AN INNER LAW OF ITS OECfANISM. 185 



The individual existence of a plant usually terminates 

 with the formation of its flowers and seed. This law ap- 

 plies at least to annuals and biennials. In herbaceous 

 perennials and shrubs, on the contrary, those branches 

 only die which terminate in flowers, or in an inflorescence. 

 With trees, at length, death extends not to the whole 

 flowering axis, but only to its upper part, which dies down 

 to the origin of the last side-shoots. And the reason is 

 plain : the mother-shoot is nourished and its life secured 

 by the daughter-shoots to which it gives birth. If the 

 reader also take the fact into consideration, that of the 

 numerous axes of a tree, only a small number, in pro- 

 portion to the others, terminate in flowers, he will clearly 

 perceive that the tree has, despite the formation of its 

 flowers, ample means of an independent continuance of its 

 growth and life. 



But, we see that, notwithstanding the numerous perma- 

 nently vegetative branches which the tree possesses, as a 

 preservative against the exhausting influences of its flowers, 

 or reproductive organs, yet nevertheless, it dies sooner or 

 later ; and this question arises for consideration : Is the 

 death of the tree brought about in accordance with a regu- 

 lar law to which its organism is subjected ? or does it pos- 

 sess a natural tendency to an unlimited duration of life, 

 which is only brought to an end, accidentally, through 

 storms and other hurtful outward influences ? The former 

 appears to me to be the correct view, and I am sustained 

 in this opinion by Unger* and Mohl,t both eminent phy- 

 siologists. 



"We have seen that every part of the tree is a representa- 

 tive of a certain stage of development through which the 

 tree has passed, whether it be leaf, shoot, or branch. But 

 each of these parts passes through certain regular stages 

 of infancy, maturity, decay, and death. 



Now the growth of all the leaf-forms temporarily put 

 forth by the tree, as well, as the shoots and branches which 



* Grundz. d. Anat. u. Thy. S. 131. 

 t Vegetabilische Zelle, S. Go. 



