48 



THE ROOT. 



8. Didymoiis Roots are those which produce a tubercle 

 each year, and when the tubercle of one year arrives at 



nearly the dimensions of the one of 

 2 5 ^M _ the preceding 



year, they an- 

 suer to the form 

 indicated by the 

 term applied to 

 them ; that is, 



double or twin< 



roots. The Or- 

 chis affords examples of this variety, 

 Fig. 25. 



9. The Pahnated Roots are such as 

 differ from the preceding only in hav- 

 ing the lobes divided, giving them somewhat the appearance 

 of a hand. The Orchis affords examples of this variety, 

 Fig. 26. 



The following varieties are generally classed as either 

 stems or buds, but are, in common parlance, called roots, and 

 we know of no disadvantage in complying with the popular 

 arrangement by describing them under this organ. 



10. The Rhizoma or Rootstock grows in nearly a horizon- 

 tal direction, emitting roots from its under side, increasing by 



one extremity only, at which 

 it puts forth leaves and 

 flower-stems, and gradually 

 dying at the other. Its sur- 

 face is generally marked by 

 irregular ridges formed by 

 the bases of decayed leaves. 

 The Calamus, Iris, Lily, 

 and some of the grasses 

 afford good examples of this 

 variety, Fig. 27. The scaly 

 roots come under the same variety, 

 as is exhibited in the Hydrophyllum 

 canadense. 



11. The Carmus Fig. 28. is that 

 variety which increases beneath the 

 earth by the development of buds in 

 the axils of the scales, but retains its 

 globular figure, and propagates itself 

 in no particular direction. The Tu- 

 lip, Arum, Gladiolus, &c. afford ex- 

 amples. 



