38 Flouers and their Pedigrees. 



one into which we cannot enter now : it must suffice 

 to say that when the daisy's ancestors were in the 

 eupatory stage of development they had apparently 

 all their florets yellow. This is likely, because almost 

 all the modern composites of every sort have yellow 

 central florets, and most of them have yellow rays as 

 well. It is only a few kinds that have red or purple 

 central florets ; and, as we shall soon see, only a few 

 also that have white or pink outer rays. 



What, then, made the daisy's ancestors produce a 

 row of external florets so different in shape and 

 colour from the internal ones ? The answer is 

 exactly analogous to that which I have already given 

 for the origin of petals themselves. Compare the 

 eupatory with the daisy once more, and you will see 

 that the one is comparatively inconspicuous, while 

 the other is very noticeable and bright-coloured. The 

 row of green bracts almost hides the blossoms of the 

 eupatorj' ; but the large white rays make a bold and 

 effective advertisement for the daisy. Certain com- 

 posites, in fact, have just repeated the same device by 

 which the earliest petal-bearing flowers sought to 

 attract the notice of insects. Those early flowers, as 

 we saw, set apart one outer row of stamens as bright- 

 coloured petals ; these later compound flower-heads 

 have set apart one outer row of florets a.s bright- 



