VENATION OF WILLOWS 



61 



The venation of the Willows has been investigated by 

 Glatfelter, who states that, in spite of variations according 



-a 



c 



Fig. 21. Leaf of Lime, Tilia europ&a, showing pinnate venation with 

 pseudo-palmate base. The secondary ribs b and c at the base come off 

 with the midrib a from a common origin : those higher up are pinnate. 

 d tertiaries forming cross-ties; e network of terminals, &c. (Ett). 



