638 RELATION TO ENVIRONMENT. 



name being written in the upper left-hand corner, and these cards could 

 then be kept in card-catalogue order. When necessary notes and references 

 could be continued on back. 



1127. Simple way to chart extent and relation of plant formations. 

 There are several simple ways of charting the location and extent of plant 

 formations. One method of illustrating the relation of formations to each 

 other is shown in fig. 535. The relation and extent of formations may be 

 illustrated as shown in fig. 536 (from MacMillan, Bull. Torr. Bot. Club, 

 23, p. 502, 1896), and as shown by Pieters (The Plants of Lake St. Clair, 

 Bull. Mich. Fish Comm., No. 2, 1894, Lansing), by Ganong (Vegetation of 

 Bay of Fundy Marshes, Bot. Gaz., 36, p. 351, 1903), and others. 



II. Natural Vegetation Regions of the Earth. 



1128. According to Griesebach. The regions established by Griese- 

 bach were based on the notion of separate centers of development and 

 distribution of the vegetation of the land. 



Twenty-four regions were recognized: 



I. Arctic region. XIII. Prairie region. 



II. Forest region of the Eastern XIV. Calif ornian Coast region. 



Continent. XV. Mexican region. 



III. Mediterranean region. XVI. West Indies region. 



IV. Region of the Asiatic Steppes. XVII. Cisequatorial South Ameri- 

 V. Chinese-Japanese region. can region. 



VI. Indian-Malayan region. XVIII. Hylaea, or Amazonian, 



VII. Sahara region. region. 



VIII. Soudan, or Central Africa, XIX. Brazilian region. 



region. XX. Tropical Andes region. 



IX. Kalahari region. XXI. Pampas region. 



X. Cape of Good Hope region. XXII. Chilean transition region. 



XI. Australian region. XXIII. Antarctic forest region. 



XII. Forest region of the Western XXIV. Oceanic Island region. 



Continent. 



1129. According to Engler. Engler's classification is based on the notion 

 of general development and migration. He recognizes four great realms, 

 which are then divided into a large number of regions and provinces. Only 

 those regions and provinces will be given here which apply to North America, 



I. THE REALMS AND THE REGIONS IN NORTH AMERICA. 

 World-realms. Region in North America. 



(1) .\rctic region (also in Europe). 



(2) Subarctic or Conifer region (also 



A. Northern extratropical Realm.. 



in Europe). 



(8) Pacific N. A. region. 



(9) Atlantic N. A. region. 



