and napiform 

 , , /> ,1 . root of Turnip. 



are such as nave some ot their 



fibres thickened and fleshy, as seen in the Peony, Dahlia, 



216. Please explain the meaning of the term axis. In what two directions 

 does it grow ? 



217. Wliat is the twofold purpose of the root? What does it imbibe ? 

 In what state is this food when imbibed ? 



218. What is said of the nature of the root? What are its only proper 

 organs ? What is said of leaves or buds ? 



219. Describe the roots of woody plants, and their growth. 



220-222. Describe tuberous roots ; fibrous ; fibro-tuberous ; tubercular. 



5* 



