RELATIONSHIPS OF METASPERMAE. 589 



(3) Middle Europe and Aral-Caspiun region. 



(4) Central Asian region. 



(5) Macaronian transition region. 



(6) Mediterranean region. 



(7) Manchurian-Japanese region. 



(8) Pacific North American region. 



(9) Atlantic North American region. 



B. Tropical Old World Realm. 



(1) West African forest region. 



(2) African-Arabian steppe region. 



(3) Malagassian region (Madagascar, Mascarenes, Seychelles). 



(4) Lower Indian region. 



(5) Tropical Himalaya region. 



(6) East Asian tropical region. 



(7) Malayan region. 



(8) Araucaria region (tropical East Australia, New Caledonia, 



northern New Zealand, Kermadec and Chatham Isles). 



(9) Polynesian region. 



(10) Sandwich Island re'gion. 



C. South American Realm. 



(1) Mexican highland region. 



(2) Tropical American region. 



(3) Andes region. 



(4) Galapagos region, 



(5) Juan-Fernande/ region. 



T>. Old Oceanic Realm (dpminant plants of more ancient types than 

 elsewhere). 



(1) Antarctic forest region of South America. 



(2) New Zealand region. • 



(3) Australian region. 



(4) Kerguelen region. 



(5) Amsterdam Island region. 



(6) Cape of Good Hope region. 



(7) Tristan d'Acunha region. 



(8) St. Helena region. 



The regions of the North American continent come under 

 two realms, as is noted above. Mexican highlands and Central 

 America botanically belong rather with South than with North 

 America. In the regions which are placed under the northern 

 extratropical realm, and contain North American areas, the 

 following divisions into provinces are established: 



(I) Sub-Arctic, or Conifer region. 



(a) Northern European province. 



(b) Northern Siberian province. 



(c) North American Lake province. (Described as sub-arctic 

 and alpine, uniting on the north with the Arctic region and on the south 

 with the Pacific and Atlantic regions of North America. Three zones 

 are recognised — I, the AUjowiuin zone, lying between Hudson Bay, New- 

 foundland and Lake Superior, characterised by Thuja occidentalis and 

 Taxus canadensis; II, Athabasca zone, bounded on the south by a line from 



