THE LEAVES. 



107 



cases is wanting. In addition to the adaptation of their 

 form, scales, especially those that protect buds, are firm and 

 resistant to cold and other unfavorable external conditions. 

 Not infrequently they are supplied with hairs or surface 

 glands, whose function is to produce and excrete resins and 



Fig. ioi. — Pitcher-plant (^Sarracenia ^urfiure'r). Leaf above A cut ofE to show 

 trumpet form One-third natural size — After Gray. 



similar materials which make the parts so covered waterproof. 

 The inner scales of buds (fig. 60) are often covered with an 

 abundant coating of woolly hairs, which serve to prevent 

 rapid change of temperature in the interior of the bud. 



134. (4) Flower leaves and bracts. — On certain parts of 

 the stem, leaves are comnionly profoundly modified to carry 

 the spore cases (c, si, fig. 66). (See p. 196.) Close below 

 these are others which may be highly colored and adapted 



