RELATIONSHIPS OF ALABAMA FLORA. 39 
the State: Veosusia alabamensis, Croton alabamensis, and Trichomanes 
petersi/. This poverty in endemic forms is easily explained by the 
absence of any serious obstacles to plant migration from and to all 
parts of the eastern section of this continent. The gradual descent of 
the Allegheny Mountains to the Coastal plain rendered the influx of 
plants from the north and east easy. The oldest types flourishing on 
the most ancient strata succumbed gradually to the vicissitudes of eons 
of time and gave way to later invaders. Completely open on the east 
and the west, the denizens of the plant world from these directions 
found no hindrance in peopling the new soils of the secondary 
(Mesozoic and Cenozoic) formations, after their rise above the water. 
RELATIONSHIP OF THE ALABAMA FLORA TO THAT OF ADJOINING 
REGIONS. 
It results from these conditions that the plant-covering of the State 
coincides closely with the flora of the adjoining regions. In its south- 
ern portion it is very intimately related to the flora of western Florida, 
Mississippi, and eastern Louisiana, equally so to that of the maritime 
plain of North and South Carolina and Georgia, and in a less degree 
to that of western Louisiana and eastern Texas. In its central parts 
the same close connection exists with the flora of the middle region 
(Piedmont region) of these States and with that of southern Arkansas. 
The flora of the northern part of the State, with its mountains and 
the Tennessee Valley, presents a similar relationship with the flora of 
the Allegheny ranges south of the Potomac River, below an elevation 
of 2.000 or 2,500 feet above sea level, and with that of the southern 
extension of the Cumberland Mountains and the rim of the Highlands 
of Tennessee. 
RELATIONSHIP OF THE ALABAMA FLORA TO FOREIGN FLORAS. ' 
EASTERN ASIA. 
Asa Gray first directed attention to the intimate relationship exist- 
ing between the flora of eastern North America and that of eastern 
Asia, particularly that of Japan.” The eastern Asiatic element is in 
this part of our continent most pronounced southward. It is here 
most strikingly manifest in the arboreal and shrubby vegetation of the 
numerous genera of the catkin-bearing families, such as walnut, chest- 
nut, oak, beech, hazlenut, ironwood, hornbeam (Ostrya), willow, wax 
myrtle; and of the coniferous family, such as pine, hemlock, cypress 
(Chamaceyparis), savin (Juniperus); to which are added elm, mul- 
berry, linden, pear, plum, service trees (Amelanchier), maple, witch 
[In this discussion the introduced and immigrated plants occurring in Alabama and 
the genera represented only by cosmopolitan species inhabiting the temperate and 
warmer regions all over the globe are disregarded. 
*Asa Gray, Memoirs N. Y. Acad., vol. 6, part 1. 1859. 
