INTRODUCTION xiii 
ied Lo very well the distributional relations of plants in our region. 
n the east Gulf Coastal Plain, where the Lower Austral life-zone 
should supposedly be represented, there occur many Transition and even 
Canadian plants which have pushed southward, west of the Appalachian 
mountains, in some past geological period and have persisted there. Again, 
in the Blue Ridge, where on ascending a high mountain the theoretical 
sequence shoul e Upper Austral—Transition—Canadian—Hudsonian, 
one finds instead a mixture of Upper Austral and Transition plants on 
the lower slopes, Canadian plants further up, but then instead of any- 
thing more boreal, a mixture of plants characterizing the Upper Austral 
of the Atlantic Coastal Plain mingled with many Transition shrubs and 
Canadian trees at the summit. It has accordingly seemed best to refer the 
plants only to the physiographie provinees in which they have been ob- 
served to grow, and to leave the untangling of the o E of life- 
zone relations to other writers. 
The physiographic province names used have been taken, with minor 
modifications, from *Physiographie Divisions of the United States.”* The 
boundaries of those lying within our limits are indicated on the accompany- 
ing sketch map (figure Hs and certain points concerning their positions are 
here diseussed. 
Physiographic province . Discuss bue 
Coastal Plain Separated in ‘¢ Atlantic?’ and 
l «€ E i Coastal Plain, “the division between these 
extending from Macon; Ga., to Gainesville, Fla. 
Piedmont Alabama. to New York; between the Coastal Plain 
and the Blue Ridge and Appalachian provinces 
Appalachian Valley l Often collectively referred to as ''Appalachian 
Appalachian Plateau provinces.’ 
New "England Includes E Canada; often di ivided into **Upland?? 
and ‘‘Coast,’’ the division between these lying 
Pond 30 miles inland. 
Interior Low Plateaus Northern Alabama to Southern Illinois, Indiana, 
| and Ohio. 
Central Lowland The POUR ‘immediately surrounding Lakes Michi- 
gan, Huron, and Eri often se d e HO 
to as the » ‘Great Lakes TEM nd.’ 
Great Plains E Texas to North Dakota. 
Ozark Plateaus Northern Arkansas to central Missouri. 
Ouachita "E | Central Arkansas to eastern Oklahoma. 
Basin-and-range Western Texas to California and southern Oregon. 
4 Nevin M. Fenneman, Ann. Assoc. Am. Geogr., 1917, reprinted 1921. 
