166 THE FLORA OF MISSISSIPPI. 



It is to be noticed that at least one northern tree, the 

 butternut {Juglans cinerea) found in this region, is only- 

 found, so far as at present known, along streams tributary 

 to the Tennessee. The fruit of this tree is heavy and 

 could only be transported by water or by animals. Their 

 occurrence along the streams might be explained by the 

 action of back water in time of high water, reinforced by the 

 activity of squirrels in disseminating the seed. The only 

 other region of the State where this tree has been noted is 

 in the northwest part of the State near the Mississippi 

 River, where its occurrence might be similarly explained. 



The general characteristics of the southern pine region 

 extend considerably farther north toward the eastern 

 line of the State than farther west, which may be accounted 

 for in the manner already suggested. 



The azalea {Rhododendron nudiflora) and mountain 

 laurel {Kalmia lati folia), shrubs of distinctive northern 

 /rtlibuoion, are found equally abundant in the Tennessee 

 River hills and along streams of the southern pine region, 

 but are not particularly common in the intervening regions. 

 In the western half of the State, particularly that part 

 north of the A. & V. Railroad, and west of the I. C. Rail- 

 road, these two species are very rare, so far as our investi- 

 gations have discovered. 



The magnolias of all species, except the sweet bay 

 {Magnolia glauca), have their chief distribution in the Loess 

 silt region, and are more abundant in the southern half 

 of the region. The distribution of the gray moss {Til- 

 landsia usneoides) corresponds quite closely with this, 

 including, however, the swamps of cypress and gum. In 

 the overflow regions, and bordering swamps of the Delta 

 and large tributary streams, the fan palmetto {Sabal minor) 

 finds its northern distribution a little north of latitude 33°. 



Lippia nodiflora and Daubentonia longifolia, which are 

 very com-mon on the sands of the Gulf coast, seem not to 

 be comm^ else vhcre in the State except in the sandy soils 

 bordering the Mississippi River as far north as Vicksburg. 

 Doubtless other strand species will be found to have a 

 similar distribution. 



