MANUAL OF THE GRASSES OF THE UNITED STATES 



711 



spreading or reflexed, flat, broadened at base, the lowermost shorter 

 and relatively slender, some of the upper ones commonly 4 to 5 mm 

 long, usually villous at the base; spikelets usually 2 in each bur. O 

 (Confused with C. tribuloldes in early manuals; C. carolinianus of re- 



FlGrRE 1592.— Ctnchrus incertus. Bur, two views of spikelet, and floret, X 5. (Curtiss, X.C.) 



cent manuals, not of Walt.) — Sandy open ground, often a weed in 

 sandy fields, Maine to Oregon, south to Florida, 

 Texas, and California; Mexican plateau, 

 coastal region of tropical America; southern 

 South America. 



7. Cenchrus tribuloides L. Dune band- 

 bub. (Fig. 1595.) Resembling C. pauci- 

 florus: culms stouter, soon branching and 



ftouiB^-DMbatkmof radiate-decumbent, rooting at the nodes; 

 sheaths usually much overlapping; burs 



(excluding spines) 5 to 6 mm wide and 8 to 9 mm high, usually 



FiGrRE 1594.— Cenchrus paucifiorm. Bur, two views of spikelet, and floret, X 5. (Hitchcock 1358% 



X. Mex.) 



conspicuously villous, o — In loose sands of the coast, St a ten 

 Island to Florida and Louisiana; Atlantic coast of tropical America 

 (fig. 1596). 



