THE FLORA OF MISSISSIPPI. 159 



Jackson Prairie Region. — This region of small prairies 

 extends in a belt varying from 10 to 30 miles wide, in a 

 direction slightly northwest and southeast across the State 

 (boundaries may be seen on the sketch map). Its great- 

 est breadth is in the extreme western part from the longi- 

 tude of Jackson to the Bluff hills; eastward it narrows 

 to the line of Alabama. The region is one of rolling to- 

 pography, in places very gently so, in others quite hilly. 

 The more hilly parts usually exhibit a red sandy loam 

 soil due to weathering of remnants of the Lafayette for- 

 mation. In the broad western part the soil is the Colum- 

 bian or Brown Loam modified somewhat by the under- 

 lying calcareous Jackson clays. The typical prairie soils 

 are rather heavy dark gray clay loams produced by weath- 

 ering of the Jackson clays and marls. This character of 

 soil is usually not found in continuity over wide areas, 

 but is patchy, the patches surrounded by one of the other 

 two types. As would be expected, the flora of this region 

 presents three rather well marked phases. The typical 

 soil, that of the true prairie type, supports a characteris- 

 tic prairie flora, the western loam part supports the flora 

 of the Brown Loam region, modified by invasions from the 

 prairie flora, and the sandy loam parts toward the east 

 support the flora of the southern long-leaf pine hills (to 

 be noticed next) modified by additions from the prairie 

 flora. 



In this brief sketch it will be necessary to notice only 

 the flora of the typical prairie, our discussion of the region 

 lying to the north giving a fairly adequate impression 

 of the part of this region overlaid by the Brown Loam, 

 and the sketch of the flora of the southern pine belt, which 

 will follow, will give, we hope, a sufficient view of the flora 

 of the more sandy portions. 



Most of the surface of even the prairie soil is or has 

 been occupied by a somewhat stunted tree growth, in 

 places quite open, in others rather dense. The trees that 

 make up almost entirely these dwarfed forests are a very 

 few. Perhaps 98 per cent is made up of the following 

 species : 



