254 DIFFICULTY OF FORMING TUEP. 



is of the first importance to know whether the perma- 

 nent grass covering of the soil may be attained by any 

 possible means. 



The normal range of the grasses, strictly speaking, is 

 not so far south. Their native climates are north of 

 the native grain districts, and in cooler and more humid 

 atmospheres ; while the southern part of the United 

 States Jias a tropical summer, and lies on the opposite 

 side of the climatological limit. We cannot anticipate 

 success in grasses taken from the colder extreme in this 

 opposite position, and probably very little for those 

 adapted to dry climates, whether warm or cold. The 

 source should be tropical or semi-tropical; and such 

 has, indeed, been the origin of many species introduced 

 and cultivated to some extent at the South. The 

 Guinea grass {Sorghum vulgar e) is of this sort, and 

 the Bermuda grass {Oynodon dactylon). The last is 

 much like the cane in its root and habit of growth, and 

 both are purely tropical forms. The sugar-cane is itself 

 frequently cultivated as a grass, with success, and all 

 these are more easily cultivated as forage plants, to be 

 used for pasturage and soiling only, than as dried in the 

 form of hay. The succulent character of the growth 

 scarcely permits curing ; and the mixture of " winter 

 grasses," or the coarser festucas often cultivated there 

 for their winter's produce, of which the gramma grass 

 and the technical " winter grass " are the principal, will, 

 ultimately, be necessary to answer the end proposed in 

 their grass cultivation, and indispensable, indeed, to 

 their agricultural prosperity. The gramma grass of 

 Texas and New Mexico may bear a considerable exten- 

 sion over the drier soils and least humid portions of the 

 South, and it has already been introduced with some 

 success. 



It has been found extremely diflScult to form a close 

 turf or sward below the latitudes of the more equa- 

 ble distribution of rain ; and this is the case south of 

 Baltimore, in latitude 39" 18', owing to the excessive and 

 often long-continued heat and drought. Even lucerne, 



