214 



OAKS 



Venation pinnate. The midrib stout and prominent 

 in its lower half, thinning out above, straight or slightly 

 sinuous to the extreme apex. The midrib gives off strong 

 secondaries at angles of 40 50, which run nearly straight 

 to the tips of the lobes and end there, the upper con- 

 verging and the middle and lower ones diverging more or 

 less. Average distance apart about ^ the length of the 

 midrib. Tertiaries leaving the outside of the secondaries at 

 acute angles, and the inner side at about 90 and looping 

 beneath the margins : the outer sometimes strong. Meshes 

 well developed, the larger rectangular and rather loose. 



Fig. 68. Oak, Quercus Robur, p. 213 (Ett). 



[Of the several varieties described, three seem worthy 

 of mention here. The var. pedunculata has the leaves 

 typically quite glabrous, shortly petiolate or sub-sessile, 

 auricled at the base, and the lobes rounded obtuse. The 



