On the Suds and Ramificalions of Plants, 239 



The same prolongations are found in hcrlaceous plants 

 ti'ith a ramified stem : for example, in the adult stems of 

 the common cabbage, &c., where one may be convinced 

 that the branches have no other origin there than that of 

 the medullarv sheath, and that they issue from real buds. 



It seems to result, from what I have here said, that the 

 reproducing organ of buds in the dicotyledon plants, is 

 effectively and exclusively ih^caseor sheath winch contains 

 the pith: it is even in the herbaceous monocotyledon 

 plants, the spaces between the knots of which form empty 

 tubes : nature, to produce branches, has formed in these 

 plants solid knots or articulations, the structure of which 

 is almost the same as that of the stems of plants the canaJ 

 of which contains pith. 



The opinion that the medullary case is the only organ 

 which (jives rise to buds, and consequently to branches, is 

 confirmed bv the observations which I made on the inser- 

 tion of old branches even in trunks entirely dry. For this 

 purpose I carefully examined the branches of the pine fir 

 and priimis spinosa (sloe-tree), shumac, oak, apple-tree, 

 Sec, and everv where I observed the same result. It 

 is true, that in the old branches the prolongations are more 

 lierbaceous, and on that account are difficult to be distin- 

 ffuished, because the one which has penetrated into the 

 principal substance of the bud, from which the branch has 

 proceeded, h.ns become ligneous : the small lateral ones are 

 not even dried, and are still entirely covered and concealed 

 both by the base of the branch, and by the annual strata of 

 the wood, which had been formed after these prolongations 

 had thrown out petioles or leaves. The perpendicular sec- 

 tion of a branched trunk always shows, whatever be the 

 number of the concentric strata of the ligneous body, that 

 the medullary sheath of the branch proceeds from the 

 medullary shealh of the trunk ; that the branch never forms 

 in the trunk an inverted cone, the summit of which is con- 

 cealed by the strata of thai part ; and that the branch of a 

 tree can never be compared, as has been done, to a plant 

 the routs of iv/iich are in a ligneous soil. The different an- 

 nual strata of a branch neve r cover each other, in any casc^ 

 at their respective bases ; and they are never separated from 

 those of the trunk. These strata are in immediate coni- 

 muiucatiou with those of the trunk, in such a manniT that 

 the strata of the branch seem to have arisen from a pro- 

 longation of those of the trunk. It is very difficult to di- 

 ctin"u;uish wlicther the medullarv sheath tal-.es its origin 



Iroiu 



