OR, MANUAI, Oif THB APIARY. 



395 



Bees never bore for nectar, but seek, or even know only of thai 

 which isfully exposed. Bees are, however, a tremendous aid 

 to the fruit-grower in the great work of cross-pollination, 

 which is imperatively necessary to his success, as has been so 

 well shown by Dr. Asa Gray and Mr. Chas. Darwin. It is true 

 that cross-pollination of the flowers, which can only be 

 accomplished by insects, and early in the season by the honey- 

 bee, is often, if not always, necessary to a full yield of fruit 

 and vegetables. In dioecious plants, like the willows and 

 many nut-bearing trees, the stamens that bear the pollen or 

 male element, are on one plant or flower (Fig. 202), and the 



Fig. 200. 



Blossoms of Pigwort, after Oray. 



A Developed stamens and pollen. 



S In right-hand flower unripe stigma. 



n Nectar. 



S In two left-hand flowers ripe 



stigma. 

 P Unripe stamens. 



pistils that grow the ovules — the female element — on another. 

 Here, then, insects must act as "marriage priests" that 

 fructification may be accomplished at all. In other plants, 

 where the organs are all in the same flower, pollination is 

 wholly dependent upon insects. The pollen-grains must reach 

 the stigma. Often this is, from the very structure of the 

 flower, entirely dependent upon insects. Often, as in the 

 willow-herb (Fig. 252) and figwort (Fig. 200), as my colleague 

 and esteemed friend. Dr. Beal, was first to discover, the 

 pollen and stigma are not ripe simultaneously, and so pollen 



