GBNERAL ASPECT 01- THE FLORA. 



The boundaries of Tennessee are embraced within the great 

 Atlantic forest region. The whole of it was in its virgin state, 

 a congeries of varied woodlands, being in the lowlands of dense 

 and massive growth, filled with pathless jangles of cane and 

 shrub, or, away from the watercourses, on the uplands, reduced 

 to o{)en and airy groves, the barrens. Here a dense sward covers 

 the ground and herbaceous growth prevails. Mountain forests 

 have always been of greater uniformity in distribution of timber. 



Xearly one-third of the entire area is now reduced to fields 

 or occupied by buildings or roads. Canebrakes have well nigh 

 <lisappeared, and the forest is in all accessible regions depleted 

 of valuable timber. 



Immigration of foreign and retirement of native species con- 

 tinually modifv the aboriginal flora aad tend to weaken charac- 

 teristics due to presence of peculiar plantforras, or collocation of 

 species, by the intricacies of mutual ])redilection and adaptation 

 to surroundings. 



Such ar(;a-, which differ amongst themselves conspicuously in 

 such properties, admit of the establishment of natural floral 

 arrondisements. 



Differences of elevation, diversity in elementary constitution 

 of the soil, and inequality in distribution of atmospheric humid- 

 ity are, in our territory, sufficiently potent to mark out four dis- 

 tinct regions. 



I. The high crests of the Alleghany ^Mountains, formed of 

 gneiss or mica-shists, with an elevation from 4,000 to 6,600 feet. 

 Subalpine region. 



II. The western slopes of the Alleghanies and their outlying 

 spurs, and the Cumberland Mountains. .Sandstones and slates. 

 Mountain-flora. Elevation 2-4,000 feet. 



III. Valley-flora, the lower division of which is coextensive 

 with the limestones (silurian) of East and Middle Tennessee. 

 Elevation 350-500 feet. The upper division or highlands has 

 siliceous and argillaceous soils, sometimes lime-tone-* of the sub- 

 carboniferous formation. Elevation about 1,000-1,200 feet. 



