40 FIELD ANT) WOODLAND PLANTS 



of early flowers, and of the times of the appearance of the leaf in 

 our trees and shriil)s, will prove of great interest when com])arcd 

 with the corresponding events and times of otlier years. Not only 

 do our spring seasons vary considerably from year to year in such 

 a manner as to alter the general times of appearance of leaf and 

 flower, but the vicissitudes of oiir climate even change the order 

 in which these events occur. 



'J'lie general study of the buds of trees sliould commence before 

 they begin to Ijurst. We commonly speak of the buds as winter 

 buds, but it should be known that they were formed in the preceding 

 summer or autumn, and have remained dormant througliout the 

 winter. There is usually a terminal hud at the tip of each twig, and 

 lateral hvds at the sides. If we examine a lateral bud we find 

 immediately beneath it a more or less distinct scar, denoting the 

 position of a leaf that fell in the autumn, thus showing that the 

 bud in question was formed in the axil or angle of the leaf. These 

 observations shoiild be verified by examining the trees in autumn, 

 while the leaves still exist. 



It is not sufficient that we are able to recognise trees when 

 in leaf ; they should be kno\^ n equally or almost as well during 

 the winter and early sjDi'ing while the branches are bare, and this 

 is usually easily accomplished by making ourselves acquainted 

 with the general form of each tree as viewed from a distance, and, 

 on closer inspection, with the nature of the bark and the character 

 of the buds. 



All our forest trees are of the exogenous ty])e ; (Jiat is, thek stems 

 increase in thickness by the addition of new wood formed outside 

 the older wood and underneath the bark. Thus the l)ark, which 

 is composed of a layer or mass of dead, sai)less cells, is gradually 

 pushed outward as the stem thickens. The result is that the bark 

 is either more or less fractured, as in the Elm and the Oak, or it 

 flakes oif and falls to the ground, as is the ease with the Plane and 

 the Birch. A new layer of bark is always formed during each 

 summer, and this, in turn, either cracks or ]>ccls away ; but while, 

 in the former instance, the accumulated bark jiresents a very rugged 

 ajipearance, and becomes very thick, in the latter ease it remains 

 smooth, and is always thin. 



Then again, how are we to accoimt for the great variety in the 

 general forms of our different trees — the irregular, crooked nature 

 of the Oak ; the slender, but denser branching of the airj^ liirch ; 

 and the tall, pj'ramidal form of the Lombardy Polar ? All this is 



