116 PLANT LIFE OF ALABAMA. 



Pine-barren flats and Hydrophy tic 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 (Ilex glabra) scarcety 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. 1 Sabbatia dodecandra. 1 



Anthaenantia rufa. Helenium brevifolium. 



Paspalum glabratum. Rhexia mariana. 1 



Panicum polyanthes. 1 Rhexia stricta. 



Sabbatia campanulata. 1 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. cydoptera) 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 Ilabenaria 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-lads 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 macrophyUum. Rynchospora rariflora. 



Sphagnum imbricatum cristatum. 1 Rynchospora oligantha. 



Sphagnum recurvum. 1 Eleocharis acicularis. 1 



Rynchospora pusilla. Eleocharis tuberculosa. 1 



Rynchospora plumosa. Scleria caroliniana. 



1 Found also in Carolinian area. 



