ALLUREMENTS OF ANIMALS FOE THE DISPERSION OF POLLEN. 169 



superfluity of pollen. All flowers which contain no honey and offer only pollen as 

 food for the insects, e.g. those of Cistuses and Roses, of Poppies and Clematises are 

 characterized by a large number of stamens containing so much pollen that in spite 

 of the extensive depredations of the insects, the necessity of pollinating the stigmas 

 is always provided for. The pollen-eating beetles, after visiting such flowers, are 

 always powdered all over with pollen, and as they cannot immediately rid them 

 selves of that which clings to their thorax, abdomen, wing-cases, and legs, when 

 they leave the flowers, they invariably carry it to other flowers. The bees and 

 humble-bees also, which enter such flowers to collect pollen, come out covered as if 

 with flour, and when subsequently they set to work energetically with their leg- 

 brushes to clear the dust from their fur, there always remains behind enough to 

 give the stigmas of other flowers their portion when they next visit them. 



Flowers which conceal honey in their depths are very economical with their 

 pollen, and in them care has been taken that it shall not be squandered or uselessly 

 scattered. Animals which frequent flowers poor in pollen are, moreover, vigorous 

 honey-suckers and do not attempt either to eat the pollen or to collect and carry it 

 into the nest for their brood. Involuntarily, they become streaked and clothed 

 with pollen, a state of affairs not always agreeable to them. At the same time it 

 cannot be very disagreeable, for the animals may be seen immediately after flying 

 out of the pollen-strewing flowers as if frightened, entering flowers of the same 

 species in the next moment where they will experience the same treatment. It 

 would indeed be strange if the same flowers should on the one hand have such 

 contrivances as will allure insects in order that they may transfer the pollen from 

 plant to plant, and on the other hand be so arranged as to shock these laden and 

 attracted guests, and disincline them to further visits. Such a contradiction never 

 does occur in the flower-world, but all the contrivances connected with the trans- 

 ference of pollen display a harmony which fills those who busy themselves with 

 these phenomena with astonishment and admiration. 



The dusty, flour-like coatings which are observed on the flowers of some 

 Orchids, particularly of the genera Meanthus and Polystachya, are very similar 

 to pollen in outward appearance, but in reality wholly different. They consist 

 of masses of loose, round cells which lie in rows like necklaces of pearls on the 

 upper side of the young petals. As a rule, this covering occurs only on the 

 unpaired leaf of the Orchid-flower known as the lip, which thus resembles a tiny 

 cup filled with flbur. The loose cells, which look like flour or dust, contain starch, 

 sugar, oil, and albuminous compounds, and so form an excellent food, serving, just 

 like the pollen-cells, to allure and please the insects. 



For the most part these dusty, flour-like coatings are rare. It more frequently 

 happens that rows and masses of cells which project from the surface of certain 

 parts of the flower, appearing to the unaided eye as papillae, hairs, swellings, and 

 warts, are offered as food to these flower-visiting insects, and must therefore be 

 reckoned so far as allurements. In the flowers of the Portulaca (Portulaca 

 oleracea) there is a ring-shaped cushion covering the spherical ovary, from its inner 



