BUDS 95 



wool or down which they afterwards lose. Those of the 

 tulip tree are enclosed for a little time in thiu pouches, 

 which serve as bud-scales, and are thus entirely shielded 

 from direct contact with the outside air. 



112. Dormant Buds. — Generally some of the buds on a 

 branch remain undeveloped in the spring, when the other 

 buds are beginning to grow, and this inactive condition 

 may last for many seasons. Finally the bud may die, or 

 some injury to the tree may destroy so many other buds 

 as to leave the dormant ones an extra supply of food, and 

 this, with other causes, may force them to develop and to 

 grow into branches. 



Sometimes the tree altogether fails to produce buds at 

 places where they would regularly occur. In the lilac the 

 terminal bud usually fails to appear, and the result is con- 

 stant forking of the branches. 



113. Adventitious Buds. — Buds which occur in irregu- 

 lar 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 siher-leafed poplar, or from the sides 

 of the trunk, as in our American elm. In many trees, for 

 instance wiUows and maples, they are sure to appear after 

 the trees have been cut back. Willows and poplars are 

 thus cut back or pollarded, as shown in Plate III, in order 

 to cause them to produce a large crop of slender twigs 

 suitable for basket-making or for withes. 



Leaves rarely produce buds, but a few kinds do so 

 when they are injured. Those of the bryophyllum, a 

 plant allied to the garden live-for-ever, when they are 

 removed from the plant while they are still green and 

 fresh, almost always send out buds from the margin. 

 These do not appear at random but are borne at the 



