76 THE OAK. 



shoot shows a number of small scars in a close spiral. 

 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 vigor 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 prolonged 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 raceform 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 mid- 

 rib at an angle of about forty-five degrees to the tip of 

 each lobe, the points of origin being alternate or nearly 

 opposite, and the angle referred to subtending forward. 

 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 



