538 ORGANOLOGY. 



can in this case only speak of death, when all the elementary organs are 

 chemically or mechanically destroyed. On the great Fucus bank of 

 Corvo and Flores we might yet find, floating about, plants of Sargassum 

 which had been cut into strips by the bark of Columbus ; and in the 

 northern drift we might expect to discover Lichens that had been trans- 

 ported, with the soil in which they grew, from Scandinavia. On the 

 primitive rocks we may find frequently examples of Lichens which, from 

 a knowledge of their slow growth, we might regard as at least a thousand 

 years old. The majority of the Fungi, on account of the delicacy of their 

 tissue, are more easily destroyed, especially through decomposition, than 

 other plants, so that we can hardly say that they die a natural death. 

 Amongst high trees we often find the so-called magic circles, formed by 

 Boletus bovinus, B. edulis, &c., having so great a circumference that 

 the plant to which their spore-fruits (sporocarpia) belonged could not 

 be less than from ten to twenty years old, the solid Polyporus igniarius, 

 Dcedalea quercina, &c., must frequently reach an age of above a century 

 before they, Dryas-like, fall to the ground, which they do not because 

 they are dead, but because the dwelling-place with which a hard fate has 

 united them can no longer exist. 



The fact is otherwise in the remaining groups of plants, which, by a 

 definite modification of the process of development, form various organs 

 essential to the idea of their existence. One of these plants can be said 

 to exist only so long as it continues to form organs necessary to the idea 

 of its existence. The occurrence of any thing to render it impossible to 

 develope itself according to its peculiar law is the death of the plant. 

 Hence the importance of the distinction earlier pointed out between 

 simple and compound plants. As the existence of the latter does not 

 depend upon the growth of an individual existence, but upon the continual 

 reproduction and formation of new individuals, we cannot speak of their 

 death, because we know of no necessity in organisms capable of repro- 

 duction that would induce in any one generation the cessation of the 

 reproductive power. There exist no observations to prove that, under 

 perfectly favourable circumstances, any tree ever died from the weakness 

 of old age. On the other hand, we have examples without number of 

 trees of prodigious age. The celebrated Castagna dei cento cavalli 

 (Castanea vescd) on .ZEtna must be a thousand years old at least. 

 The Baobab trees (Adansonia digitata) of the Green Cape demand of 

 us, according to their thickness and the number of zones in some of 

 their branches, an age of 4000 years, or thereabout. The gigantic 

 cypress (Cupressus disticha) at Santa Maria del Tule, six miles east of 

 Oaxaca, in Mexico, has a circumference of 124 Spanish feet, about 40' 

 in diameter. Now, suppose that every annual zone measured 1"', the tree 

 must be nearly 3000 years old. It is historically certain that it is older 

 than the conquest of Mexico by the Spaniards. The age of the great 

 Dragon tree (Draccena Draco) at Orotava, in Teneriffe, is supposed to 

 be 5000 years ; so that, according to the ordinary calculation of the 

 Hebrew chronology, it was a witness of the first creation. These ex- 

 amples* are quite sufficient to prove the possibility of a compound plant 

 living on without end. These plants die ordinarily in consequence of 

 mechanical injuries. A storm breaks off a branch, the broken surface is 

 exposed to the action of rain-water ; putrefaction or decay takes place, 

 the firmness of the cell-tissue of the heart-wood becomes affected ; and a 



* There is a catalogue of old trees in the Appendix. 



