336 Dr. A. Braun on the Vegetable Individual. 



uprising of organic life took its place. In the same way the stem 

 of a tree is a multistratilied ground, in whose layers the history 

 of earlier growths is legibly preserved. The number of the 

 woody layers indicates the number of the generations which have 

 perished, i. e, the age of the whole tree : a distinct annual ring 

 is the monument of a vigorous season, an indistinct one of a bad 

 season, a sickly one (which is often found among healthy ones) 

 indicates the unhealthiness of the foliage of that particular year. 

 The practised woodman can decipher many facts of the past in 

 the layers of the trunk, e. g. a good season for foliage or for seed, 

 damage by frost or by insects, &c. 



Essentially the same relations as those seen in the tree, or the 

 shrub, are to be found in the subterranean perennial growth of 

 planta redivivcE {^QxhdiQQOMS perennials), whose subterranean stem 

 (rhizoma), like the stem above the surface, emits annually a new 

 generation of herbaceous growths ; whose stalks however, unlike 

 those of the tree, do not lignify and form a part of the common 

 supporter, but die off wholly, or mostly, at the close of the season 

 of vegetation. 



The relations indicated above compel us to recognize a suc- 

 cession of generations in trees, shrubs, and perennial herbs ; and 

 thus our first idea of them as individuals is necessarily modified. 

 Another remark may be made here which confirms our idea thus 

 modified. Natural death closes the life of the individual*. The 

 development of the life of individuals in organic nature has a 

 goal, an acme ; after it has attained this goal its course draws to 

 an end. This is not the case in the tree and the perennial herb. 

 True, the tree is destroyed by time ; but this seems to result more 

 from external, and in part mechanical causes, than from any in- 

 ternal decrepitude. The more numerous the generations which 

 the tree builds up, one above the other, the greater is the distance 

 of the growing extremities from the source of their nourishment : 

 the thicker the supporting trunk, the thinner is the layer of 

 cambium which connects the new shoots with the extremities of 

 the root by which the nourishment is absorbed. This increased 



* Cf. Schleiden, Beitr. p. 151. "The idea of individual life necessarily 

 implies as its distinguishing characteristic individual death, preconditioned 

 in the organization itself." Although this remark is not universally true in 

 many respects, yet I have adopted it for the light it is calculated to throw 

 on the nature of the tree. For the very reason that natural death is the 

 result of a determinate conclusion of the development, those shoots (vege- 

 table individuals) which have no such conclusion frequently undergo no 

 death at all except that of some of their parts : but this is a concomitant of 

 animal life itself (casting the skin, moulting, and the organic changes in 

 the body). Cf. on this point Roepor, Linnaea, 1826, p. 43.9, and the fol- 

 lowing remarks on Paris, Lysimachia nummularia, Adoxa, &c., andr tbe 

 ])receding ones on Caulerpa. ^"moW ^ 



