CH. II]. THE PODOSTEMACEAE 17 



organisms necessary to make the divergence show more and more 

 as one went up in the scale. As Guppy points out in Age and 

 Area, p. 104, Hooker was definitely considering the idea or 

 nucleus of a theory of differentiation (19, ii, 306) but "no induc- 

 tive process based on Darwin's lines could have found its goal in 

 a theory of centrifugal variation. . . . Huxley was in the same case. 

 For he held views of the general differentiation of types, and his 

 road that would lead to the discovery of the causes of evolution 

 started from the Darwinian position. That road was barred to 

 him." 



One cannot conceive of any of these family differences being 

 formed under the influence of natural selection. One cannot even 

 suggest, in any single case, which of the two characters is the 

 earlier, or what advantage can be gained by one as against the 

 other, or as against any possible intermediate, if such a thing 

 could exist at all. One must also remember, in dealing with 

 natural selection, that there must have been an enormous de- 

 struction of intermediates, of which we find no fossil record of 

 any note. 



The supporters of natural selection mostly (at present, that is, 

 for they are apt to change over to the reverse explanation, that of 

 local adaptation) look upon the small and local genera and species 

 which occur in such great numbers, as being the losers in the 

 struggle for existence, i.e. the relics of a former vegetation, now 

 upon the way to extinction. A very remarkable thing about these 

 relics, which they do not attempt to explain, is that they do not 

 occur, except very rarely, in two or more different localities, with 

 a wide separation. For example, there are hardly any cases 

 known where they occur in two different continents, and few 

 where thev are found in the interior of two different countries on 

 one continent. Nor do the great majority of them belong to small 

 and isolated genera, but to the large genera (cf. p. 26), which 

 natural selection regards as the successes. The "relics" therefore 

 must have belonged to ancestral species which must have been 

 widely distributed to give rise to their present descendants. Why 

 then, when in one or more regions of slightly different conditions 

 new species were developed, did not the old species become dis- 

 continuous in its distribution, leaving relics in several different 

 places? 



Under the natural selection theory, the large genera in the big 

 families, like Senecio, Ranunculus, or Poa, are supposed to have 

 been the best adapted and therefore the most successful. But 



WED 2 



