PLANTS ON THE MOVE 189 



and there are only two courses open to it. Either 

 it may vanish altogether as four out of the five 

 toes of the horse have vanished, or it may be con- 

 verted to some other use. It has elected the latter 

 course, and has become what we call a pappus. 



The pappus is in abeyance during the flowering 

 of the dandelion. When that has been accom- 

 plished, and the fruit is safely fertilized, the pappus 

 grows, the dandelion seems to blossom anew, but 

 this time in white. A huge white bubble occupies 

 the site of the late golden flower. It is composed 

 of as many smaller white bubbles as there are 

 fruits ; the fruits are attached to the parchment 

 platform below them by the lightest possible 

 tacking, and at the first puff of wind each of them 

 goes sailing away as the car of a tiny and 

 wonderful balloon. 



An objection that the evolutionist often meets 

 with when he has pointed out some such obvious 

 fact as this, is that, useful as is, for example, 

 a full-blown balloon such as the dandelion has, 

 no advantage would be derived from the posses- 

 sion of the first slight hairiness that was the fore- 

 runner of a full-grown pappus- to-be some million 

 generations hence. The objection has very little 

 force in this particular case. Some of the com- 

 posites have still very small pappi, not nearly 

 sufficient to fly upon, and yet in every case it can 

 be shown that the flower derives benefit from them. 

 The flower-head of the leopard's bane is only a 

 little woolly, but the ripe florets take ten times as 



