HARPER'S GUIDE TO WILD FLOWERS 



Certain plants which cannot bear too great radiation from 

 their leaf - surf aces at night, "sleep," that is, fold their 

 leaflets together. Examine a clover leaf after dark, and 

 look up into a locust-tree by night. The latter looks as 

 if it were hung with strings. 



White flowers which cannot attract insects by their bright 

 colors, are apt to be strong-scented. 



Many such things, more marvelous than fairy stories, are 

 revealed to us in the study of our common flowers. 



Why Do Flowers Have Color? 



The organs concerned in the production of seed by which 

 flowering plants are propagated, are the stamens, actively, 

 and pistils, passively. 



Stamens produce in their anthers pollen grains, which must 

 be carried to the pistils, either those of the same flower or 

 of another. This process is called pollination. "Cross- 

 pollination," the transference of pollen to a different flower, 

 gives seed greater potency, so that stronger and hardier 

 plants result from it than when the pollen falls upon its 

 own pistil. How is cross-pollination to be obtained? Not 

 by any movements of the flower itself. The aid of some 

 foreign agent must be invoked. 



In the evolution of plants, flowers and insects began to 

 appear upon the earth about the same time. At first the 

 colors of all flowers were dull green, greenish white, or white. 

 The food of most insects is nectar, a sweet secretion found 

 in the very heart of flowers, which by them is converted 

 into honey. Insects fly to flowers, dive into them in their 

 efforts to secure the coveted nectar, and, in so doing, neces- 

 sarily rub their bodies against the upright stamens. If the 

 anthers are ripe and the pollen grains are free, they are caught 

 in their hairy bodies or limbs. The insects then fly to another 

 flower and leave the pollen upon its stigma, provided that 

 is ripe and ready. Many flowers, if neglected by insects, 

 cannot produce seed at all. If the stamens and pistils 

 mature at different times, or if they are so situated that they 

 cannot reach one another, self-pollination cannot take place. 

 Insects must be attracted to such flowers. 



That insects are not color-blind may be seen from the fact 

 that they will follow to their undoing "nectar paths," 



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