75 



of Rhododendron, discharges its pollen through a small 

 orifice at the apex of each cell. "In the flower bud each of 

 the ten anthers is lodged in a small cavity or pocket of the 

 corolla." When the corolla expands the filaments are curved 

 outward and backward, and when the flowers are shaken by 

 bumbaebees, which search the flowers for nectar in the bot- 

 tom of the flower, one after another of its stamens are liber- 

 ated. The pollen is thrown on the underside of the insect's 

 body. 



Some of the other members of the order have interesting 

 contrivances for the dispersal of pollen. In Vaccinium the 

 anthers are suspended inside the corolla with pores down- 

 ward, a shake causes the pollen to issue down on the insect's 

 body. In Winter Green {Pyrola secunda) the filaments are 

 curved Irke a letter S and are in a state of tension, the anth- 

 ers are in an erect position. When an insect touches the 

 petals the anthers are turned and in the meantime the pol- 

 len is turned out. 



„ , , Persoon, in 1Y94. observed that the Cowslip 



Prlmulaceae. _ ' t 



{.Primula veris var. offiicinalis) existed 

 under two forms. Some most interesting experiments have 

 been made since that time. Darwin called attention to the 

 adapation for cross-pollination. He demonstrated that the 

 pollen of the short stamen, put on the long style of the same 

 flower, is inoperative. The same is true of the pollen from 

 long stamens when placed on the long style of the same. 

 These experiments were later repeated by Hildebrand and 

 John Scott. 



In Primula elatior two kinds of flowers occur on dif- 

 ferent plants. One plant bears a long style with short sta- 

 mens, in which self-pollination is impossible; a second 

 plant bears a short style and long stamens. In this the 



