DECOMPOSITE ORGANS. CHAP. I. 



SUBSECTION IV. 



General Remarks. Such is the general outline 

 of the structure of the caudex of herbaceous plants 

 on the one hand, and of woody plants on the other, 

 whether as ascending or descending. But the struc- 

 ture of the branches or divisions is the same. For 

 they are not merely prolongations of a part of the 

 caudex diverging from the centre, and extending 

 beyond the circumference ; but they are each a 

 caudex in' miniature, furnished with a pith, wood, 

 or interwoven fibre and pulp, and bark, precisely 

 as in the caudex itself. This has been rendered 

 evident by Du Hamel in his Physique des Arbres > 

 by the following illustration.* 



If you take a horizontal section of a stem with 

 two branches a little above the cleft, the appearance 

 is that of two stems. If you take the section in 

 the fork itself, you will then find in the centre 

 two sets of concentric layers, corresponding re- 

 spectively to the two branches, but enveloped by 

 another set common to both, that forms the cir- 

 cumference of the stem. If you take the section 

 still lower you will find the layers that correspond 

 to the two branches diminishing in number, and 

 the outer layers increasing, till at last the central 

 layers disappear altogether. Thus the layers proper 

 to each branch form in the original stem an in- 

 verted cone, of which the summit is at the centre, 



* Liv. i. chap. v. 



