SECT. I. ORGANOGIIAPHY AND GLOSSOLOGY. 39 



which represents the caudex, as, for instance, in the 

 bulbs of hyacinths. Roots, however, may be developed 

 from any part of the stem and branches, if these are 

 duly subjected to the influence of moisture and shade ; 

 and some plants of tropical climates constantly produce 

 roots from their stems and branches, which descending 

 into the ground become fixed, and serve to support the 

 superincumbent vegetation, and thus enable it to ex- 

 tend over a large tract of ground. The most celebrated 

 example of the kind is the banyan-tree of the East 

 Indies (fig. 28.). In this case, it appears that when 



the roots have reached the ground, the exposed portion 

 assumes the character of a stem. It has, indeed, been 

 asserted that the stem and root are so entirely distinct, 

 that the latter is never capable of assuming the cha- 

 racter of the former. But it is not uncommon to find 

 ash-trees which have grown on the stumps of pollard 

 willows and have sent their roots through the decayed 

 wood into the ground ; the exposed roots of the ash, when 

 the willows have fallen to pieces, become coated with 

 a green bark, and do not appear to differ in any respect 

 from the trunk itself. At all events, many roots are as 

 capable of producing stems or branches, as these are of 

 o 4, 



