8 ELEMENTS OF STRUCTURAL BOTANY. 



little grain-like substance attached to the lower end or 

 its cavity. This substance, in its present condition, is 

 the ovule, and later on becomes the seed. 



You will notice that the carpel ends, at the top, !r_ a 

 little bent point, and that the convex edge is more or 

 less rough and moist, so that in flowers 

 whose anthers have burst open, a quantity 

 of pollen will be found sticking there. 

 This rough upper part of the carpel is 

 called the stigma. Fig. 1 1 shows a stigma 

 greatly magnified. In many plants the Fig. 11. 

 stigma is raised on a stalk above the ovary. Such a 

 stalk is called a style. In the Buttercup the style is so 

 short as to be almost suppressed. When the style is 

 entirely absent, the stigma is said to be sessile. The 

 hollow part of the carpel is the ovary. 



In our plant the pistil is not connected in any way 

 with the calyx, and is consequently said to be free or 

 superior, and, as the carpels are not united together, 

 the pistil is said to be apocarpous. 



8. Remove now all the carpels, and there 

 remains nothing but the swollen top of the 

 peduncle. This swollen top is the receptacle of 

 the flower. To it, in the case of the Butter- 

 cup, all four parts, calyx, corolla, stamens, 

 and pistil, are attached. When a flower has 

 all four of these parts it is said to be complete. 



9. Let us now return to our statement that 

 Fig. 12. the structure of stamens and pistils is only a 



modification of leaf -structure generally. The stamen 



Fig. 11. Stigma of Buttercup with adhering pollen-grains; highly 

 magnified. 

 Fig. 12. Diagram to show leaf-structure of a stamen. 



