94 OBJECTIONS TO THE HYPOTHESIS [pt. i 



not necessarily dying out. This is a perfectly sound position, but 

 is not really an objection to Age and Area, when this is properly 

 understood. If a genus has 5 species in one region, and an 

 outlying species 6 in another, and one can produce geological 

 evidence of former connection, whether by living or by extinct 

 species, then there is no doubt that 6 is a relic in the sense of 

 this objection. One must simply take the whole area covered 

 by 1-6 as the area of the genus in consideration of any matter 

 by Age and Area. This type of relic, however, is really rather 

 uncommon. 



A more frequent type is that so often found in temperate 

 North America, where the mountain chains, running north and 

 south, did not offer such a barrier to the ice and cold of the glacial 

 period as in the Old World. Sinnott (p. 86, footnote) instances 

 Carya and others, pointing out at the same time that many 

 occur as fossils in the Old World, and that they include most 

 of the woody endemics of north temperate America. Such en- 

 demics, showing wide taxonomic separation from the rest of 

 their surrounding forms, are, however, comparatively rare, and 

 as already pointed out, in dealing with them from an Age and 

 Area point of view, one must include the "fossil" area. 



In the tropics, or in the southern hemisphere, on the other 

 hand, and even in the north among the herbs, which Sinnott 

 has shown to be in all probability very much younger than the 

 trees and woody plants, and which are probably mostly forms 

 that have spread there since the glacial period, the endemics 

 are usually closely related to the forms aromid them, Avhether 

 other endemics or "wides." It would be absurd to apply the 

 "relic" explanation to such a case as Doona in Ceylon (p. 153) 

 or Banunculus in New Zealand, and yet on this supposition 

 Banunculiis in that country, or at any rate Veronica, must be 

 considered as a relic, though the vegetation of north temperate 

 type represented by Ranunculus, Veronica, and many other 

 genera is a very marked feature in the total vegetation of New- 

 Zealand. 



Another very serious reply to this objection is contained in 

 the fact that the endemics of a country remote from the effects 

 of the glacial period usually belong to the large and what have 

 usually been considered the "successful" genera, as has been 

 pointed out elsewhere (Chapter xv of Part II). 



The next objection (27) is based upon the supposed rapid 

 spread of introductions, and is urged to show that dispersal 



