58 



FIELD AND WOODLAND PLANTS 



the work is done, in the case of the primrose, by insects ; for not 

 only do we find that the anthers and the stigma are protected from 

 the wind, being more or less hidden in the tube of the corolla, but 

 the showy corolla, the delicate scent emitted by the flower, and 



the nectar produced at 

 the base of the tube all 

 combine to encourage 

 nectar - loving insects 

 whose proboscis is long 

 enough to reach the 

 sweets. 



While such an insect 

 is sucking the nectar 

 from a short-styled 

 primrose, the base of its 

 proboscis is rubbing 

 pollen from the anthers 

 at the top of the tube, 

 and the removal of the 

 pollen is assisted by 

 the contracted throat of 

 the corolla in this kind 

 of flower. Should that 

 insect then visit a long- 

 styled flower, the base 

 of the proboscis, now 

 dusted with pollen, will 

 transfer some of the 

 pollen cells to the stigma. 

 In the same way pollen 

 will be transferred from 

 the anthers of the long- 

 styled to the short- 

 styled flower, since the 

 stamens and stigma re- 

 spectively occupy corresponding positions in the tubes of the 

 corollas. 



On Plate I (Fig. 3) we represent the Lady's Slipper {Cypripedium 

 Calceolus) — a rare and beautiful orchis found in some of the Umestone 

 woods of North England. Its stem is downy and leafy, reaching a 

 height of about one foot. The leaves, of which there are three or 



The 8TAU OF Eethleueji. 



