Dr. A. Braun on the Vegetable Individual. 335 



leaves and flowers — excite the presentiment that this is not one 

 single being, one single life, comparable with the animal or the 

 human individual, but rather a world of united individuals which 

 have sprung from each other in a succession of generations, and 

 although they do not separate, going through their particular 

 cycles of existence, — here dying off, there reproduced, and thus 

 building themselves up in unmterrupted succession into a family- 

 tree, perennially laden with an increasing posterity. That such 

 a view, so consistent with our healthy natural feelings, is corro- 

 borated by scientific investigation, I hope to show in the follow- 

 ing observations. 



Comparing plants with animal individuals, it is at once evident 

 that the tree loses annually flowers and fruit, — the highest and 

 noblest structures which vegetable life produces, — to generate 

 them again in tiie following period of vegetation. Even the 

 whole dress of the tree, even its foliage when compared with the 

 trunk and branches, is only a supei-ficial growth periodically 

 dying off, and reproduced by the succeeding generation : in 

 the paradoxical words of Schleiden *, " No tree has leaves." 

 The leaves, in fact, never grow out of the woody portions of the 

 tree, but only on its herbaceous extremities, which grow upon 

 the woody stem as upon a ground formed by the process of vege- 

 tation. This common ground, namely the woody stem, which is 

 almost lifeless in comparison with the herbaceous parts engaged 

 in active growth, is annually covered with a vigorous sheath 

 under the protecting bark, and this sheath is the ground of the 

 nourishment of all the vegetating herbaceous extremities. This 

 sheath is the so-called cambium, a layer of active, living tissue, 

 which, contemporaneously Avith the lignitication of the herba- 

 ceous extremities of the branches, becomes a new woody layer, 

 united to the old trunk in the form of an annual ring — to be 

 covered in its turn in the folhnviiig period of vegetation with a 

 new layer, v\hich, again, will be the immediate supporter of the 

 new generations. The history of the grand development of na- 

 ture on the surface of our globe presents an analogy which may 

 perhaps serve to set this relation in a clearer hght. The suc- 

 cessive geological formations superposed during the course of 

 countless ages, present, buried in their depths, the traces of as 

 many formations of the organic world, each of which carpeted 

 the then superior stratum of the earth with a new life, until it 

 found its own grave in the succeeding formation, when a new 



* Beitr., p. 152, where the following view of the arboraceous stem, as a 

 common ground bearing many individuals, is developed ; but this whole 

 view, after all, needs to be corrected hy a precise limitation of its meaning 

 bv what follows it. 



