28 



THE VEGETATIVE FUNCTIONS OF PLANTS 



FIG. 18. New Zealand raspberry (Rubus australis}. The lower portion 

 is the petiole; the blade is reduced to three spiny veins slightly expanded 

 at the tip. 



FIG. 19. Homology of bud-scales in an ash (Fraxinus sp.). Scries 

 showing gradual transition from outer bud-scale (at left) to unexpanded 

 foliage leaf (at right). The outer bud-scale is morphologically a leaf-base. 



