88 PUOCESS OF VEGETABLES. 



lost are recovered, from their seeds being latent in the 

 soil, as I have been assured by Mr. Fairbairn of Chelsea 

 garden, and others.( 14) 



The integuments of the seed, having^ fulfilled their 

 destined office of protection, burst and decay. The 

 young root is the first part of the infant plant that comes 

 forth, and by an unerring law of Nature, it is sent down- 

 wards, to seek out nourishment as well as to fix the plant 

 to the ground. In sea- weeds, Fuci, Ulvce, and Confer- 

 Vte-, it seems merely to answer the latter purpose. In 

 the Dodder, Cuscuta, a parasitical plant, the original 

 root lasts only till the stems have established themselves 

 on some vegetable, on whose juices they feed by means 

 of other roots or fibres, and then withers away. 



The descent of the root, and the ascent of the leaf-bud 

 in a contrary direction, are ingeniously explained by Dr. 

 Darwin, Phytologia, Sect. 9. 3, on the principle of the 

 former being stimulated by moisture, and the latter by 

 air, whence each elongates itself where it is most exci- 

 ted. This is perhaps more satisfactory than any me- 

 chanical hypothesis. In whatever position seeds happen 

 to lie in the earth, the root makes more or less of a 

 curve in order to shoot downwards. Mr. Hunter sowed 

 a number of seeds in a basket of earth placed on an axis, 

 by which their position was a little altered every day. 

 After the basket had thus made two or three circumvol- 

 utions, the young roots were found to have formed as 

 many turns in attenapting to attain their natural perpen- 



(14) [Exotic plants are often found growing where the ballast 

 of vessels has been thrown, and their seeds exposed to the air.] 



