104 LIFE OF 



In the group to which our common orchids belong, 

 remarkable adaptations for securing that the pollen 

 masses brought from another flower solely through the 

 visits of insects shall reach their precise destination, 

 were brought to light. "A poet," says Darwin, "might 

 imagine that whilst the pollinia were borne through 

 the air from flower to flower, adhering to an insect's 

 body, they voluntarily and eagerly placed themselves 

 in that exact position in which alone they could hope 

 to gain their wish and perpetuate their race." As he 

 had examined all the British genera, Darwin's con- 

 clusions were indubitable. He had patiently watched 

 for hours on the grass to notice insects' visits, had 

 counted the fertilised flowers on many spikes, the 

 fertilised spikes on many plants, had dissected and 

 redissected the flowers till he saw how the fertilisation 

 must absolutely be effected ; and utilising the enthusiasm 

 of orchid growers, had excited them to do the same, till 

 his storehouse of facts was full. 



On examining the exotic forms of orchids, which are 

 so conspicuous in our conservatories, still more striking 

 facts presented themselves. In the great group of the 

 Vandese, relative position of parts, friction, viscidity, 

 elastic and hygrometric movements were all found to be 

 nicely related to one end the aid of insects in fertili- 

 sation. Without their aid not a plant in the various 

 species of twenty-nine genera which Darwin examined 

 would set a seed. In the majority of cases insects with- 

 draw the pollen masses only when retreating from the 

 flower, and, continuing their flower visits, effect a union 

 between two flowers, generally on distinct plants. In 



