16 Dr Harvey's Observations on (he 



posing this to be the case, would by no means take from 

 them the character of enth'e and perfect plants, if it could be 

 shewn that the office of roots is otherwise adequately pro- 

 vided for. And, with reference to the latter, it may be ob- 

 served, that the fact of a structure entering into their con- 

 stitution, not existing in other plants, would not at all aiFect 

 their claim to be so regarded, particularly if it could be shewn 

 that that structure is required to meet some condition of 

 their existence peculiar to themselves, or to serve some 

 ulterior purpose in the economy of nature. And the woody 

 layer, it is to be remembered, is strictly an annual formation, 

 and so far accords with the view taken of the growths in 

 question as being annual plants. 



Now, the structure referred to — the woody layer — clearly 

 subserves, immediately, the purpose of a mechanical support 

 to the growths or plants of the same year's formation with it- 

 self, and remotely that of producing timber. "Without it trees 

 could scarcely grow at all, or, if they could, would be of little 

 use to man. But it serves also the office of roots to those 

 growths or plants, being the channel by which the nutritive 

 matters in the soil are conveyed upwards to the growing 

 stems, and leaves, and flowers. And if it thus serves these 

 various purposes, the questions stated must be regarded as 

 satisfactorily disposed of. The only question will be, whether 

 the woody layer, in its origin and mode of formation, be 

 actually of the nature of, or rather identical with, roots, and 

 only secondarily intended for a mechanical support, and for 

 the production of timber ; or whether it is truly a special 

 formation for the accomplishment of these latter objects, and 

 only virtually of the nature of roots 1 



After what has been stated, however, this other question 

 is of no real practical importance in relation to our present 

 inquiry. The woody layer may be formed in the manner 

 that M. Du Petit Thenars supposes, or in that insisted on by 

 M. Mirbel and others. If in the former, it constitutes true 

 roots, and is nothing more than " a mass of roots ;"* if in 

 the latter, it is only virtually roots. The mode of its forma- 



* Dr Lindley, Introduction to BotUny, First Edition, p. 245. 



