MANUAL OF THE GRASSES OF THE UNITED STATES 



733 



Figure 1119. — Cenchrus incertus. Bur, two views of spikelet, and floret, X 5. (Curtiss, N. C.) 



100 cm. tall; blades commonly folded spreading, 20 to 90 cm. long, rather 

 but sometimes flat, 2 to 5 mm. wide; stout; blades usually flat, 2 to 7 mm. 

 raceme 4 to 10 cm. long, the burs not wide; raceme usually 3 to 8 cm. long, 

 crowded; burs about 3.5 (3 to 5) mm. the burs somewhat crowded; burs (ex- 

 wide, the body finely and densely pu- eluding spines) mostly 4 to 6 mm. 

 bescent, the base glabrous; spines wide, pubescent, often densely so; 

 few, mostly less than 5 mm. long, the spines numerous, spreading or re- 

 lower often reduced or obsolete; spike- flexed, flat, broadened at base, the 



Figure 1120. — Cenchrus pauciflorus. Bur, two views of spikelet, and floret, X 5. (Hitchcock 13582, N. Mex.) 



lets 1 to 3 in each bur. % — Open 

 sandy soil, Coastal Plain, Virginia to 

 Florida and Texas. 



6. Cenchrus pauciflorus Benth. 

 Field sandbur. (Fig. 1120.) Annual, 

 at times a short-lived perennial, 

 sometimes forming large mats; culms 



lowermost shorter and relatively slen- 

 der, some of the upper ones com- 

 monly 4 to 5 mm. long, usually villous 

 at the base; spikelets usually 2 in each 

 bur. O (Confused with C. tribu- 

 loides in early manuals; C. carolini- 

 anus of recent manuals, not of Walt.) 



