82 PLANT LIFE OF ALABAMA. 
On the rugged foothills and mountain slopes, and particularly on the 
broad, barren, limestone flats of the uplands in the eastern part of the 
valley north and east of the Tennessee River the red cedar forms 
extensive woods, of pure growth, interrupted only by bare openings 
where the rocky ground scarcely affords a foothold to shrub or herb. 
The trees in the cedar glades or cedar brakes are closely set and attain 
a height of from 50 to 75 feet, the trunk from 15 to rarely 24 inches 
in diameter, breast-high, frequently deeply ridged toward the base, 
knotty, and with the crown from 30 to 50 feet or more above the ground. 
Under these severe soil conditions the growth of the trees is exceed- 
ingly slow, particularly during the later stages of life. By counting 
the annual rings trees of the dimensions mentioned were found to be 
from 140 to 175 years old. Large supplies of the valuable timber of 
the cedar, used for piling and for telegraph and telephone poles, are 
drawn every year from the cedar glades. On the gentler slopes with 
a deeper soil covering, and in the narrow valleys with a damp and rich 
soil, red cedar occurs scattered among the hard woods and here reaches 
its greatest perfection. The trunk is smooth from the base and free 
from knots and limbs for the greater part of its height; the wood is 
straight-grained, soft, and easily worked, and possesses all the quali- 
ties for which it is so eagerly sought in the manufacture of pencil 
casings and the best qualities of hollow ware. Not long since this tree 
was abundant in the narrow valleys and rich coves south of the Ten- 
nessee River, but these resources are now becoming rapidly exhausted. 
On the sunny exposures, in the openings and borders of the forest 
which covers the calcareous hills, where the soil is deeper, a variety of 
xerophile trees of small size and of shrubs of the lower belt of the 
Carolinian area are found mingled with the red cedar. Examples are: 
Rhamnus caroliniana (buckthorn). Crataegus coccinea (red haw). 
Bumelia lycioides (bumelia). Cornus asperifolia (rough-leaf dogwood). 
Bumelia lanuginosa (shittimwood). Viburnum prunifolium (black haw). 
Ostrya virginiana (hop hornbeam). 
Xerophile herbaceous plant associattons.—The herbaceous associations 
are naturally, in the main, of xerophile character. On the exposed 
rocky flats tiny cruciferous winter annuals fill every crevice. Leaven- 
worthia awrea, L. unifiora, and L. torulosa, the first harbingers of 
spring, are followed by Draba caroliniana and D. brachycarpa. With 
the advent of warmer weather all herbaceous vegetation withers on 
these arid cedar glades, which then continue to present the aspect of 
absolute barrens. 
On the rocky banks and shelves of the sunny hillsides a varied array 
of characteristic herbs makes its flowery display. In the height of 
springtime, as observed on the southern slopes of Monte Sanoe(near 
Huntsville) and on the northern declivity of the Warrior table-land 
