228 NATURE-STUDY REVIEW [14:6— Sept., 1918 



The ray flowers have neither stamens nor pistils. Their only- 

 reason for existence is to make the head more conspicuous so as to 

 attract the insects. At the base of the ray flower is a seedlike 

 portion, which is a mere pretense. There can never be seed as it 

 has no stigma connected with it to bring pollen, neither does it 

 have stamens or tubular corolla. 



The disk flowers, whose duty it is to set seed, have corolla, five 

 stamens, and a pistil with a two-cleft stigma. The calyx consists 

 of two or more layers of thin deciduous scales. 



The Flowers of the Sunflower-head Enlarged 



i . A floret of the sunflower in the bud-stage as it appears at the center of the sunflower. 

 Note the protecting bract at the right. 



2. A floret in earliest stage of blossoming. 



3. A floret in the latest stage of bloom with the parts named. 



4. A ray or banner-flower. 



Let's go out into the garden and watch carefully for a few days 

 one of these glowing heads. First notice the florets next to the 

 ray flowers. The pollen is pushed out from the anther cases and 

 lifted above the corolla tube, so that the pollen grains can be 

 scattered. It is the growing pistil which pushes the pollen out. 

 Perhaps the next day we go out we find that in a few more rings 

 next these and nearer the center the same thing has happened, and 

 so on, each day the ring of florets approaching nearer the center. 

 Finally the pistil pushes up its style so that it stands above the end 

 of the corolla tube. The style is divided into two slender parts 

 which at first are closed up so the pollen cannot touch the stigma 



