CHAPTER IV 



PISTILS AND STAMENS 



Structure and Function of Pistils and Stamens 



' The pistils and stamens are the organs upon which the pro- 

 duction of seed depends and for this reason are called the 

 essential parts of the flower. The calyx and corolla protect the 

 essential organs and often assist in seed production, but they 

 are not essential. 



In unisexual flowers, seeds appear only ia the flowers having 

 pistils. The staminate flowers in the Corn tassel produce no 

 kernels, and in dioecious plants, 

 such as Hemp, WiUows, and the 

 Mulberry, seed and fruit are 

 limited to those individuals bearing 

 pistillate flowers. From this it 

 might appear that the stamens 

 take no part in the work of pro- 

 ducing the seed; but observations 

 show that unless stamens are close 

 at hand, the pistil will produce 

 no seed. A weU isolated Corn 

 plant with tassel removed before 

 the stamens are mature will pro- 

 duce no kernels. Some varieties 

 of Strawberries are dioecious, and 

 unless both kinds of plants are grown in the same bed, there will 

 be no seed or fruit. 



To understand just how the essential organs function in seed 

 production, a careful study of their parts must be made. 



Parts of the Pistil. — The pistil usually consists of three parts : 

 the enlarged base which is the ovary and the portion in which the 

 seeds develop; the flattened or expanded surface at the upper 

 extremity, known as the stigma; and the stalk-like part connect- 



33 



Fig. 35. — Flower of the Cherry 

 with parts of the pistil indicated, 

 o, ovary; st, stigma; s, style. 

 Much enlarged. 



