ORGANOGBAPHY AND GLOSSOLOGY. 



THE ROOT, 



The root (radix] is that part of the plant which tends towards the centre of the 

 earth ; it is not coloured green, even when exposed to light, and rarely produces 

 leaves or shoots. It serves to fix the plant in the earth, and to draw thence the 

 nourishment necessary to its growth. 



The root is absent in certain plants, which, from growing upon and drawing 

 their nourishment from others, are called parasites (p. parasiticce)* Such is the 

 Mistleto, which fixes itself beneath the bark of certain trees by the dilated base 

 of its stem. 



The root may be simple, or irregularly branched. Its axis or branches termi- 

 nate in delicate fibrils, which together are termed the root-fibres (Jibrilloe) ; the 



26. Uropwort. 

 Nodose root. 



27. Dahlia. Tuberous root. 



28. Orchis. 

 Fibrous-tuberous root. 



tips of these fibres, being soft, loose, and cellular, are named spongioles (spongiolce) . 

 The individual fibrils die annually, like leaves, and fresh ones spring from the 

 youngest parts of the root. 



Eoots with a single, descending, vertical stock, are called tap-roots (r. perpen- 

 dicularis) ; their main trunk or tap may branch (Stock, fig. 1), or remain nearly 

 simple (Carrot, fig. 24). Sometimes the original, usually simple, tap-root perishes 

 soon after germination, and is replaced by a bundle of fibrils, which spring from. 



