54 



THE IXDTAXA WEED BOOK. 



Fig. 20. a and b, spikelets, a showing the 

 bristles which sp.-ing from beneath. (After 

 Scribner.) 



their vitality for years, ready to 

 spring up whenever conditions are 

 favorable. Remedies: use of clean 

 seed ; smothering when young ; mow- 

 ing and burning stubble, followed by 

 fall plowing ; cultivation throughout 

 the season; sheep grazing in pas- 

 tures, old fields and the aftermath 

 of meadows. A flock of sheep will 

 soon clean out all the weeds in a corn 

 field, without injury to the corn, if 

 turned in for a few days in early 

 autumn. 



The green foxtail or bottle-grass 

 (/. viridis L.) is a closely allied 

 species which is also common in the 

 State. The spike is green, more 

 loosely seeded and tapers at the end, 

 and the bristles are longer and also 

 greenish. Remedies the same. 



0. CENCHRUS TRIHULOIDES 



(A. X. 1.) 



Snberect or spreading, branching free- 

 ly, 8 inches to 2 feet long; sheath loose, 

 compressed; leaves flat, 3-5 inches long, 

 smooth. Spikelets enclosed, 1 to 5 to- 

 gether, in a globular bristly or spiny 

 cover, which hardens and falls off with 

 them as a rigid bur. (Fig. 21.) 



Common in sandy soil throughout 

 the State. July-Get. The points on the 

 spines of the burs have barbs directed 

 backwards so that the bur sticks very 

 closely to wool, fur or clothing and 

 thus distributes far and wide the en- 

 closed seeds. They are said to be 

 more injurious in wool than the burs 

 of any other weed. Old Linnaeus 

 must have pricked his finger on one 

 of the barbed spines when he named 

 this grass tribuloides. It is a tribula- 

 tion indeed to barefooted boys. Very 

 troublesome also is it to wool-growers 



L. Sand-bur. Bur-grass. Hedgehog-grass. 



Fig. 21. a, bur; b, the same split to show 

 the enclosed spike'tts; c, spikelct with 

 glumes. (After Scribner.) 



