BEE FLOWERS 79 



is unnecessary and so they depend entirely upon form and odor. 

 Charles Darwin once remarked that bees are very good botanists 

 since they know that different varieties of the same species may 

 differ widely in color. On the other hand, bees do distinguish species 

 partly on the basis of color and they also depend on color to a certain 

 extent to distinguish between fresh flowers and old withered ones 

 or partly opened buds. When part of the flowers of a species are 

 painted unusual colors the bees show^ a decided preference for the 

 natural color until experience teaches them that such discrimination 

 is unnecessary. It is pretty generally agreed also that the power of 

 vision of bees is sufficiently developed to enable them to readily 

 recognize differences in form and patterns of flowers. In fact they 

 seem to be able to distinguish differences in surface and texture that 

 are so small as to be unnoticed by man. 



The sense of odor of insects has often been over-emphasized, 

 although it differs greatly in different groups. Honey-bees do not 

 have a sense of smell that is especially highly developed and when 

 they are in the immediate vicinity of flowers color and form are much 

 more important than odor in guiding them. It is true also, of course, 

 that bees cannot see for great distances. It seems to be true, there- 

 fore, that for distances greater than 20 meters odor is more important 

 than color and form, while, for intermediate distances, color in mass 

 is most used, and for distances of 1 meter or less the color and form of 

 individual flow^ers are the guiding factors. For distances that are 

 measured in miles, however, bees have simply to go hunting for 

 flowers just as men do. But it is true also that memory and habit 

 play important roles and when bees have once found a field of clover 

 or a bass wood tree they make subsequent trips to the same place 

 with apparently no more trouble than a man would have. 



50. Bee Flowers.— Flowers which are wide open and have their 

 pollen and often their nectaries freely accessible are visited by a 

 variety of insect species any of which may effect pollination. There 

 are many flowers, however, that are partly closed, that are very 

 irregular in shape, or that have their nectar concealed, which can be 

 pollinated by only one or a few species of insects. 



Some of the violets are bee flowers, that is, they are pollinated 

 almost entirely by bees. This is true especially of some of the yellow 

 violets and of the cultivated pansies (Viola tricolor). Most of the 

 blue violets, on the other hand, are not much visited by insects and 

 are often infertile. These sj)ecies, in addition to the blue flowers, 

 produce, usually later in the season, small green flowers (called 



