44 SILVA OF NORTH AMERICA. LEGUMINOS&. 
It is yellow streaked with brown, with a light yellow sapwood composed of four or five layers of annual 
growth. The specific gravity of the absolutely dry wood is 0.8034, a cubic foot weighing 50.07 
pounds. 
Robinia Neo-Mexicana was discovered in May, 1851, by Dr. George Thurber, the botanist of the 
United States and Mexican Boundary Survey Commission, on a dry hillside in the valley of the Mimbres 
River in New Mexico, and was introduced into cultivation through the Arnold Arboretum in 1882. It 
is perfectly hardy in New England, where it grows rapidly and vigorously.’ 
1 The largest plants in the Arboretum are ten or twelve feet plant in his Arboretum at Zoeschen, in Germany, produced flowers 
high but have not yet flowered. Dr.G. Dieck reports that the in the spring of 1891 (Gartenjflora, 1891, 362). 
EXPLANATION OF THE PLATE. 
Puate CXIV. Rosrnra Neo-MEXICcANA. 
. A flowering branch, natural size. 
. A calyx, enlarged. 
. A flower, the calyx and corolla removed, enlarged. 
. A pistil, enlarged. 
. A raceme of fruit, natural size. 
A legume with one valve removed, natural size. 
. Vertical section of a seed, enlarged. 
. An embryo, much magnified. 
WONHARAP Od 
. A winter branchlet, natural size. 
