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 Arca.—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 ina 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 
ninetiecth and ninety-fifth degrees of longitude. Here the tulip tree 
