BULBOUS ROOTS, iOJ 



when growing in pastures that are uniformly moist ; 

 is merely fibrous, but in dry situations, or such as are 

 occasionally wet, it becomes bulbous, and thus secures 

 a store of nutriment by which its vital powers are sup- 

 ported, while the fibrous roots are deprived of their 

 usual supplies. If once more transferred to a soil uni- 

 formly and thoroughly moist, it again becomes fibrous 

 and resumes its former luxuriant growth. In this case 

 it has been supposed that " the herb being in the first 

 instance starved, by a failure* of the nutrimental fluids 

 hitherto conveyed by the water of the soil, its growth 

 would be checked, and when checked, the same growth 

 could not, as we know by observation on vegetation in 

 general, be instantaneously renewed. A sudden fresh 

 supply of food would therefore cause an accumulation 

 of vital energy in the root, which would consequently 

 assume a degree of vigour and a luxuriant mode of 

 growth not natural to it, and become bulbous. Thus 

 it acquires a resource against such checks in future, and 

 the herb is preserved alive, though in a very far less 

 luxuriant state than when regularly and uniformy fur- 

 nished with its requisite nourishment."* And accord- 

 ingly we see that those plants which in their native situa- 

 tion find only a precarious supply of water, are suppli- 

 ed with bulbous roots for their preservation. Like 

 the thick-leaved plants, many of them were brought 

 from Africa, and their texture is happily designed to 

 encounter the privations of those countries which they 

 are intended to adorn. 



Nearly allied to bulbs are the tuberous roots which 

 consist of a single knob, or of several, connected by in- 

 tervening radicles. These knobs preserve the vital 

 energy as well as the nutritive fluids which they re 



* Smith 



