EFFORT AXD ACCOMPLISHMENT 197 



The development in the flowers is well illustrated 

 by the gentians. An Alpine gentian, the lutea, is 

 a primitive type which has survived. It has a yel- 

 low colour and a fully open flower, with almost free 

 access to its nectar. Various insects could enter 

 and sip, and they performed cross-fertilisation 

 casually and irregularly. The form a\ as modified 

 in such a way that bees, especially bumblebees, be- 

 come the most efficient bearers of the pollen. To 

 suit the bees, then, the bell-shaped flower was 

 evolved and the colour modified to blue to serve as 

 a special attraction. Thus has our beautiful gentian 

 fashioned its festal attire to please its guests. 



Beetles, the lowest in the scale in regard to the 

 power and adaptability for cross-fertilisation, visit 

 flowers of dark, dull red and violet. They seem to 

 avoid yellow flowers. Flies frequent yellow flowers. 

 Honey-bees and bumblebees have a special liking 

 for blue flowers and generally pass by the scarlet 

 ones without visiting them. Buttei-flies and moths 

 are the most highly specialised insects for the work 

 of cross-fertilisation, and they display marked in- 

 telligence and a keen sense of appreciation for bril- 

 liant colours. But the bees do much more of the 

 actual work, from the fact that they carry away 

 loads of pollen with which to feed their young, and 

 in so doing incidentally interchange pollen amongst 

 the flowers. 



