86 



■i 



THE NATURE BOOK 



foliage, and it is possible 

 to distinguish the leaves 

 — on a small scale, cer- 

 tainly, but in a wonder- 

 fully perfect condition. 

 Several pairs of leaves 

 may be readily distin- 

 guished all packed awaj' 

 in downy material, quite 

 ready for the develop- 

 ment which will come 

 with the spring. This 

 being so, the protection 

 of the buds against the 

 rigours of winter is a 

 matter of first import- 

 ance in the life of the 

 plant. Perhaps one of 

 the most obvious fea- 

 tures in our Chestnut bud 

 is the gummy substance 

 coating the exterior, and 

 which under the in- 

 fluence of warm sunshine 

 becomes very sticky. 

 This material is most 

 valuable on account of 

 its non-conductive pro- 

 perties, and doubtless plays a large part 

 in shielding the contents of the bud 

 from cold. Apart from this, however, 

 there are several layers of scales which 

 play the chief part in checking the 

 penetration of cold to the immature 

 leaves. 



Generally speaking, in nearly all trees 

 these scales represent modifications of 

 leaves which have been arrested in their 

 development or even have partially died, 

 and have thus become horny in texture. 

 In plants such as the Lilac and Rhododen- 

 dron the bud scales are modifications of 

 entire leaves, and keep green throughout 

 the winter. In one of our deciduous 

 species, the Wayfaring Tree {Viburnum 

 Lantana), the lowest leaves of all act as 

 bud scales, and these, owing to a woolly 

 coating, are able to survive through the 

 winter and finally develop as ordinary 

 foliage leaves. 



It is a wise provision wliich has ordained 

 that the tree should become denuded of 

 its fohage before the winter. This season 

 is a time of rough weather, when the 

 strong gales sweep over the country and 

 threaten to destroy all before them. Any 



PROTECTIVE BUD COVERING OF 

 A SYCAMORE TREE. 



of the large forest trees 

 in full leaf would offer 

 a tremendous resistance 

 to the wind and, of 

 course, suffer accordingly. 

 Now and again, when a 

 severe summer gale has 

 visited a part of the 

 country which is wooded, 

 it has been possible to 

 gather some idea of the 

 ha\'oc which a strong 

 wind works among trees 

 in foliage. It is inter- 

 esting to observe that 

 practically aU the so- 

 called evergreen trees 

 which are indigenous to 

 temperate regions pro- 

 duce comparatively 

 small leaves. Of these 

 the great tribe of Coni- 

 fers are typical, which 

 with their needle-hke 

 leaves do not offer 

 serious resistance to the 

 wind. 



Apart from the Firs, 

 the trees and shrubs which keep their 

 fohage all the winter produce com- 

 paratively small leaves, and these are 

 mostly of specially thickened texture so 

 that individually they may not suffer 

 from wind damage. Round the border 

 of the Holly leaf may be traced a 

 kind of selvedge, formed of thickened 

 layers of cells. This does much to 

 prevent the leaf from being torn in 

 rough weather. The small size of the 

 leaves in the case of these evergreens is 

 also to the advantage of the plant in 

 another way, by preventing snow accumu- 

 lation. The thick leafy branches of the 

 deciduous trees would provide a lodgment 

 for the faUing flakes to such an extent that 

 serious bough breakage would result. 

 The dry particles of snow find httle to 

 rest upon in the slender fohage of the 

 Fir or the small, narrow leaves of the 

 Yew. 



At all times C(jld is a great menace to 

 plant life, and a period of severe frost is 

 full of danger to the unprotected vegetable. 

 Yet the low temperature which would 

 threaten to destroy the plant seems to 

 bring about an alteration in the bearing 



