HOW PLANTS CAME TO tUFFEft. 33 



cross-fertilisation, as it is called, is good' for the 

 plants, producing very strong and vigorous 

 seedlings, the young ones so set would have 

 the best chance of flourishing and surviving in 

 the Struggle for Existence. Thus the flowers 

 which made most honey would be oftenest 

 visited and crossed, so that they would soon 

 become very numerous. Again, if they hap- 

 pened to have bright leaves near the honey, 

 they would be most readily discriminated, and 

 oftenest visited. So, in the long run, it has 

 come about that almost all the flowers fertilised 

 by insects produce honey to allure them, and 

 have brilliant petals to guide their allies to the 

 honey. That, in fact, is what beautiful flowers 

 are for to attract the fertilising bees and 

 butterflies to visit and impregnate the various 

 blossoms. 



Take one more case or, rather, the same 

 case, extended a little further. The red cam- 

 pion flowers by day, and is fertilised by butter- 

 flies; therefore it is pink, because pink is an 

 attractive colour in the daylight ; and it is scent- 

 less, because its colour alone is quite enough to 

 attract sufficient insects. But it has a close 

 relation, the white campion, which flowers by 

 night only, and lays itself out to be visited by 

 moths in the twilight. Why is this kind white ? 

 Because no other colour is seen so well in the 

 dusk ; a red or pink blossom would then be 

 almost invisible. Moreover, the white cam- 

 pion is heavily scented, as are almost all other 

 night-flowering blossoms, like the jasmine, the 

 tuberose, the stephanotis, and the gardenia. 

 3 



