The Vegetable Individual in its relation to Species. 185 
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 
anend. ‘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 cam- 
bium which connects the new shoots with the extremities of the 
root by which the nourishment is absorbed. This increased dif- 
ficulty of communication between the upper and lower extremi- 
ties is probably the cause of the decrease of vigorous growth af- 
ter the plant has arrived at a certain age. But in most cases ex- 
ternal casualties are superinduced, which accelerate the termina- 
tion of the tree’s life. It is injured by wind and weather, the de- 
cay of the injured part spreads through the whole organism, vari- 
ous fungi fix themselves upon the tree, and are especially fatal 
when they attack the roots. Oftentimes the tree breaks down 
under the weight of the productions of its own vital powers, the 
4% 
luxuriance of its fruit. hese statements are corroborated by 
being called “Neustadt an der grossen Linde” (Neustadt of the 
great Linden), whose wide-spreading branches were supported al- 
ready in 1408 by sixty-seven stone pillars, and this number was af- 
terwards increased up to more than one hundred.+. The hoary tree 
still flourishes, having survived its many scientific admirers, among 
whom was my predecessor, to whom Botany is so greatly indebted, 
Who visited and described it a few years ago, (in 1849).f Natural 
., «Cf. Schleiden: Beitr., p- 151. “The idea of individual life necessarily implies as 
saeetinguishin char teristic individual death, k diti Aree Sa ong onl 
Se. __Although this remark is not universally true in many ng, 2 Cg : = 
lusion 
adopted it for the light it is calculated to throw on the nature of 
e skin, ting, and the organic changes.in 
the body). Of on this point Roeper: Linnea, 1826, p. 439, and the following remarks 
] j ia nummularia, Adoxa, ete., the preceding ones on Caulerpa, 
t De Candolle: Physiol. Veg. I, p. 988. ° 
re elie innerungen an die grosse Linde bei Neustadt am Kocher (Flora , 1859, 
0. 
Skconp Serres, Vol. XX, No. 59.—Sept., 1855. 24 
