Dr. A. Braun on the Vegetable Individual. 351 



The stalk, or axis of the shoot, is hence indivisible in the higher 

 plants, in the same sense that the body of the higher animals is 

 indivisible*. The only pheenomenon which might be described 

 as a division of the stalk is leaf- formation. This, however, is 

 not a division into new stalks, but a formation of subordinate 

 parts belonging essentially to the stalk, as it were an eradiation 

 of the stalk itself, which may be aptly ^compared to the formation 

 of the extremities in the animal body. We may therefore justly 

 describe the shoot, or the vegetable individual, as an indivisible 

 axis, — as an axis with its appurtenant radii which are inseparable 

 from, and regularly arranged by, its own development. With 

 the first appearance of the branch a new axis is formed, and a 

 new system of subordinate radii appears. However completely the 

 branch may contrive to interweave itself with the trunk diu'ing 

 the course of its development, it always owes its origin to an 

 accessory point of vegetation which developes into a particular 

 axis. The vegetable individual thus presents in its nature a cer- 

 tain analogy to the mineral indi\idual, — the crystal, — as well as 

 to the animal individual ; for the crystal is determined by the 

 relation of its parts to one and the same system of axes. As 

 soon as this system of axes holds another position there results 

 another individual, which may be distinguished even when two 

 or more indi^idual crystals intersect, so as to form twin crystals, 

 or stellate crystals. 



In the preceding considerations on the indivisibility of the 

 axis, I described the leaves as its radiations, — as members of 

 the stalk, and belonging essentially to it, — and I attempted to 

 distinguish the leaves from the branches, by considering the latter 

 as new axes. But how are leaves and branches distinguished in 

 their genesis ? Are not the branches as much radiations or 

 lateral members of the stalk as the leaves ? It would lead me too 

 far from my subject to make a fundamental critical investigation 

 into this question, and to examine the existing views of the mode 

 of formation of leaves and branches, especially as investigations 

 into this subject have not been complete enough to enable us to 

 obtain reliable results. I can therefore only allow myself a ie^ff 

 hints in this place. The leaf originates in the earliest period of 



shoot-formation (gemmation), as was shov.n by Ehrenberg (Beitrage, &c., 

 Abh. der Akad. 1832, p. 242). Ehrenberg explains the fonn o( DtBdalince 

 as a result of incomplete termination of the individuals in gemmation ; in 

 appearance it resembles the cockscomb-like forms of fasciation as they occur 

 in a remarkable way in some monstrous Cacti of the genera Mammillaria 

 and Echinocactus, as well as in Celosia cristata, well knov.Ti as an orna- 

 mental plant. 



* [Some criticisms upon this may be given at the close of the whole 

 memoir. — A. G.] 



