44 THE EVOLUTIONIST AT LARGE. 



while they send up their female flowers by 

 means of a spiral coil, and draw them down 

 again as soon as the wind or the fertilising 

 insects have carried the pollen to its proper 

 receptacle, so as to ripen their seeds at leisure 

 beneath the pond. Similarly, you may see 

 the arrowhead and the water-lilies sending up 

 their buds to open freely in the air, or loll at 

 ease upon the surface of the stream. Thus 

 the crowfoot, too, cannot blossom to any 

 purpose below the water ; and as such among 

 its ancestors as at first tried to do so must of 

 course have failed in producing any seed, 

 they and their kind have died out for ever ; 

 while only those lucky individuals whose 

 chance lot it was to grow a little taller and 

 weedier than the rest, and so overtop the 

 stream, have handed down their race to our 

 own time. 



But as soon as the crowfoot finds itself 

 above the level of the river, all the causes 

 which made its leaf like those of other 

 aquatic plants have ceased to operate. The 



