126 SILVA OF NORTH AMERICA. LEGUMINOSE. 
New Mexico and Arizona to southern California, and extends southward into northern Mexico. It is a 
common tree in all this region, occupying dry gravelly mesas, the sides of low caiions, and the banks of 
mountain streams. 
The wood of Acacia Gregyit is heavy, very hard, strong, close-grained, and durable. It contains 
several rows of large open ducts marking the layers of annual growth, and many thin medullary rays. 
It is rich brown or red, with thin light yellow sapwood composed of five or six layers of annual growth. 
The specific gravity of the absolutely dry wood is 0.8550, a cubic foot weighing 53.28 pounds. 
A resinous gum resembling gum arabic is produced in small quantities by this species.’ 
Acacia Greggii was discovered in Nuevo Leon by Jean Louis Berlandier in 1830, and in Texas 
by Charles Wright in 1851. It was named in honor of Dr. Josiah Gregg, author of The Commerce of 
the Prairies, who made numerous early botanical explorations in Texas, New Mexico, and northern 
Mexico. 
1 Am. Jour. Pharm. lii. 409. 
EXPLANATION OF THE PLATE. 
Puate CXLITI. Acacia Greeer. 
1. A flowering branch, natural size. 
2. A flower, enlarged. 
3. Vertical section of a flower, enlarged. 
4. A fruiting branch, natural size. 
5. A seed, enlarged. 
6 and 7. Vertical sections of a seed, enlarged. 
8. An embryo, enlarged. 
