12 
INTRODUCTION 
FIG. 6. 
FIG. 6. Leaf of 
a willow (Salix sp.). 
b, blade; p, petiole; 
s, stipules. 
FIG. 7. Diagram 
to show the essential 
parts of a "flower- 
ing" plant. t.r., 
tap-root; b.r., 
branch root; cot. 
seed-leaf (cotyle- 
don); i, internode; 
a.l, leaf-axil; n, node; 
a.b, axillary bud; r, 
receptacle of floral 
organs; ca, calyx; 
per, perianth; co, 
corolla; st, stamens 
(androecium) ; pi, 
pistil (gynoecium). 
