84 MORPHOLOGY OF STEMS. 



which the aged are either increasingly incident or less able to 

 resist. A tree like the Banyan (/>!, Fig. 71), which by aerial 

 roots continues to form new trunks for the support and sustenance 

 of the spreading brandies, and thus ever advances into new soil, 

 has a truly indefinite existence ; but, then, it becomes a forest, 

 or is to be likened to a colony propagated and indefinitely in- 

 creased by suckers, offsets, or other subterranean shoots. So 

 the question of the secular continuation of the individual plant 

 becomes merged in that of continuation of the race. at least of 

 a bud-propagated race, the answer to which is wholly in the 

 domain of conjecture. 1 However this ma'y be, it is evident that 

 :i vegetable of the higher grade is not justly to be compared with 

 an animal of higher grade ; that individuality is incompletely 

 realized in the vegetable kingdom; 2 that rather 



156. The Plant is a Composite Being, or Community, lasting, in 

 the case of a tree, through an indefinite and often immense num- 

 ber of generations. These are successively produced, enjoy a 

 term of existence, and perish in their turn. Life passes onward 

 continually from the older to the newer parts, and death follows, 

 with equal step, at a narrow interval. Xo portion of the tree is 

 now living that was alive a few years ago ; the leaves die annu- 

 ally and are cast off, while the internodes or joints of stem that 

 bore them, as to their wood at least, buried deep in the trunk 

 under the wood of succeeding generations, are converted into 

 lifeless heart-wood, or perchance decayed, and the bark that 

 belonged to them is thrown off from the surface. It is the aggre- 

 gate, the blended mass alone, that long survives. Plants of 

 single cells, and of a definite form, alone exhibit complete indi- 

 viduality ; and their existence is extremely brief. The more 

 complex vegetable of a higher grade is not to be compared with 

 the animal of the highest organization, where the oll'spring always 

 separates from the parent, and the individual is simple and indi- 

 visible. But it is truly similar to the branching or arborescent 

 coral, or to other compound animals of the lowest grade, where 

 successive generations, though capable of living independently 

 and sometimes separating spontaneously, yet are usually devel- 

 oped in connection, blended in a general body, and nourished 

 more or less in common. Thus, the coral structure is built up 

 by the combined labors of a vast number of individuals, by 

 the successive labors of man}' generations. The surface or the 

 recent shoots only are alive ; beneath are only the dead remains 



1 See Darwiniana, xii. 338-355. 



2 As, perhaps, was first explicitly stated by Engelmann, in his inaugural 

 essay, De Antholysi Prodromus, Introduction, 4. 



