34 THE ROOT. PARTI. 



ing to the outer and indurated bark of aged trees, to 

 dead or decayed stumps, to rotten pieces of wood, 

 and frequently even to stones. 



These therefore are to be regarded as exceptions 

 to the rule, which includes, however, parasitical 

 plants that have generally occasioned some difficulty. 

 For although parasitical plants are not found to 

 attach themselves to the earth or soil, but to 

 some other living vegetable, as in the case of the 

 Viscum or Missletoe, which grows upon the Apple- 

 tree or the Oak, yet it is from the plant to which they 

 attach themselves that their nourishment is derived. 

 But almost all plants of the perfect class are fixed 

 in the earth by a root descending in species of large 

 growth, and sometimes even in species of small 

 growth, to a considerable depth below the surface, 

 and spreading, by means of lateral divisions, to a 

 considerable extent around the centre. The divi- 

 sions of the root of the Baobab or African Calabash- 

 tree, have been known to measure upwards of one 

 hundred feet in length. 



The collar. At the point of union between the root and upper 

 part of the plant, there may generally be perceived 

 a sort of annular bulge or protuberance surround- 

 ing or encircling it. It is most discernible in the 

 early stages of the plant's growth, and is then par- 

 ticularly conspicuous in the Horse-chesnut. It is, 

 I believe at present without a name, at least among 

 English botanists. French botanists call it Le Col- 

 let, the collar. 







