76 THE OAK 



These scars of the stipular bud-scales, like those of fallen 

 leaves, exhibit the points of rupture of the vascular 

 bundles which ran across from the bundles of the bud- 

 axis. It only remains to point out that the buds vary 

 in size and vigour according to the age and condition 

 of the tree ; the buds on oaks less than fifty years old 

 very rarely have inflorescences developed in them, and 

 I shall defer the consideration of these till we come to 

 the flower. 



The mature leaf of the oak (fig. 20) is obovate in 

 general outline, with rather deep sinuses cutting the 

 margin on each side into about six or eight rounded lobes ; 

 the apex is rounded or blunt, and some variation occurs 

 in the degree of incision between the lobes. The base 

 either tapers slightly into an evident petiole, or it is pro- 

 longed on either side of a very short petiole so as to form 

 small auricles. In the commonest variety the margins 

 and surfaces of the leaf are quite smooth, but the race- 

 form known as Quercus sessiliflora has the young leaves 

 pubescent beneath. 



The venation consists of a midrib running from base 

 to apex, and pinnate lateral ribs running from the 

 midrib at an angle of about 45 to the tip of each lobe, 

 the points of origin being alternate or nearly opposite, 

 and the angle referred to subtending forwards. These 

 principal ribs are prominent below but not at all so 

 above. The leaf-tissue (mesophyll) between these is 

 permeated by numerous smaller vascular bundles 

 united into an irregular network, but so arranged that 



