BUDS 



31 



and they are less hardy. Yet in the coldest weather buds 

 are frozen without injury, providing the freezing and sub- 

 sequent thawing are not too sudden. 

 Some buds which will grow and unfold 

 when placed in water in the latter 

 part of the winter, refuse to open at 

 an earlier period, behaving like those 

 seeds that will germinate only after 

 a definite length of time. 



34. Protection. — The means and 

 the degree of protection are various. 

 Against sudden changes of tempera- 

 ture thick, woolly covering is often 

 provided, growing from the young 

 leaves and around their bases. To 

 this several thicknesses of scales — 



modified leaves — 

 may be added. The 

 scales usually fall 

 away soon after the 

 bud bursts open in 

 spring ; but in many 

 instances, like the 

 Buckeye (Fig. 21), 

 make a little growth toward foliage. In 

 Pterocarya (Fig. 22) the younger leaves 

 are shielded only by the somewhat broad- 

 ened stalks of the 

 partly developed out- 

 er ones. When the 

 latter become, in the spring, the full 

 leaves of the season, such buds are 

 termed naked buds, i.e. without spe- 

 cialized protective scales. 



35. The slender, pointed axillary 

 buds of the Horse Brier, or Green 

 Brier, lie in the groove of the petiole 

 of the subtending leaf, and are partly 



21. Development of the 

 Ijarts of the bud 

 in the Buckeye. 



22. Naked bud of 

 Pterocarya 

 fraxinifolia. 



23. Eeniains of the 

 petiole protect- 

 ing the bud in 

 Horse Brier. 



