288 EDWARD W. BERRY 



by the lack of fragrance of its blossoms. It is a native of the 

 mountains from southwestern Virginia to Georgia, but has been 

 extensively planted in all temperate countries where the climate 

 is not prohibitive and has become extensively naturalized east 

 of the Mississippi as far north as Massachusetts. 



The rose acacia, Rohinia Jnspida Linn, of the southern Appa- 

 lachians, a shrub with pink or purple non-fragrant blossoms; 

 and the New Mexican locust, Rohinia neo-mexicana Gray, a 

 shrub or small tree of the mountain valleys of Colorado, New 

 Mexico, Arizona, and southern Utah, with handsome blossoms, 

 are both favorites outside their natural limits for ornamental 

 planting in both this country and western Europe. 



The geological history of the locust is beset with difficulties, 

 the leaflets usually becoming detached before fossilization and 

 both leaflets and pods being often impossible to differentiate 

 from other and unrelated leguminous leaflets and pods. This 

 difficulty of distinguishing between the fossil leaflets of the 

 various genera of Leguminosae has led paleobotanists to establish 

 a purely form-genus known as Leguminosites for leaflets of this 

 sort that cannot be identified with certainty beyond that they 

 are leginninous. Large numbers of species of Leguminosites 

 ranging in age from the L^pper Cretaceous through the Tertiary 

 are known. Among these are several that might well represent 

 an Upper Cretaceous locust, but such an identity is not con- 

 clusive. Certain pods from the top of the Cretaceous in 

 Colorado have been referred to Rohinia but since this genus has 

 not been recognized with certainty in the succeeding Eocene 

 deposits either in this country or elsewhere, these too must be 

 considered as questionable. Two species of locust have been 

 recognized in the Oligocene of Europe — one in France and the 

 other in Italy. It is in the Miocene, however, that the locust 

 becomes widespread and exceedingly common. At least a 

 dozen different species have been recognized from European de- 

 posits of this age and one of these from the late Miocene of 

 central France is so similar to the existing locust of North 

 America that its describer is disposed to consider the two as 

 identical. This form continued to exist in the European area in 



