6 COLIN CLOUT'S CALENDAR. 



and directs the bee straight to the mouth of the tube at 

 whose base the nectar is stored. And now again, let us cut 

 open one or two flowers of each variety, so as to lay bare 

 the interior of the tube. See, they have each two separate 

 and corresponding forms, known long ago to village 

 children as the thrum-eyed and the pin-eyed primroses 

 or cowslips. In the pin-eyed form the long head of the 

 pistil, looking for all the world like an old-fashioned 

 round-headed pin, reaches just to the top of the tube, 

 and forms the prominent object in the centre, while the 

 five stamens are fastened to the side of the tube about 

 half-way down. In the thrum-eyed form, on the con- 

 trary, the stamens make a little ring at the top of the 

 tube, while the pin-headed summit of the pistil only 

 reaches just half-way up the tube, exactly opposite the 

 same spot where the stamens are fixed in the other sort. 

 When the bee begins by visiting a thrum-eyed blossom, 

 she collects a quantity of pollen on the hairs at the top 

 of her proboscis. If she then visits a second flower of 

 the same type, she does not fertilise its pistil, but only 

 gathers a little more pollen. As soon, however, as she 

 reaches a pin-eyed blossom she unconsciously deposits 

 some of this store of pollen on the sensitive surface or 

 pin of its pistil ; while at the same time some more pollen, 

 half-way down the tube, clings to her proboscis, and is 

 similarly rubbed off against the pistil of the next thrum- 

 eyed blossom she chances to visit. The exact corre- 

 spondence in position of the various parts in the two 

 diverse forms admirably insures their due impregnation. 

 Thus each blossom is not only fertilised from another 

 flower, but even from a flower of an alternative type, 

 which is a peculiarly high modification of the ordinary 

 method. 



