FROM BUTTERCUPS TO MONICS-HOOD. 6 7 



metrical, and never one-sided, because the conditions are the same all 

 round, and the visiting insects can light upon them equally from every 

 side. But flowers which grow sideways from a spike are very apt to 

 become bilaterally symmetrical ; indeed, whenever they are not so, 

 one can always give an easy explanation of their deviation from the 

 rule. Probably the blossoms of the monk's-hood began by arranging 

 themselves in a long and handsome spike, so as more readily to attract 

 the eyes of insects ; and that was the real starting-point of all their 

 subsequent modifications. Or, to put the same thing more literally, 

 those monk's-hoods which happened to grow spike-wise succeeded best 

 in attracting the bees, and therefore were most often fertilized in the 

 proper manner. Next, we may suppose, the large green sepals, being 

 much exposed to view, began to acquire a bluish tinge, as all the 

 upper parts of highly developed plants are apt to do ; and the bluer 

 they became, the more conspicuous they looked, and therefore the 

 better they got on in competition with their neighbors, especially since 

 bees are particularly fond of blue. As each bee would necessarily 

 light on the middle or lower portion of the flower, he would begin by 

 extracting the honey from the two upper petals ; but it would be 

 rather awkward for him to turn round head downward, and suck the 

 nectaries of the three bottom ones. Hence, in course of time, espe- 

 cially after the flower began to acquire its present shape, the two top 

 petals became specialized as nectaries, while the three lower ones grad- 

 ually atrophied, since the colored sepals had practically usurped their 

 attractive function. But as the flower can only succeed by being fer- 

 tilized, all these changes must have been really subordinate to the 

 great change which was simultaneously going on in the mechanism 

 for insuring fertilization. Slowly the blossoms altered to the bilateral 

 shape they adapted themselves by the bee's unconscious selection to 

 the insect's form. The uppermost sepal grew into the hood, so arranged 

 that the bee must get under it in order to reach the long nectaries 

 containing their copious store of honey. At the same time the bee 

 must brush against the stamens, and cover his breast with a stock of 

 adhesive pollen-grains. When he flies away to the next flower he car- 

 ries the pollen with him ; and, as he rifles the nectaries in the second 

 blossom, he both deposits pollen from the last plant upon the sensitive 

 surface of the carpels in this, and also collects a fresh lot of pollen to 

 fertilize whatever other flower he may next favor with a call. The 

 increased certainty of fertilization thus obtained enables the plant to 

 dispense with some of the extra carpels which its buttercup ancestors 

 once possessed ; and, by lessening the number to three, it manages to 

 get the whole set impregnated at a single visit. But, as three seeds 

 would be a small number to depend upon in a world of overstocked 

 markets and adverse chances, it makes up for the diminution of its 

 carpels by largely increasing the stock of seeds in each. 



Thus the whole shape and arrangement of the monk's-hood bear 



