DR. M. J. SCHLEIDEN ON PHYTOGENESIS. 307 



the entire totality of the plant, take part in this formation ; and 

 although the result in this case may probably be that there can 

 be no question of an heteromorphy of a known part of a plant, 

 yet the physiological identity in signification of this and the 

 former case has not been steadily maintained, and the view has 

 thus been obscured. 



Most botanical writers set out quite at their ease, as if it were 

 self-evident, from the tree as the perfect plant, and I believe 

 it is not difficult to demonstrate that where Vegetable Physiology 

 lies very deep in error this very misconception is solely to blame. 

 Two quite distinct ideas have here been confounded, viz. the 

 highest stage of development to which vegetable life can in fact 

 raise itself, and the type upon which the idea of individual must 

 be based. Now if the first of these ideas may be truly main- 

 tained vpith regard to the tree, yet the appUcation of the second 

 to it is in every respect totally false, as has been very correctly 

 asserted before by M. Meyer {Linncea, vii, p, 424). It necessa- 

 rily belongs to the idea of a plant that it produces on its stem fo- 

 liaceous organs ; yet there is no tree that has leaves. Paradoxical 

 as this may sound, yet it is not the less true. It is a fact that 

 certainly no botanist is ignorant of, that no lignified part of a 

 plant, even though only in its second year, is capable of producing 

 a leaf; but the direct consequence is by no means so generally 

 acknowledged, that for that very reason the woody stem can- 

 not come under the idea of plant. From the error of regard- 

 ing the tree as a single plant much confusion has arisen in our 

 physiology, the definitions of the ideas of root, stem, bud, &c. 

 have become very unsettled, and bitter controversies have been 

 carried on respecting the functions of these parts, which could 

 have no result, because the one party spoke of this, the other of 

 that, this one of stalk, the other of stem, this of root-fibrils, 

 that of Ugneous root-substance. 



But the so-called lignified root is just as little a root as the 

 lignified stem is a stalk ; but both together are, according to the 

 idea, inseparable, and they form, moreover, altogether a purely 

 accidental organ in the plant, which the annual individual has 

 secreted on its surface, in order to bring into connexion, by means 

 of a single organized membrane, the whole sum of new and young 

 individuals. The tree corresponds entirely to the polypidom, 

 and it appears to me not more sound to set out from it as the type 

 m plants, than were the zoologist to set up a Gorgonia as the idea 



