A most interesting fact connected with the regeneration of the higher plants is, as has been pointed out, that even when a callus is formed over the cut-end, and new growth takes place from this callus, there is produced, not a single terminal bud, but a number of separate buds. The piece does not complete itself, but produces new buds, that make new branches. The explanation of this mode of regeneration in plants is not known. It appears to be connected with the production, by means of buds, of all the new structures. Why this should occur we do not know, and the only suggestion that offers itself is that the result may be in some way connected with the hard cell walls in plants that make difficult the organization of large areas into a new whole. As a result, the new development takes place in a small group of similar cells, that are sufficiently near together to organize themselves into a whole despite the interference met with in the cell walls. Vöchting has also studied the regeneration of pieces of the liverwort, _Lunularia vulgaris_. The results have been already partly given in the first chapter. If cross-pieces are taken from the thallus, each produces a new bud at its anterior or apical end (Fig. 9, _A, A¹_). The new bud arises from the cut-surface, or very near it, from a group of cells of the midrib that lies nearer the under side (Fig. 9, _A²_). The bud gives rise to a new thallus that springs from a narrow base at its origin from the old piece. If a piece is cut longitudinally from the thallus along the old midrib, the new bud arises at the anterior end from the midrib (Fig. 9, _B_). It comes either from the anterior cut-surface near the inner edge, or from the anterior end of the inner edge, and in some cases two new buds arise, one at each of these places. If the piece is removed from one side of the midrib it does not regenerate as quickly as when a part of the midrib is present, but when the new bud develops it arises from the anterior part of the inner edge (Fig. 9, _B¹_). If the piece is cut far out at one side, it may be a long time before the new bud arises. This difference in the rate of development of these pieces is explained by Vöchting as due to the simpler character of the cells near the midrib. If oblique pieces are cut off, with an anterior oblique cut-edge, as shown in Fig. 9, _C, C¹_, the new bud arises along the anterior surface. If the piece includes a portion of the old midrib at its inner end, the new bud arises from this (Fig. 9, _C_), but if the piece lies to one side of the midrib, the new bud arises near the anterior end of the anterior oblique surface (Fig. 9, _C¹, C_²). A number of experiments that were made in order to determine what part gravity and light may take in the regeneration gave nearly negative results. The regeneration appears to result largely from internal factors.