222 VEGETABLE ORGANOGRAPHY. 



Section III. 



Of Subterranean and Root-like Stems or Branches. 



The number of true creeping roots is smaller than is 

 generally believed ; for in several cases, this name is 

 given to true branches of the stem, which, springing 

 from very near the neck, are developed underground, or 

 on a level with the surface, as is the property of all 

 stems in similar circumstances ; it is thus that what are 

 called roots in Triiicum repens and Panicum Dactylon, 

 are true subterranean branches of the stem which shoot 

 out radicules from each of their knots. Carex arenaria 

 and several other Cyperaceae present analogous examples ; 

 it is thus that the pretended roots which the subterranean 

 pods of Vicia amphicarpa and Lathyrus amphicarpos 

 bear, are only branches of the stem buried luider ground 

 and among stones. It is also thus that the root-like 

 branches which, in the Potato, bear the tubercules, are 

 only the lower branches ; and therefore it is found ad- 

 vantageous to bank up the bottoms of the stems of this 

 plant, because by this process the number of these sub- 

 terranean branches is increased. Sometimes the base 

 of the stem itself forms a kind of horizontal trunk, which 

 elongates by one of its extremities, gradually perishes 

 at the end most distant from the neck, and shoots out 

 radical fibres throughout the w^hole of its lower surface : 

 this takes place in a great number of aquatic plants, 

 such as the Water Lilies, Potamogeton, &c. ; we find it 

 also in the herbaceous Ferns. Sometimes, lastly, the 

 principal stem, without changing its direction, is gradu- 

 ally buried by the raising up of the earth around it, and 

 takes the appearance, and also in some respects the 

 structure, of a root. De La Roche has shown a very 



