206 CONSERVATIVE ORGANS. [LECT. V. 



ceed those which the ground offers to the per- 

 pendicular. Some Grasses, also, as the common 

 Gat's Tail, Phleum pratense, floating Fox Tail, 

 Alopecurus geniculatus, and others, which in a 

 wet situation have fibrous roots, became nodose, 

 when planted in a dry sterile soil : the cause of 

 which cannot be better explained than in the 

 words of Sir J. E. Smith. Presuming the herb to 

 be starved, he adds, " by a failure of the nutri- 

 mental 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 in- 

 stantaneously 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 uniformly supplied with its requisite nourish- 

 ment *." 



The nature of the Jibrils has been already 

 mentioned. They may be regarded as the mouths 

 of the plant : for, the extremities of their vessels 

 being open, these suck up such fluid nutriment 



* Introd. to physioL and systematical Botany, p. 115. 



