38 STATE HORTICULTURAL SOCIETY. 



by which the pollen was transferred in such cases was at first ascribed 

 to the wind. A little later it was suggested that since some flowers 

 contain honey, and are visited by bees, the insects might be of some 

 use in pollination. It was not thought, however, that they affected 

 cross-pollination, the idea being that they simply shook the pollen from 

 the stamens to the pistil, in an individual flower. 



The very important part which insects take in the cross-pollination 

 of plants was not much known until about one hundred years ago. At 

 this time Sprengel was led to begin a great number of observations,, 

 which showed not only that insects carry pollen from flower to flower^ 

 but that the bright colors, scents and singular forms of flowers serve 

 the useful purpose of guiding insects to their secreted honey. 



His keen observation are of exceeding interest. He noticed the 

 tiny hair beneath which honey lies hid in a little wild geranium, and 

 found that while these hairs in no way hinder been from taking the 

 honey, they effectually turned away the rain drops from the nectaries. 

 From this he reached the conclusion that the honey was secreted for 

 the bees, and that the rain was kept out that they might have the nec- 

 tar pure and unspoiled. Noting the little yellow ring in the throat of 

 the forget-me-not, he conceived the idea that this might guide the in- 

 sects on their way to the honey. Upon further investigation he found 

 that the colored dots, lines and other figures surrounding or pointing 

 toward the honey actually do serve as honey guides, or path-finders^ 

 for the insects. Thus perceiving that the insect is guided to the nectar 

 once it has settled on the flower, he went still farther and reached the 

 wise conclusion that the bright-colored corolla itself is to guide the 

 insect from a distance to the flower. Thus it is that the beauty of our 

 peach, plum and apple blossoms serves not only to gladden the eye» 

 but also to attract these insect pollen-bearers. 



Up to this time it was supposed that honey was secreted by 

 flowers simply to furnish a food for insects, and no one even supposed 

 that the insect returned an equivalent service to the flower. SprengeU 

 hoN^ever, observed that certain varieties of iris are incapable of being 

 pollinated and producing seed if insects are excluded from them. This 

 led to his farther discovery that a great many flowers depend wholly 

 upon insects for transferring the pollen. 



In all of Sprengel's work it is perhaps remarkable that he failed 

 to learn the most important lesson which his years of patient study 

 and observation might have taught. While he was well aware of the 

 fact that insects frequently carry pollen from flower to flower, he failed 

 to learn that cross-pollination is the most important result of insect 

 visits. This great truth remained to be first hinted at by Andrew 



