120 TEST CASES [ch. xi 



single mutations. The supporters of natural selection can only 

 explain the exact nature of the oppositeness in the one case, or of 

 the phyllotaxy in the other, by supposing that anatomical neces- 

 sities are more potent than selection. Differentiation is much the 

 most simple explanation, when one sees the well and exactly 

 marked divergences that show so well, not only in leaves, but 

 throughout the whole list of the characters that mark the dif- 

 ferences in relationship of plants, and show that evolution has 

 gone on. 



TEST CASE XIII. STAMINAL CHARACTERS 



One may work through the whole list of family, or even of generic 

 characters, and find similar phenomena in all, inexplicable by 

 the theory of natural selection or of gradual adaptation, though 

 simply explained by differentiating mutation. Why in so many 

 families and other groups should a great and important dif- 

 ference be that one has one whorl of stamens, while the other has 

 two, or more? This dropping (or addition) of whole whorls of 

 stamens cannot easily be exjDlained upon adaptational grounds. 

 Fewer stamens are usually regarded as a mark of progress in 

 evolution. But why, for example, in a family mostly provided 

 with ten, like the Caryophyllaceae, should the "advanced" 

 members (which in actual fact look less advanced) only have five, 

 with no indication, fossil or other, that they have ever had ten? 

 Why does one find no trace of plants with nine, eight, seven, or 

 six? If it be of any advantage to reduce the number of stamens, 

 surely nine would be an improvement upon ten, and so on. Why 

 should the whole whorl be got rid of with no trace of intermediate 

 stages? The supporters of selection, when confronted with a 

 morphological problem like this, are obliged to defend themselves 

 by bringing in another supplementary hypothesis, this time a 

 "tendency", supposed to exist in plants, to vary the number of 

 the stamens by whole whorls at a time, which of course is more 

 in keeping with the general morphology of the flower, though it 

 is a very remarkable thing that this tendency is so widespread in 

 flowering plants, there being extremely few cases, so far as the 

 writer can remember at the moment, of intermediate stages in 

 regular flowers. In other words, the supporters of selection admit 

 that morphological facts weigh more in evolution than does selection, 

 and they also admit that large mutations can take place. And 

 whence did this tendency come, if it was not handed down from 



