84 



ELEMENTS OF BOTANY. 





Sometimes the tree fails altogether to produce buds at 

 places where they would regularly occur. In the lilac the 

 terminal bud usually fails to appear, and the result is constant 

 forking of the branches. 



113. Adventitious Buds. — Buds which occur in irregular 

 places, that is, not terminal nor in or near the axils of leaves, 

 are called adventitious buds ; they may spring from the roots, 

 as in the silver-leafed poplar, or from the sides of the trunk, 



as in our American elm. In 

 many trees, for ii)stance wil- 

 lows and maples, they are 

 sure to appear after the trees 

 have been cut back. Willows 

 are thus cut back or pollarded,. 

 as shown in Fig. 62, in order 

 to cause them to produce a. 

 large crop of slender twigs- 

 suitable for basket-making. 



Leaves rarely produce buds, 

 but a few kinds, do so when 

 they are injured ; and those 

 of the bryophyllum, a plant 

 allied to the' garden live-for- 

 ever, almost always send out 

 buds from the margin when 



they are removed from the plant while they are still green 



and fresh. 



114. Experiment 23. — Pinup a tiryophyllum leaf on the wall 

 of tlie room or lay it on the surface of moist earth, and follow, day by 

 day, the formation and development of tte buds which it may produce. 



This plant seems to rely largely upon leaf-budding to 

 reproduce itself, for in a moderately cool climate it rarely 

 flowers or seeds, but drops its living leaves freely, and from 

 each such leaf one or several new plants may be produced. 



Fig. 62. — Branches formed from Adven- 

 titious Buds on Pollarded Willows. 



