CONTENTS. 



XV 



CHAPTER XXIII. 



ON THE ARCTIC ELEMENT IN SOUTH TEMPERATE FLORAS. 



European species and genera of plants in the Southern Hemisphere — Aggressive power 

 of the Scandinavian flora — Means by which plants have migrated from north to 

 south— Newly moved soil as affording temporary stations to migrating plants — 

 Elevation and depression of the snow-line as aiding the migration of plants — 

 Changes of climate favourable to migration — The migration from north to south 

 has been long going on — Geological changes as aiding migration — Proofs of mi- 

 gration by way of the Andes— Proofs of migration by way of the Himalayas and 

 Southern Asia— Proofs of migration by way of the African highlands— Supposed 

 connection of South Africa and Australia— The endemic genera of plants in New 

 Zealand — The absence of Southern types from the Northern Hemisphere — 

 Concluding remarks on the New Zealand and South Temperate floras 



Fages 477—498 



CHAPTEE XXIV. 



SUMMARY AND CONCLUSION. 



The present volume is the development and application of a theory — Statement of 

 the Biological and Physical causes of dispersal — Investigation of the facts of dis- 

 persal — of the means of dispersal — of geographical changes affecting dispersal — 

 of climatal changes affecting dispersal — The Glacial Epoch and its causes — Alleged 

 ancient glacial epochs — "Warm polar climates and their causes — Conclusions as to 

 geological climates— How far different from those of Mr. Croll — Supposed limita- 

 tions of geological time —Time amply sufficient both for geological and biological 

 development — Insular faunas and floras— The North Atlantic Islands — The Gala- 

 pagos — St. Helena and the Sandwich Islands— Great Britain as a recent Conti- 

 nental Island — Borneo and Java — Japan and Formosa — Madagascar as an ancient 

 Continental Island — Celebes and New Zealand as anomalous Islands — The Flora 

 of New Zealand and its origin— The European element in the South Temperate 

 Floras— Concluding Remarks ....... Fages 499—512 



