146 THE STORY OF THE PLANTS. 



by making the ray-florets into mere petal-like 

 straps, wiriich da no work themselves, but simply 

 serve to attract the fertilising insects to the com- 

 pound flower-head. 



An immense number of these composites with 

 flattened ray-florets grow in our fields or are cul- 

 tivated in our gardens. In the simpler among 

 them, such as the sunflower, the corn-marigold, 

 the ragwort, and the golden-rod, both ray-florets 

 and central florets are simply yellow. But in 

 others, such as the daisy, the ox-eye daisy, the 

 aster, and the camomile, the ray-florets differ in 

 colour from those of the centre ; the latter re- 

 main yellow, while the former become white, or 

 are tinged with pink, or even flaunt forth in scar- 

 let, crimson, blue, or purple. Of this class one 

 may mention as familiar instances the dahlia, the 

 zinnia, the Michaelmas daisies, the cinerarias, and 

 ihe pretty coreopsis so common in our gardens. 

 Gardeners, however, are not content to let us ad- 

 mire these flowers as nature made them. They 

 generally " double " them — that is to say, by care- 

 fully selecting certain natural varieties, they pro- 

 duce a form in which all the florets have at last 

 become neutral and strap-shaped. This is well 

 seen in the garden chrysanthemum, where, how- 

 ever, if you open the very centre of the doubled 

 flower-head, you will generally find in its midst 

 a few remaining fertile tubular blossoms. The 

 same process is also well seen in the various 

 stages, between the single and the double dahlia. 

 Such '^double" composites can set little or no 

 seed, and are therefore from the point of view of 

 the plant mere abortions. Nor are they beauti- 

 ful to an eye accustomed to the ground plan of 

 floral architecture. Remember, of course, that 



