FLORAL MECHANISMS 



85 



on the stigma, then plunge deep into the downy 

 throat of the flower and probe for nectar. But 

 when he is satisfied, see how he becomes entangled 

 under the little bower of stamens, how he struarffles 



'&&' 



to free himself, and, in so doing, pulls the 

 anthers away from one an- 

 other, and dusts his back 

 with the fine, white pollen. 

 The anthers do not return to 

 their first position, but remain 

 forever separated, and thus we 

 can tell that a flower has re- 

 ceived a visit. Any extra pol- 

 len left over is seen to fall back 

 into the throat of the flower, 

 upon its downy filling, where 

 it may yet be gathered on the 

 face and head of another bee, 

 as powder from apowder-pufF. 



As the pollen is locked up between the anthers 

 until the bee has touched the stigma and fertilised 

 it, the flower is practically sure that none of its 

 own pollen can affect it. 



Very often the mechanism of the flower consists 

 of a little flap or valve closing at the proper time 

 over the stigma, protecting it from the touch of 

 pollen of home manufacture. We find contrivances 



TURTLE-HEAD 



