116 PLANT LIFE OF aLABAMA. 
Pine-barren flats and Hydrophytic plant associations. 
Toward the northern limit of this region the oldest strata of the 
Post-Tertiary (Neocene) beds of loose sands and compact more or less 
aluminous clays approach or attain the surface. The higher swells of 
the table-lands covered by the porous sands and gravels include level 
tracts of badly drained barrens underlaid by the older strata, flooded 
after every heavy rain, droughty during hot and dry weather. On 
these flats Cuban pine is thinly scattered and here reaches its northern 
limit of vegetation, at a distance of about 60 miles from the seashore. 
Excepting the ink berry (Z/ex glabra) scarcely any tree or shrub 
shades the ground; but a small number of grasses find a place among 
the coarse herbs forming the cover of the extremely poor soil of these 
flats. The bulk of the herbaceous vegetation consists of a few abun- 
dant mesophile species. The following are representatives species: 
Andropogon virginicus.+ Sabbatia dodecandra.! 
Anthaenantia rufa. Helenium brevifoliwum. 
Paspalum glabratum. Rhexvia mariana? 
Panicum polyanthes.* Rhexia stricta. 
Sabbatia campanulata.' Cynoctonum sessilifolium. 
There are also a number of paludial species with xerophile adapta- 
tions; that is, they are provided with strong, deeply embedded root- 
stocks to retain the needed supply of moisture during periods of hot 
and dry weather, and with rigid leaves of greatly reduced surface to 
prevent excessive transpiration. Among such plants may be men- 
tioned species of Xyris and round rushes. In exposed shallow pools 
and ditches Sagittarias (Sagittaria chapmani, S. cycloptera) having 
rigid scapes and narrow stiff leaves are most frequent, the latter fre- 
quently reduced to narrow phyllodia. On the base of the pine-clad 
ridges bordering the flats Zabenariu cristata and Psoralea simplex are 
not infrequently observed, the spindle-shaped or top-shaped roots of 
the latter deeply buried in the sand, where it is constantly moistened 
by springs. 
In many localities the declivities of the table-lands are perpetually 
wet with the water which oozes from the porous silicious strata imme- 
diately overlying the impervious clay, and the depressions inclosed 
by them are frequently covered with a dense carpet of peat mosses, 
interwoven with the long filiform rhizomes of beak rushes, spike 
rushes, and one nut rush, the following being species : 
Sphagnum macrophyllum. Rynchospora rariflora. 
Sphagnum imbricatum cristatum.) Rynchospora oligantha. 
Sphagnum recurvum.! Eleocharis acicularis.* 
Rynchospora pusilla. Eleocharis tuberculosa.! 
Rynchospora plumosa. Scleria caroliniana, 
1¥Found also in Carolinian area. 
