260 CONTRIBUTIONS TO
of producing a leaf; but the direct consequence is by no means so generally acknowledged, that for that very reason the woody stem cannot come under the idea of plant. Much confusion has arisen in our physiology from the error of regarding the tree as a single plant, the ideal definition of root, stem, bud, &c. have become very vague, and bitter controversies have been carried on with respect to the functions of these parts, which could have no result, because the one party spoke of this, the other of that, this one of the stalk, the other of the stem, this of root-fibrils, that of ligneous root-substance.
The so-called lignified root is, however, just as little a root, as the lignified stem is still a stalk, but both together form an inseparable, and, moreover, altogether purely accidental organ for the plant, which has secreted the annual individual upon its surface, in order to bring into connexion, by means of a single organized membrane, the whole sum of the newly formed young individuals. The tree corresponds precisely to the polypidom, and it appears to me to be as unsound to set out from it as the type in plants, as it would be for the zoologist to take a Gorgonia as the ideal of animal individuality. This analogy, however, is in no way weakened by the circumstance, that we meet with this woody stem most frequently in precisely the highest developed plants; but, on the contrary, it is natural that, if the animal kingdom in a certain measure receive the vegetative part of its character from the vegetable kingdom, this should connect itself by the lowest stage of animals to the highest plants, whilst even this vegetative half of the vital phe- nomena in the higher animals is in ike manner purified and ennobled by its individuality constantly gaining in independence.
With this explanation of the woody stem (the root included), it will henceforward appear by no means remarkable that this organ (as if it were a mere organized soil) can generate upon every part of its surface young vegetable individuals; that is, buds, so soon as it is in a condition to convey nutritive material to those buds from any part, whether it correspond apparently to the former root or to the stem; while this refined idea of the plant conducts to the law, that in the regular course of vegetation, neither root nor internode, but only the axilla of the leaf, is capable of generating a bud, i. e., a new axis with lateral organs.
