THE VOICE OF THE DESERT 



86 



their sweetness on the desert air or, for that matter, on the 

 jungle air. In fact, they waste it only when nobody except 

 a human being is there to smell it. It is for the bugs and 

 for a few birds, not for men, that they dye their petals or 

 waft their scents. And it is lucky for us that we either hap- 

 pen to like or have become "conditioned" to liking the 

 colors and the odors which most insects and some birds like 

 also. What a calamity for us if insects had been color blind, 

 as all mammals below the primates are! Or if , worse yet, 

 we had had our present taste in smells while all the insects 

 preferred, as a fev/ of them do, that odor of rotten meat 

 which certain flowers dependent upon them abundantly 

 provide. Would we ever have been able to discover 

 thoughts too deep for tears in a gray flower which ex- 

 haled a terrific stench? Or would we have learned by 

 now to consider it exquisite? 



The whole story, as it is usually told, of how flowers 

 developed is thus a rather tall tale, as indeed the whole 

 story of evolution is. But it does fall just short of the com- 

 pletely incredible even though we are likely to feel an 

 additional strain when we begin to bring in the more re- 

 markable features and find ourselves compelled to believe 

 in the gradual blind development of the more mtricate de- 

 vices by which a flower is often adapted to some particu- 

 lar insect or bird and the exact correspondence between, 

 say, the length of a given flower's tube and the length of 

 the moth's proboscis or the hummingbird's bill which is 

 going to reach down into it. But when we come to Pronuba 

 and the yucca we get something more staggering still. 

 That two different organisms should have simultaneously 

 adapted themselves one to another is, if I understand the 

 laws of probability, at least four times as improbable as 



