The Lady's Slipper 



(CTPRIPEDIUM CALCEOLUS) 



THIS is one of the most striking plants of the Swiss flora, and 

 while nowhere common is pretty widely distributed in the 

 limestone districts of the Alps. It is a plant of some size, 

 perhaps 12 to 24 inches in height, and grows in stony woods 

 from the lower mountain region up to 6500 feet. One to 

 three large yellow flowers are borne by each plant. Their 

 method of fertilisation is of exceptional interest. Close to 

 the attachment of the yellow slipper-shaped petal to the rest 

 of the flower is a projection bearing on each side a stigmatic 

 surface below and a mass of pollen above. The large yellow 

 petal is smooth inside and has overhanging edges, rather like 

 those of the familiar beetle-trap that is used for catching 

 cockroaches, and as we shall see in a moment it acts in a 

 similar manner. There is no honey in the flower, and it is 

 not quite clear what the small bees that have been seen 

 visiting it go there for. But at any rate when they once get 

 in they have the greatest possible difficulty in getting out 

 again, and only succeed in doing so by climbing up the 

 attached side of the flower where the edges are not over- 

 hanging, that is on either side of the central projection. In 

 doing this they are sure to brush first against the stigmatic 

 surface, leaving behind some of the pollen they may chance to 

 have sticking to them, and then against the viscid mass of 



