THE STEM OF VASCULAR PLANTS. 205 



and also often presents a deposit of nourishment, then 

 the bud is frequently developed into a branch ; this is 

 what happens in Grasses, Calamus, and Eqiiisetuvi. 

 But when the stem does not present a natural knot, 

 there are accidental causes which make it branch. I 

 shall point out some of them. 



If the top of the stem of an Endogen be cut off, the 

 buds which are found in the axils of the upper leaves 

 receive the sap which naturally would have been employed 

 in the elongation and nutrition of the central and ter- 

 minal portion ; these buds grow and form branches : if 

 one of them be better situated than the others for its 

 development, it alone elongates, and the stem seems 

 to remain simple, although it is really branched ; if two 

 or more of these buds are equally developed, the stem is 

 bifurcated. Such are the facts of which there is evidence 

 in our botanic gardens, when it is desired to multiply 

 Endogens, or to make them branch : thus, when the top 

 of a stem of Yucca, Littoea, or of every other analogous 

 plant is cut off, it causes it to produce branches. When 

 the centre of a trunk, exposed to view by this horizontal 

 section, is very watery, it is cauterized by a hot iron ; 

 by this operation its decay is prevented, and the axillary 

 buds attract the sap of the lateral parts of the trunk, 

 which is sufficient for their development. 



This, which the results of cultivation show us, is 

 also'presented to us in nature, either accidentally — as for 

 example, when the top of a stem is broken off by the 

 v/ind — or naturally, when the flowering takes place. 



The scapes of a great number of Endogens arise from 

 the summit of the stems ; as, for example, in Yucca, 

 Littoea, several species of Draccena, &c. When the 

 flowering is over, and the seeds ripe, the sap is no longer 

 attracted to the scape ; and the stem, being arrested in its 

 growth by the presence of this inert body, cannot elon- 



