AUSTRAL REGION AND ITS ZONES. 31 



AUSTRAL REGION. 



The great transcontinental Austral Region covers nearly the whole 

 of the United States' except northern New England, northern Michi- 

 gan and Minnesota, and the higher mountains generally. It embraces 

 three distinct life zones Transition, Upper Austral, and Lower 

 Austral. 



TRANSITION ZONE. 



This includes the vast forests of deciduous trees of the cooler tem- 

 perate region of the continent. Here the outposts of the northern 

 types meet those of a decidedly southern distribution. In its exten- 

 sion from east to west this zone presents three well-marked " areas," 

 or floras. 



Alleghenian Area. The humid eastern division, the Alleghenian 

 Area, extends from the coast of New England to the eastern 

 border of the grassy plains west of the Mississippi River and pushes 

 southward in a long arm along the heights of the Allegheny Moun- 

 tains to Georgia and nearly to the border of Alabama. In its forests 

 oaks, hickories, chestnuts, and locusts, with rhododendrons, azaleas, 

 andromedas, and other shrubs of the heather family, mingle with the 

 birches, aspens, mountain ash, ashes, the northern spruces, firs, hem- 

 lock, and pines, and other cone-bearing trees at home farther south. 

 In addition to small grains, the indian corn (maize) is grown here; 

 the potato, with a number of other root crops, is raised, and apples, 

 pears, cherries, and plums, and a variety of berries and fruits of the 

 orchard are common. 



Central Continental Area. This is the arid middle division of the 

 Transition Zone, and comprises the dry plains and elevated table-lands 

 extending from the eastern border of the former to the Cascade and 

 Sierra Nevada mountains, and corresponds in part to the Central prov- 

 ince of Gray and the northern prairies of other botanists. 



Pacific Area. This consists of the Pacific slope, west of these 

 mountains, recognized by botanical writers as the Pacific floral region. 



UPPER AUSTRAL ZONE. 



This zone is naturally divided into a humid eastern and an arid 

 western area or flora. 



Carolinian Area. The eastern division, or Carolinian area, com- 

 prises the lower part of the northern deciduous forest which covers 

 the coast region south of New England; an interior portion of the 

 Southern Atlantic States, including northern Georgia and the larger 

 part of the upper half of Alabama; the basin of the Ohio River to the 

 southern shores of Lake Michigan, and the great central valley of the 

 Mississippi to near latitude 43, finding its western limit between the 

 ninetieth and ninety-fifth degrees of longitude. Here the tulip tree 



