LECT. IV.] THE ROOT. 1'29 



live for several yeais, is in general woody, and is 

 to the other parts what the trunk or stem is to the 

 branches and leaves ; enlarging progressively in a 

 similar manner, and giving off lateral branching 

 shoots, which spread horizontally, or in a direc- 

 tion that forms nearly a right angle with the 

 caudex. In those plants, however, the herbace- 

 ous part of which dies annually whilst the root 

 survives, and in many annuals, the caudex is 

 also a reservoir of nutriment, which is intended 

 for the renewal of the herbaceous part in the fol- 

 lowing season, or to be expended in perfecting the 

 flower and the seed. The rootlets, radiculce *, are 

 small, or threadlike productions of the caudex, 

 terminating in Jibrils, which are extremely mi- 

 nute, the real absorbing organs of the root ; and 

 are supposed by Du Hamel-f~, Willdenow^, Sir 

 E. J. Smith and others, to die annually in the au- 

 tumn with the foliage, and to be reproduced in 

 the spring ; an opinion which Mr. Knight || re- 

 gards as incorrect, as far at least as concerns the 

 terminal fibres of woody plants. My own ex- 



* " Radicula est pars radicis fibrosa, in quam terminatur 

 " caudex descendens, et qua radix nutrimentum haurit pro 

 " vegetabilis sustentatione." Phil. 'Bot. 80. 



f Phys. des Arb. liv. i. chap. v. 



J Principles of Botany > 11. 



} Introduction to physical and systematical Botany, p. 104. 



Jl Phil. Trans. 1809. 



VOL. I. K 



