22 GROWTH OF PLANTS FROM BUDS. [LESSON 4. 



searched for, they may be detected, though of small size, hidden 

 under the bark. Sometimes, although early formed, they are con- 

 cealed all summer long under the base of the leaf- 

 stalk, hollowed out into a sort of inverted cup, like a 

 candle-extinguisher, to cover them ; as in the Locust, 

 the Yellow-wood, or more strikingly in the Button- 

 wood or Plane-tree (Fig. 50). 



44. Such large and conspicuous buds as those of 

 the Horsechestnut, Hickory, and the like, are scaly ; 

 the scales being a kind of imperfect leaves. The 

 use of the bud-scales is obvious ; namely, to protect 

 the tender young parts beneath. To do this more 

 effectually, they are often coated on the outside with 

 a varnish which is impervious to wet, while within 

 they, or the parts they enclose, are thickly clothed 

 with down or wool ; not really to keep out the cold 

 of winter, which will of course penetrate the bud in 

 time, but to shield the interior against sudden changes 

 from warm to cold, or from cold to warm, which are 

 equally injurious. Scaly buds commonly belong, as would be expect- 

 ed, to trees and shrubs of northern climates ; while naked buds are 

 usual in tropical regions, as well as in herbs everywhere which 

 branch during the summer's growth and do not endure the winter. 



45. But naked buds, or nearly naked, also occur in several of oui 

 own trees and shrubs ; sometimes pretty large ones, as those of Hob 



FIG. 49. Annual shoot of the Shagbark Hickory. 



FIG. 50. Hud and loaf of the Huttonwood, or American Plane-tree. 



