230 



Minnesota Plant Life. 



honey is secreted. In order to obtain the honey it must thrust 

 its bill along the groove where the two adhesive discs are sit- 

 uated. When the insect has sipped the drop of honey which 

 it seeks, having been drawn to it by the perfume and color of 

 the flower, it flies away, carrying with it the two pollen- 

 masses, one on each side of its bill. Immediately after the 

 insect leaves the flower the two pollen-masses bend forward 

 and the next flower visited receives these pollen-masses fairly 

 on the sticky end of the stigma, where the pollen-spores ger- 

 minate and give rise to the male orchid plants. From this sec- 

 ond flower the moth carries 

 away a fresh pair of pollen- 

 masses. 



Such very wonderful and 

 perfect devices secure what is 

 termed cross-pollination. The 

 pollen is taken from one flower 

 and carried to the stigma of 

 another upon another plant, 

 thus apparently insuring a 

 greater vitality and breadth of 

 experience in the embryo 

 plantlets which are to be de- 

 veloped in the seeds. A va- 

 riety of such mechanical de- 

 vices are employed by plants. 

 Those of the orchids with their 



automatic adhesive discs and curving-stalked pollen-masses be- 

 ing among the most marvelous in their perfection. Yet it may 

 be said that the orchids are over-refined and almost too per- 

 fect. The exactness of the machine is indeed so great that the 

 chances against its working are apparently infinitesimal. The 

 seeds, however, are so small and the embryo plantlets are pro- 

 vided with so little nutriment with which to enter upon their 

 independent life that the great majority of them must certainly 

 perish. The orchids, in their development, have given their at- 

 tention, so to speak, to the elaboration of highly complicated 

 methods of cross-pollination, but have at the same time neg- 



FIG. 104. Wild orchis. After Britton and 

 Brown. 



