12 GENERAL ASPECT OF THE FLORA. 



dtint Willd.), honey locust ( GledUschia triacanthos L.), hack- 

 berrv (Celti-s Miisis'sippiensis Bosc), some hickories {Carya alha 

 Niitt., C. tomenfom Ntt., 0. porcina Nutt.), shingle oak {Quer- 

 CH.^ iriihrkani L.), yellow chestnut oak {Q. MMenhergii Englm.), 

 post oak (O. ohUi'siloba Michx.), hop-hornbeam {Ostrya Virgin- 

 ica L.)i winged ehii ( Ubnus alata Michx.), buckthorn (Frangula 

 Caroliniana Gray), persimmon {Diospyros Virginiana L.), red 

 plum {FrwiK^ Americana Marshall), Chickasaw plum (P. Chick- 

 asaw Michx.) Of shrubs prominently: Forestiera ligustrina 

 Poir., R/uis aroinatica Ait , Ptelea trifoliaca L., Aralia spnnosa 

 L., several hawthorns: Crataegus Grus Galli L., G. cordata Ait., 

 G. tomentosa L., var. pyrifolia Gray, and var. punctata Gray, 

 Bumelia lycioides Gicrt., Symphoricarpus vulgaris Michx., Hyper- 

 icum aureuui Ban. 



The cedar barrens effect an obvious and pleasing contrast in 

 the feature of a landscape, especially in regions where, by absence 

 of streams or prominent landmarks, diversity in grouping, hab- 

 itus and coloring of the arboreus growth must relieve a weari- 

 some monotony. Middle Tennessee is, from periodic excessive 

 drynesb of the atmospliere, absolutely incongenial to every other 

 species of our native conifers. 



The somber tint of the cedar delineates a cedar barren from 

 its surroundings at a distance and serves within its environs, 

 wherever openings occur, to bring out with dazzling vividness 

 the crumbling limestone flats, overspread with the rosy Sedum 

 pulchellum and carmine-flowered Talinum, or the golden stars 

 of the (^puntia Raftiinesquii. 



The botanical interest in these cedar glades varies from a 

 delightful surprise in the survey of an unparalleled number of 

 rare and interesting plants upon small tracts, to a painful disap- 

 pointment over a fruitless ramble through long stretches. 



Depressions, where the coherent and slightly scooped lime- 

 stone banks secure a continuance of moisture, and where small 

 springs come to the surface, represent the garden spots of the 

 wilderness. Wherever again the ground swells up into rocky 

 ridges, or where from collapse of subterraneous cavities, in which 

 these regions abound, the strata are broken up and tumbled 

 about like heaps of ruins, there the rains sink too fast and so 

 deep that only the penetrating roots of the cedar can reach the 

 hidden moisture; a drought soon dries up the smaller herbage. 

 The cedars are always closely set, and it is a vexatious and ungrate- 

 ful tusk to penetrate such thickets. 



In the oak barrens we find good farming lands as far as the sub- 

 carboniferous limestone extends. As soon as the siliceous or chertv 



