334 



NATURE-STUDY 



band is rolled up and grown together at the lower end into 

 a little tube. In fact, the band may be considered a little 

 tubular corolla like the morning-glory slit open on one 

 side nearly to the base. In the sunflower and many other 

 such composites these outer strap-shaped, or ray, flowers, 

 as they are called, are merely for show, as they have neither 



pistil nor sta- 

 mens, and there- 

 fore do not form 

 seed. But in the 

 daisy, zinnia, and 

 many other flow- 

 ers they are not 

 sterile, but form 

 seeds. In the 

 central part of 

 the head are 

 other flowerSj 

 small and tubu- 

 lar, with both 

 stamens and pis- 

 tils which pro- 

 duce seeds. Note the two branched stigma projecting from 

 the centre of the little flower. Tear the corolla open and 

 note the circle of brown or yellow stamens surrounding the 

 style. The stamens open on the inside, and the style pushes 

 out the pollen as it grows out of the corolla; but it is not 

 self-fertilized thereby because it is not yet ripe or ready for 

 pollination. 



The "flowers" of the sunflower, aster, daisy, and other 

 similar composite are thus seen to be composed of a large 



FIG. 133. Sunflower. 



(Not a single flower, but a head or cluster of many small flowers.) 



