250 BULLETIN 772, U. S. DEPARTMENT OF AGRICULTURE. 



The two species are AmpMcarpon purshii Kunth (A. amphicarpon 

 (Pursh) Nash), an annual (fig. 152), with hirsute blades, found 



FIG. 151. Cenchrus tribuloides. Plant, X \ ; two views of spikelet and fertile floret, 



X 10. 



from New Jersey to Florida, and A. florid anum Chapm., a stolonif- 

 erous perennial, with glabrous blades, confined to Florida. The 

 latter often provides abundant pasture. 



