Thistles and Nettles 339 



out at the top of the anther cylinder by the length- 

 ening of the pistil. The pistil divides, at its tip, 

 into two little arms, which are thickly clothed on 

 their outsides with small pointed hairs. So, when 

 the top of the pistil emerges from the anther-ring 

 it is thickly covered, all over the outer surface, 

 with pollen. In most instances this is soon re- 

 moved, for the points on the pollen-grains cling to 

 the hairy bodies of visiting insects. A little later 

 the tips of the pistil separate so as to expose the 

 sticky or stigmatic surfaces, and in this position 

 it waits, open-armed, for a pollen-freighted friend. 

 But if no insects visit the flower the arms of the 

 pistil curve over, as do those of the dandelion, and 

 fertilize themselves with home-made pollen. How- 

 ever, Canada thistles are rarely thus thrown upon 

 their own resources, for they are immensely popu- 

 lar and entertain guests from dawn till dusk. As 

 soon as pollen has reached its stigma, or when it 

 begins to wither, the blossom bends downward and 

 outward. Having had its day and its opportuni- 

 ty, it retires into the background to give a better 

 chance to its younger sisters. The florets of the 

 white clover (Fig. 95) have learned a like habit for 

 the family good, and toward midsummer one may 

 find a white-clover head with a single blossom 



