28 



THE VEGETATrV^E FUNCTIONS OF PLANTS 



Fig. iS. — New Zealand raspberry (Rubus auslralis). 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.). Series 

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

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



