M. Miillei* on the Development of Chara. 325 



between it and the stem-bud is merely, that this can be elongated 

 to infinity, whilst the growth of the bud of the branch is very limited. 

 This limit is shown in the apex of a branch (figs. 12, 13), which 

 no longer appears as a bud, but as a simple terminal cell. The 

 explanation of this limited and unlimited development is to be 

 sought for in the fact that the cytoblastema of the stem has to 

 take a direct ascending course, whilst in the branches this is at 

 first indirect, i. e. dependent upon the stem, devious, and limited 

 by the amount of nutritious fluid. Thus the more the organs 

 are removed from the centre of the individual, so much the more 

 simple must they become, since enough nutriment is not present 

 for a higher development. We also see this in a greater degree 

 in the formation of the shoots. This is effected by the simple cy- 

 lindrical expansion of the external cells which are deposited upon the 

 central cell of the branch ; consequently exactly in the same manner 

 as the branches were formed from the stem. The difference be- 

 tween them is merely, that here the further formation ceases, so 

 that we have no more to do with buds, but merely simple cells, 

 exactly as at the apex of the branch. Hence both agree in not pos- 

 sessing the property, like the other parts of the stem and branch, 

 which lie nearer to the axis of the individual, of forming a cortical 

 layer. At the most they can only produce a few cells (articula- 

 tions) in their interior. 



The peculiarity of the branch, that its membranes rapidly be- 

 come thickened, is opposed to another property of the axial bud. 

 This always possesses closed branches, i. e. rolled up over it, 

 which are only subsequently separated from it when the indivi- 

 dual whorls of branches separate from each other by fresh in- 

 crease. New whorls of branches, i. e. the most recently formed, 

 appear in their place and surround the delicate terminal bud. 

 Thus they defend it from accidental injury, since the oldest always 

 cover the youngest, until the latter have become sufficiently strong 

 to be able to undertake the same office for the younger branches. 

 Of course this function does not occur in the shoots ; they are 

 therefore protected by becoming rapidly thickened. 



If we now compare the formation of the branches and the stem 

 in the germinating and the perfect plant, we find the following 

 essential difierence, that in the former these organs are formed by 

 intercalary or intermediate growth, whilst in the perfect plant they 

 are produced directly. In the germinating plant the whorls of 

 branches follow the formation of the stem ; in the latter the 

 branches and stem go hand and hand in development. In the 

 former there are at first always two cells where an internode is 

 about to form ; in the latter the whorls of branches mark the 

 internodes from the very commencement. Hence the former, 

 strictly speaking, are only accidental, the latter are essential. 



