950 BULLETIN 772, U. S. DEPARTMENT OF AGRICULTURE. 
The two species are Amphicarpon purshii Kunth (A. amphicarpon 
(Pursh) Nash), an annual (fig. 152), with hirsute blades, found 
Fie. 151.—Cenchrus tribuloides. Plant, X 34; two views of spikelet and fertile floret, 
x 10. 
from New Jersey to Florida, and A. floridanum Chapm., a stolonif- 
erous perennial, with glabrous blades, confined to Florida. The 
latter often provides abundant pasture. 
